Cisco ccnp bsci accreditation bgp route reflector tutorial

Cisco CCNP/ BSCI Qualification: BGP Route Reflector Tutorial

Cisco CCNP/ BSCI Certification: BGP Route Reflector Tutorial

When you're studying for your BSCI test and CCNP qualification, you rapidly realize that BGP is a whole new globe from anything you have actually previously researches. One topic that sometimes confuses CCNP prospects is when a BGP route reflector needs to be configured.

In the following example, the routers R1, R2, and R3 are done in BGP AS 100. This is not a complete mesh, nonetheless. There are peer partnerships between R1-R2 and R1-R3, yet not in between R2 and R3. R3 is advertising network 3.3.3.0/ 24 using BGP, and the path is seen on R1. R1's iBGP neighbor, R2 does not see the route.

A basic regulation of BGP is that a BGP audio speaker can not advertise a path to an iBGP next-door neighbor if that route was gained from one more iBGP neighbor. Configuring R1 as a route reflector will permit us to prevent this policy. The entire path reflector process is clear to the clients, and no arrangement is needed on those customers. We'll configure R1 as a course reflector for both R2 and R3.

R1(config)#router bgp 100

R1(config-router)#neighbor 172.12.123.2 route-reflector-client

3 d18h: %BGP-5-ADJCHANGE: neighbor 172.12.123.2 Down RR client config change

R1(config-router)#neighbor 172.12.123.3 route-reflector-client

3 d18h: %BGP-5-ADJCHANGE: next-door neighbor 172.12.123.3 Down RR client config change

The BGP adjacencies do come down when this configuration is added, so this isn't something you want to do during a top web traffic time.

Once the adjacencies return up, R2 will have the path to 3.3.3.0/ 24.

There are other feasible options to this iBGP limitation, such as setting up BGP confederations. Those remedies are generally made use of on larger BGP deployments and with various other issues in mind, however, and DANIEL Cullen achievements configuring route reflectors offers this objective just as well.