In a message written on Mon, Oct 12, 2009 at 07:13:04PM -0700, Seth Mattinen wrote:
Leo Bicknell wrote:
Worse, the problem is being made worse at an alarming rate. MPLS VPN's are quicky replacing frame relay, ATM, and leased line circuits adding MPLS lables and VPN/VRF routes to edge routers. Various RIR's are pushing "PI for all" in IPv6 based on addressing availbility. Some networks are actually finally using multicast for IPTV services, generating much larger number of entries than the global multicast table would otherwise indicate.
It's not the RIR's fault. IPv6 wasn't designed with any kind of workable site multihoming. The only goal seems to have been to limit /32's to an "ISP" but screw you if you aren't one. There was no alternative and it's been how long now? PI, multihoming, multicast, etc. is reality because the internet is now Very Serious Business for many, many people.
I may have editorialized in a way that was not completely clear. I agree that due to lack of an alternative "PI IPv6" is necessary and effectively the only option we have right now. Were IPv6 policy to only allow those who could get IPv4 PI to get IPv6 PI I would say the problem was "the same". However, the reason I say it is being made worse is that there is a subset of the RIR community who sees the lack of scarcity of addres space as a reason to provide IPv6 PI to people who cannot qualify for IPv4 PI. My impression of the current RIR policy trends are resulting in a situation that more folks will be able to get IPv6 PI than can currently get IPv4 PI. Hence why I put that in the list of things making it worse.
Yes, I know there's hacks like SHIM6 and I don't wish to go OT into a debate about them, so I'll just say that if there had been a viable alternative to multihoming as we know it I think it would have been given a go before policy got pushed to the RIR's to allow IPv6 PI.
The only idea I have seen that holds any promise is LISP. There is working code, and the idea is sound. However, like squeezing a balloon while it makes some issues better it then puts pressure in other directions. It trades off TCAM lookups for LOC/ID lookups and caching. It's not clear to me on an Internet scale system this is better; but I do hope the folks doing that work continue on the chance that it is... -- Leo Bicknell - bicknell@ufp.org - CCIE 3440 PGP keys at http://www.ufp.org/~bicknell/