IPv6 addresses for EP or why are exhanges so special ?
Cathy Wittbrodt cjw at remarque.org
Fri May 11 19:52:23 CEST 2001
HPH,
The other reason why there is an allocation policy for exchange points
(at least in the ARIN region) is because the folks who are building
exchange points may not have enough of them to justify the minimum
allocation. It seemed reasonable that they would need provider
independent space, however, so they can get it with the provisions
written in the policy. If you think about a neutral exchange point
provider who's business is to connect up providers to peer, etc, that
exchange point provider may want or need to supply the IP addresses
for that exchange point. They're providing a service and may want
to provide the address space as well.
I can't speak for the exchange providers, but setting up p2p vlans
or whatever for folks connected to the same ethernet switch may be
time consuming and also can waste quite a bit of address space
(if you're using /30s for p2p links and not /31s, per the new
yet unimplemented draft).
I hope this helps!
---CJ
From: "Hans Petter Holen" <hph at online.no>
Subject: IPv6 addresses for EP or why are exhanges so special ?
I have tried to follow this discussion, and stumbeled over a fundamental
question when trying to reason about this:
* why are exchange points so special ?
It seems to me that shared medium exchange points historicaly have used a
single subnet to interconnect. Generaly it simplifies configuration and
eases operations to have a single logical interface on the physical
interface connected to the shared medium.
But in order to excange traffic with other partners at the exchange one
needs to establish "pont to point" BGP peerings. So there is no longer any
significant configuirational advantage in having all the boxes I want to
talk to on a single subnet (I still need to figure out how to talk to the
others by establishing BGP peerings.)
On the operational side, at least back when I was directly involved in such,
it would actualy be very convenient to have logical point to point links
with all my peering partners in order to better diagnose and measure traffic
flows and flaws.
If this is the case, the IP addresses for the logical point to point links
across the exchange would best be implementedwith IP addresses from any of
the providers, or perhaps even the IPv6 equivalent of link local addresses.
I would be interested to hear comments on this approach, because if this
model makes senseto implement, it would probably make sense to document this
as some kind of "best current practice" for IP v6 exchanges in order to make
sure that the router vendors implements the proper tools to make this easy
to configure.
Looking forward to hear others opinions on this.
-hph
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