BGP RR: Two Clusters, Intra-site and Inter-site Route Reflection
Today I am going to talk about BGP route reflector with the configuration of two clusters which consists of intra-site and inter-site Route reflection. Below is the topology showing the two cluster and i will take through below topology with the configuration on the RR (Route Reflector) device.
Below are the configurations:
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| Fig 1.1- BGP RR: Two Clusters, Intra-site and Inter-site Route Reflection |
RR#sh run | sec bgp
router bgp 1
no bgp client-to-client reflection intra-cluster cluster-id 192.168.1.1
bgp log-neighbor-changes
neighbor 10.0.10.2 remote-as 1
neighbor 10.0.10.2 cluster-id 192.168.1.1
neighbor 10.0.10.2 route-reflector-client
neighbor 10.0.20.2 remote-as 1
neighbor 10.0.20.2 cluster-id 192.168.1.1
neighbor 10.0.20.2 route-reflector-client
neighbor 10.0.40.2 remote-as 1
neighbor 10.0.40.2 cluster-id 192.168.2.2
neighbor 10.0.40.2 route-reflector-client
neighbor 10.0.50.2 remote-as 1
neighbor 10.0.50.2 cluster-id 192.168.2.2
neighbor 10.0.50.2 route-reflector-client
neighbor 10.0.70.2 remote-as 1
In this case both PEs on Site 1 form the cluster 192.168.1.1 while both PEs on Site 2 form the cluster 192.168.2.2. S3PE1 is a non-client. PEs on Site 1 have direct iBGP session, intra-cluster reflection is disabled for the cluster 192.168.1.1, but still enabled for the cluster 192.168.2.2. Inter-cluster reflection is enabled.
RR#show ip bgp cluster-ids
Global cluster-id: 172.16.3.3 (configured: 0.0.0.0)
BGP client-to-client reflection: Configured Used
all (inter-cluster and intra-cluster): ENABLED
intra-cluster: ENABLED ENABLED
List of cluster-ids:
Cluster-id #-neighbors C2C-rfl-CFG C2C-rfl-USE
192.168.1.1 2 DISABLED DISABLED
192.168.2.2 2 ENABLED ENABLED
RR#show ip bgp 172.16.1.1
BGP routing table entry for 172.16.1.1/32, version 5
Paths: (1 available, best #1, table default, RIB-failure(17))
Advertised to update-groups:
3 5
Refresh Epoch 9
Local, (Received from a RR-client)
10.0.10.2 from 10.0.10.2 (172.16.1.1)
Origin IGP, metric 0, localpref 100, valid, internal, best
rx pathid: 0, tx pathid: 0x0
RR#show ip bgp update-group 3
BGP version 4 update-group 3, internal, Address Family: IPv4 Unicast
BGP Update version : 11/0, messages 0
Topology: global, highest version: 11, tail marker: 11
Format state: Current working (OK, last not in list)
Refresh blocked (not in list, last not in list)
Update messages formatted 20, replicated 20, current 0, refresh 0, limit 1000
Number of NLRIs in the update sent: max 1, min 0
Minimum time between advertisement runs is 0 seconds
Has 1 member:
10.0.70.2
RR#show ip bgp update-group 5
BGP version 4 update-group 5, internal, Address Family: IPv4 Unicast
BGP Update version : 11/0, messages 0
Route-Reflector Client
Configured with cluster-id 192.168.2.2
Topology: global, highest version: 11, tail marker: 11
Format state: Current working (OK, last not in list)
Refresh blocked (not in list, last not in list)
Update messages formatted 22, replicated 34, current 0, refresh 0, limit 1000
Number of NLRIs in the update sent: max 3, min 0
Minimum time between advertisement runs is 0 seconds
Has 2 members:
10.0.40.2 10.0.50.2
Prefix 172.16.1.1/32 recieved from S1PE1 is reflected to the clients in the cluster 192.168.2.2 and to the non-clients. At the same time, prefix 172.16.4.4/32 recieved from S2PE1 is reflected to all clients and non-clients.
RR#show ip bgp 172.16.4.4
BGP routing table entry for 172.16.4.4/32, version 9
Paths: (1 available, best #1, table default, RIB-failure(17))
Advertised to update-groups:
3 4 5
Refresh Epoch 6
Local, (Received from a RR-client)
10.0.40.2 from 10.0.40.2 (172.16.4.4)
Origin IGP, metric 0, localpref 100, valid, internal, best
rx pathid: 0, tx pathid: 0x0
RR#show ip bgp update-group 3
BGP version 4 update-group 3, internal, Address Family: IPv4 Unicast
BGP Update version : 11/0, messages 0
Topology: global, highest version: 11, tail marker: 11
Format state: Current working (OK, last not in list)
Refresh blocked (not in list, last not in list)
Update messages formatted 20, replicated 20, current 0, refresh 0, limit 1000
Number of NLRIs in the update sent: max 1, min 0
Minimum time between advertisement runs is 0 seconds
Has 1 member:
10.0.70.2
RR#show ip bgp update-group 4
BGP version 4 update-group 4, internal, Address Family: IPv4 Unicast
BGP Update version : 11/0, messages 0
Route-Reflector Client
Configured with cluster-id 192.168.1.1
Topology: global, highest version: 11, tail marker: 11
Format state: Current working (OK, last not in list)
Refresh blocked (not in list, last not in list)
Update messages formatted 26, replicated 47, current 0, refresh 0, limit 1000
Number of NLRIs in the update sent: max 3, min 0
Minimum time between advertisement runs is 0 seconds
Has 2 members:
10.0.10.2 10.0.20.2
RR#show ip bgp update-group 5
BGP version 4 update-group 5, internal, Address Family: IPv4 Unicast
BGP Update version : 11/0, messages 0
Route-Reflector Client
Configured with cluster-id 192.168.2.2
Topology: global, highest version: 11, tail marker: 11
Format state: Current working (OK, last not in list)
Refresh blocked (not in list, last not in list)
Update messages formatted 22, replicated 34, current 0, refresh 0, limit 1000
Number of NLRIs in the update sent: max 3, min 0
Minimum time between advertisement runs is 0 seconds
Has 2 members:
10.0.40.2 10.0.50.2
You can disable intra-site route-reflection for cluster 192.168.2.2 as well, but in this case clients in that cluster should have full mesh of iBGP sessions:
RR(config-router)#no bgp client-to-client reflection intra-cluster cluster-id 192.168.2.2
RR#sh ip bgp cluster-ids
Global cluster-id: 172.16.3.3 (configured: 0.0.0.0)
BGP client-to-client reflection: Configured Used
all (inter-cluster and intra-cluster): ENABLED
intra-cluster: ENABLED ENABLED
List of cluster-ids:
Cluster-id #-neighbors C2C-rfl-CFG C2C-rfl-USE
192.168.1.1 2 DISABLED DISABLED
192.168.2.2 2 DISABLED DISABLED
Intra-site reflection can be also disabled for all clusters:
RR(config-router)#no bgp client-to-client reflection intra-cluster cluster-id any
