re: [RRG] Nimrod, NIIA, HIP... as a long term solution?

[jnc@mercury.lcs.mit.edu (Noel Chiappa)]

    > From: Xu Xiaohu <xuxh@huawei.com>

    > Since Nimrod has split EID and locator, is it still necessary to deploy
    > a new locator namespace to support hierarchical routing?

Sorry, I did not understand that?

Nimrod has not been deployed, so EID and locator have not been split (in the
operational Internet). Also, of course, no other scheme which splits EID and
locator has been deployed, either.


Did you mean 'why did Nimrod deploy a new locator namespace to support
hierarchical routing'? Well, it deployed a new namespace for a variety of
reasons. Splitting location and identity was one, but we also did not like the
design of IPv4 addresses, at least for use in routing.

So, we handled both issues with the same thing, which was the new locator
namespace. Rather than just have another copy of the IPv4 namespace for the
separate location functionality, we designed a namespace in which the names
were i) optimally designed for use in the entire path-selection subsystem, and
ii) had the maximum amount of flexibility for the distant future (i.e.  30-50
years off - and if you think that is arrogant, remember that IPv4 was designed
in about 1976, and so it is *already* 30 years old, and will be around for
some time to come).


Or did you mean 'if some other scheme splits identity and location, will it
still be necessary to deploy a new locator namespace to support hierarchical
routing'? That is up to the people who design that scheme.


    > IPv4 or IPv6 is aggregatable in nature. Can't they be used directly for
    > hierarchical routing?

Let's take the IPv4 case first. First, IPv4 addresses could noqt be used
direcly because we wanted to separate location and identity. (The benefits of
separating location and identity, for such uses as multi-homing, ability to
change ISP without re-addressing everything, etc are now well understood, so I
will not explain why separating identity and location is a good thing.) We
wanted the identity functionality to stay with the IPv4 address, so hosts did
not have to be modified. So we needed another namespace for location.

The same reasoning applies now to IPv6.


    > Regarding incremental deployment, IPv4 and IPv6 will coexist for a long
    > time during IPv6 transition.

Let's not get into the future (if any) of IPv6.

    > I think the transition to the new locator namespace mentioned above
    > will encounter the same quandary.

It was never the intent to replace IPv4 addresses with the Nimrod locator
namespace, so this comment does not make sense to me; the entire point was
that they would co-exist.

	Noel

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