Re: I-D Action:draft-ietf-v6ops-ipv6-cpe-router-03.txt

[Brian E Carpenter <brian.e.carpenter@gmail.com>]

On 2010-01-10 12:58, Mark Smith wrote:
> Hi Brian,
> 
> On Sun, 10 Jan 2010 08:37:34 +1300
> Brian E Carpenter <brian.e.carpenter@gmail.com> wrote:
> 
>> On 2010-01-10 04:16, Mikael Abrahamsson wrote:
>>> On Sat, 9 Jan 2010, Mark Smith wrote:
>>>
>>>>> Why can't a CPE router send unicast RAs to other CPE
>>>>> routers as long as they are not malicious and do not
>>>>> in any way conflict with the RAs sent by SP routers?
>>>> I think on some networks that could have multicast traffic volume
>>>> related scaling issues. It's quite possible to build single Ethernet
>>>> link layers using DSL that have 100s or 1000s of CPE attached. It also
>>>> seems a bit redundant to have the CPEs fully aware of all their
>>>> neighbours' downstream prefixes, yet be unlikely to use those routes
>>>> very often.
>>> I think no ISP will ever build a network that allows for local routing
>>> like that (at least not intentionally). So far ISPs do not want
>>> customers to talk L2 directly with each other, but instead want to do
>>> the routing between customers (mostly for security reasons). I therefore
>>> think it's a moot point to try to drive any standard that by a lot of
>>> security measures tries to solve this in the CPE. It just won't be
>>> deployed because of its complexity.
>> Especially since the amount of such local traffic seems likely to
>> be tiny, and therefore not worth optimising. Does anyone have any
>> actual data on this?
>>
> 
> I don't - my motivation has been to look at it as a missed
> opportunity for better traffic locality, if the mechanism to do it was
> simple enough.
> 
> It seems to me that peer selection in peer-to-peer protocols could be
> improved by measuring the latency between peers (e.g. by looking at
> the SRTT values of the TCP connections to the peers), as lower
> latency peers would also typically have more bandwidth between them. If
> peer-to-peer as a content distribution method continues to increase, I
> think there is or will be increasing value in having customer CPE being
> more aware of more direct paths to local destinations.

That's true in theory. But since what we are aiming at with the current
draft is the first round of CPE requirements based on well established
specs, it seems out of scope. Probably a topic for discussion on
draft-wbeebee-v6ops-ipv6-cpe-router-bis?

    Brian