Where to buy Internet IP addresses

Nathan Ward nanog at daork.net
Mon May 4 04:20:15 CDT 2009


On 4/05/2009, at 8:31 PM, Mikael Abrahamsson wrote:

> 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.

That is one way to do it, sure. However it makes things hard for end  
users, having to figure out how all this stuff fits together. My non  
technical friends have a enough time with 3.5mm jack to RCA audio  
cables, but they managed to get a wireless router and plug it in and  
have it magically work for them.

>> 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.


Because it allows the home user to arrange their network however they  
want, up to 16 subnets, without having to have any knowledge of how  
things actually work.

I'm sure we can both think of a few ways to make this not cost a whole  
lot of TCAM entries, either with protocol support, or in internal  
implementation specific ways.
I can immediately think of two ways that cost no extra TCAM entries.

--
Nathan Ward





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