On Thu, Jan 6, 2011 at 8:04 PM, Jimmy Hess <mysidia@gmail.com> wrote:
It is advisable to look for much stronger reasons than "With IPv4 we did it" or With IPv4 we ran into such and such problem" due to unique characteristics of IPv4 addressing or other IPv4 conventions that had to continue to exist for compatibility reasons, etc, etc.
I certainly agree that there are many advantages to the greater address space offered by IPv6. I don't mean to advocate that we do things the same way as was necessary to conserve v4 address space, and I'm sure we all realize that RIR policies necessarily contributed to routing table growth in trade for extending the life of the available address space. I'm not blindly deploying /64 networks, either. Doing so with the current set of problems, and lack of knobs, is very foolish. My transit providers offer a mix of /126 and /124 demarc subnets so far, and /124 is what I choose to standardize on for my BGP customers and private peering, for simplicity and convenience. As I mentioned before, I currently allocate a /64 and configure a /124, so I am not painting myself into a corner either way. How many of us with an appreciable level of expertise remain concerned that our approach may need significant adjustment? How many think we know what those potential adjustments may be, and have planned to make them easy (or transparent) for ourselves and customers if they become necessary? This is what is IMO most important to a responsible IPv6 deployment. To do otherwise is inviting unpredictable future pain. I am comforted by the fact that Level3 is deploying customer demarc subnets as /126 and is NOT allocating a /64 for each, but are instead packing them densely in an IPv4 /30 fashion. They recognize problems with the /64 approach, choose not to follow the "standard" to the letter, and implement their dual-stack network in a way they presumably believe is safe and scalable. Large networks like Level3 choosing to insist that equipment vendors support this configuration, rather than have problems with densely packed subnets smaller than /64, will mean that anyone who wants to sell a router to Level3 had better make it work correctly this way, which is good for the small guy like me who thinks he will eventually transition to that configuration. Right now, I am still hedging my bet. Are there any large transit networks doing /64 on point-to-point networks to BGP customers? Who are they? What steps have they taken to eliminate problems, if any? -- Jeff S Wheeler <jsw@inconcepts.biz> Sr Network Operator / Innovative Network Concepts