Direction in and out in bgp

[prashantrecon]

Just a scenario

router 1 and router 2 (isp)

router 1 wan ip --101.2.2.1

router2(isp) wan ip-  101.2.2.2

I have network of 202.x.x.x/24

on router1

neighbour 101.2.2.2 route-map chic in

route-map chic permit 10

match ip address prefix-list dafault

set local-prefence 700

ip prefix-list default seq 5 0.0.0.0/0

Here direction in means   outbound data ? ie data leaving the network.

What happens if i excute out command instead of in?

[smitesh kharecha]

hi Prashant,

IN will apply to whatever you learn from your peer.

OUT will apply to whatever you give it to your peer.

So, in your case, whatever prefixes you are learning from your peer ( in your case 101.2.2.2 ) will have local preference set to 700 ( which is 100 by default).

HTH,

Smitesh

PS: Please rate if helpful...

[prashantrecon]

so here i have given 0.0.0.0/0

so in  direction means  from my network any data will be allowed to reach isp  router.

out means that data will reach to my router

is that correct ?

[Giuseppe Larosa]

Hello Prashant,

the in and out directions refer to the routing exchange between BGP peers as explained by Smitesh,

You are accepting only the default route 0.0.0.0/0 from the BGP peer and you are giving to this route a local preference of 700> 100. (better then default settings)

Filtering on user traffic plane can be performed in the usual way by applying ACLs directly to the interface that leads to the eBGP peer. But it is a totally different matter.

BGP sessions are in the routing / signalling plane and these filters decide what can be accepted or sent to the peer rather then filtering the user traffic.

Hope to help

Giuseppe