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VIP Super Bronze

IS-IS and BGP as CE-PE

Hi,

Does any one know or has a document that explains why IS-IS is not supported as a protocol to use on CE routers?

Also, more specifically, IS-IS is not supported, because you can not run it per VRF?

I am just trying to understand why we can't use IS-IS the same way we use OSPF.

Thanks,

Reza

2 REPLIES
Cisco Employee

Re: IS-IS and BGP as CE-PE

Reza,

ISIS is actually VRF aware.

http://www.cisco.com/en/US/docs/ios/iproute/configuration/guide/is_instance_vrf.html

What is missing is the standardization to use it as a CE-PE protocol. If you look at OSPF for instance, it required an RFC explaining how OSPF attributes could be propagated from one PE to the other using BGP extended communities (see RFC4577). This has not happen yet for ISIS and i haven't heard of anything coming soon in the IETF.

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
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Cuauhtémoc, Juárez
Ciudad de México, 06600
México
VIP Super Bronze

Re: IS-IS and BGP as CE-PE

Harold,

Thanks for the link and explanation.

I will take a look at RFC4577.

Reza

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