Hi EIGRP and RIP set TTL of 2 for HUB-SPOKE model. For example, Frame Relay usually use HUB-SPOKE mode. When 2 spoke routers want to make adjacency, the packet must go through the HUB router, If the TTL is 1, then the packet cannot arrive another spoke router. So the TTL set to 2.
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Hi ALL, I have a question about bgp advertising prefixes back to the peer which advertised the route. I am using IOS version 15.2. My topology is very simple like this: R3---------------R1--------------R2 R1 belongs to AS 1,R2 and R3 belongs to AS23. R2 advertise 10.2.1.0/24 to R1 and R3 advertise 10.3.1.0/24 to R1 but when I "show ip bgp nei 22.214.171.124(R2's interface connected to R1) advertised-route , I saw the shown below: R1#show ip bgp nei 126.96.36.199 advertised-routes BGP table version is 5, local router ID is 188.8.131.52 Status codes: s suppressed, d damped, h history, * valid, > best, i - internal, r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter, x best-external, a additional-path, c RIB-compressed, Origin codes: i - IGP, e - EGP, ? - incomplete RPKI validation codes: V valid, I invalid, N Not found Network Next Hop Metric LocPrf Weight Path *> 10.2.1.0/24 184.108.40.206 0 0 23 i *> 10.3.1.0/24 220.127.116.11 0 0 23 i Total number of prefixes 2 that R1 advertise 10.2.1.0/24 back to R2. when I shutdown the bgp session between R1 and R3, then R1 didn't advertise this route to R2 anymore. I don't know why, Can someone help me explain it? Thanks very much!
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