Re: IS-IS as PE/CE routing protocol in BGP/MPLS/VPN

Lidefeng,
Just a general observation:

- Whenever a PE router receives a MP-BGP UPDATE, it must execute the BGP
Decision Process to decide the best path to the prefix contained in the
UPDATE. When this decision process completes, the *best* route is passed
onto the IS-IS selection process for import into any relevant VRFs. Because
multiple UPDATEs for the same prefix might be received, and because IS-IS
has its own selection process for differing metric types, the BGP Decision
Process IMHO should be modified to prefer routes with internal metrics over
the routes with external metrics. The Decision process will be based on the
ISIS metric type that will be conveyed within the IS-IS Route Type Extended
Community Attribute that accompanies the ISIS VPN-IPv4 route.

There seems to be no mention of this in the draft.

- Is there a reason why you're not sending any metrics (wide/narrow) info
in the extended community?

Regards,
Manav

----- Original Message ----- 
From: "lidefeng" <[email protected]>
To: <[email protected]>
Cc: <[email protected]>; <[email protected]>
Sent: Tuesday, May 13, 2003 10:19 AM
Subject: [Isis-wg] A new draft,IS-IS as PE/CE routing protocol in
BGP/MPLS/VPN


> Hi,all,
>
> In deploying BGP/MPLS VPN,there are sites that CE run IS-IS protocol with
> PE,and the corresponding customer is reluctant to change the routing
> protocol they used in the sites,to accomodate this situation, it is
better
> to run isis protocol between PE and CE,however,ther isn't any draft to
> specify the scenario in the BGP MPLS VPN. This draft addresses this
> scenario,the abstract is as following:
>
>  IS-IS protocol, which is specified in [1], can be used as IGP between
>    the Customer Edge (CE) router and the Provider Edge (PE) router in
>    BGP/MPLS VPNs as per [1]. This document provides a detailed solution
>    for IS-IS working as PE/CE Protocol in VPN services specified in [1].
>