On Thu, Aug 6, 2009 at 11:16 AM, Paul Vixie<vi...@isc.org> wrote: > note, i went off-topic in my previous note, and i'll be answering florian > on namedroppers@ since it's not operational. chris's note was operational: > >> Date: Thu, 6 Aug 2009 10:18:11 -0400 >> From: Christopher Morrow <morrowc.li...@gmail.com> >> >> awesome, how does that work with devices in the f-root-anycast design? >> (both local hosts in the rack and if I flip from rack to rack) If I send >> along a request to a host which I do not have an association created do I >> get a failure and then re-setup? (inducing further latency) > > yes. so, association setup cost will occur once per route-change event. > note that the f-root-anycast design already hashes by flow within a rack
pulling something I didn't previously understand from an ongoing discussion on the LISP/v6ops mailing lists... most routers today only hash on tcp/udp so.. sctp isn't going to hash in the same 'deterministic' manner, or someone should probably test that that is the case. > to keep TCP from failing, so the only route-change events of interest to > this point are in wide area BGP. right, and the (I think K-root) K-root folks had a study showing <1% of sessions seemed to be failing in this manner? (nanog in Toronto I think?) >> ...: "Do loadbalancers, or loadbalanced deployments, deal with this >> properly?" (loadbalancers like F5, citrix, radware, cisco, etc...) > > as far as i know, no loadbalancer understands SCTP today. if they can be > made to pass SCTP through unmodified and only do their enhanced L4 on UDP > and TCP as they do now, all will be well. if not then a loadbalancer > upgrade or removal will be nec'y for anyone who wants to deploy SCTP. > > it's interesting to me that existing deployments of L4-aware packet level > devices can form a barrier to new kinds of L4. it's as if the internet is > really just the web, and our networks are TCP/UDP networks not IP networks. sadly, people have (and continue) to make simplifying assumptions while designing/deploying equipment. -Chris
