Re: [straw] Alissa Cooper's Discuss on draft-ietf-straw-b2bua-dtls-srtp-09: (with DISCUSS and COMMENT)

["Ben Campbell" <[e-mail]>]

On 20 Mar 2016, at 11:18, Ram Mohan R (rmohanr) wrote:

[...]

>
> -----Original Message-----
> From: Alissa Cooper <[e-mail]>

[...]

>>
>> = Sec 1.1 and 1.2 =
>>
>> The language about the narrow case for which this document’s 
>> guidance is
>> targeted is better. But I think it needs to emphasize just how much 
>> of a
>> corner case this is. RFC 7362 recommends against latching, and 
>> address
>> hiding is more often provided using TURN. Rather than saying things 
>> like
>> "there are certain B2BUAs that are typically deployed for address 
>> hiding
>> or media latching, as described in [RFC7362]” without any of that
>> context, I would suggest something like “B2BUAs may be deployed for
>> address hiding or media latching [RFC7362], although TURN is more 
>> often
>> used for this purpose and media latching is not recommended due to 
>> its
>> security properties.”
>
>
> Ok. Will add the suggested text:
>
> EXISTING:
> However, there are certain B2BUAs
>    that are typically deployed for address hiding or media latching, 
> as
>    described in [RFC7362], and such B2BUAs are able to perform their
>    functions without requiring termination of DTLS-SRTP sessions i.e.
>    these B2BUAs need not act as DTLS proxy and decrypt the RTP 
> payload.
>
>
> NEW:
> B2BUAs may be deployed for address hiding or media latching [RFC7362],
> although TURN is more often used for this purpose and media latching 
> is not
> recommended due to its security properties. Such B2BUAs are able to
> perform their
> functions without requiring termination of DTLS-SRTP sessions i.e.
> these B2BUAs need not act as DTLS proxy and decrypt the RTP payload.

I think the statement that TURN is more often used for media latching is 
at least somewhat aspirational. But I'm okay with that aspiration :-)

(The reality probably varies by market type and the "purpose" of the 
latching, but that sort of detail would only be a distraction here.)

Ben.