[AVTCORE] Comments on draft-ietf-avt-srtp-aes-gcm-01

[Qin Wu <[e-mail]>]

Hi,
This draft is well written. I would like to see this work moving forward.
Here are my minor comments to this document:

1. Section 1, Second Paragraph

  [Qin]: It looks SRTP (together with SRTCP) utilizes AES as the default cipher.
  However in some case(e.g., in ITU-T H.235.8), Public key cryptography be used with SRTP to provide end to end confidential and 
  authentication. So is it fair to assume in SRTP, both sender and receiver only use symmetric cryptography? what if asymmetric cryptography?

2. Section 1.1 Second Bullet

 [Qin]: It is not clear why four instantiations is required for each participant in the session,
 I think it is better at least to  have  a reference  to put here.

3. Section 1.2.1, First Paragraph

   [Qin]: Is the AEAD authentication tag is authentication tag 
   defined in SRTP/SRTCP packet? If not, how they are different? If yes,
   it is better to be clear about this in the draft.

4. Section 1.2.1, Second Pragraph

[Qin]: Should it say the optional SRTP Authentication Tag is NOT Recommended to be present
 to be consistent with the figure in section 1.2.5.

5. Section 1.2.5

  [Qin]: Should it also say authentication tag is not reccommended in the note to the figure?

6.Section 2.1 Four Paragraph

[Qin]: How the number of invocations is calcualted for SRTP/SRTCP respectively?

7. Section 2.2, Table 1

[Qin]: You also need to support the algorithm specified in [RFC5282],Should it say 
A detailed description of the AES-GCM family can be found in
   [RFC5116][RFC5282]?

8. Section 2.2 Last Paragraph

[Qin]: You didn't mentioned IV is formed from invocation counter in the section
1.2.2, rather than you point out "The packet counter is closely related to the invocation field",
what is missing?

 [Qin]:It is not clear to me how the invocation counter is related to each instantiation of AES-GCM?

9.Section 3

[Qin]: I can not understand this formulation and table. how do you get this formulation and table?
what's the rationale behind?

10.Section 4

[Qin]:It looks not complete since you didn't specify the SRTP transform parameters fro each profile.

Regards!
-Qin