Shane,
-----Original Message----- From: Shane Amante [mailto:sh...@castlepoint.net] Sent: Tuesday, August 24, 2010 3:35 PM To: Hemant Singh (shemant) Cc: sth...@nethelp.no; adur...@juniper.net; dtha...@wollive.windowsmedia.com.akadns.net; ipv6@ietf.org Subject: Re: 6man discussion on /127 document @ IETF78 >Hemant, >We don't statically configure, (nor would we even consider doing so), default routes or want "hidden" default routes in our Core routers. If those default routes are installed into the FIB of the >routers, (intentionally or accidentally during "implementation" of your proposal), it would have substantial negative repercussions on our operations, namely traffic forwarding loops (whee!) in our >network that would likely cause congestion, etc. Furthermore, there are way too many 'hidden' configurations/nuances inside every router vendor's implementation that I don't want to keep track of >another one ... >Please, as an operator, I really just want IPv6 /127's to be as KISS as /31's are in IPv4. I agree that simple is always desirable. We are just discussing internals of a router so that one gets around the genuine problems raised with /127 which is to not have the router start anycast forwarding on an interface configured with a /127. As for the routing loop, let's see the cases when routers are configured for a global /127 address. Router A sends a packet destined to Router B in a p-p network between the routers. The packet gets sent out Router A and Router B terminates/consumes this packet since the packet is destined to B. Likewise for B sending to A. The only other case is when A sends a packet to B where the packet destination is not B but C, so the router B looks up the routing table and finds a route to C and ships the packet out the interface that the routing table found to egress on. Only if router B does not have a route to C and then the router has no choice but to use the default route, then a loop situation arises, but then see ICMPv6 in RFC 4443 that has defined Code 3 for such a point-to-point link error. Hemant -------------------------------------------------------------------- IETF IPv6 working group mailing list ipv6@ietf.org Administrative Requests: https://www.ietf.org/mailman/listinfo/ipv6 --------------------------------------------------------------------
