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New Member

two BGP

Hi,

Is it possible to run two BGP instances on the same router in global routing table?

i.e. this would be configuration on the router (with one instance with private AS number)

router bgp 5000

neigbor 1.1.1.1

router bgp 65002

neighbor 2.2.2.2

regards,

9 REPLIES
New Member

Re: two BGP

its possible though not recommended since the router will have to maintain and form two different BGP routing tables. Just use the dual-as keyword (local-as, remote-as).

http://www.cisco.com/en/US/docs/ios/12_2sr/12_2sra/feature/guide/srbgpdas.html

would be delighted if the expert suggest other solutions...

rgds

alex

New Member

Re: two BGP

But if this other BGP routing table had limited number of routes controled by route map I think this should work fine.

Thank you very much Alex.

Re: two BGP

Nope.

However, you can do route-map and prepend the other ASN if you want to advertise your two prefix each from different ASN.

For example;

!

router bgp 5000

advertising 192.168.0.0/16

Then you want to advertise 10.0.0.0/8 using ASN65002. You can create a route-map and prepend ASN65002. Your 10.0.0.0/8 (ASN65002) will look like behind ASN5000.

New Member

Re: two BGP

Problem is that now I have iBGP session betwwen routers R1 and R2. And I need R2 to establish eBGP session with R1 (that other sesion would be to private AS number). So unfortunatelly prepend doesn't help me.

New Member

Re: two BGP

Try this....

Router bgp 5000

neighbor remote-as 65000

neighbor remote-as 65000

neighbor local-as 65002

Make sure R2 knows the route of R1 loopback ip in IGP (not via other bgp session)....

Can you share if R1 and R2 having ibgp session already, why do you want to have ebgp session between them ?

Chetan !

New Member

Re: two BGP

Thanks,

Do I need to have both neighbor R1 loopback and interface IP? And I supose it doesn't have to be loopback IP it can be interface IP(neighbor local-as 65002 )?

The reason is following. R1 is N-PE router in MPLS and R2 is router that runs full BGP to ineternet and doesn't run . I wanted somehow to inject few routes in MPLS vrf Internet, but iBGP between CPE (R1) and PE (R2) is not supported by IOS. So I needed workaround in order to establish eBGP between R1 and R2.

regards,

Hall of Fame Super Silver

Re: two BGP

Hello Antonio,

the above configuration is NOT possible on a router.

Only one BGP process can exist on a router.

When you try to add a second one an error message appears:

see the following

RT-RM-TLD066-DMZ-C-1#sh ip prot sum

Index Process Name

0 connected

1 static

2 isis

3 bgp 8234

*** IP Routing is NSF aware ***

RT-RM-TLD066-DMZ-C-1#

RT-RM-TLD066-DMZ-C-1#conf t

Enter configuration commands, one per line. End with CNTL/Z.

RT-RM-TLD066-DMZ-C-1(config)#router bgp 5000

>>>>BGP is already running; AS is 8234

RT-RM-TLD066-DMZ-C-1(config)#^Z

RT-RM-TLD066-DMZ-C-1#sh ip prot sum

Index Process Name

0 connected

1 static

2 isis

3 bgp 8234

*** IP Routing is NSF aware ***

RT-RM-TLD066-DMZ-C-1#

as suggested you can pretend to be in another As by using the neigh x local-as y command

Hope to help

Giuseppe

New Member

Re: two BGP

Thanks I think I'll do that

New Member

Re: two BGP

thanks for your help, experts!!

having thought lately on this BGP issue, its truly forbiden to use two BGP processes on a router at the same time :)

love this forum, fully recommended

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