Revisit the configuration of the iBGP routers R2#sh run | s r b router bgp 2 bgp log-neighbor-changes neighbor 184.108.40.206 remote-as 2 neighbor 220.127.116.11 update-source Loopback2 neighbor 18.104.22.168 next-hop-self neighbor 22.214.171.124 remote-as 2 neighbor 126.96.36.199 update-source Loopback2 neighbor 188.8.131.52 next-hop-self neighbor 192.168.12.1 remote-as 1 R2# R3#sh run | s r b router bgp 2 bgp … Continue reading Is full meshed iBGP necessary?
Problem 1: Did not receive prefix advertised by BGP peer. R2#sh ip bgp summary BGP router identifier 184.108.40.206, local AS number 2 BGP table version is 1, main routing table version 1 Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd 192.168.12.1 4 1 44 43 1 0 0 00:36:08 0 R2 did not … Continue reading IP routing with BGP
Split horizon Split horizon rule is to prevent routing loop. In iBGP a router which learns prefixes from a BGP speaker will not advertise to BGP speaker, this makes a full mesh iBGP peering necessary in order for other BGP speakers to know the route. The number of TCP sessions can be calculated with this … Continue reading BGP: Route reflector
Acknowledgement Without MR.Keith Barker's 21 minutes video instruction, constructing MPLS VPN lab will take a longer time. His 21 minutes video instruction summarizes all. MR. Keith Barker has amazing skills to translate complicated concepts into simpler and easier to understand concepts. Now it is clearer to me and I believe it will be easier on … Continue reading MPLS Layer 3 VPN
The diagram is complicated with an additional link, and instead of full BGP route in AS65000, the BGP route is propagated with the help of OSPF. In previous lab, the BGP full mesh was established by peering both subnets of a BGP router. However this step can be simplified by peering the BGP speaker's loopback … Continue reading BGP: Injecting IGP route into BGP without redistribution
Using the same network diagram, I would want prefix 10.20.0.0 to be filtered from advertisement by the border iBGP routers (r1 and r3). Using prefix-list is a more granular method than using ACL with distribute-list. Hide r2 prefixes from r5 This has to be done at r3 as this is the router than is doing … Continue reading BGP: Route filter with ip prefix-list
r1, r2 and r3 have full meshed BGP peering. No IGP was used. BGP synchronization Before a BGP route is advertised and added to the routing table, this route must be known via an IGP. For the case of AS65000, no IGP is used, only pure iBGP peering hence BGP synchronization will stop bgp speaker … Continue reading BGP: Full mesh BGP without IGP