Re: [rtcweb] Question about support for RFC 6520 DTLS heartbeat

Den 14. jan. 2015 23:40, skrev Michael Tuexen:
> On 14 Jan 2015, at 23:12, Harald Alvestrand <harald@alvestrand.no> wrote:
>>
>> Den 14. jan. 2015 21:06, skrev Michael Tuexen:
>>> On 14 Jan 2015, at 18:17, Martin Thomson <martin.thomson@gmail.com> wrote:
>>>>
>>>> On 14 January 2015 at 00:49, Michael Tuexen
>>>> <Michael.Tuexen@lurchi.franken.de> wrote:
>>>>> * DTLS does the PMTUD using DTLS heartbeats
>>>>> * SCTP does the PMTUD using SCTP HEARTBEAT and PADDING chunks
>>>>>
>>>>> My understanding is the RTCWeb uses the second option as described in
>>>>> http://tools.ietf.org/html/draft-ietf-rtcweb-data-channel-13#section-5
>>>>
>>>> SGTM.  That means we don't need to reference the DTLS heartbleed extension.
>>> It is not referenced in the RTCWeb documents, only in
>>> https://tools.ietf.org/html/draft-ietf-tsvwg-sctp-dtls-encaps-07
>>> which allows both options.
>>
>> So which document should we put it in that we use the second option?
>> -transport, or a post-last-call update of -datachannel?
> Do we really need a change? We have in 
> https://tools.ietf.org/html/draft-ietf-rtcweb-data-channel-13#section-5
>    Incoming ICMP or ICMPv6 messages can't be processed by the SCTP
>    layer, since there is no way to identify the corresponding
>    association.  Therefore SCTP MUST support performing Path MTU
>    discovery without relying on ICMP or ICMPv6 as specified in [RFC4821]
>    using probing messages specified in [RFC4820].  The initial Path MTU
>    at the IP layer SHOULD NOT exceed 1200 bytes for IPv4 and 1280 for
>    IPv6.

Good! I misunderstood what "it is not referenced" referred to above.

> 
> In the next revision of
> https://tools.ietf.org/html/draft-ietf-tsvwg-sctp-dtls-encaps-07#section-4
> there will be the sentence:
>    The path MTU discovery is performed by SCTP when SCTP over DTLS is
>    used for data channels (see Section 4 of
>    [I-D.ietf-rtcweb-data-channel]).

I think the section number is wrong - section 4 of data-channel is
requirements. (unless revised).

> 
> Best regards
> Michael
>>
>>>
>>> Best regards
>>> Michael
>>>>
>>>
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>>
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> 