RE: Comment on draft-coene-sctp-multihome-04.txt

["marcelo bagnulo" <mbagnulo@ing.uc3m.es>]

> I actually think this points to an important component of any solution
> that we haven't really talked about much, except when NAROS was discussed
> a few months ago - how does one determine the existence or absence of
> connectivity between two locators?

Fully agree, this is complex and important.

We have tried to discuss this point in the Host Centric draft

There are two different scenarios IMHO.
- how to discover reachability when initating a communication
- how to discover reachability (or unreachability) during a communication
(in order to preserve it)

We have basically discused the first case in the draft.

The second case have been discused some times in the ml, regarding some
ideas like ULP hints, source address of incoming packets as a strong hint
about which path is working and so on

We wanted to also include such discussion in our draft but we couldn't make
it on time, but it will probably be included in the next version.

regards, marcelo

 For SCTP or any other solution,
> it's only when connectivity exists between an address pair that they
> are any use.
>
> By the way, you also say
>
> >
> >     As a practical matter, it is recommended that IP addresses in a
> >     multihomed endpoint be assigned IP endpoints from different TLA's to
> >     ensure against network failure.
>
> The term "TLA" no longer exists in IPv6 and in any case, it is a false
> assumption that two different high-order network prefixes imply
> two different paths. They might, but they might not.
>
>   Brian
>
>