Re: [multimob] Volunteers to review draft-ietf-multimob-fast-handover-01
"Rahman, Akbar" <Akbar.Rahman@InterDigital.com> Wed, 26 September 2012 20:19 UTC
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Date: Wed, 26 Sep 2012 16:19:50 -0400
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Thread-Topic: RE: [multimob] Volunteers to review draft-ietf-multimob-fast-handover-01
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From: "Rahman, Akbar" <Akbar.Rahman@InterDigital.com>
To: sarikaya@ieee.org, multimob@ietf.org
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Subject: Re: [multimob] Volunteers to review draft-ietf-multimob-fast-handover-01
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Hi, As per my action, I have reviewed draft-ietf-multimob-fast-handover-01 and have the following feedback to the authors: 1. In general, the I-D is well written and in pretty good technical shape. However, I had the following comments that I suggest be incorporated into an update before the WGLC. Detailed Comments: 2. Section 1 (Introduction) o I find the last paragraph in this section ("The solution described in this document ...") to be ambiguous and hard to "prove". How can you really demonstrate that the approach can be applied to "possible architectural evolutions"? I would suggest removing this type of claim unless you can be more specific. o The above comment also applies to the similar statement in the abstract, and section 6. o In paragraph 3, should it be "active multicast content delivery" instead of "active multicast subscription"? o In paragraph 4, I was not really sure if the base [RFC5949] can perform the mechanism or not? (I.E. Does it necessarily require modifications to [RFC5949] to perform the mechanism?) 3. Section 2 (Terminology) o The description of "Proactive handover" is confusing ("... the MN de-registration from the pMAG previously to receive the MN registration from the nMAG"). 4. Section 3 (Overview) o It would help a lot for readability (and understandability) to have a high level architecture picture in this section. Something along the lines of Figure 1 of RFC 6224 would be an obvious starting point. o The 2nd paragraph stresses that subscription info for an MN to the LMA is only updated after a handover event. This may be true, but later sections (e.g. Fig. 1) do specify other new info being exchanged without a handover event. So this should also be mentioned for balance. 5. Section 4.2.1.1.2 (De-registration process) o In the S=1 description, it refers to the "IP addresses of the subscribed group and the source providing it". I interpret the "source" to be referring to the Source-Specific Multicast (SSM) of [RFC4604]. But I understand that an MN can also do a non SSM Join (i.e. indicate only the subscribed group IP address and no source). Is this supported in the draft? (This comment applies to many places in the document). 6. Section 5.1.1 (Multicast Activity set to ON) o In Figure 1 and the corresponding text it indicates that the "Act Ind(start)" for the particular MN is sent by the MAG to the LMA as soon as the MLD Report is sent. I understand that this message will be sent for each similar MN that attaches to the MAG (along with a corresponding ACK). What are the signaling load implications for this between the MAG and the LMA? o (My understanding is that in Fig. 1 the flag "A=1" is sent in a PBU which normally would not have been sent at this point for unicast. Please correct me if I am wrong). 7. Section 7 (Benefits of layer-2 triggers for fast handover) o It was unclear what the main point of this section is (i.e. what is the standards text)? I especially found the last sentence confusing ("... and that not all the multicast applications could take benefit of it, that functionality could be seen as optional for multicast handover optimization.") 8. Section 8 (Security Considerations) o You obviously need to complete this section before WGLC. 9. Section 10 (Contributors) o Somehow the phrase ".. has largely contributed.." does not read well (perhaps just change "largely" to "extensively"). 10.General: I recall that the authors mentioned that they would do some simulations to prove the benefit of this approach vs the baseline [RFC6224] approach. I think that will be very useful so that the WG can trade the complexity vs. performance benefits of this approach. I did in general find the complexity of even understanding all the different options (reactive vs. proactive, Flag setting, prevention of unicast traffic delays, etc.) to be a bit daunting. I had to go back to your PPT presentations from the IETF meetings to piece everything together (as those slides nicely captured the high level flow). If we had the simulations then we could justify all the complexity. Or even better perhaps support fewer options that give the majority of the benefits? This to me is a key open issue. That's all. /Akbar -----Original Message----- From: multimob-bounces@ietf.org [mailto:multimob-bounces@ietf.org] On Behalf Of Behcet Sarikaya Sent: Tuesday, September 25, 2012 4:38 PM To: multimob@ietf.org Subject: [multimob] Volunteers to review draft-ietf-multimob-fast-handover-01 Hi all, In IETF84, three people volunteered to review draft-ietf-multimob-fast-handover-01, Thomas, Akbar and Costas. The volunteers, thanks for volunteering and please post your reviews on the list soon. Regards, Behcet _______________________________________________ multimob mailing list multimob@ietf.org https://www.ietf.org/mailman/listinfo/multimob
- [multimob] Volunteers to review draft-ietf-multim… Behcet Sarikaya
- Re: [multimob] Volunteers to review draft-ietf-mu… Rahman, Akbar
- Re: [multimob] Volunteers to review draft-ietf-mu… LUIS MIGUEL CONTRERAS MURILLO