Search Results

Search found 53262 results on 2131 pages for 'application architecture'.

Page 22/2131 | < Previous Page | 18 19 20 21 22 23 24 25 26 27 28 29  | Next Page >

  • 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.

    Read the article

  • 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.

    Read the article

  • 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); } } }

    Read the article

  • 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

    Read the article

  • Shutting down a WPF application from App.xaml.cs

    - by Johannes Rössel
    I am currently writing a WPF application which does command-line argument handling in App.xaml.cs (which is necessary because the Startup event seems to be the recommended way of getting at those arguments). Based on the arguments I want to exit the program at that point already which, as far as I know, should be done in WPF with Application.Current.Shutdown() or in this case (as I am in the current application object) probably also just this.Shutdown(). The only problem is that this doesn't seem to work right. I've stepped through with the debugger and code after the Shutdown() line still gets executed which leads to errors afterwards in the method, since I expected the application not to live that long. Also the main window (declared in the StartupUri attribute in XAML) still gets loaded. I've checked the documentation of that method and found nothing in the remarks that tell me that I shouldn't use it during Application.Startup or Application at all. So, what is the right way to exit the program at that point, i. e. the Startup event handler in an Application object?

    Read the article

  • 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.

    Read the article

  • How do I get the current Application Name (in terms of IIS) in a classic asp Web application

    - by Mr AH
    I have a classic asp application which retrieves the current application name and sets an Application variable containing that name. This name is important (I wont go into why) and is essentially the friendly name in IIS. The problem is, the implementation used to get this name is flawed, it a) assumes the home directory contains the string wwwroot, and b) assumes the folder name is the same as the application name. I can no longer guarantee these conditions. I would have thought the application name is know at run-time but I can't seem to find it in either Session or Application variables (at application start up entry point in global.asa). Any ideas?

    Read the article

  • JSP Model 2 Architecture and Dependency Injection

    - by Robert
    If I'm writing a web application that uses the model 2 architecture, is it possible to use the Google Guice framework (or really any IoC container)? The reason I ask this question is because everything I've researched about DI, IoC, et cetera always uses Spring, Hibernate or some other framework/container in their examples. I'm just using Java classes, controllers, and JSP's to build this application and I can't find any good documentation about the subject.

    Read the article

  • Monitoring ASP.NET Application

    - by imran_ku07
        Introduction:          There are times when you may need to monitor your ASP.NET application's CPU and memory consumption, so that you can fine-tune your ASP.NET application(whether Web Form, MVC or WebMatrix). Also, sometimes you may need to see all the exceptions(and their details) of your application raising, whether they are handled or not. If you are creating an ASP.NET application in .NET Framework 4.0, then you can easily monitor your application's CPU or memory consumption and see how many exceptions your application raising. In this article I will show you how you can do this.       Description:           With .NET Framework 4.0, you can turn on the monitoring of CPU and memory consumption by setting AppDomain.MonitoringEnabled property to true. Also, in .NET Framework 4.0, you can register a callback method to AppDomain.FirstChanceException event to monitor the exceptions being thrown within your application's AppDomain. Turning on the monitoring and registering a callback method will add some additional overhead to your application, which will hurt your application performance. So it is better to turn on these features only if you have following properties in web.config file,   <add key="AppDomainMonitoringEnabled" value="true"/> <add key="FirstChanceExceptionMonitoringEnabled" value="true"/>             In case if you wonder what does FirstChanceException mean. It simply means the first notification of an exception raised by your application. Even CLR invokes this notification before the catch block that handles the exception. Now just update global.asax.cs file as,   string _item = "__RequestExceptionKey"; protected void Application_Start() { SetupMonitoring(); } private void SetupMonitoring() { bool appDomainMonitoringEnabled, firstChanceExceptionMonitoringEnabled; bool.TryParse(ConfigurationManager.AppSettings["AppDomainMonitoringEnabled"], out appDomainMonitoringEnabled); bool.TryParse(ConfigurationManager.AppSettings["FirstChanceExceptionMonitoringEnabled"], out firstChanceExceptionMonitoringEnabled); if (appDomainMonitoringEnabled) { AppDomain.MonitoringIsEnabled = true; } if (firstChanceExceptionMonitoringEnabled) { AppDomain.CurrentDomain.FirstChanceException += (object source, FirstChanceExceptionEventArgs e) => { if (HttpContext.Current == null)// If no context available, ignore it return; if (HttpContext.Current.Items[_item] == null) HttpContext.Current.Items[_item] = new RequestException { Exceptions = new List<Exception>() }; (HttpContext.Current.Items[_item] as RequestException).Exceptions.Add(e.Exception); }; } } protected void Application_EndRequest() { if (Context.Items[_item] != null) { //Only add the request if atleast one exception is raised var reqExc = Context.Items[_item] as RequestException; reqExc.Url = Request.Url.AbsoluteUri; Application.Lock(); if (Application["AllExc"] == null) Application["AllExc"] = new List<RequestException>(); (Application["AllExc"] as List<RequestException>).Add(reqExc); Application.UnLock(); } }               Now browse to Monitoring.cshtml file, you will see the following screen,                            The above screen shows you the total bytes allocated, total bytes in use and CPU usage of your application. The above screen also shows you all the exceptions raised by your application which is very helpful for you. I have uploaded a sample project on github at here. You can find Monitoring.cshtml file on this sample project. You can use this approach in ASP.NET MVC, ASP.NET WebForm and WebMatrix application.       Summary:          This is very important for administrators/developers to manage and administer their web application after deploying to production server. This article will help administrators/developers to see the memory and CPU usage of their web application. This will also help administrators/developers to see all the exceptions your application is throwing whether they are swallowed or not. Hopefully you will enjoy this article too.   SyntaxHighlighter.all()

    Read the article

  • Load balancing application servers with Alteon 2424-SSL

    - by antispam
    We are having problems with load balancing configuration and we would like to clear the situation. We need to load balance among four JavaEE web application servers. The servers are configured as host1 port 7001 host1 port 7002 host2 port 7001 host2 port 7002 Do any of you know if it is possible with Nortel 2424-SSL application switch? Which would be the best configuration for it? (vips, ports, groups, services, ...) Thank you very much.

    Read the article

  • is GTK Installation (PHP for desktop) affect the web application?

    - by Harshal Mahajan
    I just going to install the GTK for creating a desktop application. But I want to know if we install the GTK then is it affect our web application server or php.ini or other features of web based application? I know there is no requirement of server for desktop but the GTK create the other php.ini . so is it affect my other applications? I downloaded the GTK Tool kit from here. So I am just little bit confusing that it should not affect my all running web applications. I think the php for desktop is a very interesting issue for all of us, so I just want to know the affection of desktop on web?

    Read the article

  • Mailing List Application?

    - by marienbad
    Mailing lists are great, but they're a fundamentally different beast than email. It seems strange to me to keep mailing lists in my email program (Gmail). Of course I have folders set up to automatically keep them out of my inbox, but if I have hundreds of mailing lists, it gets really out of hand. Is there an application (or web application) that is designed specifically as a mailing list "client"?

    Read the article

  • launch an application from HTML with arguments

    - by Jugglingnutcase
    Is there a way to allow an HTML file to open an application on the local computer and send that application arguments? We have an application that allows a user to set a link to an external application. We also provide a summary page in HTML (they usually interact with the application from outside the browser) with the link in HTML as well. We can get applications to launch if the program exists, but cant seem to send arguments through the HTML link. Is this even possible?

    Read the article

  • Silverlight 4 business application themes

    - by David Brunelle
    Hi, We are starting a new SilverLight 4 Business Application project and are looking for theme. All we can find on the web are Navigation Application themes, which when applied to business application project, don't work. Most even have compilation errors. Is there a place on the web to get theme specifically for that project or is there a way to translate navigation application theme into business application theme? Thank you

    Read the article

  • ASP.NET Application Level vs. Session Level and Global.asax...confused

    - by contactmatt
    The following text is from the book I'm reading, 'MCTS Self-Paced Training Kit (Exam 70-515) Web Applications Development with ASP.NET 4". It gives the rundown of the Application Life Cycle. A user first makes a request for a page in your site. The request is routed to the processing pipeline, which forwards it to the ASP.NET runtime. The ASP.NET runtime creates an instance of the ApplicationManager class; this class instance represents the .NET framework domain that will be used to execute requests for your application. An application domain isolates global variables from other applications and allows each application to load and unload separately, as required. After the application domain has been created, an instance of the HostingEnvironment class is created. This class provides access to items inside the hosting environment, such as directory folders. ASP.NET creates instances of the core objects that will be used to process the request. This includes HttpContext, HttpRequest, and HttpResponse objects. ASP.NET creates an instance of the HttpApplication class (or an instance is reused). This class is also the base class for a site’s Global.asax file. You can use this class to trap events that happen when your application starts or stops. When ASP.NET creates an instance of HttpApplication, it also creates the modules configured for the application, such as the SessionStateModule. Finally, ASP.NET processes request through the HttpApplication pipleline. This pipeline also includes a set of events for validating requests, mapping URLs, accessing the cache, and more. The book then demonstrated an example of using the Global.asax file: <script runat="server"> void Application_Start(object sender, EventArgs e) { Application["UsersOnline"] = 0; } void Session_Start(object sender, EventArgs e) { Application.Lock(); Application["UsersOnline"] = (int)Application["UsersOnline"] + 1; Application.UnLock(); } void Session_End(object sender, EventArgs e) { Application.Lock(); Application["UsersOnline"] = (int)Application["UsersOnline"] - 1; Application.UnLock(); } </script> When does an application start? Whats the difference between session and application level? I'm rather confused on how this is managed. I thought that Application level classes "sat on top of" an AppDomain object, and the AppDomain contained information specific to that Session for that user. Could someone please explain how IIS manages Applicaiton level classes, and how an HttpApplication class sits under an AppDomain? Anything is appreciated.

    Read the article

  • Error launching application after ClickOnce deployment - "An application for this deployment is alre

    - by digiduck
    As part of my continuous integration build the application is deployed as a ClickOnce application. This works great the first time, but when I try the launch the app after an update has been deployed I get the following error. An application for this deployment is already installed with a different application identity. If I run mage.exe -cc to clear the application cache for all ClickOnce apps then I can launch the application just fine. Has anyone run into this before? How can I fix this? Here are the steps in my build script that publish the ClickOnce application. ./tools/windows_sdk/mage.exe -New Application -Processor msil -ToFile "C:\temp\build\RoadrunnerTrap.exe.manifest" -Name "Roadrunner Trap" -Version 1.0.0.1 -FromDirectory "C:\temp\build" # artifacts from C:\temp\build\ are copied to \\server\publish\v1.0.0.1\ ./tools/windows_sdk/mage.exe -New Deployment -Processor msil -Install false -Publisher "Acme, Inc." -ProviderUrl "\\server\publish\RoadrunnerTrap.application" -Name "Roadrunner Trap" -AppManifest "\\server\publish\v1.0.0.1\RoadrunnerTrap.exe.manifest" -ToFile "\\server\publish\RoadrunnerTrap.application" Note that the version number does change with every deployment.

    Read the article

  • Display iphone application settings within your application

    - by Dougnukem
    The iphone supports a means of defining your application's settings such that it will automatically create a UI in the Settings app. I want to also allow the user to edit the application settings within the application but it'd be nice to reuse the same UI that is automatically created. See: Application Settings Is there a way to have your application display the settings using the same UI that the Settings application does?

    Read the article

  • MSSQL 2008 License for both Web application and desktop application

    - by Bayonian
    I have ASP.NET web application using MSSQL express at the moment. But I want to use MSSQL 2008. But I'm NOT sure about what kind of license I should buy. I'm considering the Processor License according to this document. I'm not sure if it's the right choice. If I buy User CAL. should I buy only 1 CAL for my web application? or for all visitors who visit my web site? I also have a Windows desktop application that write/read data from the server. Do I need a seperate license with for this Windows application if I buy Processor License. Thank you for suggestion.

    Read the article

  • MSSQL 2008 License for both Web application and desktop application [closed]

    - by Angkor Wat
    I have ASP.NET web application using MSSQL express at the moment. But I want to use MSSQL 2008. But I'm NOT sure about what kind of license I should buy. I'm considering the Processor License according to this document. I'm not sure if it's the right choice. If I buy User CAL. should I buy only 1 CAL for my web application? or for all visitors who visit my web site? I also have a Windows desktop application that write/read data from the server. Do I need a seperate license with for this Windows application if I buy Processor License. Thank you for suggestion.

    Read the article

  • Application upgrade triggered from web application on Ubuntu/Linux

    - by Witek
    On my ubuntu server I have an application MyApp which runs as a daemon with its own user myapp. Then I have a web application MyPortal which runs in apace httpd as user www-data. This application serves a web page with a Redeploy MyApp button. When clicking this button I want to start the script redeploymyapp. This script stops the MyApp deamon, upgrades the application and starts the daemon again. The problem is, that the redeploymyapp script needs to be executed by the user myapp, while MyPortal is running as www-data. What is te best way to solve this problem?

    Read the article

  • Web application and remote storage of files

    - by Matt
    Hi have a web application that can store lots and lots of files on the server. i.e. users upload data to it. The files are stored below a particular storage path. The web host will be an IBM xseries 345. However, the disks are really expensive so we would like to put the files onto a less expensive server. Now here is the question. Should I use an NFS mount on the IBM server of a path on the storage server? Or should I write some scripts to upload the files to the storage server instead. Both the storage server and the web host are on the same network. Only the web server is visible to the world. Is NFS performance suitable for an expected low to moderately loaded server?

    Read the article

  • 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

    Read the article

  • Comparison of Architecture presentation patterns MVP(SC),MVP(PV),PM,MVVM and MVC

    This article will compare four important architecture presentation patterns i.e. MVP(SC),MVP(PV),PM,MVVM and MVC. Many developers are confused around what is the difference between these patterns and when should we use what. This article will first kick start with a background and explain different...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.

    Read the article

< Previous Page | 18 19 20 21 22 23 24 25 26 27 28 29  | Next Page >