You'll probably need to use as prepends to control traffic in both directions from the ISP side...
To control user's OUTBOUND traffic patterns: -------------------------------------------- On the BGP connections to these users, for any of the less preferred routes (from AS2 and AS3), you want to setup a route-map to match those less preferred AS's and then do an as prepend to increase the ASPATH length, and thus make them less favorable from the user's perspective. This is cause the user's OUTBOUND traffic to prefer links through any AS that doesn't have the ASPATH increased. You could also use MEDs to accomplish the task, but you need to make sure that the user has his equipment configured to accept them. The as prepends can't really be ignored by the user's routers. To control user's INBOUND traffic patterns: ------------------------------------------- On the BGP connections to less prefered AS's (AS2,AS3), you need to have a route-map on your outbound route announcements. This route-map needs to match any routes for your users and set an as prepend on these routes before announcing them. You might have to do more than one prepend to get the results you want, depending on how your provider connections are setup. But again, this step will increase the ASPATH length on user routes announced to the less prefered AS's. Hope this helps. Rob Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=43976&t=43962 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
