MPLS L3VPN Part 2 with Narbik Kocharians: Lesson 4: Configuring IGP and Redistribution

     

    Lesson 4: Configuring IGP and Redistribution

     

    In this free training video, Narbik Kocharians continues by moving on to the sixth step in his process: configuring IGP between CE and PE routers. He begins by going to router one, and sees where he is going to run EIGRP. He finishes the CE router, and proceeds to router two.

     

    In 15 code, Narbik points out that autonomous code under address family is a hidden command. Narbik explains that what Cisco did was instead of configuring it directly under the address family, they included it as part of an address family IP4 command. Before moving onto router six, Narbik makes sure to verify his configuration.

     

    Narbik then moves on to the last step, Route Redistribution. Before he begins, Narbik talks about a few things to be aware of. For example, if he runs static routes or BGP between the CE and PE router, the directly connected link is not redistributed. If you run OSPF between routers one and two, if the PE router is redistributing some external routes into OSPF, those external routes will not be redistributed into BGP. Unless, when redistributing OSPF into BGP, the distinction of redistribute OSPF process ID match internal type 1, external type 2 is made. Narbik verifies this, and begins to proceed with redistribute.

     

    Narbik recommends that you redistribute one direction, and then test and verify that everything up to that point works before redistributing in the other direction. he then demonstrates this by redistributing OSPF into BGP in router two. Once he redistributes EIGRP, he verifies it. Narbik points out that one thing you should be aware of is that EIGRP composite metric becomes BGP's med on one side.

     

    Now that the routes are visible, they should also be visible on router five. Narbik then proceeds to redistribute BGP to EIGRP. Narbik notes that when using EIGRP named mode, you would not be able to use 1.1.1.1.1. The reason he is able to is because he is using Classic Mode. Finally, Narbik verifies the routes on router six.

     

    The way Narbik typically tests these connections is by going to router one, and uses a debug ip icmp. Then he goes to router six, and pings the loopback interface. This will not be successful, but that's not what he's looking for. What Narbik is looking for is to see five icmp echo reply messages on router one.

     

    If he sees the echo reply messages, he knows that everything up to this point works fine, and he is free to start performing redistribution. So he goes to router five, and redistributes EIGRP into BGP. With this, Narbik notes that he can see the routes on router two, which he does. Then he redistributes BGP into EIGRP so that the customer router will see the routes from router six. Narbik sees that the test is successful, and concludes the session.

     

    Lesson 1: IP Addressing and IGP within the core

    Lesson 2: Configuring LDP

    Lesson 3: Configuring iBGP

    Lesson 4: Configuring IGP and Redistribution

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