Hello All, Thanks for comments, will digg BGP communities.
2008/1/12, Jon Lewis <[EMAIL PROTECTED]>: > > On Fri, 11 Jan 2008, Roman Bestuzhev wrote: > > > I am thinking about load balancing between both ISPs. I have read about > a > > technique when you divide your block to several pieces, for example to > two > > /22 blocks and advertise one of them to one ISP and other block to > another > > ISP and at the same time advertise whole prefix to both ISPs, /21 in > this > > case. This leads to getting incoming traffic trough both providers and > you > > can control which subnets in your AS connect to Internet trough which > ISP. > > You can probably achieve some level of load sharing without resorting to > polluting the DFZ. First thing to look at is relative as-path length. If > provider A is more of a "Tier 1" provider than provider B, then you might > try prepending your ASN once on announcements to A. > > If A supports it, you may be able to use community tagging to tell them to > do some prepending when your route is propogated to certain peers, thus > causing those peers to be more likely to use your B provider path. > > If you do resort to chopping up your CIDR, make sure you announce both the > aggregate and subnets...so those who filter those sorts of "garbage > routes" can do so without losing connectivity to your network. > > > My question: is this scheme used widely and would this scheme work well > in > > Used widely and correct/advisable are different things. Lots of networks > announce their CIDRs as individual /24s. It doesn't mean you should. > > ---------------------------------------------------------------------- > Jon Lewis | I route > Senior Network Engineer | therefore you are > Atlantic Net | > _________ http://www.lewis.org/~jlewis/pgp for PGP public key_________ > -- Roman Bestuzhev, System Administrator _______________________________________________ cisco-nsp mailing list cisco-nsp@puck.nether.net https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/