Cisco CCNP / BSCI Tutorial: The BGP Attribute NEXT_HOP

When you are learning for the BSCI examination on the way to earning your CCNP accreditation, you've got to learn the usage of BGP attributes. These features permit you to change the path or paths that BGP use to attain certain destination when numerous paths to that destination occur.

In this free BGP tutorial, we are likely to take a peek in the NEXT_HOP characteristic. You may be thinking "hey, how complicated can this credit be?" It's not to difficult at all, but this being Cisco, there is 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 reach a spot. In the following illustration, R1 is a heart switch and R2 and R3 are spokes. All three routers come in BGP AS 100, with R1 having a connection with both R2 and R3. There's no BGP peering between R3 and R2.

R3 is advertising the community 33.3.0.0 /24 via BGP, and the value of the attribute on R1 is the IP address on R3 that's utilized in the peer relationship, 172.12.123.3. Dig up more on our related web resource - Browse this URL: try linklicious.me affiliate. To read more, consider checking out: indexification.

The problem with the next-hop credit comes in once the route is marketed to BGP peers. If R3 were in a different AS from R1 and R2, the route would be then advertised by R1 to R2 with the attribute set to 172.12.123.3. The next-hop value is stored, when a BGP speaker advertises a path to iBGP colleagues that has been originally learned from an eBGP look.

Here, all three routers are in AS 100. If you are interested in marketing, you will likely fancy to research about best backlinksindexer.com. What will the attribute be set to when R1 advertises the route to its iBGP friend R2?

R2#show internet protocol address bgp

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There will be no next-hop credit for the route on R2, since the route will not appear on R2. By default, a BGP speaker won't advertise a to iBGP neighbors when the route was first learned from another iBGP neighbor.

Luckily for all of us, there are several ways around this rule. The most frequent is using route reflectors, and we'll look at RRs in the next free BGP tutorial.. To compare additional info, you are encouraged to take a peep at: click for backlink indexer.