General: 

It is becomes clear from the paper that you are working in this area and
have experience about writing such papers and documents . The presentation
is professional. It is good and clear and accessible also to a reader with
no ietf experience. However, in the context of this seminar, you could have
taken the opportunity to be more specific about the cryptography used in the
protocols, the GDOI, in particular (see also below).

Detailed comments: 

1. A list of abbrevations  would be helpful. 

2. Section 2.2. below Fig 2, paragraph 3: SPI is not explained 

3. Section 3.2.1: What are the tasks of S-GCKS?  S-GC/KS = S-GCKS ? 

4. Section 3.2.3: Be more specific about cryptography in GROUPKEY_PULL: 
- What is KE payload? Is it KE_I and KE_R ? Are they Diffie-Hellman keys?
How is perfect secrecy achieved if KE is used?

- liveness (not liveliness) 
- Is the key for data security association sent in KD? 
- Are the nonces Ni and Nr? How are they used for key derivation? 
- You say the hashes include nonce values. Which hashes? How are the hashes
computed? 
I am just saying that in its current form the presentation raises more
questions than it gives answers to.