North American Network Operators Group|
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Re: v6 subnet size for DSL & leased line customers
Randy Bush wrote: >>> vendors, like everyone else, will do what is in their best interests. >>> as i am an operator, not a vendor, that is often not what is in my best >>> interest, marketing literature aside. i believe it benefits the ops >>> community to be honest when the two do not seem to coincide. >> If the ops community doesn't provide enough addresses and a way to use >> them then the vendors will do the same thing they did in v4. > > i presume you mean nat v6/v6. this would be a real mess and i don't > think anyone is contending it is desirable. but this discussion is > ostensibly operators trying to understand what is actually appropriate > and useful for a class of customers, i believe those of the consumer, > soho, and similar scale. > > to summarize the positions i think i have heard > o one /64 subnet per device, but the proponent gave no estimate of the > number of devices > o /48 > o /56 > o /64 It plausible that if one were to assign a single /64 and reserve a 56 to delegate per customer that you could number about 16 million customers per /32 with a few hundred thousand /64s remaining for infrastrucuture. size of an agregate for a pop might be /48 (~250 customers) to /40 (65k customers) to /36 (1 million customers) A large retail isp might under those circumstances be able to get away with order of /28 to /30 in total. > the latter three all assuming that the allocation would be different if > the site had actual need and justification. > > personally, i do not see an end site needing more than 256 subnets *by > default*, though i can certainly believe a small minority of them need > more and would use the escape clause. so, if we, for the moment, stick > to the one /64 per subnet religion, than a /56 seems sufficient for the > default allocation. > > personally, i have a hard time thinking that any but a teensie minority, > who can use the escape clause, need more than 256. hence, i just don't > buy the /48 position.