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RE: MORE..BGP - Community attribute posted 11/16/2003
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Thank4s Jonathan. I got it.

Bye.


From: "Jonathan V Hays" <jhays@xxxxxxxx>
To: "'Silvio Nunes'" <silvio_98@xxxxxxxxxxx>, <ccielab@xxxxxxxxxxxxxx>
Subject: RE: MORE..BGP - Community attribute Date: Sun, 16 Nov 2003 09:44:40 -0500


Silvio,

The LOCAL-AS attribute works in exactly the opposite manner: the route
can only be advertised to peers within the same sub-AS within a
confederation. The LOCAL-AS route will not be advertised to other AS's,
even if the other AS is in the same confederation. See the excerpt from
this link, included below.

http://www.cisco.com/univercd/cc/td/doc/product/software/ios122/122cgcr/
fipr_c/ipcprt2/1cfbgp.htm#1001855

The communities attribute is an optional, transitive, global attribute
in the numerical range from 1 to 4,294,967,200. Along with Internet
community, there are a few predefined, well-known communities, as
follows:

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-Do not advertise this route to peers outside the local
autonomous system. This route will not be advertised to other autonomous
systems or sub-autonomous systems when confederations are configured.
Based on


>-----Original Message----- >From: nobody@xxxxxxxxxxxxxx [mailto:nobody@xxxxxxxxxxxxxx] On >Behalf Of Silvio Nunes >Sent: Sunday, November 16, 2003 9:24 AM >To: ccielab@xxxxxxxxxxxxxx >Subject: MORE..BGP - Community attribute > > >Regarding LOCAL-AS attribute, I4d like to confirm: > >A route with a LOCAL_AS attribute can be advertised to peers in other >subautonomous systems within a confederation, but I4m trying >and it is not >working... the route cannot be advertised to another >subautonomous systems.. > >AS3 (R3)......[ AS10 (subAS5 -R5)----- (subAS5 - R2) ........ >(subAS6 - R6)] >| >| >222.222.222.0 > >In this example, R2 (in the same subAS) has 222.222.222.0. R6 >(in another >subAS) cannot get the same route: > >(R5) >router bgp 5 >bgp router-id 5.5.5.5 >bgp cluster-id 3368601605 >bgp log-neighbor-changes >bgp confederation identifier 10 >bgp confederation peers 6 >neighbor 2.2.2.2 remote-as 5 >neighbor 2.2.2.2 ebgp-multihop 5 >neighbor 2.2.2.2 update-source Loopback0 >neighbor 2.2.2.2 send-community >neighbor 2.2.2.2 route-map MODCOMMUNITY out >neighbor 3.3.3.3 remote-as 3 >neighbor 3.3.3.3 ebgp-multihop 5 >neighbor 3.3.3.3 update-source Loopback0 > >access-list 33 permit 222.222.222.0 0.0.0.255 > >route-map MODCOMMUNITY permit 10 >match ip address 33 >set community local-as >! > >_________________________________________________________________ >MSN Hotmail, o maior webmail do Brasil. http://www.hotmail.com > >_______________________________________________________________________ >Please help support GroupStudy by purchasing your study materials from: >http://shop.groupstudy.com > >Subscription information may be found at: >http://www.groupstudy.com/list/CCIELab.html > > >



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