Re: [tsvwg] draft-ietf-tsvwg-sctp-dtls-encaps-08.txt

[[e-mail]]

It looks like we are getting towards a point where it would be useful to
issue a new draft, so with this in mind I have a few comments (no Chair's
hat yet), so please feel free to comment on these comments...


I think the abstract  could benefit from a little explanation of the need
for DTLS encapsulation, given RFC 6951, and  RTCweb wishes to use UDP with
security. That's implied right now, and I think should be explicit.

I'd really encourage you to add this diagram to the intro, this wouldn't
hurt, and it makes it obvious!

 "
                               +----------+
                               |   SCTP   |
                               +----------+
                               |   DTLS   |
                               +----------+
                               | ICE/UDP  |
                               +----------+

                       Figure 1: Basic stack diagram"

And suggest you follow with something like:

   This encapsulation of SCTP over DTLS over UDP or ICE/UDP (see [RFC5245])
   can provide a NAT traversal solution together with confidentiality,
   source authentication, and integrity protected transfers. "

 This new text:
 "In case of a window based congestion..."
 Maybe would be clearer as:
 "The window-based congestion control method specified in [RFC4960],
 resets the congestion window and slow start threshold to their initial
 values."

 In 6.2, is it perhaps clearer to say exactly what is done, to help the DTLS
 reader understand e.g.
 "and can be used to send probe packets (HEARTBEAT chunks
 bundled with PADDING chunks [RFC4960])."

 I think it would be useful to also mention: "Path MTU discovery
 is required by SCTP when SCTP over DTLS is used
 for data channels (section 4 of draft-ietf-rtcweb-data-channel-13]."

Best wishes,

Gorry