From: Jonathan V Hays (jhays@jtan.com)
Date: Sun Nov 16 2003 - 10:32:40 GMT-3
Correct. The NO-EXPORT attribute (or any other community attribute) will
not be sent to any neighbor by default (regardless of the AS). You must
configure "neighbor send-community" for every neighbor you want the
community sent to. And when the neighbor receives the community
attribute it has the same requirement.
>-----Original Message-----
>From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On
>Behalf Of Silvio Nunes
>Sent: Sunday, November 16, 2003 7:42 AM
>To: ccielab@groupstudy.com
>Subject: BGP - Community attribute
>
>
>Hi All,
>
>
>AS 1 (R1)------- AS 2 (R2) -- AS 2 (R3)--------- AS 3 (R4)
> |
> |
> |
>network
>200.200.200.0
>
>R1 is advertising the network 200.200.200.0 to AS2 with the NO-EXPORT
>attribute.
>So, R2 and R3 cannot advertise this network to another AS (ebgp peer).
>
>My question is: Do I need configure the command send-community
>in R2 to R3 ?
>
>
>Because in R2 I can see the atribute NO-EXPORT configured for
>200.200.200.0,
>but not in R3 without this send-community,
>so R4 receive this route.
>
>Example:
>
>R2#sh ip bgp 200.200.200.0
>BGP routing table entry for 200.200.200.0/24, version 2
>Paths: (1 available, best #1, table Default-IP-Routing-Table,
>not advertised
>to
>EBGP peer)
>Advertised to non peer-group peers:
>3.3.3.3
>5
>1.1.1.1 (metric 20) from 1.1.1.1 (1.1.1.1)
>Origin IGP, localpref 100, valid, external, best
>Community: no-export
>
>R3#sh ip bgp 200.200.200.0
>BGP routing table entry for 200.200.200.0/24, version 2
>Paths: (1 available, best #1, table Default-IP-Routing-Table)
>Advertised to non peer-group peers:
>4.4.4.4
>5
>1.1.1.1 (metric 50) from 2.2.2.2 (2.2.2.2)
>Origin IGP, localpref 100, valid, internal, best
>
>
>Ex:
>(R1)
>router bgp 1
>no synchronization
>bgp router-id 1.1.1.1
>bgp log-neighbor-changes
>neighbor 2.2.2.2 remote-as 6
>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
>network 200.200.200.0
>
>(R2)
>router bgp 2
>bgp router-id 2.2.2.2
>bgp log-neighbor-changes
>neighbor 1.1.1.1 remote-as 1
>neighbor 1.1.1.1 ebgp-multihop 5
>neighbor 1.1.1.1 update-source Loopback0
>neighbor 3.3.3.3 remote-as 2
>neighbor 3.3.3.3 update-source Loopback0
>neighbor 3.3.3.3 send-community >>>>>>>>>>>> Is really necessary ?
>
>_________________________________________________________________
>MSN Messenger: converse com os seus amigos online.
>http://messenger.msn.com.br
>
>_______________________________________________________________________
>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
This archive was generated by hypermail 2.1.4 : Fri Dec 12 2003 - 12:29:12 GMT-3