![]() ![]() Let’s start with JHB = Router1 I will explain the first router in more detail. My goal was to have failover (redundancy) between JHB (Router 1) and CPT (Router 2) on both the Internet and the private network and if either side of the link where to drop, OSPF would find the best route and restore connectivity via another link/connection and at the same time distribute the new route to all other connect routers. The middle sites are connected to both Internet and the private network. On the left we have three sites connected to the Internet and on the right we have two sites connected via a private multiprotocol label switching (MPLS) network. Attached is a simple network diagram with basic network configuration.įrom the above diagram you can see that there are seven sites. In this article I will be using a lab of virtual Mikrotik routers. So, as you can see, the configuration of an L2TPv3 pseudowire can be pretty simple.After weeks of having issues on my network with numerous outages I decided to build in some kind of automatic failover using an Open Shortest Path First (OSPF) network. The configuration of ‘Amerstam.PE' is very similar to that of ‘London.PE': The digest password] command is also used to link to the previously specified L2TPv3 class.įinally, the xconnect peer-ip-address vcid pw-class name command is used specify the IP address of the peer LCCE, the previously configured pseudowire class name, and to bind the attachment circuit (the circuit between ‘' and ‘London.PE') to the L2TPv3 pseudowire. An L2TPv3 class is optional, but recommended because it allows you configure a number of control channel parameters such as authentication. Next is the L2TPv3 class, which is configured using the l2tp-class name command. Make sure that there is IP reachability between the loopback interfaces at either end of the L2TPv3 pseudowire (here ‘London.PE' and ‘Amsterdam.PE') otherwise the L2TPv3 pseudowire will not function. It's a very good idea to use a loopback interface for this purpose as they do not go down (unlike physical interfaces). ![]() The address on this interface is the address from which and to which L2TPv3 packets will be sent. Once CEF has been enabled, you should configure a loopback interface to use as an endpoint for L2TPv3 pseudowires (interface loopback 0 on ‘London.PE'). But if it is disabled, make sure that you enable it, otherwise L2TPv3 pseudowires will not function. CEF is enabled by default, so the ip cef command, which is used to enable CEF, is not explicitly shown above. Xconnect 172.16.1.3 1001 pw-class mjlnet.PW.To.AmsterdamĪs previously mentioned, the first step in configuring an L2TPv3 pseudowire is to ensure that CEF is enabled. ![]() The configuration for an Ethernet port pseudowire (used to transport ‘raw' Ethernet frames) on ‘London.PE' is shown below: In the figure above, these endpoints are named ‘London.PE' and ‘Amsterdam.PE'. The five steps must be configured on both endpoints (both LCCEs). Configure a loopback interface to use as the pseudowire endpoint. Configure Cisco Express Forwarding (CEF). The configuration of an L2TPv3 pseudowire (with dynamic session establishment) can be broken down into five steps: ‘London.PE' decapsulates the Ethernet frame and sends it across the attachment circuit to ‘'. ![]() Of course, the same process happens in reverse when ‘Amsterdam.PE' receives an Ethernet frame from ‘' - it encapsulates the Ethernet frame with an L2TPv3 header/sublayer and sends it over the IP backbone network to ‘London.PE'. When ‘Amsterdam.PE' receives the L2TPv3 packet from ‘London.PE', it removes the L2TPv3 header/sublayer, and sends the Ethernet frame over the attachment circuit to ‘'. When ‘London.PE' receives an Ethernet frame on the attachment circuit from ‘', it encapsulates that frame with an L2TPv3 header/sublayer and send the resulting packet across the IP backbone network to ‘Amsterdam.PE'. The following figure illustrates the process that ‘London.PE' uses to send Ethernet frames over the pseudowire to ‘Amsterdam.PE.': Data channel messages, on the other hand, are the messages that actually carry the Layer-2 protocols and connections over the IP backbone.īelow is a figure that I'll use to illustrate the various concepts and configuration details.Īs already mentioned, an L2TPv3 pseudowire can be used to transport a variety of Layer-2 circuit types, but I'll use an Ethernet port pseudowire between ‘London.PE' and ‘Amsterdam.PE' as an example here. ![]()
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