North American Network Operators Group

Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical

Re: URPF on small BGP-enabled customers?

  • From: Pete Templin
  • Date: Fri Jun 03 11:19:27 2005

Andre Oppermann wrote:

No, my proposal works as long as the customer advertizes their prefixes
via BGP, not matter how long the path or what community attributes are
set (for example NOEXPORT).  No matter how they send it, as long as they
send it, it works fine.  Unlike uRPF which depends on exactly this path
being the best path of all path available.  All this trouble of routing
decisions which affect uRPF is avoided.  That is also why it feeds the
received prefixes into an ACL which then is applied to the interface
versus doing two FIB lookups (one on source IP and one on destination
And my proposal works as long as the customer advertises their prefixes via BGP, with the added caveat that ACLs don't have to be updated (i.e. uRPF works and is used). I'd have to re-check my customer-side route maps, but I think they'll open the uRPF for all possible permutations of <community>.