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New Member

two bgp as

Is it possible to have two different BGP AS in the same router?

Thank's

Marcelo

1 ACCEPTED SOLUTION

Accepted Solutions
Cisco Employee

Re: two bgp as

Marcelo,

You cannot use this command on an iBGP peer. You can inverse the logic though, change your "router bgp" ASN to 65200 and use the local-as command on the peer to ASN 11664 instead as follow:

router bgp 65200

neighbor 77.1.248.25 remote-as 65200

neighbor 154.0.17.129 remote-as 11664

neighbor 154.0.17.129 local-as 65194 no-prepend replace-as

Regards,

Harold Ritter
Sr. Technical Leader
CCIE 4168 (R&S, SP)
harold@cisco.com
México móvil: +52 1 55 8312 4915
Cisco México 
Paseo de la Reforma 222 Piso 19
Cuauhtémoc, Juárez
Ciudad de México, 06600
México
10 REPLIES
Hall of Fame Super Gold

Re: two bgp as

Yes, in a kind of virtual manner. That is because you can manipulate AS numbers in any way you want.

New Member

Re: two bgp as

Thank's

Can you tell me some link with an example?

Marcelo

Hall of Fame Super Gold

Re: two bgp as

Are you familiar with BGP configuration and AS path manipulation ? All that is documented in the cisco manuals.

That is the pre-requisite for what you want to do.

Cisco Employee

Re: two bgp as

Marcelo,

You might want to check the following example.

http://www.cisco.com/en/US/docs/ios/12_4t/ip_route/configuration/guide/brbpeer.html#wp1126960

Regards,

Harold Ritter
Sr. Technical Leader
CCIE 4168 (R&S, SP)
harold@cisco.com
México móvil: +52 1 55 8312 4915
Cisco México 
Paseo de la Reforma 222 Piso 19
Cuauhtémoc, Juárez
Ciudad de México, 06600
México
New Member

Re: two bgp as

I applied this configuration but I can't get the peering. There is the following error:

Jun 11 10:38:04: %BGP-3-NOTIFICATION: sent to neighbor 77.1.248.25 3/11 (invalid or corrupt AS path) 3 bytes 400200

Cisco Employee

Re: two bgp as

Marcelo,

Can you send a bit more info about the topology and configuration that you are trying to implement.

Regards,

Harold Ritter
Sr. Technical Leader
CCIE 4168 (R&S, SP)
harold@cisco.com
México móvil: +52 1 55 8312 4915
Cisco México 
Paseo de la Reforma 222 Piso 19
Cuauhtémoc, Juárez
Ciudad de México, 06600
México
New Member

Re: two bgp as

This is the configuration. I need peering with 2 differente AS. The AS 65200 see me as 65200 y de 11664 see me as 65194.

!

router bgp 65194

no synchronization

bgp log-neighbor-changes

redistribute connected

neighbor 77.1.248.25 remote-as 65200

neighbor 77.1.248.25 local-as 65200 no-prepend replace-as

neighbor 154.0.17.129 remote-as 11664

neighbor 154.0.17.129 send-community

no auto-summary

!

Cisco Employee

Re: two bgp as

Marcelo,

You cannot use this command on an iBGP peer. You can inverse the logic though, change your "router bgp" ASN to 65200 and use the local-as command on the peer to ASN 11664 instead as follow:

router bgp 65200

neighbor 77.1.248.25 remote-as 65200

neighbor 154.0.17.129 remote-as 11664

neighbor 154.0.17.129 local-as 65194 no-prepend replace-as

Regards,

Harold Ritter
Sr. Technical Leader
CCIE 4168 (R&S, SP)
harold@cisco.com
México móvil: +52 1 55 8312 4915
Cisco México 
Paseo de la Reforma 222 Piso 19
Cuauhtémoc, Juárez
Ciudad de México, 06600
México
New Member

Re: two bgp as

Thank's Hritter. Your answer resolved my issue.

Marcelo

Cisco Employee

Re: two bgp as

Marcelo,

You can only assign one AS number to your BGP router process but you can change that AS number when you connect to BGP peers by using the local-as feature.

Regards,

Harold Ritter
Sr. Technical Leader
CCIE 4168 (R&S, SP)
harold@cisco.com
México móvil: +52 1 55 8312 4915
Cisco México 
Paseo de la Reforma 222 Piso 19
Cuauhtémoc, Juárez
Ciudad de México, 06600
México
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