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  • Attend free workshop on 3/16: Architecture Analysis Patterns

    On Tuesday, 3/16/2010, Headspring is offering another free monthly workshop.  This month, I am leading the workshop, and the topic is: Architecture Analysis Patterns: How to reason about the structure of an application Layering, a fundamental concept of software architecture: Layer helps to separate dependencies and to decouple concerns. Most of the industry does layering in name only. It's lip service. In 23 slides and accompanying commentary, we will explore the fundamental concept of separating...Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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  • A brief introduction to BRM and architecture

    - by Yani Miguel
    Oracle Communications Billing and Revenue Management (Oracle BRM) is the telcos industry´s leading solution intended for communications service providers. This post encourages to know BRM starting with the basics. History Portal was a billing and revenue managament solution to communications industry created by Portal Software. In 2006 Oracle acquired Portal Software and the solution was renamed BRM. Today Oracle BRM is the first end-to-end packaged enterprise software suite for the communications industry, however BRM is just one more product in the catalog of OSS solutions that Oracle offers. BRM can bill and manage all communications services including wireline, wireless, broadband, cable, voice over IP, IPTV, music, and video. BRM Architecture BRM´s architecture consists of 4 layers or tiers. Through these layers are the data, bussines logic and interfaces to connect graphical client tools.Application tier This layer provides GUI client tools enabling communication to other layers through open APIs. Some BRM client applications are: Customer Center Pricing Center Universal Event Loader Web Server BRM Billing Application Collections Center Permissioning Center Furthermore, this layer is where are provided real-time external events. Bussines Process Tier Although all layers are equally important, I think it deserves more atention because in this tier BRM functionality is implemented. All functions that give life to BRM are in this layer coded in C language called Opcodes (System Processes in the image). Any changes or additional functionality should be made here, so when we try to customize the product, we will most of the time programming in this layer (Business Policies in the image).Bussines Process Tier Features: Implements Portal system functionalityValidates data from the application tierModifies Portal behavior through business policies. Business policies can by customized.Triggers external systems using event notification. Object Tier This layer is responsible for transfer the BRM requests into database language and translate BRM requests into external system requests. Without it, the business logic (data from Bussines Process Tier) could not be understood by the relational database. Data tier Data tier is responsable for the storage of BRM database and other external systems databases. External systems include credit card, tax, and directory servers. Finally, It's important to note that BRM is designed to easily integrate with the following solutions:AIA 2.4 Siebel CRM E-Business Suite - G/L onlyCommunications Services Gatekeeper Oracle BI Publisher. Personally, I think that BRM could improve migrating client-server architecture to a fully web platform that works with Oracle Middleware like any product of the Fusion Middleware family. Hopefully there are already initiatives in this area.

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  • Webcast: Applications Integration Architecture

    - by LuciaC
    Webcast: Applications Integration Architecture - Overview and Best Practices Date:  November 12, 2013.Join us for an Overview and Best Practices live webcast on Applications Integration Architecture (AIA). We are covering following topics in this Webcast : AIA Overview AIA - Where it Stands Pre-Install, Pre-Upgrade Concerns Understanding Dependency Certification Matrix Documentation Information Center Demonstration - How to evaluate certified combination Software Download/Installable Demonstration - edelivery Download Overview Reference Information Q & A (15 Minutes)  We will be holding 2 separate sessions to accommodate different timezones: EMEA / APAC - timezone Session : Tuesday, 12-NOV-2013 at 09:00 UK / 10:00 CET / 14:30 India / 18:00 Japan / 20:00 AEDT Details & Registration : Doc ID 1590146.1 Direct registration link USA - timezone Session : Wednesday, 13-NOV-2013 at 18:00 UK / 19:00 CET / 10:00 PST / 11:00 MST / 13:00 EST Details & Registration : Doc ID 1590147.1 Direct registration link If you have any question about the schedules or if you have a suggestion for an Advisor Webcast to be planned in future, please send an E-Mail to Ruediger Ziegler. Remember that you can access a full listing of all future webcasts as well as replays from Doc ID 740966.1.

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  • Hybrid IT or Cloud Initiative – a Perfect Enterprise Architecture Maturation Opportunity

    - by Ted McLaughlan
    Normal 0 false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin-top:0in; mso-para-margin-right:0in; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0in; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} All too often in the growth and maturation of Enterprise Architecture initiatives, the effort stalls or is delayed due to lack of “applied traction”. By this, I mean the EA activities - whether targeted towards compliance, risk mitigation or value opportunity propositions – may not be attached to measurable, active, visible projects that could advance and prove the value of EA. EA doesn’t work by itself, in a vacuum, without collaborative engagement and a means of proving usefulness. A critical vehicle to this proof is successful orchestration and use of assets and investment resources to meet a high-profile business objective – i.e. a successful project. More and more organizations are now exploring and considering some degree of IT outsourcing, buying and using external services and solutions to deliver their IT and business requirements – vs. building and operating in-house, in their own data centers. The rapid growth and success of “Cloud” services makes some decisions easier and some IT projects more successful, while dramatically lowering IT risks and enabling rapid growth. This is particularly true for “Software as a Service” (SaaS) applications, which essentially are complete web applications hosted and delivered over the Internet. Whether SaaS solutions – or any kind of cloud solution - are actually, ultimately the most cost-effective approach truly depends on the organization’s business and IT investment strategy. This leads us to Enterprise Architecture, the connectivity between business strategy and investment objectives, and the capabilities purchased or created to meet them. If an EA framework already exists, the approach to selecting a cloud-based solution and integrating it with internal IT systems (i.e. a “Hybrid IT” solution) is well-served by leveraging EA methods. If an EA framework doesn’t exist, or is simply not mature enough to address complex, integrated IT objectives – a hybrid IT/cloud initiative is the perfect project to advance and prove the value of EA. Why is this? For starters, the success of any complex IT integration project - spanning multiple systems, contracts and organizations, public and private – depends on active collaboration and coordination among the project stakeholders. For a hybrid IT initiative, inclusive of one or more cloud services providers, the IT services, business workflow and data governance challenges alone can be extremely complex, requiring many diverse layers of organizational expertise and authority. Establishing subject matter expertise, authorities and strategic guidance across all the disciplines involved in a hybrid-IT or hybrid-cloud system requires top-level, comprehensive experience and collaborative leadership. Tools and practices reflecting industry expertise and EA alignment can also be very helpful – such as Oracle’s “Cloud Candidate Selection Tool”. Using tools like this, and facilitating this critical collaboration by leading, organizing and coordinating the input and expertise into a shared, referenceable, reusable set of authority models and practices – this is where EA shines, and where Enterprise Architects can be most valuable. The “enterprise”, in this case, becomes something greater than the core organization – it includes internal systems, public cloud services, 3rd-party IT platforms and datacenters, distributed users and devices; a whole greater than the sum of its parts. Through facilitated project collaboration, leading to identification or creation of solid governance models and processes, a durable and useful Enterprise Architecture framework will usually emerge by itself, if not actually identified and managed as such. The transition from planning collaboration to actual coordination, where the program plan, schedule and resources become synchronized and aligned to other investments in the organization portfolio, is where EA methods and artifacts appear and become most useful. The actual scope and use of these artifacts, in the context of this project, can then set the stage for the most desirable, helpful and pragmatic form of the now-maturing EA framework and community of practice. Considering or starting a hybrid-IT or hybrid-cloud initiative? Running into some complex relationship challenges? This is the perfect time to take advantage of your new, growing or possibly latent Enterprise Architecture practice.

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  • Unable to install Steam 64bit - Wrong architecture (Lubuntu 12.04)

    - by Ian
    I'm on a new install of Lubuntu 12.04 on an Acer Aspire 5534 (specifications here, tl;dr: AMD dual-core 64bit) trying to install steam_latest.deb from the Steam website. When I open gdebi to install, it tells me that it's uninstallable because it's for a i386 architecture. I've tried installing ia32-libs (installed, no success), gdebi --add-architecture i386 (with and without --force, command unknown). This is all I've found to fix the problem, but none of it has worked for me. Any suggestions are welcome, thanks for your time.

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  • SPAMMED Architecture Framework (SAF)

    I am working on moving my blog to wordpress and as part of the effort I am cleaning up and rearranging some of my older posts. Since my readership has increased substantially compared with the time I started blogging I think some of them are worth republishing. I think that the series on SPAMMED, my software architecture meta-framework falls under the category. Overview There is very little guidance on how one can go about designing/developing an architecture for a software project. The SPAMMED...Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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  • Want to develop my own primitive physics engine, don't know how to start with it's high-level architecture. Suggestions?

    - by Violet Giraffe
    Few years ago I tried to make a simple 3D game - billiards. Completed like 50%, stuck with physics. Basically, I only need to calculate balls rolling over flat surface, but it would be nice to make something more flexible. I know all the formulas and laws (most of them, anyway). the problem is I have no idea of how to make good physics engine architecture-wise. I tried google and other forums but didn't find what I was looking for. The only suggestion was to look at open-source engine, but I'm not that good a programmer to make heads or tails out of it...

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  • Designing a system with different business rules for different customers

    - by user1595846
    My company is rewriting our proprietary business application. The current architecture is poorly done and inflexible. It is coded more procedural oriented as opposed to object oriented. It has become difficult to maintain. Our system is a web application written in .Net Webforms. I am considering ASP.Net MVC for the rewrite. We intend to rewrite it with a good, solid architecture with the goal of maintainability and reusable classes for some of our other systems and services. We would also like the system to be customizable for different customers in the event that we market the system. I am considering redesigning the system based on the layered architecture (Presentation, Business, Data Access layers) described in the Microsoft Patterns and Practices Application Architecture Guide. http://msdn.microsoft.com/en-us/library/ff650706.aspx Hopefully this isn't too open ended, but how would you recommend allowing for different business logic/rules for different customers? I'm aware of Windows Workflow Foundation, but from what I've read about it, it seems many business rules could be too complicated to handle there. Also, Can anyone point me to where I can download an example of a .net solution that is based on the Application Architecture Guide? I have already downloaded the Layered Architecture Solution Guidance and the Expense Sample on codeplex. I was looking for something a bit larger and more robust that I could step through the code and see how it works. If you feel there are better architectures to base our redesign on please feel free to share. I appreciate your help!

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  • gtksourceview-sharp help

    - by mail_321
    Is there any quick tutorial on the net on how to get started with using gtksourceview-sharp? I have gtksourceview-sharp.dll but I can't get it to work, even when I have the libgtksourceview-1.0-0.dll in the same directory with it... Thanks!

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  • Why do we need different CPU architecture for server & mini/mainframe & mixed-core?

    - by claws
    Hello, I was just wondering what other CPU architectures are available other than INTEL & AMD. So, found List of CPU architectures on Wikipedia. It categorizes notable CPU architectures into following categories. Embedded CPU architectures Microcomputer CPU architectures Workstation/Server CPU architectures Mini/Mainframe CPU architectures Mixed core CPU architectures I was analyzing the purposes and have few doubts. I taking Microcomputer CPU (PC) architecture as reference and comparing others. Embedded CPU architecture: They are a completely new world. Embedded systems are small & do very specific task mostly real time & low power consuming so we do not need so many & such wide registers available in a microcomputer CPU (typical PC). In other words we do need a new small & tiny architecture. Hence new architecture & new instruction RISC. The above point also clarifies why do we need a separate operating system (RTOS). Workstation/Server CPU architectures I don't know what is a workstation. Someone clarify regarding the workstation. As of the server. It is dedicated to run a specific software (server software like httpd, mysql etc.). Even if other processes run we need to give server process priority therefore there is a need for new scheduling scheme and thus we need operating system different than general purpose one. If you have any more points for the need of server OS please mention. But I don't get why do we need a new CPU Architecture. Why cant Microcomputer CPU architecture do the job. Can someone please clarify? Mini/Mainframe CPU architectures Again I don't know what are these & what miniframes or mainframes used for? I just know they are very big and occupy complete floor. But I never read about some real world problems they are trying to solve. If any one working on one of these. Share your knowledge. Can some one clarify its purpose & why is it that microcomputer CPU archicture not suitable for it? Is there a new kind of operating system for this too? Why? Mixed core CPU architectures Never heard of these. If possible please keep your answer in this format: XYZ CPU architectures Purpose of XYZ Need for a new architecture. why can't current microcomputer CPU architecture work? They go upto 3GHZ & have upto 8 cores. Need for a new Operating System Why do we need a new kind of operating system for this kind of archictures?

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  • xcode 5.1: libCordova.a architecture problems

    - by inorganik
    Yesterday (3/10/14) when iOS 7.1 was released I also upgraded to Xcode 5.1 and found that my PhoneGap/Cordova project would no longer compile to my iPhone 5s. I also upgraded Cordova to the most recent release: v 3.4.0-0.1.3. I have read many different solutions on SO that relate so changing active architectures and building only active architectures, and none of them work. So here's what I've tried and the errors I get. Initially I got the error: missing required architecture arm64 in file <long file path omitted> libCordova.a Undefined symbols for architecture arm64 So I tried the following. I selected the CordovaLib sub-project in my project, and in both the project and target, I went to Build Settings under Architectures and made sure that arm64 was not included in any of the Debug or Release architectures. At this time Build Active Architecture Only is set to "Yes". That resulted in the following error: file was built for archive which is not the architecture being linked (armv7): <long file path omitted> libCordova.a Undefined symbols for architecture armv7 Setting Build Active Architecture Only to "No", the error again becomes: missing required architecture arm64 in file <long file path omitted> libCordova.a Undefined symbols for architecture arm64 I'm not sure what else to try. The project's architecture settings only includes the key "Base SDK" which is set to iOS 7.1. The project's target does not have architectures settings. Anyway I'm fairly certain the problem lies with the embedded CordovaLib sub-project. What can I do to make this thing compile to my device successfully? Update: same issue on Apache's Jira: https://issues.apache.org/jira/browse/CB-6223

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  • 3-Tier Architecture in asp.net

    - by Aamir Hasan
    Three-tier (layer) is a client-server architecture in which the user interface, business process (business rules) and data storage and data access are developed and maintained as independent modules or most often on separate platforms. Basically, there are 3 layers, tier 1 (presentation tier, GUI tier), tier 2 (business objects, business logic tier) and tier 3 (data access tier). These tiers can be developed and tested separately. 3 - Tier Architecture is like following : 1. Presentation Layer 2.Data Manager Layer 3. Data Access Layer  The communication between all these layers need to be done using Business Entities. 1. Presentation Layer is the one where the UI comes into picture 2. Data Manager Layer is the one where all the maipulative code is written. Basically in this layer all the functional code needs to mentioned. 3. Data Access Layer is the one which communicates directly to the database. Data from one layer to other needs to be tranformed using Entities.

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  • Oracle Technology Network Virtual Developer Day: Service Oriented Architecture (SOA)

    - by programmarketingOTN
    Register now! Oracle Technology Network Virtual Developer Day: Service Oriented Architecture (SOA) - Discover the Power of Oracle SOA Suite 11gTuesday July 12, 2011 - ?9:00 a.m. PT – 1:30 p.m. PT / 12 Noon EDT - 4:30 p.m. EDTOTN is proud to host another Virtual Developer Day, this time focusing on SOA (click here to check out on-demand version of Rich Enterprise Applications and WebLogic)  Save yourself/company some money and join us online for this hands-on virtual workshop. Through developer-focused product presentations and demonstrations delivered by Oracle product and technology experts, there is no faster or more efficient way to jumpstart your Oracle SOA suite learning.Over the course of the Virtual Developer Day, you will learn how an SOA approach can be implemented, whether starting fresh with new services or reusing existing services. Using Oracle SOA Suite 11g components, you will explore, modify, execute, and monitor an SOA composite application. Topics include SCA, BPEL process execution, adapters, business rules and more.Java and WebLogic experience not required for the presentations or demonstrations but it is a plus for the hands-on lab.Come to this event if you are    •    Exploring ways to deliver services faster    •    Integrating packaged and/or legacy applications    •    Developing service orchestration    •    Planning or starting new development projectsRegister online now for this FREE event.AGENDA - Tuesday July 12, 2011?9:00 a.m. PT – 1:30 p.m. PT / 12 Noon EDT - 4:30 p.m. PT EDT  Time  Title  9:00 AM Keynote  9:15 AM Presentation 1 Service Oriented Architecture (SOA) Overview  9:45 AM Demonstration 1 Mediator and Adapters  10:15 AM Presentation 2 BPEL Service Orchestration and Business Rules  10:45 AM Demonstration 2 BPEL Service Orchestration  11:15 AM Demonstration 3 Oracle Business Rules  11:45 AM Hands-on Lab time  1:30 PM Close Register online now for this FREE event.

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  • Alternatives to Component Based Architecture?

    - by Ben Lakey
    Usually when I develop a game I will use an architecture like what you see below. What other architectures are popular for simple game development? I'm concerned about having a narrow view of what exists out there for architectures beyond this. Is this an example of component-based architecture? Or is this something else? What would that look like? What alternatives exist? public abstract class ComponentBase { protected final Collection<ComponentBase> subComponents = new LinkedList<ComponentBase>(); private boolean enableInput; private boolean isVisible; protected ComponentBase(boolean enableInput, boolean isVisible) { this.enableInput = enableInput; this.isVisible = isVisible; } public void render(Graphics2D graphics) { for(ComponentBase gameComponent : this.subComponents) { if(gameComponent.isVisible()) { gameComponent.render(graphics); } } } public void input(InputData input) { for(ComponentBase gameComponent : this.subComponents) { if(gameComponent.inputIsEnabled()) { gameComponent.input(input); } } } ... getters/setters ... public void update(long elapsedTimeMillis) { for(ComponentBase gameComponent : this.subComponents) { gameComponent.update(elapsedTimeMillis); } } }

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  • Visual Studio 2010 Modeling and Architecture Tools

    - by MikeParks
    Jennifer Marsman (Microsoft Evangelist) and Cameron Skinner (Microsoft Visual Studio Product Unit Manager) recently stopped by our office while they were passing through Louisville on their tour to give us a presentation on the new Visual Studio 2010 Modeling and Architecture Tools. I checked out these new features when Visual Studio 2010 Beta versions originally rolled out and have been really impressed with this stuff ever since then. So it was pretty cool to actually learn some new techniques from Cameron himself since he helped write the actual code behind some of those features. If you've upgraded to Visual Studio 2010 recently I would highly recommend using the Architecture tools. They're awesome. If you want to make improvements to it, they even have their own SDK for it. There are plenty of blogs out there to show you how to use it. I've been waiting to find a tool that works like this where I can really analyze the code in solutions and projects and see how everything ties together. It's really handy if you're asked to work on a new project and aren't familiar with how it works. Just run the tools, analyze the DLL's, learn how everything works, and then you'll be ready to implement new code! It's a great tool to learn new systems quick and easy and it's all housed within the Visual Studio IDE. I just wanted to write a blog to brag about it a little bit, so I figured I'd throw this up here. It's a must have tool for Developers/Architects. Here's some screenshots of when I was using it earlier:   Thanks everyone! - Mike

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  • The Increasing Focus on Architecture

    - by Bob Rhubart
    If you follow my updates on Twitter or on the OTN ArchBeat page on Facebook you have probably noticed that I'm a regular reader of Joe McKendrick's SOA blog on ZDNet. Usually I'm content to simply share a link on my social networks when I find one of McKendrick's posts interesting. But with a recent post, In the cloud era, let's start calling IT what it is: 'Innovation Team', McKendrick hit on a point that warrants more than a quick link: "IT is no longer just a department full of people who code, build and maintain systems. IT is the business partner that plans and strategizes what types of technology solutions the business needs to move forward." Of course, what McKendrick is describing is an increased focus on architecture. Assuming that McKendrick's assessment is correct — and I do — that expanding focus, from coding, building, and maintaining systems to planning and strategizing technology solutions that serve the business, isn't limited to the organizational level. The individual roles within the IT organization will also have to shift to a more broadly architectural mindset. McKendrick's post references Dr. Irving Wladawsky-Berger's assessment of cloud computing as a critical "third model" of computing to emerge in the 50-year history of Information Technology. As computing itself evolves, the underlying roles that make computing possible must evolve accordingly. That evolution will be defined by an increased focus on architecture.

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  • Diving into OpenStack Network Architecture - Part 1

    - by Ronen Kofman
    v\:* {behavior:url(#default#VML);} o\:* {behavior:url(#default#VML);} w\:* {behavior:url(#default#VML);} .shape {behavior:url(#default#VML);} rkofman Normal rkofman 83 3045 2014-05-23T21:11:00Z 2014-05-27T06:58:00Z 3 1883 10739 Oracle Corporation 89 25 12597 12.00 140 Clean Clean false false false false EN-US X-NONE HE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin-top:0in; mso-para-margin-right:0in; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0in; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:Arial; mso-bidi-theme-font:minor-bidi; mso-bidi-language:AR-SA;} Before we begin OpenStack networking has very powerful capabilities but at the same time it is quite complicated. In this blog series we will review an existing OpenStack setup using the Oracle OpenStack Tech Preview and explain the different network components through use cases and examples. The goal is to show how the different pieces come together and provide a bigger picture view of the network architecture in OpenStack. This can be very helpful to users making their first steps in OpenStack or anyone wishes to understand how networking works in this environment.  We will go through the basics first and build the examples as we go. According to the recent Icehouse user survey and the one before it, Neutron with Open vSwitch plug-in is the most widely used network setup both in production and in POCs (in terms of number of customers) and so in this blog series we will analyze this specific OpenStack networking setup. As we know there are many options to setup OpenStack networking and while Neturon + Open vSwitch is the most popular setup there is no claim that it is either best or the most efficient option. Neutron + Open vSwitch is an example, one which provides a good starting point for anyone interested in understanding OpenStack networking. Even if you are using different kind of network setup such as different Neutron plug-in or even not using Neutron at all this will still be a good starting point to understand the network architecture in OpenStack. The setup we are using for the examples is the one used in the Oracle OpenStack Tech Preview. Installing it is simple and it would be helpful to have it as reference. In this setup we use eth2 on all servers for VM network, all VM traffic will be flowing through this interface.The Oracle OpenStack Tech Preview is using VLANs for L2 isolation to provide tenant and network isolation. The following diagram shows how we have configured our deployment: This first post is a bit long and will focus on some basic concepts in OpenStack networking. The components we will be discussing are Open vSwitch, network namespaces, Linux bridge and veth pairs. Note that this is not meant to be a comprehensive review of these components, it is meant to describe the component as much as needed to understand OpenStack network architecture. All the components described here can be further explored using other resources. Open vSwitch (OVS) In the Oracle OpenStack Tech Preview OVS is used to connect virtual machines to the physical port (in our case eth2) as shown in the deployment diagram. OVS contains bridges and ports, the OVS bridges are different from the Linux bridge (controlled by the brctl command) which are also used in this setup. To get started let’s view the OVS structure, use the following command: # ovs-vsctl show 7ec51567-ab42-49e8-906d-b854309c9edf     Bridge br-int         Port br-int             Interface br-int type: internal         Port "int-br-eth2"             Interface "int-br-eth2"     Bridge "br-eth2"         Port "br-eth2"             Interface "br-eth2" type: internal         Port "eth2"             Interface "eth2"         Port "phy-br-eth2"             Interface "phy-br-eth2" ovs_version: "1.11.0" We see a standard post deployment OVS on a compute node with two bridges and several ports hanging off of each of them. The example above is a compute node without any VMs, we can see that the physical port eth2 is connected to a bridge called “br-eth2”. We also see two ports "int-br-eth2" and "phy-br-eth2" which are actually a veth pair and form virtual wire between the two bridges, veth pairs are discussed later in this post. When a virtual machine is created a port is created on one the br-int bridge and this port is eventually connected to the virtual machine (we will discuss the exact connectivity later in the series). Here is how OVS looks after a VM was launched: # ovs-vsctl show efd98c87-dc62-422d-8f73-a68c2a14e73d     Bridge br-int         Port "int-br-eth2"             Interface "int-br-eth2"         Port br-int             Interface br-int type: internal         Port "qvocb64ea96-9f" tag: 1             Interface "qvocb64ea96-9f"     Bridge "br-eth2"         Port "phy-br-eth2"             Interface "phy-br-eth2"         Port "br-eth2"             Interface "br-eth2" type: internal         Port "eth2"             Interface "eth2" ovs_version: "1.11.0" Bridge "br-int" now has a new port "qvocb64ea96-9f" which connects to the VM and tagged with VLAN 1. Every VM which will be launched will add a port on the “br-int” bridge for every network interface the VM has. Another useful command on OVS is dump-flows for example: # ovs-ofctl dump-flows br-int NXST_FLOW reply (xid=0x4): cookie=0x0, duration=735.544s, table=0, n_packets=70, n_bytes=9976, idle_age=17, priority=3,in_port=1,dl_vlan=1000 actions=mod_vlan_vid:1,NORMAL cookie=0x0, duration=76679.786s, table=0, n_packets=0, n_bytes=0, idle_age=65534, hard_age=65534, priority=2,in_port=1 actions=drop cookie=0x0, duration=76681.36s, table=0, n_packets=68, n_bytes=7950, idle_age=17, hard_age=65534, priority=1 actions=NORMAL As we see the port which is connected to the VM has the VLAN tag 1. However the port on the VM network (eth2) will be using tag 1000. OVS is modifying the vlan as the packet flow from the VM to the physical interface. In OpenStack the Open vSwitch agent takes care of programming the flows in Open vSwitch so the users do not have to deal with this at all. If you wish to learn more about how to program the Open vSwitch you can read more about it at http://openvswitch.org looking at the documentation describing the ovs-ofctl command. Network Namespaces (netns) Network namespaces is a very cool Linux feature can be used for many purposes and is heavily used in OpenStack networking. Network namespaces are isolated containers which can hold a network configuration and is not seen from outside of the namespace. A network namespace can be used to encapsulate specific network functionality or provide a network service in isolation as well as simply help to organize a complicated network setup. Using the Oracle OpenStack Tech Preview we are using the latest Unbreakable Enterprise Kernel R3 (UEK3), this kernel provides a complete support for netns. Let's see how namespaces work through couple of examples to control network namespaces we use the ip netns command: Defining a new namespace: # ip netns add my-ns # ip netns list my-ns As mentioned the namespace is an isolated container, we can perform all the normal actions in the namespace context using the exec command for example running the ifconfig command: # ip netns exec my-ns ifconfig -a lo        Link encap:Local Loopback           LOOPBACK  MTU:16436 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:0           RX bytes:0 (0.0 b)  TX bytes:0 (0.0 b) We can run every command in the namespace context, this is especially useful for debug using tcpdump command, we can ping or ssh or define iptables all within the namespace. Connecting the namespace to the outside world: There are various ways to connect into a namespaces and between namespaces we will focus on how this is done in OpenStack. OpenStack uses a combination of Open vSwitch and network namespaces. OVS defines the interfaces and then we can add those interfaces to namespace. So first let's add a bridge to OVS: # ovs-vsctl add-br my-bridge Now let's add a port on the OVS and make it internal: # ovs-vsctl add-port my-bridge my-port # ovs-vsctl set Interface my-port type=internal And let's connect it into the namespace: # ip link set my-port netns my-ns Looking inside the namespace: # ip netns exec my-ns ifconfig -a lo        Link encap:Local Loopback           LOOPBACK  MTU:65536 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:0           RX bytes:0 (0.0 b)  TX bytes:0 (0.0 b) my-port   Link encap:Ethernet HWaddr 22:04:45:E2:85:21           BROADCAST  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:0           RX bytes:0 (0.0 b)  TX bytes:0 (0.0 b) Now we can add more ports to the OVS bridge and connect it to other namespaces or other device like physical interfaces. Neutron is using network namespaces to implement network services such as DCHP, routing, gateway, firewall, load balance and more. In the next post we will go into this in further details. Linux Bridge and veth pairs Linux bridge is used to connect the port from OVS to the VM. Every port goes from the OVS bridge to a Linux bridge and from there to the VM. The reason for using regular Linux bridges is for security groups’ enforcement. Security groups are implemented using iptables and iptables can only be applied to Linux bridges and not to OVS bridges. Veth pairs are used extensively throughout the network setup in OpenStack and are also a good tool to debug a network problem. Veth pairs are simply a virtual wire and so veths always come in pairs. Typically one side of the veth pair will connect to a bridge and the other side to another bridge or simply left as a usable interface. In this example we will create some veth pairs, connect them to bridges and test connectivity. This example is using regular Linux server and not an OpenStack node: Creating a veth pair, note that we define names for both ends: # ip link add veth0 type veth peer name veth1 # ifconfig -a . . veth0     Link encap:Ethernet HWaddr 5E:2C:E6:03:D0:17           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) veth1     Link encap:Ethernet HWaddr E6:B6:E2:6D:42:B8           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) . . To make the example more meaningful this we will create the following setup: veth0 => veth1 => br-eth3 => eth3 ======> eth2 on another Linux server br-eth3 – a regular Linux bridge which will be connected to veth1 and eth3 eth3 – a physical interface with no IP on it, connected to a private network eth2 – a physical interface on the remote Linux box connected to the private network and configured with the IP of 50.50.50.1 Once we create the setup we will ping 50.50.50.1 (the remote IP) through veth0 to test that the connection is up: # brctl addbr br-eth3 # brctl addif br-eth3 eth3 # brctl addif br-eth3 veth1 # brctl show bridge name     bridge id               STP enabled     interfaces br-eth3         8000.00505682e7f6       no              eth3                                                         veth1 # ifconfig veth0 50.50.50.50 # ping -I veth0 50.50.50.51 PING 50.50.50.51 (50.50.50.51) from 50.50.50.50 veth0: 56(84) bytes of data. 64 bytes from 50.50.50.51: icmp_seq=1 ttl=64 time=0.454 ms 64 bytes from 50.50.50.51: icmp_seq=2 ttl=64 time=0.298 ms When the naming is not as obvious as the previous example and we don't know who are the paired veth interfaces we can use the ethtool command to figure this out. The ethtool command returns an index we can look up using ip link command, for example: # ethtool -S veth1 NIC statistics: peer_ifindex: 12 # ip link . . 12: veth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000 Summary That’s all for now, we quickly reviewed OVS, network namespaces, Linux bridges and veth pairs. These components are heavily used in the OpenStack network architecture we are exploring and understanding them well will be very useful when reviewing the different use cases. In the next post we will look at how the OpenStack network is laid out connecting the virtual machines to each other and to the external world. @RonenKofman

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