nanog mailing list archives

Re: Where to buy Internet IP addresses


From: Mikael Abrahamsson <swmike () swm pp se>
Date: Mon, 4 May 2009 10:31:10 +0200 (CEST)

On Mon, 4 May 2009, Nathan Ward wrote:

I think that they have to be forwarded. What do you do if people chain three routers? How does your actual CPE know to dish out a /60 and not a /64 or something? What if someone chains four? What if someone puts three devices behind the second?

This is a CPE problem, the main homegateway can decide to dish out /64s to all other home routers, this means they can have a bunch. It also means they can't chain 3 in serial, unless the home user decides to hand out /60s to each and only have 3 of them connected to the main CPE.

These are weird topologies, sure, but coming up with some algorithm to handle some of them and not others is going to be too complicated, and leave some people without a workable solution.

This is where innovation will happen in the home market, but only if we hand them a /56 to start with.

Forwarding these requests up to the ISP's router and having several PDs per end customer is in my opinion the best way to go.

Why is this better? Why do you want to waste your tcam entries like that? A single /56 per customer makes you have the fewest amount of tcam entries in any solution I can imagine. All other solutions require more.

--
Mikael Abrahamsson    email: swmike () swm pp se


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