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  • Iptables rules make communication so slow

    - by mmc18
    When I have send a request to an application running on a machine which following firewall rules are applied, it waits so long. When I have deactivated the iptables rule, it responses immediately. What makes communication so slow? -A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT -A INPUT -p tcp -m tcp --dport 22 -j ACCEPT -A INPUT -p esp -j ACCEPT -A INPUT -i ppp+ -j ACCEPT -A INPUT -p udp -m udp --dport 500 -j ACCEPT -A INPUT -p udp -m udp --dport 4500 -j ACCEPT -A INPUT -p udp -m udp --dport 1701 -j ACCEPT -A INPUT -i lo -j ACCEPT -A INPUT -i lo -m state --state NEW,RELATED,ESTABLISHED -j ACCEPT -A INPUT -m limit --limit 5/min -j LOG --log-prefix "iptables denied: " --log-level 7 -A FORWARD -i ppp+ -m state --state NEW,RELATED,ESTABLISHED -j ACCEPT

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  • How can I ensure that my static ip address is read from /etc/network/interfaces rather than dhcp?

    - by jonderry
    This is a follow up to the following question. I'm trying to set a static IP by changing /etc/network/interfaces to the following: # interfaces(5) file used by ifup(8) and ifdown(8) auto lo iface lo inet loopback auto eth0 iface eth0 inet static address 192.168.2.133 netmask 255.255.255.0 gateway 192.168.2.1 dns-nameservers 8.8.8.8 and then running /sbin/ifdown eth0; /sbin/ifup eth0. However, the change in IP address doesn't appear to take effect without editing /etc/dhcp/dhclient.conf and commenting out the following before running ifdown; ifup: request subnet-mask, broadcast-address, time-offset, routers, domain-name, domain-name-servers, domain-search, host-name, dhcp6.name-servers, dhcp6.domain-search, netbios-name-servers, netbios-scope, interface-mtu, rfc3442-classless-static-routes, ntp-servers, dhcp6.fqdn, dhcp6.sntp-servers; Strangely, after commenting out this line, running ifdown; ifup works, but when I uncomment it, the behavior does not revert to the previous behavior of ignoring changes to my settings in /etc/network/interfaces (this doesn't seem like a problem, but I really need to be able to repeat this problem so that I can be confident that my solution is robust) Also, I'd rather not have to edit /etc/dhcp/dhclient.conf to change my static IP since it seems I should be able to do this by only editing interfaces. Can anyone explain the issues I'm seeing above and suggest the best way of making changes to static IP addresses take effect that admits reproducibility so that I can be sure that my approach works?

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  • It is okay to set MASQUERADE at 2 network interfaces in a Linux server?

    - by Patrick L
    There is a Linux server with 3 network interfaces, eth0, eth1, eth2. IP forwarding has been turn on in this server. eth0 is connected to 10.0.1.0/24. Its IP is 10.0.1.1. eth1 is connected to 172.16.1.0/24. Its IP is 172.16.1.1. Server A can ping router C at 172.16.1.2. eth2 is connected to 192.168.1.0/24. Its IP is 192.168.1.1. Server A can ping server B at 192.168.1.2. Router C is able to route to 172.16.2.0/24 and 172.16.3.0/24. [10.0.1.0/24] | 172.16.2.0/24------| | [C]------172.16.1.0/24------[A]------192.168.1.0/24------[B] 172.16.3.0/24------| We have set MASQUERADE at eth0. When server B (192.168.1.2) connect to 10.0.1.0/24, IP MASQUERADE will happen at eth0. Can we set MASQUERADE at eth1? Is it okay to set MASQUERADE at more than 1 network interfaces in Linux?

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  • How do i network ten branch office with voip, video calling and files sharing.

    - by Oluwalogbon
    Am an IT person, have done some networking job for my organization like Lan and wireless within the area, configure windows server to manage staff account My company has ten branch (In each state) in my country and am giving a task to connect dose branch together, which there will be VOIP, Video calling and sharing of files within the branch. I need someone to help me with this project..what and what did I need to put in place

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  • My server is taking too long to respond when I connect to it outside the local network [closed]

    - by Buzu
    I have my local server online most of the time because it is easy for clients to access a url and see how their project is coming along. They can see updates in real time. However, I got a message from one of my clients saying that the server was not responding. I have a hosts file, and in that file I have my server's address pointed to the local ip. This is because some problem with the ftp. Due to this setup, I had not noticed that the server was not accessible from outside the local network. The address is http://imbuzu.dyndns.info SSH works fine, I can connect from my windows machine to the server, but HTTP does not. The server is taking too long to respond. Looking at the logs, I see that the last incoming connection to the server from outside the network is this: 77.242.153.180 - - [04/Dec/2012:12:11:01 -0800] "\xce\x89\x8d\x85b\ro" 400 317 "-" "-" I'm going to restart the server, but I doubt that will have any effect on it. --EDIT-- I restarted the server, and it did not help. Also, I pinged the server and it seems to be resolving correctly.

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  • Problem with setup VPN in Ubuntu Server 12.04

    - by Yozone W.
    I have a problem with setup VPN server on my Ubuntu VPS, here is my server environments: Ubuntu Server 12.04 x86_64 xl2tpd 1.3.1+dfsg-1 pppd 2.4.5-5ubuntu1 openswan 1:2.6.38-1~precise1 After install software and configuration: ipsec verify Checking your system to see if IPsec got installed and started correctly: Version check and ipsec on-path [OK] Linux Openswan U2.6.38/K3.2.0-24-virtual (netkey) Checking for IPsec support in kernel [OK] SAref kernel support [N/A] NETKEY: Testing XFRM related proc values [OK] [OK] [OK] Checking that pluto is running [OK] Pluto listening for IKE on udp 500 [OK] Pluto listening for NAT-T on udp 4500 [OK] Checking for 'ip' command [OK] Checking /bin/sh is not /bin/dash [WARNING] Checking for 'iptables' command [OK] Opportunistic Encryption Support [DISABLED] /var/log/auth.log message: Oct 16 06:50:54 vpn pluto[3963]: packet from [My IP Address]:2251: received Vendor ID payload [RFC 3947] method set to=115 Oct 16 06:50:54 vpn pluto[3963]: packet from [My IP Address]:2251: received Vendor ID payload [draft-ietf-ipsec-nat-t-ike] meth=114, but already using method 115 Oct 16 06:50:54 vpn pluto[3963]: packet from [My IP Address]:2251: received Vendor ID payload [draft-ietf-ipsec-nat-t-ike-08] meth=113, but already using method 115 Oct 16 06:50:54 vpn pluto[3963]: packet from [My IP Address]:2251: received Vendor ID payload [draft-ietf-ipsec-nat-t-ike-07] meth=112, but already using method 115 Oct 16 06:50:54 vpn pluto[3963]: packet from [My IP Address]:2251: received Vendor ID payload [draft-ietf-ipsec-nat-t-ike-06] meth=111, but already using method 115 Oct 16 06:50:54 vpn pluto[3963]: packet from [My IP Address]:2251: received Vendor ID payload [draft-ietf-ipsec-nat-t-ike-05] meth=110, but already using method 115 Oct 16 06:50:54 vpn pluto[3963]: packet from [My IP Address]:2251: received Vendor ID payload [draft-ietf-ipsec-nat-t-ike-04] meth=109, but already using method 115 Oct 16 06:50:54 vpn pluto[3963]: packet from [My IP Address]:2251: received Vendor ID payload [draft-ietf-ipsec-nat-t-ike-03] meth=108, but already using method 115 Oct 16 06:50:54 vpn pluto[3963]: packet from [My IP Address]:2251: received Vendor ID payload [draft-ietf-ipsec-nat-t-ike-02] meth=107, but already using method 115 Oct 16 06:50:54 vpn pluto[3963]: packet from [My IP Address]:2251: received Vendor ID payload [draft-ietf-ipsec-nat-t-ike-02_n] meth=106, but already using method 115 Oct 16 06:50:54 vpn pluto[3963]: packet from [My IP Address]:2251: ignoring Vendor ID payload [FRAGMENTATION 80000000] Oct 16 06:50:54 vpn pluto[3963]: packet from [My IP Address]:2251: received Vendor ID payload [Dead Peer Detection] Oct 16 06:50:54 vpn pluto[3963]: "L2TP-PSK-NAT"[5] [My IP Address] #5: responding to Main Mode from unknown peer [My IP Address] Oct 16 06:50:54 vpn pluto[3963]: "L2TP-PSK-NAT"[5] [My IP Address] #5: transition from state STATE_MAIN_R0 to state STATE_MAIN_R1 Oct 16 06:50:54 vpn pluto[3963]: "L2TP-PSK-NAT"[5] [My IP Address] #5: STATE_MAIN_R1: sent MR1, expecting MI2 Oct 16 06:50:55 vpn pluto[3963]: "L2TP-PSK-NAT"[5] [My IP Address] #5: NAT-Traversal: Result using draft-ietf-ipsec-nat-t-ike (MacOS X): peer is NATed Oct 16 06:50:55 vpn pluto[3963]: "L2TP-PSK-NAT"[5] [My IP Address] #5: transition from state STATE_MAIN_R1 to state STATE_MAIN_R2 Oct 16 06:50:55 vpn pluto[3963]: "L2TP-PSK-NAT"[5] [My IP Address] #5: STATE_MAIN_R2: sent MR2, expecting MI3 Oct 16 06:50:55 vpn pluto[3963]: "L2TP-PSK-NAT"[5] [My IP Address] #5: ignoring informational payload, type IPSEC_INITIAL_CONTACT msgid=00000000 Oct 16 06:50:55 vpn pluto[3963]: "L2TP-PSK-NAT"[5] [My IP Address] #5: Main mode peer ID is ID_IPV4_ADDR: '192.168.12.52' Oct 16 06:50:55 vpn pluto[3963]: "L2TP-PSK-NAT"[5] [My IP Address] #5: switched from "L2TP-PSK-NAT" to "L2TP-PSK-NAT" Oct 16 06:50:55 vpn pluto[3963]: "L2TP-PSK-NAT"[6] [My IP Address] #5: deleting connection "L2TP-PSK-NAT" instance with peer [My IP Address] {isakmp=#0/ipsec=#0} Oct 16 06:50:55 vpn pluto[3963]: "L2TP-PSK-NAT"[6] [My IP Address] #5: transition from state STATE_MAIN_R2 to state STATE_MAIN_R3 Oct 16 06:50:55 vpn pluto[3963]: "L2TP-PSK-NAT"[6] [My IP Address] #5: new NAT mapping for #5, was [My IP Address]:2251, now [My IP Address]:2847 Oct 16 06:50:55 vpn pluto[3963]: "L2TP-PSK-NAT"[6] [My IP Address] #5: STATE_MAIN_R3: sent MR3, ISAKMP SA established {auth=OAKLEY_PRESHARED_KEY cipher=aes_256 prf=oakley_sha group=modp1024} Oct 16 06:50:55 vpn pluto[3963]: "L2TP-PSK-NAT"[6] [My IP Address] #5: Dead Peer Detection (RFC 3706): enabled Oct 16 06:50:56 vpn pluto[3963]: "L2TP-PSK-NAT"[6] [My IP Address] #5: the peer proposed: [My Server IP Address]/32:17/1701 -> 192.168.12.52/32:17/0 Oct 16 06:50:56 vpn pluto[3963]: "L2TP-PSK-NAT"[6] [My IP Address] #5: NAT-Traversal: received 2 NAT-OA. using first, ignoring others Oct 16 06:50:56 vpn pluto[3963]: "L2TP-PSK-NAT"[6] [My IP Address] #6: responding to Quick Mode proposal {msgid:8579b1fb} Oct 16 06:50:56 vpn pluto[3963]: "L2TP-PSK-NAT"[6] [My IP Address] #6: us: [My Server IP Address]<[My Server IP Address]>:17/1701 Oct 16 06:50:56 vpn pluto[3963]: "L2TP-PSK-NAT"[6] [My IP Address] #6: them: [My IP Address][192.168.12.52]:17/65280===192.168.12.52/32 Oct 16 06:50:56 vpn pluto[3963]: "L2TP-PSK-NAT"[6] [My IP Address] #6: transition from state STATE_QUICK_R0 to state STATE_QUICK_R1 Oct 16 06:50:56 vpn pluto[3963]: "L2TP-PSK-NAT"[6] [My IP Address] #6: STATE_QUICK_R1: sent QR1, inbound IPsec SA installed, expecting QI2 Oct 16 06:50:56 vpn pluto[3963]: "L2TP-PSK-NAT"[6] [My IP Address] #6: Dead Peer Detection (RFC 3706): enabled Oct 16 06:50:56 vpn pluto[3963]: "L2TP-PSK-NAT"[6] [My IP Address] #6: transition from state STATE_QUICK_R1 to state STATE_QUICK_R2 Oct 16 06:50:56 vpn pluto[3963]: "L2TP-PSK-NAT"[6] [My IP Address] #6: STATE_QUICK_R2: IPsec SA established transport mode {ESP=>0x08bda158 <0x4920a374 xfrm=AES_256-HMAC_SHA1 NATOA=192.168.12.52 NATD=[My IP Address]:2847 DPD=enabled} Oct 16 06:51:16 vpn pluto[3963]: "L2TP-PSK-NAT"[6] [My IP Address] #5: received Delete SA(0x08bda158) payload: deleting IPSEC State #6 Oct 16 06:51:16 vpn pluto[3963]: "L2TP-PSK-NAT"[6] [My IP Address] #5: ERROR: netlink XFRM_MSG_DELPOLICY response for flow eroute_connection delete included errno 2: No such file or directory Oct 16 06:51:16 vpn pluto[3963]: "L2TP-PSK-NAT"[6] [My IP Address] #5: received and ignored informational message Oct 16 06:51:16 vpn pluto[3963]: "L2TP-PSK-NAT"[6] [My IP Address] #5: received Delete SA payload: deleting ISAKMP State #5 Oct 16 06:51:16 vpn pluto[3963]: "L2TP-PSK-NAT"[6] [My IP Address]: deleting connection "L2TP-PSK-NAT" instance with peer [My IP Address] {isakmp=#0/ipsec=#0} Oct 16 06:51:16 vpn pluto[3963]: packet from [My IP Address]:2847: received and ignored informational message xl2tpd -D message: xl2tpd[4289]: Enabling IPsec SAref processing for L2TP transport mode SAs xl2tpd[4289]: IPsec SAref does not work with L2TP kernel mode yet, enabling forceuserspace=yes xl2tpd[4289]: setsockopt recvref[30]: Protocol not available xl2tpd[4289]: This binary does not support kernel L2TP. xl2tpd[4289]: xl2tpd version xl2tpd-1.3.1 started on vpn.netools.me PID:4289 xl2tpd[4289]: Written by Mark Spencer, Copyright (C) 1998, Adtran, Inc. xl2tpd[4289]: Forked by Scott Balmos and David Stipp, (C) 2001 xl2tpd[4289]: Inherited by Jeff McAdams, (C) 2002 xl2tpd[4289]: Forked again by Xelerance (www.xelerance.com) (C) 2006 xl2tpd[4289]: Listening on IP address [My Server IP Address], port 1701 Then it just stopped here, and have no any response. I can't connect VPN on my mac client, the /var/log/system.log message: Oct 16 15:17:36 azone-iMac.local configd[17]: SCNC: start, triggered by SystemUIServer, type L2TP, status 0 Oct 16 15:17:36 azone-iMac.local pppd[3799]: pppd 2.4.2 (Apple version 596.13) started by azone, uid 501 Oct 16 15:17:38 azone-iMac.local pppd[3799]: L2TP connecting to server 'vpn.netools.me' ([My Server IP Address])... Oct 16 15:17:38 azone-iMac.local pppd[3799]: IPSec connection started Oct 16 15:17:38 azone-iMac.local racoon[359]: Connecting. Oct 16 15:17:38 azone-iMac.local racoon[359]: IPSec Phase1 started (Initiated by me). Oct 16 15:17:38 azone-iMac.local racoon[359]: IKE Packet: transmit success. (Initiator, Main-Mode message 1). Oct 16 15:17:38 azone-iMac.local racoon[359]: IKE Packet: receive success. (Initiator, Main-Mode message 2). Oct 16 15:17:38 azone-iMac.local racoon[359]: IKE Packet: transmit success. (Initiator, Main-Mode message 3). Oct 16 15:17:38 azone-iMac.local racoon[359]: IKE Packet: receive success. (Initiator, Main-Mode message 4). Oct 16 15:17:38 azone-iMac.local racoon[359]: IKE Packet: transmit success. (Initiator, Main-Mode message 5). Oct 16 15:17:38 azone-iMac.local racoon[359]: IKEv1 Phase1 AUTH: success. (Initiator, Main-Mode Message 6). Oct 16 15:17:38 azone-iMac.local racoon[359]: IKE Packet: receive success. (Initiator, Main-Mode message 6). Oct 16 15:17:38 azone-iMac.local racoon[359]: IKEv1 Phase1 Initiator: success. (Initiator, Main-Mode). Oct 16 15:17:38 azone-iMac.local racoon[359]: IPSec Phase1 established (Initiated by me). Oct 16 15:17:39 azone-iMac.local racoon[359]: IPSec Phase2 started (Initiated by me). Oct 16 15:17:39 azone-iMac.local racoon[359]: IKE Packet: transmit success. (Initiator, Quick-Mode message 1). Oct 16 15:17:39 azone-iMac.local racoon[359]: IKE Packet: receive success. (Initiator, Quick-Mode message 2). Oct 16 15:17:39 azone-iMac.local racoon[359]: IKE Packet: transmit success. (Initiator, Quick-Mode message 3). Oct 16 15:17:39 azone-iMac.local racoon[359]: IKEv1 Phase2 Initiator: success. (Initiator, Quick-Mode). Oct 16 15:17:39 azone-iMac.local racoon[359]: IPSec Phase2 established (Initiated by me). Oct 16 15:17:39 azone-iMac.local pppd[3799]: IPSec connection established Oct 16 15:17:59 azone-iMac.local pppd[3799]: L2TP cannot connect to the server Oct 16 15:17:59 azone-iMac.local racoon[359]: IPSec disconnecting from server [My Server IP Address] Oct 16 15:17:59 azone-iMac.local racoon[359]: IKE Packet: transmit success. (Information message). Oct 16 15:17:59 azone-iMac.local racoon[359]: IKEv1 Information-Notice: transmit success. (Delete IPSEC-SA). Oct 16 15:17:59 azone-iMac.local racoon[359]: IKE Packet: transmit success. (Information message). Oct 16 15:17:59 azone-iMac.local racoon[359]: IKEv1 Information-Notice: transmit success. (Delete ISAKMP-SA). Anyone help? Thanks a million!

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  • Parallelism in .NET – Part 4, Imperative Data Parallelism: Aggregation

    - by Reed
    In the article on simple data parallelism, I described how to perform an operation on an entire collection of elements in parallel.  Often, this is not adequate, as the parallel operation is going to be performing some form of aggregation. Simple examples of this might include taking the sum of the results of processing a function on each element in the collection, or finding the minimum of the collection given some criteria.  This can be done using the techniques described in simple data parallelism, however, special care needs to be taken into account to synchronize the shared data appropriately.  The Task Parallel Library has tools to assist in this synchronization. The main issue with aggregation when parallelizing a routine is that you need to handle synchronization of data.  Since multiple threads will need to write to a shared portion of data.  Suppose, for example, that we wanted to parallelize a simple loop that looked for the minimum value within a dataset: double min = double.MaxValue; foreach(var item in collection) { double value = item.PerformComputation(); min = System.Math.Min(min, value); } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } This seems like a good candidate for parallelization, but there is a problem here.  If we just wrap this into a call to Parallel.ForEach, we’ll introduce a critical race condition, and get the wrong answer.  Let’s look at what happens here: // Buggy code! Do not use! double min = double.MaxValue; Parallel.ForEach(collection, item => { double value = item.PerformComputation(); min = System.Math.Min(min, value); }); This code has a fatal flaw: min will be checked, then set, by multiple threads simultaneously.  Two threads may perform the check at the same time, and set the wrong value for min.  Say we get a value of 1 in thread 1, and a value of 2 in thread 2, and these two elements are the first two to run.  If both hit the min check line at the same time, both will determine that min should change, to 1 and 2 respectively.  If element 1 happens to set the variable first, then element 2 sets the min variable, we’ll detect a min value of 2 instead of 1.  This can lead to wrong answers. Unfortunately, fixing this, with the Parallel.ForEach call we’re using, would require adding locking.  We would need to rewrite this like: // Safe, but slow double min = double.MaxValue; // Make a "lock" object object syncObject = new object(); Parallel.ForEach(collection, item => { double value = item.PerformComputation(); lock(syncObject) min = System.Math.Min(min, value); }); This will potentially add a huge amount of overhead to our calculation.  Since we can potentially block while waiting on the lock for every single iteration, we will most likely slow this down to where it is actually quite a bit slower than our serial implementation.  The problem is the lock statement – any time you use lock(object), you’re almost assuring reduced performance in a parallel situation.  This leads to two observations I’ll make: When parallelizing a routine, try to avoid locks. That being said: Always add any and all required synchronization to avoid race conditions. These two observations tend to be opposing forces – we often need to synchronize our algorithms, but we also want to avoid the synchronization when possible.  Looking at our routine, there is no way to directly avoid this lock, since each element is potentially being run on a separate thread, and this lock is necessary in order for our routine to function correctly every time. However, this isn’t the only way to design this routine to implement this algorithm.  Realize that, although our collection may have thousands or even millions of elements, we have a limited number of Processing Elements (PE).  Processing Element is the standard term for a hardware element which can process and execute instructions.  This typically is a core in your processor, but many modern systems have multiple hardware execution threads per core.  The Task Parallel Library will not execute the work for each item in the collection as a separate work item. Instead, when Parallel.ForEach executes, it will partition the collection into larger “chunks” which get processed on different threads via the ThreadPool.  This helps reduce the threading overhead, and help the overall speed.  In general, the Parallel class will only use one thread per PE in the system. Given the fact that there are typically fewer threads than work items, we can rethink our algorithm design.  We can parallelize our algorithm more effectively by approaching it differently.  Because the basic aggregation we are doing here (Min) is communitive, we do not need to perform this in a given order.  We knew this to be true already – otherwise, we wouldn’t have been able to parallelize this routine in the first place.  With this in mind, we can treat each thread’s work independently, allowing each thread to serially process many elements with no locking, then, after all the threads are complete, “merge” together the results. This can be accomplished via a different set of overloads in the Parallel class: Parallel.ForEach<TSource,TLocal>.  The idea behind these overloads is to allow each thread to begin by initializing some local state (TLocal).  The thread will then process an entire set of items in the source collection, providing that state to the delegate which processes an individual item.  Finally, at the end, a separate delegate is run which allows you to handle merging that local state into your final results. To rewriting our routine using Parallel.ForEach<TSource,TLocal>, we need to provide three delegates instead of one.  The most basic version of this function is declared as: public static ParallelLoopResult ForEach<TSource, TLocal>( IEnumerable<TSource> source, Func<TLocal> localInit, Func<TSource, ParallelLoopState, TLocal, TLocal> body, Action<TLocal> localFinally ) The first delegate (the localInit argument) is defined as Func<TLocal>.  This delegate initializes our local state.  It should return some object we can use to track the results of a single thread’s operations. The second delegate (the body argument) is where our main processing occurs, although now, instead of being an Action<T>, we actually provide a Func<TSource, ParallelLoopState, TLocal, TLocal> delegate.  This delegate will receive three arguments: our original element from the collection (TSource), a ParallelLoopState which we can use for early termination, and the instance of our local state we created (TLocal).  It should do whatever processing you wish to occur per element, then return the value of the local state after processing is completed. The third delegate (the localFinally argument) is defined as Action<TLocal>.  This delegate is passed our local state after it’s been processed by all of the elements this thread will handle.  This is where you can merge your final results together.  This may require synchronization, but now, instead of synchronizing once per element (potentially millions of times), you’ll only have to synchronize once per thread, which is an ideal situation. Now that I’ve explained how this works, lets look at the code: // Safe, and fast! double min = double.MaxValue; // Make a "lock" object object syncObject = new object(); Parallel.ForEach( collection, // First, we provide a local state initialization delegate. () => double.MaxValue, // Next, we supply the body, which takes the original item, loop state, // and local state, and returns a new local state (item, loopState, localState) => { double value = item.PerformComputation(); return System.Math.Min(localState, value); }, // Finally, we provide an Action<TLocal>, to "merge" results together localState => { // This requires locking, but it's only once per used thread lock(syncObj) min = System.Math.Min(min, localState); } ); Although this is a bit more complicated than the previous version, it is now both thread-safe, and has minimal locking.  This same approach can be used by Parallel.For, although now, it’s Parallel.For<TLocal>.  When working with Parallel.For<TLocal>, you use the same triplet of delegates, with the same purpose and results. Also, many times, you can completely avoid locking by using a method of the Interlocked class to perform the final aggregation in an atomic operation.  The MSDN example demonstrating this same technique using Parallel.For uses the Interlocked class instead of a lock, since they are doing a sum operation on a long variable, which is possible via Interlocked.Add. By taking advantage of local state, we can use the Parallel class methods to parallelize algorithms such as aggregation, which, at first, may seem like poor candidates for parallelization.  Doing so requires careful consideration, and often requires a slight redesign of the algorithm, but the performance gains can be significant if handled in a way to avoid excessive synchronization.

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  • Problem with setup VPN on Ubuntu Server 12.04

    - by Yozone W.
    I have a problem with setup VPN server on my Ubuntu VPS, here is my server environments: Ubuntu Server 12.04 x86_64 xl2tpd 1.3.1+dfsg-1 pppd 2.4.5-5ubuntu1 openswan 1:2.6.38-1~precise1 After install software and configuration: ipsec verify Checking your system to see if IPsec got installed and started correctly: Version check and ipsec on-path [OK] Linux Openswan U2.6.38/K3.2.0-24-virtual (netkey) Checking for IPsec support in kernel [OK] SAref kernel support [N/A] NETKEY: Testing XFRM related proc values [OK] [OK] [OK] Checking that pluto is running [OK] Pluto listening for IKE on udp 500 [OK] Pluto listening for NAT-T on udp 4500 [OK] Checking for 'ip' command [OK] Checking /bin/sh is not /bin/dash [WARNING] Checking for 'iptables' command [OK] Opportunistic Encryption Support [DISABLED] /var/log/auth.log message: Oct 16 06:50:54 vpn pluto[3963]: packet from [My IP Address]:2251: received Vendor ID payload [RFC 3947] method set to=115 Oct 16 06:50:54 vpn pluto[3963]: packet from [My IP Address]:2251: received Vendor ID payload [draft-ietf-ipsec-nat-t-ike] meth=114, but already using method 115 Oct 16 06:50:54 vpn pluto[3963]: packet from [My IP Address]:2251: received Vendor ID payload [draft-ietf-ipsec-nat-t-ike-08] meth=113, but already using method 115 Oct 16 06:50:54 vpn pluto[3963]: packet from [My IP Address]:2251: received Vendor ID payload [draft-ietf-ipsec-nat-t-ike-07] meth=112, but already using method 115 Oct 16 06:50:54 vpn pluto[3963]: packet from [My IP Address]:2251: received Vendor ID payload [draft-ietf-ipsec-nat-t-ike-06] meth=111, but already using method 115 Oct 16 06:50:54 vpn pluto[3963]: packet from [My IP Address]:2251: received Vendor ID payload [draft-ietf-ipsec-nat-t-ike-05] meth=110, but already using method 115 Oct 16 06:50:54 vpn pluto[3963]: packet from [My IP Address]:2251: received Vendor ID payload [draft-ietf-ipsec-nat-t-ike-04] meth=109, but already using method 115 Oct 16 06:50:54 vpn pluto[3963]: packet from [My IP Address]:2251: received Vendor ID payload [draft-ietf-ipsec-nat-t-ike-03] meth=108, but already using method 115 Oct 16 06:50:54 vpn pluto[3963]: packet from [My IP Address]:2251: received Vendor ID payload [draft-ietf-ipsec-nat-t-ike-02] meth=107, but already using method 115 Oct 16 06:50:54 vpn pluto[3963]: packet from [My IP Address]:2251: received Vendor ID payload [draft-ietf-ipsec-nat-t-ike-02_n] meth=106, but already using method 115 Oct 16 06:50:54 vpn pluto[3963]: packet from [My IP Address]:2251: ignoring Vendor ID payload [FRAGMENTATION 80000000] Oct 16 06:50:54 vpn pluto[3963]: packet from [My IP Address]:2251: received Vendor ID payload [Dead Peer Detection] Oct 16 06:50:54 vpn pluto[3963]: "L2TP-PSK-NAT"[5] [My IP Address] #5: responding to Main Mode from unknown peer [My IP Address] Oct 16 06:50:54 vpn pluto[3963]: "L2TP-PSK-NAT"[5] [My IP Address] #5: transition from state STATE_MAIN_R0 to state STATE_MAIN_R1 Oct 16 06:50:54 vpn pluto[3963]: "L2TP-PSK-NAT"[5] [My IP Address] #5: STATE_MAIN_R1: sent MR1, expecting MI2 Oct 16 06:50:55 vpn pluto[3963]: "L2TP-PSK-NAT"[5] [My IP Address] #5: NAT-Traversal: Result using draft-ietf-ipsec-nat-t-ike (MacOS X): peer is NATed Oct 16 06:50:55 vpn pluto[3963]: "L2TP-PSK-NAT"[5] [My IP Address] #5: transition from state STATE_MAIN_R1 to state STATE_MAIN_R2 Oct 16 06:50:55 vpn pluto[3963]: "L2TP-PSK-NAT"[5] [My IP Address] #5: STATE_MAIN_R2: sent MR2, expecting MI3 Oct 16 06:50:55 vpn pluto[3963]: "L2TP-PSK-NAT"[5] [My IP Address] #5: ignoring informational payload, type IPSEC_INITIAL_CONTACT msgid=00000000 Oct 16 06:50:55 vpn pluto[3963]: "L2TP-PSK-NAT"[5] [My IP Address] #5: Main mode peer ID is ID_IPV4_ADDR: '192.168.12.52' Oct 16 06:50:55 vpn pluto[3963]: "L2TP-PSK-NAT"[5] [My IP Address] #5: switched from "L2TP-PSK-NAT" to "L2TP-PSK-NAT" Oct 16 06:50:55 vpn pluto[3963]: "L2TP-PSK-NAT"[6] [My IP Address] #5: deleting connection "L2TP-PSK-NAT" instance with peer [My IP Address] {isakmp=#0/ipsec=#0} Oct 16 06:50:55 vpn pluto[3963]: "L2TP-PSK-NAT"[6] [My IP Address] #5: transition from state STATE_MAIN_R2 to state STATE_MAIN_R3 Oct 16 06:50:55 vpn pluto[3963]: "L2TP-PSK-NAT"[6] [My IP Address] #5: new NAT mapping for #5, was [My IP Address]:2251, now [My IP Address]:2847 Oct 16 06:50:55 vpn pluto[3963]: "L2TP-PSK-NAT"[6] [My IP Address] #5: STATE_MAIN_R3: sent MR3, ISAKMP SA established {auth=OAKLEY_PRESHARED_KEY cipher=aes_256 prf=oakley_sha group=modp1024} Oct 16 06:50:55 vpn pluto[3963]: "L2TP-PSK-NAT"[6] [My IP Address] #5: Dead Peer Detection (RFC 3706): enabled Oct 16 06:50:56 vpn pluto[3963]: "L2TP-PSK-NAT"[6] [My IP Address] #5: the peer proposed: [My Server IP Address]/32:17/1701 -> 192.168.12.52/32:17/0 Oct 16 06:50:56 vpn pluto[3963]: "L2TP-PSK-NAT"[6] [My IP Address] #5: NAT-Traversal: received 2 NAT-OA. using first, ignoring others Oct 16 06:50:56 vpn pluto[3963]: "L2TP-PSK-NAT"[6] [My IP Address] #6: responding to Quick Mode proposal {msgid:8579b1fb} Oct 16 06:50:56 vpn pluto[3963]: "L2TP-PSK-NAT"[6] [My IP Address] #6: us: [My Server IP Address]<[My Server IP Address]>:17/1701 Oct 16 06:50:56 vpn pluto[3963]: "L2TP-PSK-NAT"[6] [My IP Address] #6: them: [My IP Address][192.168.12.52]:17/65280===192.168.12.52/32 Oct 16 06:50:56 vpn pluto[3963]: "L2TP-PSK-NAT"[6] [My IP Address] #6: transition from state STATE_QUICK_R0 to state STATE_QUICK_R1 Oct 16 06:50:56 vpn pluto[3963]: "L2TP-PSK-NAT"[6] [My IP Address] #6: STATE_QUICK_R1: sent QR1, inbound IPsec SA installed, expecting QI2 Oct 16 06:50:56 vpn pluto[3963]: "L2TP-PSK-NAT"[6] [My IP Address] #6: Dead Peer Detection (RFC 3706): enabled Oct 16 06:50:56 vpn pluto[3963]: "L2TP-PSK-NAT"[6] [My IP Address] #6: transition from state STATE_QUICK_R1 to state STATE_QUICK_R2 Oct 16 06:50:56 vpn pluto[3963]: "L2TP-PSK-NAT"[6] [My IP Address] #6: STATE_QUICK_R2: IPsec SA established transport mode {ESP=>0x08bda158 <0x4920a374 xfrm=AES_256-HMAC_SHA1 NATOA=192.168.12.52 NATD=[My IP Address]:2847 DPD=enabled} Oct 16 06:51:16 vpn pluto[3963]: "L2TP-PSK-NAT"[6] [My IP Address] #5: received Delete SA(0x08bda158) payload: deleting IPSEC State #6 Oct 16 06:51:16 vpn pluto[3963]: "L2TP-PSK-NAT"[6] [My IP Address] #5: ERROR: netlink XFRM_MSG_DELPOLICY response for flow eroute_connection delete included errno 2: No such file or directory Oct 16 06:51:16 vpn pluto[3963]: "L2TP-PSK-NAT"[6] [My IP Address] #5: received and ignored informational message Oct 16 06:51:16 vpn pluto[3963]: "L2TP-PSK-NAT"[6] [My IP Address] #5: received Delete SA payload: deleting ISAKMP State #5 Oct 16 06:51:16 vpn pluto[3963]: "L2TP-PSK-NAT"[6] [My IP Address]: deleting connection "L2TP-PSK-NAT" instance with peer [My IP Address] {isakmp=#0/ipsec=#0} Oct 16 06:51:16 vpn pluto[3963]: packet from [My IP Address]:2847: received and ignored informational message xl2tpd -D message: xl2tpd[4289]: Enabling IPsec SAref processing for L2TP transport mode SAs xl2tpd[4289]: IPsec SAref does not work with L2TP kernel mode yet, enabling forceuserspace=yes xl2tpd[4289]: setsockopt recvref[30]: Protocol not available xl2tpd[4289]: This binary does not support kernel L2TP. xl2tpd[4289]: xl2tpd version xl2tpd-1.3.1 started on vpn.netools.me PID:4289 xl2tpd[4289]: Written by Mark Spencer, Copyright (C) 1998, Adtran, Inc. xl2tpd[4289]: Forked by Scott Balmos and David Stipp, (C) 2001 xl2tpd[4289]: Inherited by Jeff McAdams, (C) 2002 xl2tpd[4289]: Forked again by Xelerance (www.xelerance.com) (C) 2006 xl2tpd[4289]: Listening on IP address [My Server IP Address], port 1701 Then it just stopped here, and have no any response. I can't connect VPN on my mac client, the /var/log/system.log message: Oct 16 15:17:36 azone-iMac.local configd[17]: SCNC: start, triggered by SystemUIServer, type L2TP, status 0 Oct 16 15:17:36 azone-iMac.local pppd[3799]: pppd 2.4.2 (Apple version 596.13) started by azone, uid 501 Oct 16 15:17:38 azone-iMac.local pppd[3799]: L2TP connecting to server 'vpn.netools.me' ([My Server IP Address])... Oct 16 15:17:38 azone-iMac.local pppd[3799]: IPSec connection started Oct 16 15:17:38 azone-iMac.local racoon[359]: Connecting. Oct 16 15:17:38 azone-iMac.local racoon[359]: IPSec Phase1 started (Initiated by me). Oct 16 15:17:38 azone-iMac.local racoon[359]: IKE Packet: transmit success. (Initiator, Main-Mode message 1). Oct 16 15:17:38 azone-iMac.local racoon[359]: IKE Packet: receive success. (Initiator, Main-Mode message 2). Oct 16 15:17:38 azone-iMac.local racoon[359]: IKE Packet: transmit success. (Initiator, Main-Mode message 3). Oct 16 15:17:38 azone-iMac.local racoon[359]: IKE Packet: receive success. (Initiator, Main-Mode message 4). Oct 16 15:17:38 azone-iMac.local racoon[359]: IKE Packet: transmit success. (Initiator, Main-Mode message 5). Oct 16 15:17:38 azone-iMac.local racoon[359]: IKEv1 Phase1 AUTH: success. (Initiator, Main-Mode Message 6). Oct 16 15:17:38 azone-iMac.local racoon[359]: IKE Packet: receive success. (Initiator, Main-Mode message 6). Oct 16 15:17:38 azone-iMac.local racoon[359]: IKEv1 Phase1 Initiator: success. (Initiator, Main-Mode). Oct 16 15:17:38 azone-iMac.local racoon[359]: IPSec Phase1 established (Initiated by me). Oct 16 15:17:39 azone-iMac.local racoon[359]: IPSec Phase2 started (Initiated by me). Oct 16 15:17:39 azone-iMac.local racoon[359]: IKE Packet: transmit success. (Initiator, Quick-Mode message 1). Oct 16 15:17:39 azone-iMac.local racoon[359]: IKE Packet: receive success. (Initiator, Quick-Mode message 2). Oct 16 15:17:39 azone-iMac.local racoon[359]: IKE Packet: transmit success. (Initiator, Quick-Mode message 3). Oct 16 15:17:39 azone-iMac.local racoon[359]: IKEv1 Phase2 Initiator: success. (Initiator, Quick-Mode). Oct 16 15:17:39 azone-iMac.local racoon[359]: IPSec Phase2 established (Initiated by me). Oct 16 15:17:39 azone-iMac.local pppd[3799]: IPSec connection established Oct 16 15:17:59 azone-iMac.local pppd[3799]: L2TP cannot connect to the server Oct 16 15:17:59 azone-iMac.local racoon[359]: IPSec disconnecting from server [My Server IP Address] Oct 16 15:17:59 azone-iMac.local racoon[359]: IKE Packet: transmit success. (Information message). Oct 16 15:17:59 azone-iMac.local racoon[359]: IKEv1 Information-Notice: transmit success. (Delete IPSEC-SA). Oct 16 15:17:59 azone-iMac.local racoon[359]: IKE Packet: transmit success. (Information message). Oct 16 15:17:59 azone-iMac.local racoon[359]: IKEv1 Information-Notice: transmit success. (Delete ISAKMP-SA). Anyone help? Thanks a million!

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  • How do I get this Cisco VPN client to connect?

    - by WebWeasel
    I've got Ubuntu 10.10 64 bit and installed network-manager-vpnc and configured the connection but I keep getting this: NetworkManager[1217]: <info> Starting VPN service 'org.freedesktop.NetworkManager.vpnc'... NetworkManager[1217]: <info> VPN service 'org.freedesktop.NetworkManager.vpnc' started (org.freedesktop.NetworkManager.vpnc), PID 4420 NetworkManager[1217]: <info> VPN service 'org.freedesktop.NetworkManager.vpnc' appeared, activating connections NetworkManager[1217]: <info> VPN plugin state changed: 1 NetworkManager[1217]: <info> VPN plugin state changed: 3 NetworkManager[1217]: <info> VPN connection 'CSI' (Connect) reply received. modem-manager: (net/tun0): could not get port's parent device NetworkManager[1217]: SCPlugin-Ifupdown: devices added (path: /sys/devices/virtual/net/tun0, iface: tun0) NetworkManager[1217]: SCPlugin-Ifupdown: device added (path: /sys/devices/virtual/net/tun0, iface: tun0): no ifupdown configuration found. kernel: [ 2281.723506] tun0: Disabled Privacy Extensions avahi-daemon[1109]: Withdrawing workstation service for tun0. NetworkManager[1217]: SCPlugin-Ifupdown: devices removed (path: /sys/devices/virtual/net/tun0, iface: tun0) NetworkManager[1217]: <warn> VPN plugin failed: 1 NetworkManager[1217]: <info> VPN plugin state changed: 6 NetworkManager[1217]: <info> VPN plugin state change reason: 0 NetworkManager[1217]: <warn> error disconnecting VPN: Could not process the request because no VPN connection was active. NetworkManager[1217]: <info> Policy set 'Auto eth0' (eth0) as default for IPv4 routing and DNS. NetworkManager[1217]: <info> Starting VPN service 'org.freedesktop.NetworkManager.vpnc'... NetworkManager[1217]: <info> VPN service 'org.freedesktop.NetworkManager.vpnc' started (org.freedesktop.NetworkManager.vpnc), PID 4547 NetworkManager[1217]: <info> VPN service 'org.freedesktop.NetworkManager.vpnc' appeared, activating connections NetworkManager[1217]: <info> VPN plugin state changed: 1 NetworkManager[1217]: <info> VPN plugin state changed: 3 I've seen a couple of bugs on Launchpad that could be the same thing or have I done something wrong?

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  • Action button: only true once per press

    - by Sidar
    I'm using SFML2.0 and am trying to make a wrapper class for my controller/joystick. I read all the input data from my controller and send it off to my controllable object. I want to have two types of buttons per button press, one that is continues(true false state ) and one that is an action and is set to false after the next frame update. Here is an example of how I set my button A to true or false with the SFML api. Whereas data is my struct of buttons, and A holds my true/false state every update. data.A = sf::Joystick::isButtonPressed(i,st::input::A); But I've also added "data.actionA" which represents the one time action state. Basically what I want is for actionA to be set false after the update its been set to true. I'm trying to keep track of the previous state. But I seem to fall into this loop where it toggles between true and false every update. Anyone an idea? Edit: Since I can't answer my own question yet here is my solution: data.actionA = data.A = sf::Joystick::isButtonPressed(i,st::input::A); if(prev.A) data.actionA = false; First I always set the actionA to the value of the button state. Then I check if the previous state of A is true. If so we negate the value.

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  • Design For Asynchronous User Interface

    - by Sohnee
    I have been working on a integration that has posed an interesting user interface conundrum that I would like suggestions for. The user interface is displayed within a third party product. The state of the interface is supplied by calls to a service I have written. There can be small delays between the actual state changing the the user interface changing due to the polling for state by the third party. When a user interacts with the user interface, requests are sent back to my application. This then affects the state and the next state poll request will update the user interface. The problem is that the delay between pressing a button and seeing the user interface update is perhaps 1 or 2 seconds and in usability testing I can see that people are clicking again before the user interface updates, thinking that they haven't properly clicked the first time. Given the constraints (we can only update the user interface via the polling mechanism - if we updated it when they clicked, the polling might return and overwrite the change causing unpredictable / undesirable results)... what can we do to make the user experience better. My current idea is to show a message for a couple of seconds so people know their click was accepted, the message would not be affected by the state polling, so wouldn't be prematurely removed / overwritten etc. I'm sure there are other ideas out there and I'm also confident someone has a better idea that I have!

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  • D key not working on Ubuntu

    - by Jonathan
    For some inexplicable reason the capital d key on my Ubuntu system is no longer producing output. Hitting caps lock and then d produces a D. I've tried multiple keyboards and the issue is the same. There's nothing bound to Shift+d under System Preferences Keyboard Shortcuts. xev produces the following: shift + a KeyPress event, serial 36, synthetic NO, window 0x4c00001, root 0x27a, subw 0x0, time 31268952, (130,-16), root:(1000,525), state 0x10, keycode 62 (keysym 0xffe2, Shift_R), same_screen YES, XLookupString gives 0 bytes: XmbLookupString gives 0 bytes: XFilterEvent returns: False KeyPress event, serial 36, synthetic NO, window 0x4c00001, root 0x27a, subw 0x0, time 31269376, (130,-16), root:(1000,525), state 0x11, keycode 38 (keysym 0x41, A), same_screen YES, XLookupString gives 1 bytes: (41) "A" XmbLookupString gives 1 bytes: (41) "A" XFilterEvent returns: False KeyRelease event, serial 36, synthetic NO, window 0x4c00001, root 0x27a, subw 0x0, time 31269584, (130,-16), root:(1000,525), state 0x11, keycode 38 (keysym 0x41, A), same_screen YES, XLookupString gives 1 bytes: (41) "A" XFilterEvent returns: False KeyRelease event, serial 36, synthetic NO, window 0x4c00001, root 0x27a, subw 0x0, time 31269608, (130,-16), root:(1000,525), state 0x11, keycode 62 (keysym 0xffe2, Shift_R), same_screen YES, XLookupString gives 0 bytes: XFilterEvent returns: False shift + d KeyPress event, serial 36, synthetic NO, window 0x4c00001, root 0x27a, subw 0x0, time 31102792, (115,-13), root:(985,528), state 0x10, keycode 62 (keysym 0xffe2, Shift_R), same_screen YES, XLookupString gives 0 bytes: XmbLookupString gives 0 bytes: XFilterEvent returns: False FocusOut event, serial 36, synthetic NO, window 0x4c00001, mode NotifyGrab, detail NotifyAncestor FocusIn event, serial 36, synthetic NO, window 0x4c00001, mode NotifyUngrab, detail NotifyAncestor KeymapNotify event, serial 36, synthetic NO, window 0x0, keys: 2 0 0 0 0 0 0 64 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 KeyRelease event, serial 36, synthetic NO, window 0x4c00001, root 0x27a, subw 0x0, time 31103104, (115,-13), root:(985,528), state 0x11, keycode 62 (keysym 0xffe2, Shift_R), same_screen YES, XLookupString gives 0 bytes: XFilterEvent returns: False

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  • What are functional-programming ways of implementing Conway's Game of Life

    - by George Mauer
    I recently implemented for fun Conway's Game of Life in Javascript (actually coffeescript but same thing). Since javascript can be used as a functional language I was trying to stay to that end of the spectrum. I was not happy with my results. I am a fairly good OO programmer and my solution smacked of same-old-same-old. So long question short: what is the (pseudocode) functional style of doing it? Here is Pseudocode for my attempt: class Node update: (board) -> get number_of_alive_neighbors from board get this_is_alive from board if this_is_alive and number_of_alive_neighbors < 2 then die if this_is_alive and number_of_alive_neighbors > 3 then die if not this_is_alive and number_of_alive_neighbors == 3 then alive class NodeLocations at: (x, y) -> return node value at x,y of: (node) -> return x,y of node class Board getNeighbors: (node) -> use node_locations to check 8 neighbors around node and return count nodes = for 1..100 new Node state = new NodeState(nodes) locations = new NodeLocations(nodes) board = new Board(locations, state) executeRound: state = clone state accumulated_changes = for n in nodes n.update(board) apply accumulated_changes to state board = new Board(locations, state)

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  • Custom Session Management using HashTable

    - by kaleidoscope
    ASP.NET session state lets you associate a server-side string or object dictionary containing state data with a particular HTTP client session. A session is defined as a series of requests issued by the same client within a certain period of time, and is managed by associating a session ID with each unique client. The ID is supplied by the client on each request, either in a cookie or as a special fragment of the request URL. The session data is stored on the server side in one of the supported session state stores, which include in-process memory, SQL Server™ database, and the ASP.NET State Server service. The latter two modes enable session state to be shared among multiple Web servers on a Web farm and do not require server affinity. Implement Custom session Handler you need to follow following process : 1. Create class library which will inherit from  SessionStateStoreProviderBase abstract Class. 2. Implement all abstract Method in your base class. 3.Change Mode of session to “Custom” in web.config file and provide Provider as your Namespace with classname. <sessionState mode=”Custom” customProvider=”Namespace.classname”> <Providers> <add name=”Name” type=”Namespace.classname”> </sessionstate> For more Details Please refer following links :   http://msdn.microsoft.com/en-us/magazine/cc163730.aspx http://msdn.microsoft.com/en-us/library/system.web.sessionstate.sessionstatestoreproviderbase.aspx - Chandraprakash, S Technorati Tags: Chandraprakash,Session state Managment

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  • How lookaheads are propagated in "channel" method of building LALR parser?

    - by greenoldman
    The method is described in Dragon Book, however I read about it in ""Parsing Techniques" by D.Grune and C.J.H.Jacobs". I start from my understanding of building channels for NFA: channels are built once, they are like water channels with current you "drop" lookahead symbols in right places (sources) of the channel, and they propagate with "current" when symbol propagates, there are no barriers (the only sufficient things for propagation are presence of channel and direction/current); i.e. lookahead cannot just die out of the blue Is that right? If I am correct, then eof lookahead should be present in all states, because the source of it is the start production, and all other production states are reachable from start state. How the DFA is made out of this NFA is not perfectly clear for me -- the authors of the mentioned book write about preserving channels, but I see no purpose, if you propagated lookaheads. If the channels have to be preserved, are they cut off from the source if the DFA state does not include source NFA state? I assume no -- the channels still runs between DFA states, not only within given DFA state. In the effect eof should still be present in all items in all states. But when you take a look at DFA presented in book (pdf is from errata): DFA for LALR (fig. 9.34 in the book, p.301) you will see there are items without eof in lookahead. The grammar for this DFA is: S -> E E -> E - T E -> T T -> ( E ) T -> n So how it was computed, when eof was dropped, and on what condition? Update It is textual pdf, so two interesting states (in DFA; # is eof): State 1: S--- >•E[#] E--- >•E-T[#-] E--- >•T[#-] T--- >•n[#-] T--- >•(E)[#-] State 6: T--- >(•E)[#-)] E--- >•E-T[-)] E--- >•T[-)] T--- >•n[-)] T--- >•(E)[-)] Arc from 1 to 6 is labeled (.

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  • which style of member-access is preferable

    - by itwasntpete
    the purpose of oop using classes is to encapsulate members from the outer space. i always read that accessing members should be done by methods. for example: template<typename T> class foo_1 { T state_; public: // following below }; the most common doing that by my professor was to have a get and set method. // variant 1 T const& getState() { return state_; } void setState(T const& v) { state_ = v; } or like this: // variant 2 // in my opinion it is easier to read T const& state() { return state_; } void state(T const& v) { state_ = v; } assume the state_ is a variable, which is checked periodically and there is no need to ensure the value (state) is consistent. Is there any disadvantage of accessing the state by reference? for example: // variant 3 // do it by reference T& state() { return state_; } or even directly, if I declare the variable as public. template<typename T> class foo { public: // variant 4 T state; }; In variant 4 I could even ensure consistence by using c++11 atomic. So my question is, which one should I prefer?, Is there any coding standard which would decline one of these pattern? for some code see here

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  • Capital D key not working / producing output

    - by Jonathan
    For some inexplicable reason the capital d key on my Ubuntu system is no longer producing output. Hitting caps lock and then d produces a D. I've tried multiple keyboards and the issue is the same. There's nothing bound to Shift+d under System Preferences Keyboard Shortcuts. xev produces the following: shift + a KeyPress event, serial 36, synthetic NO, window 0x4c00001, root 0x27a, subw 0x0, time 31268952, (130,-16), root:(1000,525), state 0x10, keycode 62 (keysym 0xffe2, Shift_R), same_screen YES, XLookupString gives 0 bytes: XmbLookupString gives 0 bytes: XFilterEvent returns: False KeyPress event, serial 36, synthetic NO, window 0x4c00001, root 0x27a, subw 0x0, time 31269376, (130,-16), root:(1000,525), state 0x11, keycode 38 (keysym 0x41, A), same_screen YES, XLookupString gives 1 bytes: (41) "A" XmbLookupString gives 1 bytes: (41) "A" XFilterEvent returns: False KeyRelease event, serial 36, synthetic NO, window 0x4c00001, root 0x27a, subw 0x0, time 31269584, (130,-16), root:(1000,525), state 0x11, keycode 38 (keysym 0x41, A), same_screen YES, XLookupString gives 1 bytes: (41) "A" XFilterEvent returns: False KeyRelease event, serial 36, synthetic NO, window 0x4c00001, root 0x27a, subw 0x0, time 31269608, (130,-16), root:(1000,525), state 0x11, keycode 62 (keysym 0xffe2, Shift_R), same_screen YES, XLookupString gives 0 bytes: XFilterEvent returns: False shift + d KeyPress event, serial 36, synthetic NO, window 0x4c00001, root 0x27a, subw 0x0, time 31102792, (115,-13), root:(985,528), state 0x10, keycode 62 (keysym 0xffe2, Shift_R), same_screen YES, XLookupString gives 0 bytes: XmbLookupString gives 0 bytes: XFilterEvent returns: False FocusOut event, serial 36, synthetic NO, window 0x4c00001, mode NotifyGrab, detail NotifyAncestor FocusIn event, serial 36, synthetic NO, window 0x4c00001, mode NotifyUngrab, detail NotifyAncestor KeymapNotify event, serial 36, synthetic NO, window 0x0, keys: 2 0 0 0 0 0 0 64 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 KeyRelease event, serial 36, synthetic NO, window 0x4c00001, root 0x27a, subw 0x0, time 31103104, (115,-13), root:(985,528), state 0x11, keycode 62 (keysym 0xffe2, Shift_R), same_screen YES, XLookupString gives 0 bytes: XFilterEvent returns: False

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  • Wireless (Broadcom) just stopped working after putting machine to sleep!

    - by tommed
    Had the wireless working on my Dell Studio 15 for months now (Ubuntu 10.04 64bit, now 10.10 64bit). But I shut the lid this morning, which put the machine to sleep; when I openend it again the wireless would no longer connect to anything :'( I rebooted the machine, but that didn't help. I then did ifconfig eth1 {down,up}, but that didn't help, then I did iwconfig eth1 power {down,on}, but that didn't work. So I uninstalled the wireless driver (Broadcom STA) from additional drivers (reboot in the middle), but it still won't work anymore!! This is the trace from daemon.log, looks like it is a driver issue? Nov 28 12:26:39 ulap NetworkManager[1218]: (eth1): supplicant connection state: disconnected - scanning Nov 28 12:26:39 ulap NetworkManager[1218]: (eth1): supplicant connection state: scanning - disconnected Nov 28 12:26:45 ulap NetworkManager[1218]: (eth1): supplicant connection state: disconnected - scanning Nov 28 12:26:50 ulap wpa_supplicant[1295]: Trying to associate with MY_MAC_CODE (SSID='MY_WIRESS_SSID' freq=2417 MHz) Nov 28 12:26:50 ulap wpa_supplicant[1295]: Association request to the driver failed Nov 28 12:26:50 ulap NetworkManager[1218]: (eth1): supplicant connection state: scanning - associating Nov 28 12:26:51 ulap wpa_supplicant[1295]: Associated with MY_MAC_CODE Nov 28 12:26:51 ulap NetworkManager[1218]: (eth1): supplicant connection state: associating - associated Nov 28 12:27:01 ulap wpa_supplicant[1295]: Authentication with MY_MAC_CODE timed out. Nov 28 12:27:01 ulap NetworkManager[1218]: (eth1): supplicant connection state: associated - disconnected Anyone seen this, or know how I can get around this issue? It had been working fine up until now?! Even ran update-manager, but there wasn't any changes to the wireless drivers (or any related networking areas). Running the most up-to-date version of 10.10 x64. My android phone and other devices are still working on the wireless.

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  • Are there some cases where Python threads can safely manipulate shared state?

    - by erikg
    Some discussion in another question has encouraged me to to better understand cases where locking is required in multithreaded Python programs. Per this article on threading in Python, I have several solid, testable examples of pitfalls that can occur when multiple threads access shared state. The example race condition provided on this page involves races between threads reading and manipulating a shared variable stored in a dictionary. I think the case for a race here is very obvious, and fortunately is eminently testable. However, I have been unable to evoke a race condition with atomic operations such as list appends or variable increments. This test exhaustively attempts to demonstrate such a race: from threading import Thread, Lock import operator def contains_all_ints(l, n): l.sort() for i in xrange(0, n): if l[i] != i: return False return True def test(ntests): results = [] threads = [] def lockless_append(i): results.append(i) for i in xrange(0, ntests): threads.append(Thread(target=lockless_append, args=(i,))) threads[i].start() for i in xrange(0, ntests): threads[i].join() if len(results) != ntests or not contains_all_ints(results, ntests): return False else: return True for i in range(0,100): if test(100000): print "OK", i else: print "appending to a list without locks *is* unsafe" exit() I have run the test above without failure (100x 100k multithreaded appends). Can anyone get it to fail? Is there another class of object which can be made to misbehave via atomic, incremental, modification by threads? Do these implicitly 'atomic' semantics apply to other operations in Python? Is this directly related to the GIL?

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  • Operation is not valid due to the current state of the object?

    - by Bill
    I am programming in C#; the code was working about a week ago, however it throws an exception and I don't understand at all what could be wrong with it. Var root = new CalculationNode(); -> Throw exception. In the call stack thats the only thing listed, I've been told that it could be that I need a clean build, but I am open to any ideas or suggestions. Thanks, -Bill Update: Exception's Detail System.InvalidOperationException was unhandled by user code Message=Operation is not valid due to the current state of the object. Source=Calculator.Logic StackTrace: at ~.Calculator.Logic.MyBaseExpressionParser.Parse(String expression) in ~\Source\Calculator.Logic\MyBaseExpressionParser.cs:line 44 at ~.Calculator.Logic.Tests.MyBaseCalculatorServiceTests.BasicMathDivision() in ~\Projects\Tests\Calculator.Logic.Tests\MyBaseCalculatorServiceTests.cs:line 60 InnerException: CalculationNode's code: public sealed calss CalculationNode { public CalculationNode() { this.Left = null; this.Right = null; this.Element = new CalculationElement(); } public CalculationNode Left {get;set;} public CalculationNode Right {get;set;} public CalculationElement Element {get; set;} } CalculationElement's code: public sealed class CalculationElement { public CalculationElement() { Value = string.Empty; IsOperator = false; } public string Value {get; set} public bool IsOperator {get; set} }

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  • Why does a change of Session State provider lead to an ASPx page yielding garbage?

    - by Rory Becker
    I have an aspnet webapp which has worked very well up until now. I was recently asked to explore ways of making it scale better. I found that seperation of database and Webapp would help. Further I was told that if I changed my session providing mechanism to SQLServer, I would be able to duplicate the Web Stack to several machines which could each call back to the state server allowing the load to be distirbuted better. This sounds logical. So I created an ASPState database using ASPNet_RegSQL.exe as detailed in many locations across the web and changed the web.config on my app from: <sessionState mode="InProc" cookieless="false" timeout="20" /> To: <sessionState mode="SQLServer" sqlConnectionString="Server=SomeSQLServer;user=SomeUser;password=SomePassword" cookieless="false" timeout="20" /> Then I addressed my app, which presented me with its logon screen and I duly logged in. Once in I was presented, not with the page I was expecting, but with: I can change the sessionstate back and forth. This problem goes away and then comes back based on which set of configuration I use. Why is this happening?

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  • Schizophrenic Ubuntu 12.10-12.04: Atheros 922 PCI WIFI is disabled in Unity but enabled in terminal - How to getit to work?

    - by zewone
    I am trying to get my PCI Wireless Atheros 922 card to work. It is disabled in Unity: both the network utility and the desktop (see screenshot http://www.amisdurailhalanzy.be/Screenshot%20from%202012-10-25%2013:19:54.png) I tried many different advises on many different forums. Installed 12.10 instead of 12.04, enabled all interfaces... etc. I have read about the aht9 driver... The terminal shows no hw or sw lock for the Atheros card, nevertheless, it is still disabled. Nothing worked so far, the card is still disabled. Any help is much appreciated. Here are more tech details: myuser@adri1:~$ sudo lshw -C network *-network:0 DISABLED description: Wireless interface product: AR922X Wireless Network Adapter vendor: Atheros Communications Inc. physical id: 2 bus info: pci@0000:03:02.0 logical name: wlan1 version: 01 serial: 00:18:e7:cd:68:b1 width: 32 bits clock: 66MHz capabilities: pm bus_master cap_list ethernet physical wireless configuration: broadcast=yes driver=ath9k driverversion=3.5.0-17-generic firmware=N/A latency=168 link=no multicast=yes wireless=IEEE 802.11bgn resources: irq:18 memory:d8000000-d800ffff *-network:1 description: Ethernet interface product: VT6105/VT6106S [Rhine-III] vendor: VIA Technologies, Inc. physical id: 6 bus info: pci@0000:03:06.0 logical name: eth0 version: 8b serial: 00:11:09:a3:76:4a size: 10Mbit/s capacity: 100Mbit/s width: 32 bits clock: 33MHz capabilities: pm bus_master cap_list ethernet physical tp mii 10bt 10bt-fd 100bt 100bt-fd autonegotiation configuration: autonegotiation=on broadcast=yes driver=via-rhine driverversion=1.5.0 duplex=half latency=32 link=no maxlatency=8 mingnt=3 multicast=yes port=MII speed=10Mbit/s resources: irq:18 ioport:d300(size=256) memory:d8013000-d80130ff *-network DISABLED description: Wireless interface physical id: 1 bus info: usb@1:8.1 logical name: wlan0 serial: 00:11:09:51:75:36 capabilities: ethernet physical wireless configuration: broadcast=yes driver=rt2500usb driverversion=3.5.0-17-generic firmware=N/A link=no multicast=yes wireless=IEEE 802.11bg myuser@adri1:~$ sudo rfkill list all 0: hci0: Bluetooth Soft blocked: no Hard blocked: no 1: phy1: Wireless LAN Soft blocked: no Hard blocked: yes 2: phy0: Wireless LAN Soft blocked: no Hard blocked: no myuser@adri1:~$ dmesg | grep wlan0 [ 15.114235] IPv6: ADDRCONF(NETDEV_UP): wlan0: link is not ready myuser@adri1:~$ dmesg | egrep 'ath|firm' [ 14.617562] ath: EEPROM regdomain: 0x30 [ 14.617568] ath: EEPROM indicates we should expect a direct regpair map [ 14.617572] ath: Country alpha2 being used: AM [ 14.617575] ath: Regpair used: 0x30 [ 14.637778] ieee80211 phy0: >Selected rate control algorithm 'ath9k_rate_control' [ 14.639410] Registered led device: ath9k-phy0 myuser@adri1:~$ dmesg | grep wlan1 [ 15.119922] IPv6: ADDRCONF(NETDEV_UP): wlan1: link is not ready myuser@adri1:~$ lspci -nn | grep 'Atheros' 03:02.0 Network controller [0280]: Atheros Communications Inc. AR922X Wireless Network Adapter [168c:0029] (rev 01) myuser@adri1:~$ sudo ifconfig eth0 Link encap:Ethernet HWaddr 00:11:09:a3:76:4a inet addr:192.168.2.2 Bcast:192.168.2.255 Mask:255.255.255.0 inet6 addr: fe80::211:9ff:fea3:764a/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:5457 errors:0 dropped:0 overruns:0 frame:0 TX packets:2548 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:3425684 (3.4 MB) TX bytes:282192 (282.1 KB) lo Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 inet6 addr: ::1/128 Scope:Host UP LOOPBACK RUNNING MTU:16436 Metric:1 RX packets:590 errors:0 dropped:0 overruns:0 frame:0 TX packets:590 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:53729 (53.7 KB) TX bytes:53729 (53.7 KB) myuser@adri1:~$ sudo iwconfig wlan0 IEEE 802.11bg ESSID:off/any Mode:Managed Access Point: Not-Associated Tx-Power=off Retry long limit:7 RTS thr:off Fragment thr:off Encryption key:off Power Management:on lo no wireless extensions. eth0 no wireless extensions. wlan1 IEEE 802.11bgn ESSID:off/any Mode:Managed Access Point: Not-Associated Tx-Power=0 dBm Retry long limit:7 RTS thr:off Fragment thr:off Encryption key:off Power Management:off myuser@adri1:~$ lsmod | grep "ath9k" ath9k 116549 0 mac80211 461161 3 rt2x00usb,rt2x00lib,ath9k ath9k_common 13783 1 ath9k ath9k_hw 376155 2 ath9k,ath9k_common ath 19187 3 ath9k,ath9k_common,ath9k_hw cfg80211 175375 4 rt2x00lib,ath9k,mac80211,ath myuser@adri1:~$ iwlist scan wlan0 Failed to read scan data : Network is down lo Interface doesn't support scanning. eth0 Interface doesn't support scanning. wlan1 Failed to read scan data : Network is down myuser@adri1:~$ lsb_release -d Description: Ubuntu 12.10 myuser@adri1:~$ uname -mr 3.5.0-17-generic i686 ![Schizophrenic Ubuntu](http://www.amisdurailhalanzy.be/Screenshot%20from%202012-10-25%2013:19:54.png) Any help much appreciated... Thanks, Philippe

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  • Intermittent internet connectivity

    - by Rob Oplawar
    UPDATED: I recently built a new computer and set it up to dual-boot Windows 7 and Ubuntu 11.10. In Windows, using the same hardware, my LAN connectivity is solid. In Ubuntu, however, my network interface periodically dies and resets itself; I'll have a solid connection for 30 seconds, and then it will go out for 30 seconds. When I tail the log: tail -f /var/log/kern.log I see "eth0 link up" messages appear periodically, corresponding with the return of connectivity. I posted the original question months ago, and misinterpreted what was going on. With a working Internet connection in Windows, I ignored the problem for some months. See my answer below for the solution (drivers). ORIGINAL POST In Ubuntu, although I maintain a solid connection to my LAN (pinging the router IP address consistently returns a good result), my internet connectivity drops in and out. When I continuously ping 74.125.227.18 (a google.com server), I get responses for a while, then I start getting "Destination Host Unreachable" for a while, then I get responses again. This happens consistently, dropping the connection for about 30 seconds out of every minute or two. Whether I configure my network via the network manager or via /etc/network/interfaces seems to make no difference. I configure with the following settings: address 192.168.1.101 network 192.168.1.0 gateway 192.168.1.99 (my router's IP address) netmask 255.255.255.0 (confirmed as the right netmask for the router) broadcast 192.168.1.255 (also confirmed with the router). ifconfig confirms that these settings are working: eth0 Link encap:Ethernet HWaddr 50:e5:49:40:da:a6 inet addr:192.168.1.101 Bcast:192.168.1.255 Mask:255.255.255.0 inet6 addr: fe80::52e5:49ff:fe40:daa6/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:11557 errors:0 dropped:11557 overruns:0 frame:11557 TX packets:13117 errors:0 dropped:211 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:9551488 (9.5 MB) TX bytes:1930952 (1.9 MB) Interrupt:41 Base address:0xa000 I get the same issue when I use automatic DHCP address settings, although I did confirm that there is no other machine on the network with the static IP address I want to use. As I said, the connection to the local network stays solid - I never have any trouble pinging 192.168.1.* - it's internet addresses that I intermittently cannot reach. It's not a DNS issue because pinging known IP addresses directly shows the same behavior. Also, I don't think it's a hardware issue, as I never have any internet connectivity problems on the same machine in Windows. The network hardware is built into the motherboard: Gigabyte Z68XP-UD3P. I managed to bring the OS fully up to date, according to the update manager, but it didn't fix the issue, and with my limited understanding of network architecture I'm at my wit's end. The only clue I can see is that ifconfig is reporting a lot of dropped packets, but I'm not sure what to do about it. UPDATE: It seems my problem is a little more generic than I described; now when I try pinging my router and google simultaneously, they both go unreachable at the same time. Running ifdown eth0 and then ifup eth0 brings it back temporarily; if I just wait it comes back after a couple of minutes. I'll broaden my search through intermittent network connectivity problems.

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  • Wireless connection works but the internet is too slow to use in Ubuntu 11.04

    - by Garrin
    The internet is so slow as to be unusable. And I'm not being picky. Even after minutes I can't get my Google home page to load. I tried installing a package through apt-get and was getting rates between 0 and a few hundred bytes/s. That's bytes, not kilobytes! Mostly 0 however (no exaggeration, it spends large amounts of time stalled). And I would go to a speed test web site of some kind but I can't since nothing will load. Briefly put, the laptop I am using was connected to two wireless networks while using Ubuntu 11.04 without any issues before this. It was also connected to a wired network without any issues. It dual boats Windows 7 which has never had any issues, not even with the current wireless network. Just to be clear, on the current wi-fi network, Windows 7 encounters no issues (speedtest.net puts the network speed at 1mb/s) but my network connection in Ubuntu 11.04 is so slow as to literally be unusable. I am unfamiliar with the router except for the fact that it boasts a Rogers logo (that's a large ISP/cable provider in Canada for those not familiar with the land of igloos and polar bears). I am far from the router and some desktop widget I use tells me the signal strength is at 58% (it seems fairly reliable and this would appear to match up with the filled bars in the network icon). I should also mention I'm just renting a room in this house so I'm not the network administrator and while I can access the 192.168.0.1 router page, the password wasn't set to 'password' so it's not much use to me. Here are a bunch of commands I ran which don't tell me a whole lot but I thought might be more instructive to the wise around here: lspci (just showing my network card): 05:00.0 Network controller: Atheros Communications Inc. AR928X Wireless Network Adapter (PCI-Express) (rev 01) This one is self explanatory. PING www.googele.com (216.65.41.185) 56(84) bytes of data. 64 bytes from nnw.net (216.65.41.185): icmp_req=1 ttl=51 time=267 ms 64 bytes from nnw.net (216.65.41.185): icmp_req=2 ttl=51 time=190 ms 64 bytes from nnw.net (216.65.41.185): icmp_req=3 ttl=51 time=212 ms 64 bytes from nnw.net (216.65.41.185): icmp_req=4 ttl=51 time=207 ms 64 bytes from nnw.net (216.65.41.185): icmp_req=5 ttl=51 time=220 ms --- www.googele.com ping statistics --- 5 packets transmitted, 5 received, 0% packet loss, time 4003ms rtt min/avg/max/mdev = 190.079/219.699/267.963/26.121 ms ifconfig eth0 Link encap:Ethernet HWaddr 20:6a:8a:02:20:da UP BROADCAST MULTICAST MTU:1500 Metric:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:0 (0.0 B) TX bytes:0 (0.0 B) Interrupt:42 lo Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 inet6 addr: ::1/128 Scope:Host UP LOOPBACK RUNNING MTU:16436 Metric:1 RX packets:16 errors:0 dropped:0 overruns:0 frame:0 TX packets:16 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:960 (960.0 B) TX bytes:960 (960.0 B) wlan0 Link encap:Ethernet HWaddr 20:7c:8f:05:c6:bf inet addr:192.168.0.16 Bcast:192.168.0.255 Mask:255.255.255.0 inet6 addr: fe80::227c:8fff:fe05:c6bf/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:982 errors:0 dropped:0 overruns:0 frame:0 TX packets:658 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:497250 (497.2 KB) TX bytes:95076 (95.0 KB) Thank you

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  • Is there a Telecommunications Reference Architecture?

    - by raul.goycoolea
    @font-face { font-family: "Arial"; }@font-face { font-family: "Courier New"; }@font-face { font-family: "Wingdings"; }@font-face { font-family: "Cambria"; }p.MsoNormal, li.MsoNormal, div.MsoNormal { margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: "Times New Roman"; }p.MsoListParagraph, li.MsoListParagraph, div.MsoListParagraph { margin: 0cm 0cm 0.0001pt 36pt; font-size: 12pt; font-family: "Times New Roman"; }p.MsoListParagraphCxSpFirst, li.MsoListParagraphCxSpFirst, div.MsoListParagraphCxSpFirst { margin: 0cm 0cm 0.0001pt 36pt; font-size: 12pt; font-family: "Times New Roman"; }p.MsoListParagraphCxSpMiddle, li.MsoListParagraphCxSpMiddle, div.MsoListParagraphCxSpMiddle { margin: 0cm 0cm 0.0001pt 36pt; font-size: 12pt; font-family: "Times New Roman"; }p.MsoListParagraphCxSpLast, li.MsoListParagraphCxSpLast, div.MsoListParagraphCxSpLast { margin: 0cm 0cm 0.0001pt 36pt; font-size: 12pt; font-family: "Times New Roman"; }div.Section1 { page: Section1; }ol { margin-bottom: 0cm; }ul { margin-bottom: 0cm; } Abstract   Reference architecture provides needed architectural information that can be provided in advance to an enterprise to enable consistent architectural best practices. Enterprise Reference Architecture helps business owners to actualize their strategies, vision, objectives, and principles. It evaluates the IT systems, based on Reference Architecture goals, principles, and standards. It helps to reduce IT costs by increasing functionality, availability, scalability, etc. Telecom Reference Architecture provides customers with the flexibility to view bundled service bills online with the provision of multiple services. It provides real-time, flexible billing and charging systems, to handle complex promotions, discounts, and settlements with multiple parties. This paper attempts to describe the Reference Architecture for the Telecom Enterprises. It lays the foundation for a Telecom Reference Architecture by articulating the requirements, drivers, and pitfalls for telecom service providers. It describes generic reference architecture for telecom enterprises and moves on to explain how to achieve Enterprise Reference Architecture by using SOA.   Introduction   A Reference Architecture provides a methodology, set of practices, template, and standards based on a set of successful solutions implemented earlier. These solutions have been generalized and structured for the depiction of both a logical and a physical architecture, based on the harvesting of a set of patterns that describe observations in a number of successful implementations. It helps as a reference for the various architectures that an enterprise can implement to solve various problems. It can be used as the starting point or the point of comparisons for various departments/business entities of a company, or for the various companies for an enterprise. It provides multiple views for multiple stakeholders.   Major artifacts of the Enterprise Reference Architecture are methodologies, standards, metadata, documents, design patterns, etc.   Purpose of Reference Architecture   In most cases, architects spend a lot of time researching, investigating, defining, and re-arguing architectural decisions. It is like reinventing the wheel as their peers in other organizations or even the same organization have already spent a lot of time and effort defining their own architectural practices. This prevents an organization from learning from its own experiences and applying that knowledge for increased effectiveness.   Reference architecture provides missing architectural information that can be provided in advance to project team members to enable consistent architectural best practices.   Enterprise Reference Architecture helps an enterprise to achieve the following at the abstract level:   ·       Reference architecture is more of a communication channel to an enterprise ·       Helps the business owners to accommodate to their strategies, vision, objectives, and principles. ·       Evaluates the IT systems based on Reference Architecture Principles ·       Reduces IT spending through increasing functionality, availability, scalability, etc ·       A Real-time Integration Model helps to reduce the latency of the data updates Is used to define a single source of Information ·       Provides a clear view on how to manage information and security ·       Defines the policy around the data ownership, product boundaries, etc. ·       Helps with cost optimization across project and solution portfolios by eliminating unused or duplicate investments and assets ·       Has a shorter implementation time and cost   Once the reference architecture is in place, the set of architectural principles, standards, reference models, and best practices ensure that the aligned investments have the greatest possible likelihood of success in both the near term and the long term (TCO).     Common pitfalls for Telecom Service Providers   Telecom Reference Architecture serves as the first step towards maturity for a telecom service provider. During the course of our assignments/experiences with telecom players, we have come across the following observations – Some of these indicate a lack of maturity of the telecom service provider:   ·       In markets that are growing and not so mature, it has been observed that telcos have a significant amount of in-house or home-grown applications. In some of these markets, the growth has been so rapid that IT has been unable to cope with business demands. Telcos have shown a tendency to come up with workarounds in their IT applications so as to meet business needs. ·       Even for core functions like provisioning or mediation, some telcos have tried to manage with home-grown applications. ·       Most of the applications do not have the required scalability or maintainability to sustain growth in volumes or functionality. ·       Applications face interoperability issues with other applications in the operator's landscape. Integrating a new application or network element requires considerable effort on the part of the other applications. ·       Application boundaries are not clear, and functionality that is not in the initial scope of that application gets pushed onto it. This results in the development of the multiple, small applications without proper boundaries. ·       Usage of Legacy OSS/BSS systems, poor Integration across Multiple COTS Products and Internal Systems. Most of the Integrations are developed on ad-hoc basis and Point-to-Point Integration. ·       Redundancy of the business functions in different applications • Fragmented data across the different applications and no integrated view of the strategic data • Lot of performance Issues due to the usage of the complex integration across OSS and BSS systems   However, this is where the maturity of the telecom industry as a whole can be of help. The collaborative efforts of telcos to overcome some of these problems have resulted in bodies like the TM Forum. They have come up with frameworks for business processes, data, applications, and technology for telecom service providers. These could be a good starting point for telcos to clean up their enterprise landscape.   Industry Trends in Telecom Reference Architecture   Telecom reference architectures are evolving rapidly because telcos are facing business and IT challenges.   “The reality is that there probably is no killer application, no silver bullet that the telcos can latch onto to carry them into a 21st Century.... Instead, there are probably hundreds – perhaps thousands – of niche applications.... And the only way to find which of these works for you is to try out lots of them, ramp up the ones that work, and discontinue the ones that fail.” – Martin Creaner President & CTO TM Forum.   The following trends have been observed in telecom reference architecture:   ·       Transformation of business structures to align with customer requirements ·       Adoption of more Internet-like technical architectures. The Web 2.0 concept is increasingly being used. ·       Virtualization of the traditional operations support system (OSS) ·       Adoption of SOA to support development of IP-based services ·       Adoption of frameworks like Service Delivery Platforms (SDPs) and IP Multimedia Subsystem ·       (IMS) to enable seamless deployment of various services over fixed and mobile networks ·       Replacement of in-house, customized, and stove-piped OSS/BSS with standards-based COTS products ·       Compliance with industry standards and frameworks like eTOM, SID, and TAM to enable seamless integration with other standards-based products   Drivers of Reference Architecture   The drivers of the Reference Architecture are Reference Architecture Goals, Principles, and Enterprise Vision and Telecom Transformation. The details are depicted below diagram. @font-face { font-family: "Cambria"; }p.MsoNormal, li.MsoNormal, div.MsoNormal { margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: "Times New Roman"; }p.MsoCaption, li.MsoCaption, div.MsoCaption { margin: 0cm 0cm 10pt; font-size: 9pt; font-family: "Times New Roman"; color: rgb(79, 129, 189); font-weight: bold; }div.Section1 { page: Section1; } Figure 1. Drivers for Reference Architecture @font-face { font-family: "Arial"; }@font-face { font-family: "Courier New"; }@font-face { font-family: "Wingdings"; }@font-face { font-family: "Cambria"; }p.MsoNormal, li.MsoNormal, div.MsoNormal { margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: "Times New Roman"; }p.MsoListParagraph, li.MsoListParagraph, div.MsoListParagraph { margin: 0cm 0cm 0.0001pt 36pt; font-size: 12pt; font-family: "Times New Roman"; }p.MsoListParagraphCxSpFirst, li.MsoListParagraphCxSpFirst, div.MsoListParagraphCxSpFirst { margin: 0cm 0cm 0.0001pt 36pt; font-size: 12pt; font-family: "Times New Roman"; }p.MsoListParagraphCxSpMiddle, li.MsoListParagraphCxSpMiddle, div.MsoListParagraphCxSpMiddle { margin: 0cm 0cm 0.0001pt 36pt; font-size: 12pt; font-family: "Times New Roman"; }p.MsoListParagraphCxSpLast, li.MsoListParagraphCxSpLast, div.MsoListParagraphCxSpLast { margin: 0cm 0cm 0.0001pt 36pt; font-size: 12pt; font-family: "Times New Roman"; }div.Section1 { page: Section1; }ol { margin-bottom: 0cm; }ul { margin-bottom: 0cm; } Today’s telecom reference architectures should seamlessly integrate traditional legacy-based applications and transition to next-generation network technologies (e.g., IP multimedia subsystems). This has resulted in new requirements for flexible, real-time billing and OSS/BSS systems and implications on the service provider’s organizational requirements and structure.   Telecom reference architectures are today expected to:   ·       Integrate voice, messaging, email and other VAS over fixed and mobile networks, back end systems ·       Be able to provision multiple services and service bundles • Deliver converged voice, video and data services ·       Leverage the existing Network Infrastructure ·       Provide real-time, flexible billing and charging systems to handle complex promotions, discounts, and settlements with multiple parties. ·       Support charging of advanced data services such as VoIP, On-Demand, Services (e.g.  Video), IMS/SIP Services, Mobile Money, Content Services and IPTV. ·       Help in faster deployment of new services • Serve as an effective platform for collaboration between network IT and business organizations ·       Harness the potential of converging technology, networks, devices and content to develop multimedia services and solutions of ever-increasing sophistication on a single Internet Protocol (IP) ·       Ensure better service delivery and zero revenue leakage through real-time balance and credit management ·       Lower operating costs to drive profitability   Enterprise Reference Architecture   The Enterprise Reference Architecture (RA) fills the gap between the concepts and vocabulary defined by the reference model and the implementation. Reference architecture provides detailed architectural information in a common format such that solutions can be repeatedly designed and deployed in a consistent, high-quality, supportable fashion. This paper attempts to describe the Reference Architecture for the Telecom Application Usage and how to achieve the Enterprise Level Reference Architecture using SOA.   • Telecom Reference Architecture • Enterprise SOA based Reference Architecture   Telecom Reference Architecture   Tele Management Forum’s New Generation Operations Systems and Software (NGOSS) is an architectural framework for organizing, integrating, and implementing telecom systems. NGOSS is a component-based framework consisting of the following elements:   ·       The enhanced Telecom Operations Map (eTOM) is a business process framework. ·       The Shared Information Data (SID) model provides a comprehensive information framework that may be specialized for the needs of a particular organization. ·       The Telecom Application Map (TAM) is an application framework to depict the functional footprint of applications, relative to the horizontal processes within eTOM. ·       The Technology Neutral Architecture (TNA) is an integrated framework. TNA is an architecture that is sustainable through technology changes.   NGOSS Architecture Standards are:   ·       Centralized data ·       Loosely coupled distributed systems ·       Application components/re-use  ·       A technology-neutral system framework with technology specific implementations ·       Interoperability to service provider data/processes ·       Allows more re-use of business components across multiple business scenarios ·       Workflow automation   The traditional operator systems architecture consists of four layers,   ·       Business Support System (BSS) layer, with focus toward customers and business partners. Manages order, subscriber, pricing, rating, and billing information. ·       Operations Support System (OSS) layer, built around product, service, and resource inventories. ·       Networks layer – consists of Network elements and 3rd Party Systems. ·       Integration Layer – to maximize application communication and overall solution flexibility.   Reference architecture for telecom enterprises is depicted below. @font-face { font-family: "Arial"; }@font-face { font-family: "Courier New"; }@font-face { font-family: "Wingdings"; }@font-face { font-family: "Cambria"; }p.MsoNormal, li.MsoNormal, div.MsoNormal { margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: "Times New Roman"; }p.MsoCaption, li.MsoCaption, div.MsoCaption { margin: 0cm 0cm 10pt; font-size: 9pt; font-family: "Times New Roman"; color: rgb(79, 129, 189); font-weight: bold; }p.MsoListParagraph, li.MsoListParagraph, div.MsoListParagraph { margin: 0cm 0cm 0.0001pt 36pt; font-size: 12pt; font-family: "Times New Roman"; }p.MsoListParagraphCxSpFirst, li.MsoListParagraphCxSpFirst, div.MsoListParagraphCxSpFirst { margin: 0cm 0cm 0.0001pt 36pt; font-size: 12pt; font-family: "Times New Roman"; }p.MsoListParagraphCxSpMiddle, li.MsoListParagraphCxSpMiddle, div.MsoListParagraphCxSpMiddle { margin: 0cm 0cm 0.0001pt 36pt; font-size: 12pt; font-family: "Times New Roman"; }p.MsoListParagraphCxSpLast, li.MsoListParagraphCxSpLast, div.MsoListParagraphCxSpLast { margin: 0cm 0cm 0.0001pt 36pt; font-size: 12pt; font-family: "Times New Roman"; }div.Section1 { page: Section1; }ol { margin-bottom: 0cm; }ul { margin-bottom: 0cm; } Figure 2. Telecom Reference Architecture   The major building blocks of any Telecom Service Provider architecture are as follows:   1. Customer Relationship Management   CRM encompasses the end-to-end lifecycle of the customer: customer initiation/acquisition, sales, ordering, and service activation, customer care and support, proactive campaigns, cross sell/up sell, and retention/loyalty.   CRM also includes the collection of customer information and its application to personalize, customize, and integrate delivery of service to a customer, as well as to identify opportunities for increasing the value of the customer to the enterprise.   The key functionalities related to Customer Relationship Management are   ·       Manage the end-to-end lifecycle of a customer request for products. ·       Create and manage customer profiles. ·       Manage all interactions with customers – inquiries, requests, and responses. ·       Provide updates to Billing and other south bound systems on customer/account related updates such as customer/ account creation, deletion, modification, request bills, final bill, duplicate bills, credit limits through Middleware. ·       Work with Order Management System, Product, and Service Management components within CRM. ·       Manage customer preferences – Involve all the touch points and channels to the customer, including contact center, retail stores, dealers, self service, and field service, as well as via any media (phone, face to face, web, mobile device, chat, email, SMS, mail, the customer's bill, etc.). ·       Support single interface for customer contact details, preferences, account details, offers, customer premise equipment, bill details, bill cycle details, and customer interactions.   CRM applications interact with customers through customer touch points like portals, point-of-sale terminals, interactive voice response systems, etc. The requests by customers are sent via fulfillment/provisioning to billing system for ordering processing.   2. Billing and Revenue Management   Billing and Revenue Management handles the collection of appropriate usage records and production of timely and accurate bills – for providing pre-bill usage information and billing to customers; for processing their payments; and for performing payment collections. In addition, it handles customer inquiries about bills, provides billing inquiry status, and is responsible for resolving billing problems to the customer's satisfaction in a timely manner. This process grouping also supports prepayment for services.   The key functionalities provided by these applications are   ·       To ensure that enterprise revenue is billed and invoices delivered appropriately to customers. ·       To manage customers’ billing accounts, process their payments, perform payment collections, and monitor the status of the account balance. ·       To ensure the timely and effective fulfillment of all customer bill inquiries and complaints. ·       Collect the usage records from mediation and ensure appropriate rating and discounting of all usage and pricing. ·       Support revenue sharing; split charging where usage is guided to an account different from the service consumer. ·       Support prepaid and post-paid rating. ·       Send notification on approach / exceeding the usage thresholds as enforced by the subscribed offer, and / or as setup by the customer. ·       Support prepaid, post paid, and hybrid (where some services are prepaid and the rest of the services post paid) customers and conversion from post paid to prepaid, and vice versa. ·       Support different billing function requirements like charge prorating, promotion, discount, adjustment, waiver, write-off, account receivable, GL Interface, late payment fee, credit control, dunning, account or service suspension, re-activation, expiry, termination, contract violation penalty, etc. ·       Initiate direct debit to collect payment against an invoice outstanding. ·       Send notification to Middleware on different events; for example, payment receipt, pre-suspension, threshold exceed, etc.   Billing systems typically get usage data from mediation systems for rating and billing. They get provisioning requests from order management systems and inquiries from CRM systems. Convergent and real-time billing systems can directly get usage details from network elements.   3. Mediation   Mediation systems transform/translate the Raw or Native Usage Data Records into a general format that is acceptable to billing for their rating purposes.   The following lists the high-level roles and responsibilities executed by the Mediation system in the end-to-end solution.   ·       Collect Usage Data Records from different data sources – like network elements, routers, servers – via different protocol and interfaces. ·       Process Usage Data Records – Mediation will process Usage Data Records as per the source format. ·       Validate Usage Data Records from each source. ·       Segregates Usage Data Records coming from each source to multiple, based on the segregation requirement of end Application. ·       Aggregates Usage Data Records based on the aggregation rule if any from different sources. ·       Consolidates multiple Usage Data Records from each source. ·       Delivers formatted Usage Data Records to different end application like Billing, Interconnect, Fraud Management, etc. ·       Generates audit trail for incoming Usage Data Records and keeps track of all the Usage Data Records at various stages of mediation process. ·       Checks duplicate Usage Data Records across files for a given time window.   4. Fulfillment   This area is responsible for providing customers with their requested products in a timely and correct manner. It translates the customer's business or personal need into a solution that can be delivered using the specific products in the enterprise's portfolio. This process informs the customers of the status of their purchase order, and ensures completion on time, as well as ensuring a delighted customer. These processes are responsible for accepting and issuing orders. They deal with pre-order feasibility determination, credit authorization, order issuance, order status and tracking, customer update on customer order activities, and customer notification on order completion. Order management and provisioning applications fall into this category.   The key functionalities provided by these applications are   ·       Issuing new customer orders, modifying open customer orders, or canceling open customer orders; ·       Verifying whether specific non-standard offerings sought by customers are feasible and supportable; ·       Checking the credit worthiness of customers as part of the customer order process; ·       Testing the completed offering to ensure it is working correctly; ·       Updating of the Customer Inventory Database to reflect that the specific product offering has been allocated, modified, or cancelled; ·       Assigning and tracking customer provisioning activities; ·       Managing customer provisioning jeopardy conditions; and ·       Reporting progress on customer orders and other processes to customer.   These applications typically get orders from CRM systems. They interact with network elements and billing systems for fulfillment of orders.   5. Enterprise Management   This process area includes those processes that manage enterprise-wide activities and needs, or have application within the enterprise as a whole. They encompass all business management processes that   ·       Are necessary to support the whole of the enterprise, including processes for financial management, legal management, regulatory management, process, cost, and quality management, etc.;   ·       Are responsible for setting corporate policies, strategies, and directions, and for providing guidelines and targets for the whole of the business, including strategy development and planning for areas, such as Enterprise Architecture, that are integral to the direction and development of the business;   ·       Occur throughout the enterprise, including processes for project management, performance assessments, cost assessments, etc.     (i) Enterprise Risk Management:   Enterprise Risk Management focuses on assuring that risks and threats to the enterprise value and/or reputation are identified, and appropriate controls are in place to minimize or eliminate the identified risks. The identified risks may be physical or logical/virtual. Successful risk management ensures that the enterprise can support its mission critical operations, processes, applications, and communications in the face of serious incidents such as security threats/violations and fraud attempts. Two key areas covered in Risk Management by telecom operators are:   ·       Revenue Assurance: Revenue assurance system will be responsible for identifying revenue loss scenarios across components/systems, and will help in rectifying the problems. The following lists the high-level roles and responsibilities executed by the Revenue Assurance system in the end-to-end solution. o   Identify all usage information dropped when networks are being upgraded. o   Interconnect bill verification. o   Identify where services are routinely provisioned but never billed. o   Identify poor sales policies that are intensifying collections problems. o   Find leakage where usage is sent to error bucket and never billed for. o   Find leakage where field service, CRM, and network build-out are not optimized.   ·       Fraud Management: Involves collecting data from different systems to identify abnormalities in traffic patterns, usage patterns, and subscription patterns to report suspicious activity that might suggest fraudulent usage of resources, resulting in revenue losses to the operator.   The key roles and responsibilities of the system component are as follows:   o   Fraud management system will capture and monitor high usage (over a certain threshold) in terms of duration, value, and number of calls for each subscriber. The threshold for each subscriber is decided by the system and fixed automatically. o   Fraud management will be able to detect the unauthorized access to services for certain subscribers. These subscribers may have been provided unauthorized services by employees. The component will raise the alert to the operator the very first time of such illegal calls or calls which are not billed. o   The solution will be to have an alarm management system that will deliver alarms to the operator/provider whenever it detects a fraud, thus minimizing fraud by catching it the first time it occurs. o   The Fraud Management system will be capable of interfacing with switches, mediation systems, and billing systems   (ii) Knowledge Management   This process focuses on knowledge management, technology research within the enterprise, and the evaluation of potential technology acquisitions.   Key responsibilities of knowledge base management are to   ·       Maintain knowledge base – Creation and updating of knowledge base on ongoing basis. ·       Search knowledge base – Search of knowledge base on keywords or category browse ·       Maintain metadata – Management of metadata on knowledge base to ensure effective management and search. ·       Run report generator. ·       Provide content – Add content to the knowledge base, e.g., user guides, operational manual, etc.   (iii) Document Management   It focuses on maintaining a repository of all electronic documents or images of paper documents relevant to the enterprise using a system.   (iv) Data Management   It manages data as a valuable resource for any enterprise. For telecom enterprises, the typical areas covered are Master Data Management, Data Warehousing, and Business Intelligence. It is also responsible for data governance, security, quality, and database management.   Key responsibilities of Data Management are   ·       Using ETL, extract the data from CRM, Billing, web content, ERP, campaign management, financial, network operations, asset management info, customer contact data, customer measures, benchmarks, process data, e.g., process inputs, outputs, and measures, into Enterprise Data Warehouse. ·       Management of data traceability with source, data related business rules/decisions, data quality, data cleansing data reconciliation, competitors data – storage for all the enterprise data (customer profiles, products, offers, revenues, etc.) ·       Get online update through night time replication or physical backup process at regular frequency. ·       Provide the data access to business intelligence and other systems for their analysis, report generation, and use.   (v) Business Intelligence   It uses the Enterprise Data to provide the various analysis and reports that contain prospects and analytics for customer retention, acquisition of new customers due to the offers, and SLAs. It will generate right and optimized plans – bolt-ons for the customers.   The following lists the high-level roles and responsibilities executed by the Business Intelligence system at the Enterprise Level:   ·       It will do Pattern analysis and reports problem. ·       It will do Data Analysis – Statistical analysis, data profiling, affinity analysis of data, customer segment wise usage patterns on offers, products, service and revenue generation against services and customer segments. ·       It will do Performance (business, system, and forecast) analysis, churn propensity, response time, and SLAs analysis. ·       It will support for online and offline analysis, and report drill down capability. ·       It will collect, store, and report various SLA data. ·       It will provide the necessary intelligence for marketing and working on campaigns, etc., with cost benefit analysis and predictions.   It will advise on customer promotions with additional services based on loyalty and credit history of customer   ·       It will Interface with Enterprise Data Management system for data to run reports and analysis tasks. It will interface with the campaign schedules, based on historical success evidence.   (vi) Stakeholder and External Relations Management   It manages the enterprise's relationship with stakeholders and outside entities. Stakeholders include shareholders, employee organizations, etc. Outside entities include regulators, local community, and unions. Some of the processes within this grouping are Shareholder Relations, External Affairs, Labor Relations, and Public Relations.   (vii) Enterprise Resource Planning   It is used to manage internal and external resources, including tangible assets, financial resources, materials, and human resources. Its purpose is to facilitate the flow of information between all business functions inside the boundaries of the enterprise and manage the connections to outside stakeholders. ERP systems consolidate all business operations into a uniform and enterprise wide system environment.   The key roles and responsibilities for Enterprise System are given below:   ·        It will handle responsibilities such as core accounting, financial, and management reporting. ·       It will interface with CRM for capturing customer account and details. ·       It will interface with billing to capture the billing revenue and other financial data. ·       It will be responsible for executing the dunning process. Billing will send the required feed to ERP for execution of dunning. ·       It will interface with the CRM and Billing through batch interfaces. Enterprise management systems are like horizontals in the enterprise and typically interact with all major telecom systems. E.g., an ERP system interacts with CRM, Fulfillment, and Billing systems for different kinds of data exchanges.   6. External Interfaces/Touch Points   The typical external parties are customers, suppliers/partners, employees, shareholders, and other stakeholders. External interactions from/to a Service Provider to other parties can be achieved by a variety of mechanisms, including:   ·       Exchange of emails or faxes ·       Call Centers ·       Web Portals ·       Business-to-Business (B2B) automated transactions   These applications provide an Internet technology driven interface to external parties to undertake a variety of business functions directly for themselves. These can provide fully or partially automated service to external parties through various touch points.   Typical characteristics of these touch points are   ·       Pre-integrated self-service system, including stand-alone web framework or integration front end with a portal engine ·       Self services layer exposing atomic web services/APIs for reuse by multiple systems across the architectural environment ·       Portlets driven connectivity exposing data and services interoperability through a portal engine or web application   These touch points mostly interact with the CRM systems for requests, inquiries, and responses.   7. Middleware   The component will be primarily responsible for integrating the different systems components under a common platform. It should provide a Standards-Based Platform for building Service Oriented Architecture and Composite Applications. The following lists the high-level roles and responsibilities executed by the Middleware component in the end-to-end solution.   ·       As an integration framework, covering to and fro interfaces ·       Provide a web service framework with service registry. ·       Support SOA framework with SOA service registry. ·       Each of the interfaces from / to Middleware to other components would handle data transformation, translation, and mapping of data points. ·       Receive data from the caller / activate and/or forward the data to the recipient system in XML format. ·       Use standard XML for data exchange. ·       Provide the response back to the service/call initiator. ·       Provide a tracking until the response completion. ·       Keep a store transitional data against each call/transaction. ·       Interface through Middleware to get any information that is possible and allowed from the existing systems to enterprise systems; e.g., customer profile and customer history, etc. ·       Provide the data in a common unified format to the SOA calls across systems, and follow the Enterprise Architecture directive. ·       Provide an audit trail for all transactions being handled by the component.   8. Network Elements   The term Network Element means a facility or equipment used in the provision of a telecommunications service. Such terms also includes features, functions, and capabilities that are provided by means of such facility or equipment, including subscriber numbers, databases, signaling systems, and information sufficient for billing and collection or used in the transmission, routing, or other provision of a telecommunications service.   Typical network elements in a GSM network are Home Location Register (HLR), Intelligent Network (IN), Mobile Switching Center (MSC), SMS Center (SMSC), and network elements for other value added services like Push-to-talk (PTT), Ring Back Tone (RBT), etc.   Network elements are invoked when subscribers use their telecom devices for any kind of usage. These elements generate usage data and pass it on to downstream systems like mediation and billing system for rating and billing. They also integrate with provisioning systems for order/service fulfillment.   9. 3rd Party Applications   3rd Party systems are applications like content providers, payment gateways, point of sale terminals, and databases/applications maintained by the Government.   Depending on applicability and the type of functionality provided by 3rd party applications, the integration with different telecom systems like CRM, provisioning, and billing will be done.   10. Service Delivery Platform   A service delivery platform (SDP) provides the architecture for the rapid deployment, provisioning, execution, management, and billing of value added telecom services. SDPs are based on the concept of SOA and layered architecture. They support the delivery of voice, data services, and content in network and device-independent fashion. They allow application developers to aggregate network capabilities, services, and sources of content. SDPs typically contain layers for web services exposure, service application development, and network abstraction.   SOA Reference Architecture   SOA concept is based on the principle of developing reusable business service and building applications by composing those services, instead of building monolithic applications in silos. It’s about bridging the gap between business and IT through a set of business-aligned IT services, using a set of design principles, patterns, and techniques.   In an SOA, resources are made available to participants in a value net, enterprise, line of business (typically spanning multiple applications within an enterprise or across multiple enterprises). It consists of a set of business-aligned IT services that collectively fulfill an organization’s business processes and goals. We can choreograph these services into composite applications and invoke them through standard protocols. SOA, apart from agility and reusability, enables:   ·       The business to specify processes as orchestrations of reusable services ·       Technology agnostic business design, with technology hidden behind service interface ·       A contractual-like interaction between business and IT, based on service SLAs ·       Accountability and governance, better aligned to business services ·       Applications interconnections untangling by allowing access only through service interfaces, reducing the daunting side effects of change ·       Reduced pressure to replace legacy and extended lifetime for legacy applications, through encapsulation in services   ·       A Cloud Computing paradigm, using web services technologies, that makes possible service outsourcing on an on-demand, utility-like, pay-per-usage basis   The following section represents the Reference Architecture of logical view for the Telecom Solution. The new custom built application needs to align with this logical architecture in the long run to achieve EA benefits.   Packaged implementation applications, such as ERP billing applications, need to expose their functions as service providers (as other applications consume) and interact with other applications as service consumers.   COT applications need to expose services through wrappers such as adapters to utilize existing resources and at the same time achieve Enterprise Architecture goal and objectives.   The following are the various layers for Enterprise level deployment of SOA. This diagram captures the abstract view of Enterprise SOA layers and important components of each layer. Layered architecture means decomposition of services such that most interactions occur between adjacent layers. However, there is no strict rule that top layers should not directly communicate with bottom layers.   The diagram below represents the important logical pieces that would result from overall SOA transformation. @font-face { font-family: "Arial"; }@font-face { font-family: "Courier New"; }@font-face { font-family: "Wingdings"; }@font-face { font-family: "Cambria"; }p.MsoNormal, li.MsoNormal, div.MsoNormal { margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: "Times New Roman"; }p.MsoCaption, li.MsoCaption, div.MsoCaption { margin: 0cm 0cm 10pt; font-size: 9pt; font-family: "Times New Roman"; color: rgb(79, 129, 189); font-weight: bold; }p.MsoListParagraph, li.MsoListParagraph, div.MsoListParagraph { margin: 0cm 0cm 0.0001pt 36pt; font-size: 12pt; font-family: "Times New Roman"; }p.MsoListParagraphCxSpFirst, li.MsoListParagraphCxSpFirst, div.MsoListParagraphCxSpFirst { margin: 0cm 0cm 0.0001pt 36pt; font-size: 12pt; font-family: "Times New Roman"; }p.MsoListParagraphCxSpMiddle, li.MsoListParagraphCxSpMiddle, div.MsoListParagraphCxSpMiddle { margin: 0cm 0cm 0.0001pt 36pt; font-size: 12pt; font-family: "Times New Roman"; }p.MsoListParagraphCxSpLast, li.MsoListParagraphCxSpLast, div.MsoListParagraphCxSpLast { margin: 0cm 0cm 0.0001pt 36pt; font-size: 12pt; font-family: "Times New Roman"; }div.Section1 { page: Section1; }ol { margin-bottom: 0cm; }ul { margin-bottom: 0cm; } Figure 3. Enterprise SOA Reference Architecture 1.          Operational System Layer: This layer consists of all packaged applications like CRM, ERP, custom built applications, COTS based applications like Billing, Revenue Management, Fulfilment, and the Enterprise databases that are essential and contribute directly or indirectly to the Enterprise OSS/BSS Transformation.   ERP holds the data of Asset Lifecycle Management, Supply Chain, and Advanced Procurement and Human Capital Management, etc.   CRM holds the data related to Order, Sales, and Marketing, Customer Care, Partner Relationship Management, Loyalty, etc.   Content Management handles Enterprise Search and Query. Billing application consists of the following components:   ·       Collections Management, Customer Billing Management, Invoices, Real-Time Rating, Discounting, and Applying of Charges ·       Enterprise databases will hold both the application and service data, whether structured or unstructured.   MDM - Master data majorly consists of Customer, Order, Product, and Service Data.     2.          Enterprise Component Layer:   This layer consists of the Application Services and Common Services that are responsible for realizing the functionality and maintaining the QoS of the exposed services. This layer uses container-based technologies such as application servers to implement the components, workload management, high availability, and load balancing.   Application Services: This Service Layer enables application, technology, and database abstraction so that the complex accessing logic is hidden from the other service layers. This is a basic service layer, which exposes application functionalities and data as reusable services. The three types of the Application access services are:   ·       Application Access Service: This Service Layer exposes application level functionalities as a reusable service between BSS to BSS and BSS to OSS integration. This layer is enabled using disparate technology such as Web Service, Integration Servers, and Adaptors, etc.   ·       Data Access Service: This Service Layer exposes application data services as a reusable reference data service. This is done via direct interaction with application data. and provides the federated query.   ·       Network Access Service: This Service Layer exposes provisioning layer as a reusable service from OSS to OSS integration. This integration service emphasizes the need for high performance, stateless process flows, and distributed design.   Common Services encompasses management of structured, semi-structured, and unstructured data such as information services, portal services, interaction services, infrastructure services, and security services, etc.   3.          Integration Layer:   This consists of service infrastructure components like service bus, service gateway for partner integration, service registry, service repository, and BPEL processor. Service bus will carry the service invocation payloads/messages between consumers and providers. The other important functions expected from it are itinerary based routing, distributed caching of routing information, transformations, and all qualities of service for messaging-like reliability, scalability, and availability, etc. Service registry will hold all contracts (wsdl) of services, and it helps developers to locate or discover service during design time or runtime.   • BPEL processor would be useful in orchestrating the services to compose a complex business scenario or process. • Workflow and business rules management are also required to support manual triggering of certain activities within business process. based on the rules setup and also the state machine information. Application, data, and service mediation layer typically forms the overall composite application development framework or SOA Framework.   4.          Business Process Layer: These are typically the intermediate services layer and represent Shared Business Process Services. At Enterprise Level, these services are from Customer Management, Order Management, Billing, Finance, and Asset Management application domains.   5.          Access Layer: This layer consists of portals for Enterprise and provides a single view of Enterprise information management and dashboard services.   6.          Channel Layer: This consists of various devices; applications that form part of extended enterprise; browsers through which users access the applications.   7.          Client Layer: This designates the different types of users accessing the enterprise applications. The type of user typically would be an important factor in determining the level of access to applications.   8.          Vertical pieces like management, monitoring, security, and development cut across all horizontal layers Management and monitoring involves all aspects of SOA-like services, SLAs, and other QoS lifecycle processes for both applications and services surrounding SOA governance.     9.          EA Governance, Reference Architecture, Roadmap, Principles, and Best Practices:   EA Governance is important in terms of providing the overall direction to SOA implementation within the enterprise. This involves board-level involvement, in addition to business and IT executives. At a high level, this involves managing the SOA projects implementation, managing SOA infrastructure, and controlling the entire effort through all fine-tuned IT processes in accordance with COBIT (Control Objectives for Information Technology).   Devising tools and techniques to promote reuse culture, and the SOA way of doing things needs competency centers to be established in addition to training the workforce to take up new roles that are suited to SOA journey.   Conclusions   Reference Architectures can serve as the basis for disparate architecture efforts throughout the organization, even if they use different tools and technologies. Reference architectures provide best practices and approaches in the independent way a vendor deals with technology and standards. Reference Architectures model the abstract architectural elements for an enterprise independent of the technologies, protocols, and products that are used to implement an SOA. Telecom enterprises today are facing significant business and technology challenges due to growing competition, a multitude of services, and convergence. Adopting architectural best practices could go a long way in meeting these challenges. The use of SOA-based architecture for communication to each of the external systems like Billing, CRM, etc., in OSS/BSS system has made the architecture very loosely coupled, with greater flexibility. Any change in the external systems would be absorbed at the Integration Layer without affecting the rest of the ecosystem. The use of a Business Process Management (BPM) tool makes the management and maintenance of the business processes easy, with better performance in terms of lead time, quality, and cost. Since the Architecture is based on standards, it will lower the cost of deploying and managing OSS/BSS applications over their lifecycles.

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