Jeroen Massar wrote:
Eliot Lear wrote:
Mark Andrews wrote:
I would have thought that router renumbering should be no
harder that host renumbering. Essentially all you are
changing is the higher (/48 normally) prefix bits. All
that is required is a method to distribute the set of
prefixes in use with a set of tags (global, deprecated,
ula, advertise in RA, etc.).
I think there has been hype on both sides of this question. Router
renumbering used to be VERY annoying. I've now published several times
on the subject
Any links to the papers?
There are two that I can point you at, and perhaps the temporal
difference would be at least amusing:
* Renumbering: Threat or Menace?, Lear, Katinsky, Tharp, et al,
Proceedings of the Tenth Systems Administration Conference (LISA96)
* Procedures for Renumbering an IPv6 Network Without a Flag Day,
Baker, Lear, Droms, RFC 4192, September, 2005.
I would also add that Tim Chown has done an extensive amount of work in
this space.
Indeed, but except for firewalling, it is why I mentioned using a "local"
space (PI) or some other 'globally unique chunk that they can keep'.
Certainly we've heard this argument from large enterprise customers.
One will then configure all the internal setups (snmp,syslog,sflow/netflow
etc) using the forever addresses and won't have to care about those anymore.
Sure.
Routing internally can also happen using those addresses, though the scary
bit is of course when the MTU does change or a Host/Net unreach has to be
sent, the router has to pick the correct global address and not the one
which is only used inside the network.
This really depends on just how scary an enterprise routing
configuration is. They can be quite complex depending on both their
internal and external connectivity, and each has some implications for
the other. There are quite a number of enterprises that make heavy use
of BGP internally. But certainly the point of ULAs was to provide some
stability in this area. I think LISP (draft-farinacci-lisp-00.txt) has
promise here as well, as may Robin's iVIP proposal (see the ram archives
for details).
In my opinion, this means that the router of the future needs to look a
little different, and this has implications for other subsystems.
[..goodbits..]
Which is indeed why I am thinking that ID/LOC is the way to go. One internal
prefix on the local network, and whatever prefix is on the global Internet.
Apply ID/LOC when your packets are going somewhere where you can't use your
local prefix.
If your point is that you should never have to renumber, then that's a
lovely way to go. It will still happen, of course, as companies merge
and grow. I think IPv6 helps with the latter, but the former is still a
challenge simply because topologies change.
Eliot
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