Site Multihoming in IPv6 (multi6)

Dave Crocker | 2 Nov 18:31

Re: I-D ACTION:draft-nordmark-multi6-sim-01.txt (Fwd)

Erik,

EN>         Title           : Strong Identity Multihoming using 128 bit Identifiers (SIM/CBID128)

It would be helpful for the different proposals and specifications to
discussion adoption, administration, use and performance issues, as well as
design rationale.

Your spec has the Protocol Walthrough, which gives detail about some of the
usage effort. Explicit discussion about the critical adoption requirements
would be particularly helpful.

I am probably not reading the specification correctly, but it appears that SIM
requires:

ADOPTION

1. Modification to both endpoints, using a shim layer directly above IP

2. Addition of a DNS record type and expected modification of DNS servers, to
do differential processing, based on presence or absence of records of that
type, when a query for that record type is made

3. Modification of intermediate routers, to do locator re-writing.

DESIGN

As the spec notes, deferred validation of new locators adds complexity to the
protocol.

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headers

marcelo bagnulo | 3 Nov 15:04

RE: I-D ACTION:draft-nordmark-multi6-sim-01.txt (Fwd)

> As the spec notes, deferred validation of new locators adds
> complexity to the protocol.
>
> My question is, therefore, why you chose deferred validation,
> versus automatic validation?

I like defferred validation, becuase you don't incurr in aditional costs
until you really need to. I guess that most of the communication will only
use one locator during its lifetime, so it seems wasteful to verify multiple
locators in this case.

Regards, marcelo

headers

Erik Nordmark | 3 Nov 14:16

Re: I-D ACTION:draft-nordmark-multi6-sim-01.txt (Fwd)

> ADOPTION
> 
> 1. Modification to both endpoints, using a shim layer directly above IP

Yes.

> 2. Addition of a DNS record type and expected modification of DNS servers, to
> do differential processing, based on presence or absence of records of that
> type, when a query for that record type is made

There is a new DNS rr type needed, but there is no differential processing
in the DNS servers. The hosts query for the new "ID" record and AAAA records.

> 3. Modification of intermediate routers, to do locator re-writing.

Not required from the outset, but for some failures having locator re-writing
simplifies and speeds up failure recovery.
Thus one could start deploying this type of approach without any upgraded
routers.

> DESIGN
> 
> As the spec notes, deferred validation of new locators adds complexity to the
> protocol.
> 
> My question is, therefore, why you chose deferred validation, versus
> automatic validation? In general, it would be helpful to understand the
> reasons for the various choices made in SIM.

The overhead of performing a public-key signed response to the challenge

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