Cisco RFC1997 implementation clarification.

Tue Jul 10 04:10:41 UTC 2001

While researching an RFC1997 issue this morning, I made the following
observations:

According to RFC1997:

"
Well-known Communities

   The following communities have global significance and their
   operations shall be implemented in any community-attribute-aware BGP
   speaker.

      NO_EXPORT (0xFFFFFF01)
         All routes received carrying a communities attribute
         containing this value MUST NOT be advertised outside a BGP
         confederation boundary (a stand-alone autonomous system that
         is not part of a confederation should be considered a
         confederation itself).
      NO_ADVERTISE (0xFFFFFF02)
         All routes received carrying a communities attribute
         containing this value MUST NOT be advertised to other BGP
         peers.
      NO_EXPORT_SUBCONFED (0xFFFFFF03)
         All routes received carrying a communities attribute
         containing this value MUST NOT be advertised to external BGP
         peers (this includes peers in other members autonomous
         systems inside a BGP confederation).
"

On Cisco's site at
http://www.cisco.com/univercd/cc/td/doc/product/software/ios120/12cgcr/np1_c/1cprt1/1cbgp.htm#5082

I find the following:

"
internet - Advertise this route to the Internet community. All routers
           belong to it.

no-export - Do not advertise this route to EBGP peers.

no-advertise - Do not advertise this route to any peer (internal or
               external).

local-as - Send this route to peers in other sub-autonomous systems within
           the local confederation. Do not advertise this route to an
           external system.
"

Unless I'm mistaken, there are some potential interop issues with this.

CISCO no-export = RFC1997 NO_EXPORT_SUBCONFED

CISCO no-advertise = RFC1997 NO_ADVERTISE

CISCO local-as = RFC1997 NO_EXPORT

Can someone more familiar with the RFC1997 implementation in IOS comment
on this?

Thanks,

---
John Fraizer
EnterZone, Inc