What is Route Reflector in BGP?

The Route Reflector (RR) is one of the ways to eliminate the full mesh of IBGP peers in the network. The route reflector allows all IBGP speakers in the autonomous system to understand the available routes without creating a loop. SPOTO will introduce the basic knowledge of RR used in BGP, and you can master some details on how to work it. SPOTO has a 16-year IT training, and it will provide all kinds of certification exams that can help you get a high-level job and income.if you want to have a bright future, you can believe in SPOTO.

There are three types of peering in route reflector:

1.EBGP neighbor

2.IBGP client neighbor

3.IBGP non-client neighbor

When we configure the route reflector (RR), we must tell the router whether another IBGP router is a client or a non-client. An IBGP client is an IBGP router that the route reflector "reflects" to. The non-client is just a normal IBGP neighbor.

When a route reflector forwards route updates, there are a few rules that must follow:

·A route learned from an EBGP neighbor can be forwarded to another EBGP neighbor, a client, and non-client.

·A route learned from a client can be forwarded to another EBGP neighbor, client, and non-client.

·A route learned from a non-client can be forwarded to another EBGP neighbor and client, but not to a non-client.

In other words: Route Reflector - rr notifies other iBGP peers of routes received from an iBGP peer. All valid client update server route reflectors - rr and server updates to all valid clients.

Each client only establishes a neighbor relationship with the server, and the client does not allow neighbor relationships with other clients. The route reflector (server) establishes a neighbor relationship with the other server (if you have multiple servers) and the client.

I hope now you have an idea what is route reflector, so let see the configuration:

Route-Reflector Configuration:-

Topology:

Goal:

·configure the topology as per our diagram.

·configure EIGRP 65100 to provide connectivity between peers

·advertise all the directly connected interfaces

·configure BGP AS 65100 as per our diagram using loopbacks.

·configure router 5 as Route-Reflector server and rest of the routers will play client role.

R1#show ip interface brief

Interface IP-Address OK? Method Status Protocol

FastEthernet0/0 10.1.1.1 YES manual up up

Serial3/0 1.1.1.1 YES manual up up

Serial3/3 4.1.1.2 YES manual up up

Serial3/6 15.1.1.1 YES manual up up

Loopback0 11.0.0.1 YES manual up up

Loopback1 11.0.1.1 YES manual up up

Loopback2 11.0.2.1 YES manual up up

Loopback3 11.0.3.1 YES manual up up

R2#show ip interface brief

Interface IP-Address OK? Method Status Protocol

FastEthernet0/0 20.1.1.1 YES manual up up

Serial3/0 1.1.1.2 YES manual up up

Serial3/1 2.1.1.1 YES manual up up

Serial3/4 25.1.1.1 YES manual up up

Loopback0 12.0.0.1 YES manual up up

Loopback1 12.0.1.1 YES manual up up

Loopback2 12.0.2.1 YES manual up up

Loopback3 12.0.3.1 YES manual up up

R3#show ip interface brief

Interface IP-Address OK? Method Status Protocol

FastEthernet0/0 30.1.1.1 YES manual up up

Serial3/1 2.1.1.2 YES manual up up

Serial3/2 3.1.1.1 YES manual up up

Serial3/5 35.1.1.1 YES manual up up

Loopback0 13.0.0.1 YES manual up up

Loopback1 13.0.1.1 YES manual up up

Loopback2 13.0.2.1 YES manual up up

Loopback3 13.0.3.1 YES manual up up

R4#show ip interface brief

Interface IP-Address OK? Method Status Protocol

FastEthernet0/0 40.1.1.1 YES manual up up

Serial3/2 3.1.1.2 YES manual up up

Serial3/3 4.1.1.1 YES manual up up

Serial3/7 45.1.1.1 YES manual up up

Loopback0 14.0.0.1 YES manual up up

Loopback1 14.0.1.1 YES manual up up

Loopback2 14.0.2.1 YES manual up up

Loopback3 14.0.3.1 YES manual up up

R5#show ip interface brief

Interface IP-Address OK? Method Status Protocol

FastEthernet0/0 50.1.1.1 YES manual up up

Serial3/4 5.1.1.2 YES manual up up

Serial3/5 35.1.1.2 YES manual up up

Serial3/6 15.1.1.2 YES manual up up

Serial3/7 45.1.1.2 YES manual up up

Loopback0 150.0.0.1 YES manual up up

Loopback1 150.0.1.1 YES manual up up

Loopback2 150.0.2.1 YES manual up up

Loopback3 150.0.3.1 YES manual up up

R1(config)#router eigrp 65100

R1(config-router)#network 1.0.0.0

R1(config-router)#network 4.0.0.0

R1(config-router)#network 15.0.0.0

R1(config-router)#network 11.0.0.0

R1(config-router)#network 10.0.0.0

R1(config-router)#no auto-summary

R1(config-router)#exit

R2(config)#router eigrp 65100

R2(config-router)#network 1.0.0.0

R2(config-router)#network 2.0.0.0

R2(config-router)#network 20.0.0.0

R2(config-router)#network 12.0.0.0

R2(config-router)#network 25.0.0.0

R2(config-router)#no auto-summary

R2(config-router)#exit

R3(config)#router eigrp 65100

R3(config-router)#network 2.0.0.0

R3(config-router)#network 3.0.0.0

R3(config-router)#network 13.0.0.0

R3(config-router)#network 30.0.0.0

R3(config-router)#no auto-summary

R3(config-router)#exit

R4(config)#router eigrp 65100

R4(config-router)#network 3.0.0.0

R4(config-router)#network 4.0.0.0

R4(config-router)#network 14.0.0.0

R4(config-router)#network 40.0.0.0

R4(config-router)#network 45.0.0.0

R4(config-router)#no auto-summary

R4(config-router)#exit

R5(config)#router eigrp 65100

R5(config-router)#network 150.0.0.0

R5(config-router)#network 50.0.0.0

R5(config-router)#network 15.0.0.0

R5(config-router)#network 25.0.0.0

R5(config-router)#network 35.0.0.0

R5(config-router)#network 45.0.0.0

R5(config-router)#no auto-summary

R5(config-router)#exit

R1(config)#router bgp 65100

R1(config-router)#neighbor 12.0.0.1 remote-as 65100

R1(config-router)#neighbor 12.0.0.1 update-source loopback 0

R1(config-router)#neighbor 14.0.0.1 remote-as 65100

R1(config-router)#neighbor 14.0.0.1 update-source loopback 0

R1(config-router)#network 10.0.0.0

R1(config-router)#no synchronization

R1(config-router)#no auto-summary

R1(config-router)#exit

R2(config)#router bgp 65100

R2(config-router)#neighbor 11.0.0.1 remote-as 65100

R2(config-router)#neighbor 11.0.0.1 update-source loopback 0

R2(config-router)#neighbor 13.0.0.1 remote-as 65100

R2(config-router)#neighbor 13.0.0.1 update-source loopback 0

R2(config-router)# neighbor 150.0.0.1 remote-as 65100

R2(config-router)# neighbor 150.0.0.1 update-source loopback 0

R2(config-router)#network 20.0.0.0

R2(config-router)#no auto-summary

R2(config-router)#no synchronization

R2(config-router)#exit

R3(config)#router bgp 65100

R3(config-router)#neighbor 12.0.0.1 remote-as 65100

R3(config-router)#neighbor 12.0.0.1 update-source loopback 0

R3(config-router)#neighbor 14.0.0.1 remote-as 65100

R3(config-router)#neighbor 14.0.0.1 update-source loopback 0

R3(config-router)#neighbor 150.0.0.1 remote-as 65100

R3(config-router)#neighbor 150.0.0.1 update-source loopback 0

R3(config-router)#network 30.0.0.0

R3(config-router)#no auto-summary

R3(config-router)#no synchronization

R3(config-router)#exit

R4(config)#router bgp 65100

R4(config-router)#neighbor 13.0.0.1 remote-as 65100

R4(config-router)#neighbor 13.0.0.1 update-source loopback 0

R4(config-router)#neighbor 11.0.0.1 remote-as 65100

R4(config-router)#neighbor 11.0.0.1 update-source loopback 0

R4(config-router)# neighbor 150.0.0.1 remote-as 65100

R4(config-router)# neighbor 150.0.0.1 update-source loopback 0

R4(config-router)#network 40.0.0.0

R4(config-router)#no auto-summary

R4(config-router)#no synchronization

R4(config-router)#exit

R5(config)#router bgp 65100

R5(config-router)#neighbor 11.0.0.1 remote-as 65100

R5(config-router)#neighbor 11.0.0.1 update-source loopback 0

R5(config-router)#neighbor 12.0.0.1 remote-as 65100

R5(config-router)#neighbor 12.0.0.1 update-source loopback 0

R5(config-router)#neighbor 13.0.0.1 remote-as 65100

R5(config-router)#neighbor 13.0.0.1 update-source loopback 0

R5(config-router)#neighbor 14.0.0.1 remote-as 65100

R5(config-router)#neighbor 14.0.0.1 update-source loopback 0

R5(config)#router bgp 65100

R5(config-router)#neighbor 11.0.0.1 route-reflector-client

*Dec 7 14:07:56.415: %BGP-5-ADJCHANGE: neighbor 11.0.0.1 Down RR client config change

*Dec 7 14:07:56.419: %BGP_SESSION-5-ADJCHANGE: neighbor 11.0.0.1 IPv4 Unicast topology base removed from session RR client config change

*Dec 7 14:07:57.291: %BGP-5-ADJCHANGE: neighbor 11.0.0.1 Up

R5(config-router)#neighbor 12.0.0.1 route-reflector-client

*Dec 7 14:08:04.183: %BGP-5-ADJCHANGE: neighbor 12.0.0.1 Down RR client config change

*Dec 7 14:08:04.187: %BGP_SESSION-5-ADJCHANGE: neighbor 12.0.0.1 IPv4 Unicast topology base removed from session RR client config change

*Dec 7 14:08:04.407: %BGP-5-ADJCHANGE: neighbor 12.0.0.1 Up

R5(config-router)#neighbor 13.0.0.1 route-reflector-client

*Dec 7 14:08:15.187: %BGP-5-ADJCHANGE: neighbor 13.0.0.1 Down RR client config change

*Dec 7 14:08:15.187: %BGP_SESSION-5-ADJCHANGE: neighbor 13.0.0.1 IPv4 Unicast topology base removed from session RR client config change

*Dec 7 14:08:15.683: %BGP-5-ADJCHANGE: neighbor 13.0.0.1 Up

R5(config-router)#neighbor 14.0.0.1 route-reflector-client

*Dec 7 14:08:33.659: %BGP-5-ADJCHANGE: neighbor 14.0.0.1 Down RR client config change

*Dec 7 14:08:33.663: %BGP_SESSION-5-ADJCHANGE: neighbor 14.0.0.1 IPv4 Unicast topology base removed from session RR client config change

*Dec 7 14:08:33.983: %BGP-5-ADJCHANGE: neighbor 14.0.0.1 Up

R5(config-router)#end

R5#show ip bgp 10.1.1.1

BGP routing table entry for 10.0.0.0/8, version 7

Paths: (1 available, best #1, table default, RIB-failure(17))

Advertised to update-groups:

Refresh Epoch 2

Local, (Received from a RR-client)

11.0.0.1 (metric 2297856) from 11.0.0.1 (11.0.3.1)

Origin IGP, metric 0, localpref 100, valid, internal, best

rx pathid: 0, tx pathid: 0x0

R5#show ip bgp 20.1.1.1

BGP routing table entry for 20.0.0.0/8, version 9

Paths: (1 available, best #1, table default, RIB-failure(17))

Advertised to update-groups:

Refresh Epoch 2

Local, (Received from a RR-client)

12.0.0.1 (metric 2297856) from 12.0.0.1 (12.0.3.1)

Origin IGP, metric 0, localpref 100, valid, internal, best

rx pathid: 0, tx pathid: 0x0

R5#show ip bgp 30.1.1.1

BGP routing table entry for 30.0.0.0/8, version 11

Paths: (1 available, best #1, table default, RIB-failure(17))

Advertised to update-groups:

Refresh Epoch 2

Local, (Received from a RR-client)

13.0.0.1 (metric 2809856) from 13.0.0.1 (13.0.3.1)

Origin IGP, metric 0, localpref 100, valid, internal, best

rx pathid: 0, tx pathid: 0x0

R5#show ip bgp 40.1.1.1

BGP routing table entry for 40.0.0.0/8, version 13

Paths: (1 available, best #1, table default, RIB-failure(17))

Advertised to update-groups:

Refresh Epoch 2

Local, (Received from a RR-client)

14.0.0.1 (metric 2297856) from 14.0.0.1 (14.0.3.1)

Origin IGP, metric 0, localpref 100, valid, internal, best

rx pathid: 0, tx pathid: 0x0

R1#show ip bgp 20.1.1.1

BGP routing table entry for 20.0.0.0/8, version 3

Paths: (2 available, best #2, table default, RIB-failure(17))

Not advertised to any peer

Refresh Epoch 1

Local

12.0.0.1 (metric 2297856) from 150.0.0.1 (150.0.3.1)

Origin IGP, metric 0, localpref 100, valid, internal

Originator: 12.0.3.1, Cluster list: 150.0.3.1

rx pathid: 0, tx pathid: 0

Refresh Epoch 1

Local

12.0.0.1 (metric 2297856) from 12.0.0.1 (12.0.3.1)

Origin IGP, metric 0, localpref 100, valid, internal, best

rx pathid: 0, tx pathid: 0x0

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