At 01:53 AM 4/6/2003 +0000, Bullwinkle wrote: >In other words, for purposes of testing, there are ONLY two ways to remove >things from the AS_PATH. 1) the technique you describe, which is to create
Both these techniques are invalid in my opinion. If you create a new route, you haven't changed the AS-PATH on another route at all. In these cases, you have two routes, not one modified one. >an aggregate and advertise that aggregate only ( although refresh my >memory - an aggregate might still contain full AS_PATH information - don't >have my book handy ) OR to create an appropriate route to null 0, then enter >that route into the BGP process, while filtering those that contain the >AS_PATH you want to remove. > > >AS1-----------------------------AS2-------------------------AS3 > >192.168.x.x subnets ------advertised into AS2 > > ip route 192.0.0.0 255.0.0.0 >null 0 >bgp process command: network 192.0.0.0 mask 255.0.0.0 > >filter the more specific BGP routes. > >AS3 should see just the route to null 0, which does originate in AS2 > >do I have that right? Do you agree? > >-- >------------------------------------------------- > >Bullwinkle: Hey, Rocky, watch me pull a CCIE out of my hat! > >Rocky: Bullwinkle, that trick NEVER works.... > >Bullwinkle: This time FOR SURE!!!!!!! >( pulls snarling Proctor out of hat ) >No doubt about it. I gotta get me a new hat! > > > >""Salvatore De Luca"" wrote in message >news:[EMAIL PROTECTED] > > I hear ya.. that's why if this was a TEST situation, the statement: > > > > ip as-path access-list 1 permit _2_ & ! _2_ _1$ would permit routes > > traversing AS2 but deny any routes traversed though AS2 Originating in >AS1. > > In which case 150.50.200.0 aggregated element should be the nlri "Fresh > > Route" point for AS3's knowledge. Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=66965&t=66928 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
