BGP and OSPF correct network topology

[Pasquale Di Dio]

Hi everyone,

I have this problem. 

I have to configure an Autonomous System that have :

- 4 bgp router that talks iBGP

- that have ring topology

I tried 2 ways (please see the attached picture named "1st configuration"):

1. Used 4 bgp router with OSPFConfig.xml and BGPConfig.xml file to have:
1. OSPFConfig.xml that configure the iBGP
2. BGPConfig.xml that configure the eBGP

In this case I have this kind of error when it will start the update message (after 18.5s) to build the routing table:

<!> Error in module (inet::bgp::BGPRouting) UniCampaniaNet2.bgpRimicBE.bgp (id=81) at event #6117, t=18.5000172328: No configuration interface for peer address: 10.10.1.254.

TRAPPING on the exception above, due to a debug-on-errors=true configuration option. Is your debugger ready?

Simulation terminated with exit code: 133

Working directory: /home/pako/omnetpp-4.6/samples/inet/examples/UniCampaniaNet2/Rimic_noOspf

Command line: opp_run -r 0 -c General -n ../..:../../../src:../../../tutorials -l ../../../src/INET omnetppTCP.ini

Environment variables:

PATH=/home/pako/omnetpp-4.6/bin::/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games

LD_LIBRARY_PATH=/home/pako/omnetpp-4.6/lib::/home/pako/omnetpp-4.6/samples/inet/src:

OMNETPP_IMAGE_PATH=/home/pako/omnetpp-4.6/images

 Obviously all the interface seem's to be correctly configurated.

The 2nd way i i tried is (please see the attached picture named "2nd configuration") :

1. Used 4 BGP router  and 4 OSPF Router with OSPFConfig.xml and BGPConfig.xml file to have:
1. OSPFConfig.xml that configure the ospf protocol of the OSPF Router
2. BGPConfig.xml that configure the bgp protocol of the BGP Router 

In this case I have that the routing tables were build INCORRECTLY, and  raffic coming from "outside the ring", doesn't exit from the "ring" because of a SYN message "bouncing" from BGProuter to OSPFRouter.

The question are : 

Which kind of configuration is that correct to simulate eBGP outside the ring and iBGP inside the ring? 

I need that protocols build routing tables dinamically, and the phisical topology must be ring.

Sniffing packets with WireShark doesn't work, because OSPF/BGP packets aren't build correctly inside. 

Do you have some suggestion for debug and understand why the routing table were build incorrectly? 

Thank you in advice for any type of suggestion.