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Forum Replies

  1. Hi Rene,

    Can we use "frame-relay interface-dlci DLCI NUMBER" command in frame-relay multipoint connection ?

  2. You could yes, basically all the command does is say "this DLCI number belongs to this interface".

  3. @Forrest That's right, in that example I only solved the problem for the ping from R3 to R2 by adding a frame-relay map on R2. For the other way around, you should add a map on R3 as well.

    The underlying problem here is that EIGRP expects the network to be multi-access, this means that all devices should be able to reach each other directly. In reality, only the hub can reach the spokes directly. You won't be able to estalish an EIGRP adjacency between R2/R3 directly with only PVCs to the hub.

    It's better to use frame-relay point-to-point everywhere instead. You won't have issues with split horizon and spoke-to-spoke connectivity.

    Trying OSPF instead of EIGRP is also an option. Take a look at this example:

    https://networklessons.com/ospf/ospf-next-hop-ip-address-with-different-network-types/

    Depending on the OSPF network type, OSPF will use different IP addresses for the next hop which solves the missing frame-relay maps problem.

    In the hub and spoke topology, the hub is always a single point of failure. You could solve this by adding a second hub. Two hubs routers on your main network, all spoke routers connected to both hubs. It's similar to the DMVPN topology with two hubs:

    https://networklessons.com/security/dmvpn-dual-hub-single-cloud/

    @Nirosh you will need a routing protocol (like EIGRP) to advertise any networks BEHIND the hub or spoke routers. If there is no connectivity between two (spoke) routers, you will have to add some additional frame-relay maps.

    Rene

  4. Hi,

    My question is if we have to configure also the spoke routers with the same type of logical sub-interface that we use in the hub? In other examples, and I used it as well on GNS3, I configured my hub router with logical sub-interfaces (point-to-point)/(multi-point) but for the spoke routers I always used the physical interface regardless the setup on the hub router. Is this approach correct ? Thus my configuration on the spokes was always done with the "frame-relay map ip ", which I take into account both for the hub router and rest of spokes. Thus I use it as many times as necessary, and the difference is in the . However, in your examples, you use also sub-ifs on spokes, so to conclude what's the correct approach for the spoke routers? Physical or logical sub-ifs ?

  5. Hello Konstantinos!

    The spoke routers can be configured to function using a subinterface or using the physical interface for both point to point configurations (each link between routers has its own subnet) or point to multipoint configurations (all routers are in the same subnet). It is a good idea however to use subinterfaces because the numbers used for the subinterface can correspond to the DLCIs of the PVC. It is also a more symmetric configuration having both ends configured in the same way. The functionality will be the same however.

    I hope this has been helpful!

    Laz

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