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​BGP - iBGP IPv4 Unicast Route Reflector

Picture
This lab example adds a route reflector to the iBGP configuration of AS 100.



CSR14
router bgp 100
 bgp log-neighbor-changes
 no bgp default ipv4-unicast
 neighbor 100.9.9.9 remote-as 100
 neighbor 100.9.9.9 update-source Loopback0
 neighbor 100.13.13.13 remote-as 100
 neighbor 100.13.13.13 update-source Loopback0
 !
 address-family ipv4
  network 100.14.14.14 mask 255.255.255.255
  neighbor 100.9.9.9 activate
  neighbor 100.9.9.9 route-reflector-client
  neighbor 100.13.13.13 activate
  neighbor 100.13.13.13 route-reflector-client
 exit-address-family




XR13
router bgp 100
 address-family ipv4 unicast
 !
 !
 neighbor 100.14.14.14
  remote-as 100
  update-source Loopback0
  address-family ipv4 unicast



IOS9
router bgp 100
 bgp log-neighbor-changes
 neighbor 100.14.14.14 remote-as 100
 neighbor 100.14.14.14 update-source Loopback0




CSR14#show bgp ipv4 unicast summary 
BGP router identifier 100.14.14.14, local AS number 100
BGP table version is 2, main routing table version 2
3 network entries using 744 bytes of memory
5 path entries using 600 bytes of memory
3/1 BGP path/bestpath attribute entries using 768 bytes of memory
1 BGP AS-PATH entries using 24 bytes of memory
0 BGP route-map cache entries using 0 bytes of memory
0 BGP filter-list cache entries using 0 bytes of memory
BGP using 2136 total bytes of memory
BGP activity 4/1 prefixes, 7/2 paths, scan interval 60 secs

Neighbor        V           AS MsgRcvd MsgSent   TblVer  InQ OutQ Up/Down  State/PfxRcd
100.8.8.8       4          100     744     757        2    0    0 11:16:17        0
100.9.9.9       4          100      22      18        2    0    0 00:12:43        2
100.11.11.11    4          100     745     748        2    0    0 11:11:01        0
100.13.13.13    4          100      16      16        2    0    0 00:11:56        2




CSR14#show bgp ipv4 unicast         
BGP table version is 2, local router ID is 100.14.14.14
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
 * i 100.1.15.0/24    100.13.15.15             0    100      0 15 ?
 * i                  100.9.15.15              0    100      0 15 ?
 *>  100.14.14.14/32  0.0.0.0                  0         32768 i
 * i 100.15.15.15/32  100.13.15.15             0    100      0 15 i
 * i                  100.9.15.15              0    100      0 15 i

You'll notice that now CSR14 is now learning the routes that CSR15 has advertised but neither route is a best route. This is because the next hop information is set to the eBGP peering IP of CSR15 from both XR13 and IOS9. The next hop needs to be modified to something that CSR14 can recurse to, either the IP address of the loopback of each iBGP peer that advertised the routes or advertise the connected /24 prefixes used by the eBGP routers that connect AS 100 to AS 15.
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  • Home
  • Technology VoD!
    • Cisco >
      • Route & Switch / Enterprise Infrastructure
  • Technology Breakdowns!
    • Route&Switch/Ent. Infra. >
      • L2 Technologies
      • L3 Technologies
      • VPN Technologies
      • Services >
        • IOS - Dynamic NAT
        • HSRP - IPv4 Setup
        • HSRP - Priority and Preemption
    • Service Provider >
      • IGPs (Interior Gateway Protocols)
      • First Hop Redundancy >
        • HSRP (Hot Standby Router Protocol) >
          • HSRP - IOS/IOS XE Setup
          • HSRP - IOS XR Setup
      • BGP (Border Gateway Protocol)
      • Inter AS Multicast (MSDP)
      • Intra-AS MPLS
      • Inter-AS MPLS
    • Security >
      • IOS Firewall
      • ASA Firewall
      • FirePOWER Threat Defense >
        • FTD - FTD NGFW Device Setup and FMC Integration
      • VPNs >
        • PKI
        • Site to Site VPNs
        • Remote Access VPNs >
          • IOS Remote Access
          • ASA Remote Access
    • Data Center >
      • Nexus 9000v >
        • Nexus 9000v - Enabling Features
        • Nexus 9000v - VLANs and Trunks
        • Nexus 9000v - LACP Port Channels
        • Nexus 9000v - vPC (Virtual Port Channel)
        • Nexus 9000v - OSPFv2
        • Nexus 9000v - VXLAN - Ingress Replication Flood and Learn
        • Nexus 9000v - IP Multicast
        • Nexus 9000v - VxLAN - Multicast Flood and Learn
        • Nexus 9000v - VxLAN - BGP EVPN with Multicast
        • Nexus 9000v - VxLAN - BGP EVPN w/Ingress Replication
        • Nexus 9000v - VxLAN - Inter-VxLAN Routing with BGP EVPN
        • Nexus 9000v - VXLAN - External Routing
      • Nexus 7000v
    • Palo Alto