No-Client-To-Client-Reflection

Scenario to verify BGP no-client-to-client-reflection parameter configuration.

In standard iBGP, the split-horizon rule prevents a router from re-announcing routes learned from one iBGP peer to another iBGP peer. Route Reflectors override this rule for their clients, reflecting routes between them to avoid full-mesh requirements.

The no-client-to-client-reflection parameter re-enables a form of split-horizon specifically between Route Reflector clients. When configured, the RR will not reflect routes from one client to another client. This is useful when RR clients have direct iBGP sessions between themselves or when you want finer control over route propagation.

In this test, DUT0 acts as a Route Reflector with two clients: DUT1 and DUT2. First, with default RR behavior, routes from DUT1 are reflected to DUT2. Then, after enabling no-client-to-client-reflection, the route is no longer reflected between clients.

Test BGP No Client To Client Reflection

Description

This test demonstrates the effect of no-client-to-client-reflection on a Route Reflector. First, with default behavior, DUT0 (RR) reflects routes from DUT1 to DUT2 (both are RR clients). Then, after enabling no-client-to-client-reflection, the route from DUT1 is no longer reflected to DUT2.

Scenario

Note

First we configure the Route Reflector with default behavior (client-to-client reflection enabled).

Step 1: Set the following configuration in DUT0 :

set interfaces ethernet eth0 address 10.10.0.1/24
set interfaces ethernet eth1 address 20.20.0.1/24
set protocols bgp 100 neighbor client1 remote-address 10.10.0.2
set protocols bgp 100 neighbor client1 remote-as 100
set protocols bgp 100 neighbor client1 route-reflector-client
set protocols bgp 100 neighbor client2 remote-address 20.20.0.2
set protocols bgp 100 neighbor client2 remote-as 100
set protocols bgp 100 neighbor client2 route-reflector-client
set system login user admin authentication encrypted-password '$6$GSjsCj8gHLv$/VcqU6FLi6CT2Oxn0MJQ2C2tqnRDrYKNF8HIYWJp68nvXvPdFccDsT04.WtigUONbKYrgKg8d6rEs8PjljMkH0'

Step 2: Set the following configuration in DUT1 :

set interfaces ethernet eth0 address 10.10.0.2/24
set protocols bgp 100 neighbor rr remote-address 10.10.0.1
set protocols bgp 100 neighbor rr remote-as 100
set protocols bgp 100 redistribute connected
set system login user admin authentication encrypted-password '$6$GSjsCj8gHLv$/VcqU6FLi6CT2Oxn0MJQ2C2tqnRDrYKNF8HIYWJp68nvXvPdFccDsT04.WtigUONbKYrgKg8d6rEs8PjljMkH0'

Step 3: Set the following configuration in DUT2 :

set interfaces ethernet eth1 address 20.20.0.2/24
set protocols bgp 100 neighbor rr remote-address 20.20.0.1
set protocols bgp 100 neighbor rr remote-as 100
set system login user admin authentication encrypted-password '$6$GSjsCj8gHLv$/VcqU6FLi6CT2Oxn0MJQ2C2tqnRDrYKNF8HIYWJp68nvXvPdFccDsT04.WtigUONbKYrgKg8d6rEs8PjljMkH0'

Attention

Verify iBGP sessions establish between DUT0 (RR) and both clients.

Step 4: Run command protocols bgp show ip summary at DUT0 and check if output matches the following regular expressions:

10.10.0.2.*Established[\s\S]+20.20.0.2.*Established

Attention

Verify DUT0 receives route 10.10.0.0/24.

Step 5: Run command protocols bgp show ip at DUT0 and check if output matches the following regular expressions:

10.10.0.0/24

Note

With default behavior, DUT2 receives the reflected route.

Step 6: Run command protocols bgp show ip at DUT2 and check if output matches the following regular expressions:

10.10.0.0/24

Note

Now we enable no-client-to-client-reflection to disable route reflection between clients.

Step 7: Modify the following configuration lines in DUT0 :

set protocols bgp 100 parameters no-client-to-client-reflection

Attention

Verify iBGP sessions remain established after configuration change.

Step 8: Run command protocols bgp show ip summary at DUT0 and check if output matches the following regular expressions:

10.10.0.2.*Established[\s\S]+20.20.0.2.*Established

Attention

Verify DUT2 no longer receives the route due to disabled client-to-client reflection.

Step 9: Run command protocols bgp show ip at DUT2 and check if output does not match the following regular expressions:

10.10.0.0/24