[secdir] Secdir review of draft-ietf-dart-dscp-rtp-07

[Tina TSOU <[e-mail]>]

Dear all,

I have reviewed this document as part of the security directorate's ongoing effort to review all IETF documents being processed by the IESG.  These comments were written primarily for the benefit of the security area directors. Document editors and WG chairs should treat these comments just like any other last call comments.

IMHO, the document is almost ready. I just have minor comments:

** Technical **

* Page 6:
For IPv6, addition of the flow label [RFC6437] to network 5-tuples
results in network 6-tuples, but in practice, use of a flow label is
unlikely to result in a finer-grain traffic subset than the
corresponding network 5-tuple (e.g., the flow label is likely to
represent the combination of two ports with use of the UDP
protocol).

The flow label is different in each direction. Hence, if anything, you
should talk about 7-tuples rather than 6-tuples.


* Page 6, Section 2.2:

What about the drawbacks of multiplexing? -- You don't describe any.
What about Head of Line blocking?



* Page 13, Section 5.1:

When a protocol that provides reliable delivery receives a packet
other than the next expected packet, the protocol usually assumes
that the expected packet has been lost and respond with a
retransmission request for that packet.

Note: There is no "retransmission request" in TCP. Aditionally:
s/respond/responds/


* Page 13, Section 5.1:
This should not be done for current transport protocols within a
single network 5-tuple, with the exception of UDP and UDP-Lite.

This text is rather confusing. Maybe rephrase as "This should not be
done for transport protocol instances of current protocols, except of
UDP and UDP-Lite"?


* Security considerations section

Maybe Section 3.3 of RFC 6274 wuld be of use here?



** Nits/Editorial **

* Page 2:

The results of using multiple DSCPs to obtain different QoS
treatments within a single network 5-tuple (e.g., reordering) have
transport protocol interactions, particularly with congestion
control functionality.

Please "(e.g., reordering)" right after "treatments".

* Page 2:

s/requirments/requirements/


* Page 3:
Please add references for VP8 and H264


* Page 5:
RTP is usually carried over a datagram protocol, such as
UDP[RFC0768], UDP-Lite [RFC3828] or DCCP [RFC4340]; UDP is most
commonly used, but a non-datagram protocol (e.g., TCP) may also be
used.

Add missing space in "UDP[RFC0768]".


* Page 6:
When TURN selects use of TCP, the entire real-time communications
session is carried over a single TCP 5-tuple.

s/five-tuple/connection/

* Page 8, Section 3:
The DiffServ architecture[RFC2475] maintains distinctions among:

Please add the missing space


* Page 8:
s/loading/load/


* Page 11, Section 3.2:
Better results may be achieved when DSCPs are used to spread traffic
among a smaller number of DiffServ-based traffic subsets or
aggregates, see [I-D.geib-tsvwg-diffserv-intercon] for one proposal.

Please put the "see [I-D..]" within parenthesis.


* Page 13, Section 5.1:
Reordering also affects other forms of congestion control, such as
techniques for RTP congestion control that were under development
when this memo was published, see [I-D.ietf-rmcat-cc-requirements]
for requirements.

Please put the "see [I-D..." within parethesis -- i.e. "(see [I-D..)".


* Page 17, section 5.4:
SSRC

Please expand this acronym.


* Page 18, Section 6:
, see Section 5.2 above.

Please put this text within parenthesis.


Thank you,
Tina