North American Network Operators Group Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical Re: BGP4 COMMUNITY attribute
many of your questions are for MCI and not nanog > In the preparation for upcoming 2nd (multihomed) connection to Internet > I am looking into > COMMUNITY attribute of BGP4 as a way (in conjunction with my own > LOCAL_PREF) of load balancing > traffic between my two internet links (both T3). After reading CISCO > documentation I am still not > clear on some issues: > > 1. Is COMMUNITY a transitive attribute only between me and my immediate > upstream supplier or > is it being propagated further into Internet (so I can influence how > somebody ,say, 5 AS hops > away from me sees my routes) ? the attribute is defined as transitive (i.e., once associated with a route it *stays* associated with the route). however, in practice, many providers are configured to not send communities to other providers > 2. If COMMUNITY propagates into big I, and I set COMMUNITY to 3561:70 > (for MCI to set > LOCAL_PREF on my routes to 70) and my next hop supplier sets COMMUNITY > of my routes to > 3561:80, what happens ? what MCI is going to do ? is one of your immediate upstream provider's MCI? if so, then you would tag routes with 3561:70 and MCI would immediately see and react to that. however, you imply that your "next hop supplier" isn't MCI, which makes it a bit odd for you to be sending communities for MCI, but is doable if your "next hop supplier" agrees to carry your communities all the way to MCI > 3. Is COMMUNITY a CISCO only or is it part of RFC ? Has any other router > vendor implemented > this parameter ? rfc1997. i think there's a GateD with communities /jws > 4. Which major Internet providers have COMMUNITY/LOCAL_PREF implemented > (I am aware of MCI and Sprint) ? > > 5. Your experiences, comments, suggestions ..... > > > Thanks in advance, Walter > > > > Walter Towbin > Telus Advanced Communications > phone: 403-543-2032, fax: 403-543-2030, cell: 403-620-0019 > [email protected] > - - - - - - - - - - - - - - - - -
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