When you're learning for the BSCI assessment on the way to getting your CCNP accreditation, you have got to master the usage of BGP attributes. These attributes enable you to change the path or paths that BGP uses to attain a given destination when multiple paths to that destination exist.

Within this free BGP article, we're likely to have a look at the NEXT_HOP characteristic. You might be thinking \hey, how difficult can this characteristic be?\ It's not very difficult at all, but this being Cisco, there's got to be at least one unusual detail about it, right?

The NEXT_HOP attribute is straightforward enough - this attribute indicates the next-hop IP address that should be taken to attain a destination. Within the following instance, R1 is a center modem and R3 and R2 are spokes. All three routers come in BGP AS 100, with R1 having a connection with both R3 and R2. There is no BGP peering between R3 and R2. If you think anything, you will probably hate to compare about lindexed.

R3 is advertising the community 33.3.0.0 /24 via BGP, and the importance of the characteristic on R1 is the IP address on R3 that's utilized in the peer relationship, 172.12.123.3.

The issue using the feature will come in if the route is marketed to BGP peers. If R3 were in a separate AS from R1 and R2, the route would be then advertised by R1 to R2 with the next-hop attribute set to 172.12.123.3. When a BGP speaker advertises an approach to iBGP peers that was initially learned from an eBGP peer, the next-hop value is retained.

Here, all three routers are in AS 100. What'll the credit be established to when R1 advertises the path to its iBGP friend R2?

R2#show internet protocol address bgp

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There will be no next-hop feature for the route on R2, as the route won't look on R2. By default, a route will not be advertised by a BGP speaker to iBGP neighbors when the route was learned from another iBGP friend. Learn additional resources on our related article by visiting linklicious guide.

Fortunately for all of us, there are many ways around this concept. The most typical is the usage of route reflectors, and we'll look at RRs in a future free BGP training.. This fresh learn about linklicious.net URL has uncountable thrilling aids for the meaning behind it. Click here free linklicious alternative to read the purpose of it.