I suppose so because prepend is so easily defeated, but sometimes you don't own a prefix shorter than the one you need to advertise. Assuming I understand your suggestion correctly.
2011/12/15 Holmes,David A <dhol...@mwdh2o.com> > For this very reason I have advocated using longest prefix BGP routing for > some years now, and checking periodically for the expected path, as it > became obvious from investigating traceroutes that traffic was not being > routed as intended using AS prepends. > > -----Original Message----- > From: Keegan Holley [mailto:keegan.hol...@sungard.com] > Sent: Wednesday, December 14, 2011 10:08 PM > To: NANOG > Subject: local_preference for transit traffic? > > Had in interesting conversation with a transit AS on behalf of a customer > where I found out they are using communities to raise the local preference > of routes that do not originate locally by default before sending to a > other larger transit AS's. Obviously this isn't something that was asked > of them and it took a few days to find since the customer is not a large > company and neither them nor my company has a link or business relationship > with the AS in question. This seemed strange to me for obvious reasons, > but I was curious if anyone else was doing this and why. You obviously > cannot use prepend to affect transit traffic again for obvious reasons. > MED is a weak metric but it at least only affects traffic that was already > going to transit your AS. The larger transit AS was favoring a lower > bandwidth link for the customer and causing them to drop packets > mysteriously. Just wondering if this practice seemed as strange to others > as it does to me. > > This communication, together with any attachments or embedded links, is > for the sole use of the intended recipient(s) and may contain information > that is confidential or legally protected. If you are not the intended > recipient, you are hereby notified that any review, disclosure, copying, > dissemination, distribution or use of this communication is strictly > prohibited. If you have received this communication in error, please notify > the sender immediately by return e-mail message and delete the original and > all copies of the communication, along with any attachments or embedded > links, from your system. > >
