Re: [Slim] Open Issues on draft-ietf-slim-negotiating-human-language

[Adam Roach <[e-mail]>]

On 4/26/17 3:55 PM, Gunnar Hellström wrote:
>
> Bernard, thanks for the summary. We need decisions on these issues and 
> move on.
>
> How do you propose that decisions are taken?
>
> A brief comment on #38 - routing: My memory of the discussion and 
> decision is that we would not describe the routing logic and actions, 
> but we should aim at producing indications that would have high 
> likelihood to be usable for routing calls to appropriate call parties. 
> Thus it needs to be possible to interrogate the indications by proxies 
> even if TLS is used.
>

TLS is hop-by-hop in SIP (meaning it hides exactly nothing from 
proxies), so that's not an issue. The chances of S/MIME being broadly 
deployed in SIP do seem kind of slim, but thinking about what would 
happen if the body were encrypted is a good litmus test for "have I 
*really* messed up my layering?"

Given that the direction selected by the WG is to represent language 
values in SDP, I think this document can *either* say that routing is 
100% out of scope and unaddressed, *or* it can add some SIP-level header 
fields that bear on routing according to human languages. Anything that 
tries to split the difference is likely to cause architectural pain in 
the future, and an approach that I would counsel very strongly against.

/a