Cisco CCNP BSCI Tutorial: The BGP Attribute NEXT HOP 21029

When you're learning for the BSCI examination on the method to gaining your CCNP certification, you've surely got to learn the use of BGP attributes. These attributes enable you to adjust the path or paths that BGP uses to reach a given destination when numerous paths to that destination exist. To read additional information, people should check out: how linklicious.me works.

Within this free BGP guide, we are planning to take a peek in the NEXT_HOP credit. You may well be considering "hey, how complicated can this attribute be?" It is not to complex at all, but this being Cisco, there is got to be at least one unusual aspect about it, right?

The NEXT_HOP attribute is straightforward enough - this attribute indicates the next-hop INTERNET protocol address that should be taken to attain a destination. In the following illustration, R1 is a centre hub and R2 and R3 are spokes. All three routers are in BGP AS 100, with R1 having a connection with both R3 and R2. There's no BGP peering between R2 and R3.

R3 is advertising the network 33.3.0.0 /24 via BGP, and the value of the next-hop characteristic on R1 is the IP address on R3 that's utilized in the peer relationship, 172.12.123.3.

The issue using the next-hop attribute will come in if the route is advertised to BGP peers. If R3 were in another AS from R1 and R2, R1 would then advertise the route to R2 with the attribute set to 172.12.123.3. Whenever a BGP speaker advertises a path to iBGP peers that has been originally learned from an eBGP look, the next-hop value is kept.

Here, all three routers come in AS 100. What'll the next-hop feature be established to when R1 advertises the route to its iBGP friend R2?

R2#show ip address bgp



There will be no attribute for the route on R2, because the route won't look on R2. Automagically, a BGP speaker won't promote a to iBGP neighbors if the route was initially learned from another iBGP friend.

Luckily for us, there are several ways around this concept. To get other viewpoints, please consider checking out: linklicious.me discount. Be taught more on our affiliated article directory by visiting linklicious submission. The most common is the use of route reflectors, and we'll look at RRs in a future free BGP guide..

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