In a message written on Fri, Apr 24, 2009 at 05:06:15PM +0000, Stephen Stuart wrote:
Your argument, and Leo's, is fundamentally the complacency argument that I pointed out earlier. You're content with how things are, despite the failure modes, and despite inefficiencies that the IXP operator is forced to have in *their* business model because of your complacency.
I do not think that is my argument. I have looked at the failure modes and the cost of fixing them and decided that it is cheaper and easier to deal with the failure modes than it is to deal with the fix. Quite frankly, I think the failure modes have been grossly overblown. The number of incidents of shared network badness that have caused problems are actually few and far between. I can't attribute any down-time to shared-network badness at exchanges (note, colos are a different story) in a good 5-7 years. On the contrary, I can attribute downtime already to paranoia about it. When I had an ethernet interface fail at a colo provider to remain nameless I was forced to call the noc, have them put the port in a "quarantine" vlan, watch it with tcpdump for a hour, and then return it to service. Total additional downtime after the bad interface was replaced, 2 hours. I have no idea how watching an interface in a vlan with tcpdump supposedly protects a shared network. Remember the 7513's, where adding or removing a dot1q subinterface might bounce the entire trunk? I know of several providers to this day that won't add/remove subinterfaces during the day, but turning up BGP sessions on shared lans can be done all day long. The scheme proposed with private vlan's to every provider adds a significant amount of engineering time, documentation, and general effort to public peering. Public peering barely makes economic sense when its cost is as close to free as we can get it, virtually any increase makes it useless. We've already seen many major networks drop public peering all together because the internal time and effort to deal with small peers is not worth the benefit. Important volumes of traffic will be carried outside of a shared switch. The colo provider cannot provision a switching platform at a cost effective rate to handle all cross connects. So in the world of PNI's, the public switch, and shared segment already select for small players. You may want to peer with them because you think it's fair and good, you may do it to qualify up and comers for PNI's, but you're not /public peering/ for profit in 99% of the cases. All this is not to say private VLAN's aren't a service that could be offered. There may be a niche for particular size networks with particular sized flows to use them for good purposes. Colo providers should look at providing the service. A replacement for a shared, multi-access peering LAN? No. No. No. -- Leo Bicknell - bicknell@ufp.org - CCIE 3440 PGP keys at http://www.ufp.org/~bicknell/