Search Results

Search found 1086 results on 44 pages for 'switches'.

Page 9/44 | < Previous Page | 5 6 7 8 9 10 11 12 13 14 15 16  | Next Page >

  • Lot of Multicast traffic on LAN

    - by Nel
    Recently the whole network at work is being hit by multicast traffic originating on the LAN itself. I did some investigating and the service which seems to be responsible is ws-discovery. I have attached a screenshot of wireshark capturing the traffic. I have tried shutting down the source machine from which it was originating, but the multicast traffic still seems to be present in the network. My network topology 2 subnets - 10.10.10.0/24 and 10.20.10.0/24. Gateway is a debian system. We have 3 switches for 3 floors. They are all unmanaged Dlink 24-port switches. Multicast blocking at switch level is out of the question. Any solutions? :(

    Read the article

  • Server-to-Switch Trunking in Procurve switch, what does this mean?

    - by MattUebel
    I am looking to set up switch redundancy in a new datacenter environment. IEEE 802.3ad seems to be the go-to concept on this, at least when paired with a technology that gets around the "single switch" limitation for the link aggregation. Looking through the brochure for a procurve switch I see: Server-to-Switch Distributed Trunking, which allows a server to connect to two switches with one logical trunk; increases resiliency and enables load sharing in virtualized data centers http://www.procurve.com/docs/products/brochures/5400_3500%20Product%20Brochure4AA0-4236ENW.pdf I am trying to figure out how this relates to the 802.3a standard, as it seems that it would give me what I want (one server has 2 nics, each of which is connected to separate switches, together forming a single logical nic which would provide the happy redundancy we want), but I guess I am looking for someone familiar with this concept and could add to it.

    Read the article

  • Does an unmanaged 4/8-port GBit Ethernet switch with a GBIC port exist?

    - by Aaron Digulla
    I'm looking for a simple unmanaged switch with 4-8 GBit Ethernet ports and a fiber port (either as a GBIC slot or pre-installed with a 1000BASE-SX port). Does something like that exist? [EDIT] I want to connect to places in my home without drilling large holes though the floors. Therefore, I'm looking for a cheap way to connect two GBit switches via fiber. I tried with a media converter (GBit <- multimode fiber) but that costs about 50% throughput. So I was hoping that there is a cheap, small GBit switch which has a GBIC slot). All I found so far are very expensive managed switches with 12 or 24 ports for industry use.

    Read the article

  • LAN not picking up gigabit connection through patch panel

    - by user332555
    I have just purchased 2 FVS318G switches to install at my store. How this is set up is the server is in the back room. We have Cat 5E ran up through the ceiling and is patched into a panel in the back room. The 2 switches I just purchased are right next to the server in the back where all the cables patch in. I do a direct connection from the server to switch, avoiding the patch panel completely, and receive 1.0 gbps connection no problem. When i patch in the register computers from the front into the panel and then to the switch I am only getting 100 mbps on the registers up front. The patch panel does say Cat 5E on it but I am not sure if there is any interference in the line somewhere and I cannot get the full 1.0 gbps to the front registers like I want. Any ideas??

    Read the article

  • What equipment do real ISP's use?

    - by Allanrbo
    In a dormitory of 550 residents, people often mistakenly set up DHCP servers for the whole network by plugging in their private Wi-Fi routers wrongly. Also recently, someone mistakenly configured their PC to a static IP being the same as that of the default gateway. We use cheap 3Com switches at the moment. I know that Cisco switches support DHCP snooping to solve the DHCP problem, but that still does not solve the default gateway IP takeover problem. What sort of switch equipment do real ISP's use so their customers cannot break the network for the other customers? What we ended up doing In case anyone are courious, we ended up doing seperate VLANs for each user. And as a matter of fact, not just the 550 users, but for 2500 users (11 dorms). Here's a page describing the setup: http://k-net.dk/technicalsetup/ (the section "Transparent firewall using VLANs"). There was no significant load on the router server as I feared in one of the comments below. Even at 800Mpbs.

    Read the article

  • hung up troubleshooting packet discards

    - by Chris Satola
    I realize my question is generic, but hopefully someone may have some guidance for me. My network consists of Cisco switches. I am seeing a significant amount (upwards of millions of packets per day) transmit drops between two switches. One being a 3750 and the other a 3560. The peak throughput of this link is only upper 400Mbps, so it shouldn't be a bandwidth issue. At this point, I am sort of clueless where to look or what tools I can use to determine what packets are dropping and why. I can setup a SPAN port on that link and wireshark it, but I don't know if that could tell me anything. Does anyone have any suggestions? Thanks in advance.

    Read the article

  • Help with proposed iSCSI SAN VMware implementation.

    - by obsidian
    We have four (with plans to grow to four more) Dell servers with 6 NICs. They are running VMware ESXi 4.1. We would like to connect all of them to an Openfiler iSCSI SAN via HP ProCurve 1810G switches. Based on the design below, is there anything I should be concerned about or anything unusual that I should look out for when making the iSCSI network configurations on the servers, switches and OpenFiler? Should I bond the connections on the servers or simply setup them up for failover? The primary goal is to maximize IOPS. Thanks in advance.

    Read the article

  • How can I set up VLANs in a way that won't put me at risk for VLAN hopping?

    - by hobodave
    We're planning to migrate our production network from a VLAN-less configuration to a tagged VLAN (802.1q) configuration. This diagram summarizes the planned configuration: One significant detail is that a large portion of these hosts will actually be VMs on a single bare-metal machine. In fact, the only physical machines will be DB01, DB02, the firewalls and the switches. All other machines will be virtualized on a single host. One concern that has been is that this approach is complicated (overcomplicated implied), and that the VLANs are only providing an illusion of security, because "VLAN hopping is easy". Is this a valid concern, given that multiple VLANs will be used for a single physical switch port due to virtualization? How would I setup my VLANs appropriately to prevent this risk? Also, I've heard that VMWare ESX has something called "virtual switches". Is this unique to the VMWare hypervisor? If not, is it available with KVM (my planned hypervisor of choice)?. How does that come into play?

    Read the article

  • Converge Voice and Data networks using Sonicwall

    - by skinneejoe
    We are looking to converge VOIP and Data traffic onto a single wire so that our client's VOIP phones pass data through to the users computer. We are specing out a new Sonicwall NSA appliance to handle routing functions and layer 2 switches to manage VLANS. Not a huge network, medium sized. What should I know about converging the networks onto a single wire? Obviously I'll want to prioritize voice traffic, is this handled solely in the Sonicwall with QoS configurations or do the layer 2 switches need to be configured differently? Any other pitfalls I should be aware of, or any good resources for learning more?

    Read the article

  • Should I limit end-user gigabit ports to avoid saturating uplink/trunk connections?

    - by Joel Coel
    We have a campus with 16 buildings and older 850nm 1Gbps fiber links between the buildings, that all come to a core switch for our servers that also uses 1Gbps ports. We're finally starting to replace our aging 10/100 end-user switches, and much of what we're looking at are 1 Gbps units. My question is, since the trunk/uplink lines are still 1Gbps, if I were to install 1 Gbps switches for end users, should I limit the ports to 100Mbps until I can also upgrade the trunks to avoid allowing a bad-behaving host to saturate a trunk line (since we're a college, we have plenty of mis-behaving hosts) and thereby create a DoS situation for a building, or will TCP congestion control typically take care of that for me? What if we have a lot of UDP traffic (games, video chats, even a small amount of bittorrent)?

    Read the article

  • Are VLANs necessary for my environment?

    - by kleefaj
    Greetings. I'm the new network manager for a school. I've inherited an environment made up of several Windows servers, about 100 Windows clients, ten printers, one Cisco router, six Cisco switches, and 1 HP switch. Also, we're using VoIP. There are four floors in our building. The hosts on each floor are assigned to a separate VLAN. An office on the first floor has its own VLAN. All the switches are on their own VLAN. The IP phones are on their own VLAN. And the servers are on their own VLAN. For the number of hosts on the network, are all these VLANs really buying me anything? I'm new to the VLAN concept but it seems overly complicated for this environment. Or it's genius and I just don't get it. Any thoughts? Thanks, Jeff

    Read the article

  • What could be the maximum number of hosts on a 100BaseTX ethernet network ?

    - by snowflake
    Hello, I'm having two ip networks (192.168.1.x and 192.168.2.x) bridged on a server, but all hosts (fixed IPs) are on the same physical 100BaseTX ethernet (with a daisy chain of 48ports switchs). Often, I loose link between the server and hosts of the second network. Usually if I reboot the host, the connection work again, and if I force connection to be active, the connection keep alive until I ping after a while without active connection. I'm wondering how many hosts can be connected on the same network without troubles, and eventually how many switches can be daisy chained ? I suppose maximum length between hosts to be 100meters to the hub or 200meters between extremity of the network. Somebody is suggesting 8 switches here : http://www.tek-tips.com/viewthread.cfm?qid=1137879&page=12 Any comments on how to find a solution to the problem and not answering directly to the question are welcomed!

    Read the article

  • Multicasting Windows 7 Image

    - by LawnChairSkank
    I am trying to deploy some new machines with windows 7 for the first time in our computer labs. We used to use third party imaging software and then run sysprep after the image was copied(XP), but it seems you can't go that route with windows 7. We set up a new imaging server with the windows system image manager, but when we try to multicast the image it pretty much takes down our whole staff and faculty network. I heard you can turn on a multicast feature on our cisco switches to help with the issue, but that it also slows the switches to a crawl. Another idea we have tried was pulling the the computer lab switch off the main network and plugging the imaging server directly into the computer lab switch so the multicast doesn't take down our network, but it doesn't seem to work without being able to hit a domain controller. Is there a way to multicast without taking out the network? I feel like I am missing something... Thanks in advance

    Read the article

  • How to troubleshoot slow powerconnect 62xx management interface

    - by Hannes
    Our Dell Powerconnect 62xx switches have a very high packetloss on the management interface. I presume this is caused by a new appliance which uses multicast for communication but I am not sure. Our network setup is following: servers a - Dell PC6248 | servers b - Dell PC6248 |- juniper core router servers c - Dell PC6248 | What we see is that the multicast traffic arrives at all servers (but only the servers b use the multicast) and I fear that this multicast traffic floods the switch management interface. The switches' management interfaces are reachable via vlan101, all other traffic is sent over other vlans. When I tcpdump on one of the 2 servers with a vlan 101 ip address, I only get a few arp requests but almost nothing. When I try to ping between these 2 servers, it works like a charm. I would like to know what a good way is to troubleshoot this problem and maybe help me understand what is going wrong on that subnet.

    Read the article

  • Set 802.1Q tagged port on VLAN1 on Dell PowerConnect switch

    - by Javier
    I'm having big troubles when adding this Dell switch to my network. Here we use several VLANs to segment traffic. All switches (3com and DLink mostly) have configured the same VLANs, most ports are 'untagged' and belong to a single VLAN, except for the ports used to join together the switches (in a star topology), these ports belong to all VLANs and use 802.1Q tags. So far, it works really well. But on this new switch (a Dell PowerConnect 5448), the settings are very different (and confusing). I have configured the same VLANs, an the uplink ports are set in 'general' mode (supposed to be fully 802.1Q compliant), I can set the VLAN membership as 'T' on these ports for all VLANs except VLAN 1. It always stay as 'U' on VLAN 1. Any ideas?

    Read the article

  • Encryption over gigabit carrier ethernet

    - by Roy
    I would like to encrypt traffic between two data centres. Communication between the sites is provided as a standard provider bridge (s-vlan/802.1ad), so that our local vlan tags (c-vlan/802.1q) are preserved on the trunk. The communication traverse several layer 2 hops in the provider network. Border switches on both sides are Catalyst 3750-X with the MACSec service module, but I assume MACSec is out of the question, as I don't see any way to ensure L2 equality between the switches over a trunk, although it may be possible over a provider bridge. MPLS (using EoMPLS) would certainly allow this option, but is not available in this case. Either way, equipment can always be replaced to accommodate technology and topology choices. How do I go about finding viable technology options that can provide layer 2 point-to-point encryption over ethernet carrier networks?

    Read the article

  • How much does a IPtables router slow down a connection?

    - by RayQuang
    Hi, I would like to know if introducing a new gateway in my network will slow things down. The question may sound unclear but here is an illustration: Before Installing gateway server Main Router <=> switches <=> servers after installing gateway Server Main Router <=> IPtables router <=> switches <=> servers My question is. How much will this delay incoming outgoing requests / file transfers. thanks, RayQuang

    Read the article

  • Cisco: changing VTP mode server/client to transparent

    - by J. Smith
    I have around 40 L2 switches (2960, 3560, 3500, 3750) running in VTP client mode and one L3 switch (6500) running in VTP server mode, all connected together. I would like to switch everything in VTP transparent mode without any interruption of service. I've already test on a poc version with 3 switches (Catalyst 2950, 3560 and 3750). Using serial and SSH connection, it is seems working but i'm not sure it is enough representative compare to the real network. Knowing that the VTP Pruning is enabled, I am wondering what would be the best procedure to proceed the changement. I've read that we could lost connection by keeping it enabled. Should I change the server or clients first? Is it important to change the VTP domain and VTP Pruning parameters?

    Read the article

  • netgear GS108TV2 RSTP configuration

    - by jhowland
    I have a large set of GS108TV2 units--my goal is to set up a network which is comprised of several loops for redundancy/fault tolerance. I have a minimal 3 switch loop configured, with RSTP enabled on two ports on each switch. I have my bridge max age set to 6, and my bridge forward delay set to 4, which are the minimum values allowed. Hello time is fixed at 2 seconds. The switches respond to a cable being removed from a socket, but it takes too long. I cannot get the switch to respond to a loss of connection on one of the redundant ports in less than 20 seconds. Is there any way to configure these switches to respond faster than 20 seconds? That is unacceptable for my application. thanks in advance for any help

    Read the article

  • Boot.ini on Windows Server 2003 R2

    - by Jason H.
    I have a Windows Server 2003 R2 with 48 GB of RAM; server has been running strong for quite some time. Recently our boot.ini was modified causing issues, most likely by our remote administrators. Now the server is only showing 14 GB of RAM. This has caused major performance issues for our end users. Our remote administrators have stated "we don't change the boot.ini settings(switches)". However, I know for a fact that all of the local administrators have not modified the switches (due to lack of permissions). The real question.. Is it possible to "audit" who has modified the boot.ini? If thats not possible, can the boot.ini be set via startup? Any help would be greatly appreciated. This is an ongoing issue that I would love to resolve.

    Read the article

  • Unexpected advantage of Engineered Systems

    - by user12244672
    It's not surprising that Engineered Systems accelerate the debugging and resolution of customer issues. But what has surprised me is just how much faster issue resolution is with Engineered Systems such as SPARC SuperCluster. These are powerful, complex, systems used by customers wanting extreme database performance, app performance, and cost saving server consolidation. A SPARC SuperCluster consists or 2 or 4 powerful T4-4 compute nodes, 3 or 6 extreme performance Exadata Storage Cells, a ZFS Storage Appliance 7320 for general purpose storage, and ultra fast Infiniband switches.  Each with its own firmware. It runs Solaris 11, Solaris 10, 11gR2, LDoms virtualization, and Zones virtualization on the T4-4 compute nodes, a modified version of Solaris 11 in the ZFS Storage Appliance, a modified and highly tuned version of Oracle Linux running Exadata software on the Storage Cells, another Linux derivative in the Infiniband switches, etc. It has an Infiniband data network between the components, a 10Gb data network to the outside world, and a 1Gb management network. And customers can run whatever middleware and apps they want on it, clustered in whatever way they want. In one word, powerful.  In another, complex. The system is highly Engineered.  But it's designed to run general purpose applications. That is, the physical components, configuration, cabling, virtualization technologies, switches, firmware, Operating System versions, network protocols, tunables, etc. are all preset for optimum performance and robustness. That improves the customer experience as what the customer runs leverages our technical know-how and best practices and is what we've tested intensely within Oracle. It should also make debugging easier by fixing a large number of variables which would otherwise be in play if a customer or Systems Integrator had assembled such a complex system themselves from the constituent components.  For example, there's myriad network protocols which could be used with Infiniband.  Myriad ways the components could be interconnected, myriad tunable settings, etc. But what has really surprised me - and I've been working in this area for 15 years now - is just how much easier and faster Engineered Systems have made debugging and issue resolution. All those error opportunities for sub-optimal cabling, unusual network protocols, sub-optimal deployment of virtualization technologies, issues with 3rd party storage, issues with 3rd party multi-pathing products, etc., are simply taken out of the equation. All those error opportunities for making an issue unique to a particular set-up, the "why aren't we seeing this on any other system ?" type questions, the doubts, just go away when we or a customer discover an issue on an Engineered System. It enables a really honed response, getting to the root cause much, much faster than would otherwise be the case. Here's a couple of examples from the last month, one found in-house by my team, one found by a customer: Example 1: We found a node eviction issue running 11gR2 with Solaris 11 SRU 12 under extreme load on what we call our ExaLego test system (mimics an Exadata / SuperCluster 11gR2 Exadata Storage Cell set-up).  We quickly established that an enhancement in SRU12 enabled an 11gR2 process to query Infiniband's Subnet Manager, replacing a fallback mechanism it had used previously.  Under abnormally heavy load, the query could return results which were misinterpreted resulting in node eviction.  In several daily joint debugging sessions between the Solaris, Infiniband, and 11gR2 teams, the issue was fully root caused, evaluated, and a fix agreed upon.  That fix went back into all Solaris releases the following Monday.  From initial issue discovery to the fix being put back into all Solaris releases was just 10 days. Example 2: A customer reported sporadic performance degradation.  The reasons were unclear and the information sparse.  The SPARC SuperCluster Engineered Systems support teams which comprises both SPARC/Solaris and Database/Exadata experts worked to root cause the issue.  A number of contributing factors were discovered, including tunable parameters.  An intense collaborative investigation between the engineering teams identified the root cause to a CPU bound networking thread which was being starved of CPU cycles under extreme load.  Workarounds were identified.  Modifications have been put back into 11gR2 to alleviate the issue and a development project already underway within Solaris has been sped up to provide the final resolution on the Solaris side.  The fixed SPARC SuperCluster configuration greatly aided issue reproduction and dramatically sped up root cause analysis, allowing the correct workarounds and fixes to be identified, prioritized, and implemented.  The customer is now extremely happy with performance and robustness.  Since the configuration is common to other customers, the lessons learned are being proactively rolled out to other customers and incorporated into the installation procedures for future customers.  This effectively acts as a turbo-boost to performance and reliability for all SPARC SuperCluster customers.  If this had occurred in a "home grown" system of this complexity, I expect it would have taken at least 6 months to get to the bottom of the issue.  But because it was an Engineered System, known, understood, and qualified by both the Solaris and Database teams, we were able to collaborate closely to identify cause and effect and expedite a solution for the customer.  That is a key advantage of Engineered Systems which should not be underestimated.  Indeed, the initial issue mitigation on the Database side followed by final fix on the Solaris side, highlights the high degree of collaboration and excellent teamwork between the Oracle engineering teams.  It's a compelling advantage of the integrated Oracle Red Stack in general and Engineered Systems in particular.

    Read the article

  • Using Ribbon as tab control

    - by zendar
    I would like to create application with ribbon interface that looks and behaves like this: application have one main form with ribbon ribbon has multiple tabs when user switches tab on ribbon, panel below ribbon changes and displays content related to ribbon panel. That way, ribbon tab acts as if it is tab over whole window. For example, ribbon have two tabs: people and tasks. When current ribbon panel is "people", below ribbon is displayed grid with people data. Ribbon contains command for manipulating people data. When user switches to "tasks" tab on ribbon, application should display form with tasks below ribbon. Question is can ribbon be used in this scenario? I read "OFFICE FLUENT™ USER INTERFACE DESIGN GUIDELINES" that describe what you can and cannot do with ribbon, but I could not find anything about this.

    Read the article

  • Tomcat JNDI Connection Pool docs - Random Connection Closed Exceptions

    - by Andy Faibishenko
    I found this in the Tomcat documentation here What I don't understand is why they close all the JDBC objects twice - once in the try{} block and once in the finally{} block. Why not just close them once in the finally{} clause? This is the relevant docs: Random Connection Closed Exceptions These can occur when one request gets a db connection from the connection pool and closes it twice. When using a connection pool, closing the connection just returns it to the pool for reuse by another request, it doesn't close the connection. And Tomcat uses multiple threads to handle concurrent requests. Here is an example of the sequence of events which could cause this error in Tomcat: Request 1 running in Thread 1 gets a db connection. Request 1 closes the db connection. The JVM switches the running thread to Thread 2 Request 2 running in Thread 2 gets a db connection (the same db connection just closed by Request 1). The JVM switches the running thread back to Thread 1 Request 1 closes the db connection a second time in a finally block. The JVM switches the running thread back to Thread 2 Request 2 Thread 2 tries to use the db connection but fails because Request 1 closed it. Here is an example of properly written code to use a db connection obtained from a connection pool: Connection conn = null; Statement stmt = null; // Or PreparedStatement if needed ResultSet rs = null; try { conn = ... get connection from connection pool ... stmt = conn.createStatement("select ..."); rs = stmt.executeQuery(); ... iterate through the result set ... rs.close(); rs = null; stmt.close(); stmt = null; conn.close(); // Return to connection pool conn = null; // Make sure we don't close it twice } catch (SQLException e) { ... deal with errors ... } finally { // Always make sure result sets and statements are closed, // and the connection is returned to the pool if (rs != null) { try { rs.close(); } catch (SQLException e) { ; } rs = null; } if (stmt != null) { try { stmt.close(); } catch (SQLException e) { ; } stmt = null; } if (conn != null) { try { conn.close(); } catch (SQLException e) { ; } conn = null; } }

    Read the article

  • Untar, ungz, gz, tar - how do you remember all the useful options?

    - by deadprogrammer
    I am pretty sure I am not the only one with the following problem: every time I need to uncompress a file in *nix I can't remember all the switches, and end up googling it, which is surprizing considering how often I need to do this. Do you have a good compression cheat sheet? Or how about a mnemonic for all those nasty switches in tar? I am making this article a wiki so that we can create a nice cheat sheet here. Oh, and about man pages: is there's one thing they are not helpful for, it's for figuring out how to uncompress a file.

    Read the article

  • What's the best way to implement one-dimensional collision detection?

    - by cyclotis04
    I'm writing a piece of simulation software, and need an efficient way to test for collisions along a line. The simulation is of a train crossing several switches on a track. When a wheel comes within N inches of the switch, the switch turns on, then turns off when the wheel leaves. Since all wheels are the same size, and all switches are the same size, I can represent them as a single coordinate X along the track. Switch distances and wheel distances don't change in relation to each other, once set. This is a fairly trivial problem when done through brute force by placing the X coordinates in lists, and traversing them, but I need a way to do so efficiently, because it needs to be extremely accurate, even when the train is moving at high speeds. There's a ton of tutorials on 2D collision detection, but I'm not sure the best way to go about this unique 1D scenario.

    Read the article

< Previous Page | 5 6 7 8 9 10 11 12 13 14 15 16  | Next Page >