What is BGP Route Reflectors (RR)? How to configure?

Route reflectors (RR) are one method to eliminate the full mesh of IBGP peers in your network. The route reflector allows all IBGP speakers within your autonomous system to learn about the available routes without creating loops.

There are three types of peering in route reflectors:

1. EBGP neighbor
2. IBGP client neighbor
3. IBGP non-client neighbor

When configuring a route reflector (RR), we must tell the router whether the other IBGP router is a client or non-client. An IBGP client is an IBGP router that the route reflector will “reflect” routes to, the non-client is just a regular IBGP neighbor.

When a route reflector forwards a route update, there are a few rules that must be followed:

• A route learned from an EBGP neighbor can be forwarded to another EBGP neighbor, a client, and a non-client.
• A route learned from a client can be forwarded to another EBGP neighbor, client or 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 to advertise route received from an iBGP peers to other iBGP peers. All the valid clients update server Route Reflector-RR and server update to all the valid clients.

Each client only establishes a neighbor relationship with servers, clients are not allowed to establish neighbors with other clients. Route Reflector (servers) establish neighbor relationships with other servers (if you have more the one server) and clients.

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

Before we start  BGP configuration check out some important of BGP CCIE exam topics.

Here is the lists of all BGP labs and theories CCNA to CCIE 

1.Introduction of BGP

2.BGP Neighbors

3.BGP Peer Group

4.BGP Attributes

5.BGP Weight Attribute

6.BGP Local Preference (Local_Pref)

7.BGP Multi Exit Discriminator (MED)

8.BGP AS Path Prepending

9.BGP Route Reflectors (RR)

10.BGP Communities_No-advertise configuration

11.BGP community Local-AS

12.BGP Confederations and configuration

13.BGP Route filtering methods

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, and configure BGP AS 65100 as per our diagram using loopbacks.
• configure router 5 as a Route-Reflector server and the rest of the routers will play the 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                   25.1.1.2        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)#neighbor 150.0.0.1 remote-as 65100

R1(config-router)#neighbor 150.0.0.1 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:

     2

  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:

     2

  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:

     2

  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:

     2

  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

 

 

Instagram

YouTube

Facebook

Twitter

LINKEDIN