-----Original Message----- From: Jared Mauch [mailto:jared@puck.nether.net] Sent: Wednesday, November 10, 2010 3:31 PM To: Greg Whynott Cc: nanog@nanog.org list Subject: Re: AS path question.
People prepend, and think 'more is better' vs using communities and other 'complex' methods of managing their traffic.
It's also the easy tool from the shed. 'set as-path prepend blah' is easier than
In this day and age, I'm still surprised at how many people think AS Path prepending is the preferred way to influence inbound traffic paths. As many providers have default local-pref policies in place which prefer routes learned from the customer over routes learned from another peer, it is often the case that a supposed secondary path is actual the preferred path from the view of that upstream provider. IMO, a combination of both community tagging to influence localpref coupled with AS Path prepending on the secondary link is the best approach, and seems to accommodate both steady state as well as failure scenarios properly. Stefan Fouant