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10
Replies

BGP Help reqd.

mahesh-gohil
Level 1
Level 1

Hi all,

I am attaching a network diagram

I have used minimum BGP configuration

I want to know what additional configuration required without using any IGP on all routers so that I can reach from every router to every router

Regards

Mahesh

1 Accepted Solution

Accepted Solutions

Mahesh

You need to advertise out the networks in AS100 to the 7613 router. You can use "network" statements under your BGP config

eg

3750

router bgp 100

network 2.2.2.4 mask 255.255.255.252

etc..

It would be better if you used a different network for the 7613 -> 3750 connection then you could just summarise out the 2.2.2.x networks from the 3750 ie

router bgp 100

network 2.2.2.0 mask 255.255.255.0

HTH

Jon

View solution in original post

10 Replies 10

mohammedmahmoud
Level 11
Level 11

Hi,

You need full mesh iBGP between you iBGP routers, and make sure the peering IPs are pingable from each router (use static routes).

HTH, please do rate all helpful replies,

Mohammed Mahmoud.

Jon Marshall
Hall of Fame
Hall of Fame

Hi

Mohammed is spot on. Just to give another option. Rather than full mesh IBGP you could set up your 3750 as a route-reflector for the 2811 and the RAS routers. This would achive the same effect.

HTH

Jon

Hi,

Jon is completely right, using RR is the best practice, and even if you want to simplify the configuration, using RR is not a hard task.

HTH,

Mohammed Mahmoud.

Ok I have changed config of 3750 like

3750# router bgp 100

no synchronization

bgp log-neighbor-changes

neighbor 2.2.2.1 remote-as 200

neighbor 2.2.2.1 next-hop-self

neighbor 2.2.2.6 remote-as 100

neighbor 2.2.2.6 route-reflector-client

neighbor 2.2.2.18 remote-as 100

neighbor 2.2.2.18 route-reflector-client

no auto-summary

Now I am not able to ping from 2811 to RAS

Do i need static router and where ?

Regards

Hi,

Yes you need static routing on both 2811 and RAS pointing to each other peer ips having the next-hop as the 3750 (and the 3750 will route between its directed interfaces).

HTH,

Mohammed Mahmoud.

ok i had given static route on 2811 as

ip route 2.2.2.16 255.255.255.252 2.2.2.5

and on RAS

ip route 2.2.2.4 255.255.255.252 2.2.2.17

and that is working

Now to reach from RAS and 2811 to 7613 what should I do

Regards

Mahesh

Hi,

This case is slightly different, as the 2811 to 7613 is eBGP not iBGP, and thus you'll need "ebgp-multihop 2" on both sides, plus static routing as before.

HTH,

Mohammed Mahmoud.

Mahesh

You need to advertise out the networks in AS100 to the 7613 router. You can use "network" statements under your BGP config

eg

3750

router bgp 100

network 2.2.2.4 mask 255.255.255.252

etc..

It would be better if you used a different network for the 7613 -> 3750 connection then you could just summarise out the 2.2.2.x networks from the 3750 ie

router bgp 100

network 2.2.2.0 mask 255.255.255.0

HTH

Jon

Hi

Yes you can use static routes or

1) use network statements under the BGP config to advertise out the subnets on 2811 and RAS.

2) use the "redistribute connected" command under the BGP config.

Depends how many subnets you are using on each router.

HTH

Jon

Thanks everybody

Now I had many option without IGP

Really thanks

Mahesh

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