Re: [Anima-signaling] Draft message on proposed change to GRASP

[Brian E Carpenter <[e-mail]>]

On 23/04/2016 00:37, Michael Richardson wrote:
> 
> Brian E Carpenter <[e-mail]> wrote:
>     > We propose to redefine the locator returned by GRASP discovery accordingly. For
>     > the IPv6 case that would give:
> 
>     > locator-option /= [ipv6-locator-option, port-number]
>     > ipv6-locator-option = bytes .size 16
>     > port-number = 0..65535
> 
> This is a good thing.

OK, I'll wait a day or two for other opinions. Also I think there is
a case for including the protocol (TCP, UDP or theoretically some other
transport). If an ASA supports both TCP and UDP it could return two
discovery responses.

> Also consider that the ACP addressing document can provide a multitude
> (a /96 was suggested) of IPv6 addresses to each node.
> 
> Is equality of the ipv6-locator-option important anywhere for saying that two
> conversations involve the same speakers?  or is there another identifier
> available?

That's a complicated question. I don't think it affects the current protocol
design, which discovers and caches addresses per objective anyway. A node could
contain numerous ASAs and they each could support several Objectives, and if they
each had a different IP address, GRASP wouldn't care. But it gets back to trust.
At the moment we're assuming that if a node is trusted, all the ASAs in it are
equally trusted, so we don't seem to need an additional identifier. If that
changed, I think we'd have to re-invent the former Device Identity Option in
GRASP in a slightly different form.

    Brian