Re: WGLC #2 starts for draft-ietf-dmm-requirements-03

Hi,

Below are my comments regarding multicast-related text, as one of the 
co-authors.

Em 15/04/2013 21:18, Jouni Korhonen escreveu:
> Hi,
>
> My WGLC comments of the I-D as a chair, not the document co-author. I will
> also put them one by one into the issue tracker.
>
> - Jouni
(...)
>
> 7) Section 1
>
>     Moreover, the availability of multi-mode devices and the possibility
>     of using several network interfaces simultaneously have motivated the
>     development of even more protocol extensions to add more capabilities
>     and to combine IP multicasting to the base protocol.  In the end,
>     deployment is further complicated with the multitude of extensions.
>
> o While "multi-mode" is correct, within IETF I would say "multiple
>    interface host" is better.
> o I do not understand how "to combine IP multicasting to the base protocol"
>    relates to the paragraph.
> o What is the "base protocol" here?

### Comments on 7) ###
SF: In previous version, we tried to motivate for IP multicast 
considerations within the Introduction by touching down previous text 
while addressing the justifiability of DMM. But seeing "to combine IP 
multicasting .." again, it doesn't seem to be perfectly aligned with 
sub-concluding sentence on the availability of multi-mode terminals. 
Additionally, "Base Protocol" was meant to refer to any mobility 
protocol to which multicast support was designed or added as an 
afterthought. So, our revised text is as follows:

-->"Moreover, the availability of multi-mode devices and the possibility 
of using several network interfaces simultaneously have motivated the 
development of even more protocol extensions to add more capabilities 
and to combine IP multicasting to the base protocol. In the end, 
deployment is further complicated with the multitude of extensions.
As an effective transport method for multimedia data delivery, IP 
multicast support, including optimizations, has been introduced but by 
"patching-up" procedures, after completing the design of the reference 
mobility protocol(s), leading to network inefficiency and non-optimal 
routing."
>
> 20) Section 4.7
>
> 4.7.  Flexible multicast distribution
>
>     REQ7:  DMM should enable multicast solutions in flexible distribution
>            scenario.  This flexibility enables different IP multicast
>            flows with respect to a mobile host to be managed (e.g.,
>            subscribed, received and/or transmitted) using multiple
>            endpoints.
>
> o What is "flexible distribution scenario"? That is not mentioned earlier
>    or defined.
> o I would reword the section title to something else like plain
>    "Multicast" or "Multicast considerations".
> o "..using multiple endpoint." is supposed to mean what? I kind of
>    understand that as an aggregation or what does it intend to say?
### Comments on 20) ###

SF: Besides the revision of the sub-section title, we also revised REQ7 
and motivation parts to give a better description.

--> "4.7. Multicast Considerations

DMM should enable multicast solutions in flexible distribution scenario. 
This flexibility pertains to the preservation of IP multicast nature 
from the perspective of a mobility entity and transmission of multicast 
packets to/from various multicast-enabled entities. Therefore, this 
flexibility enables different IP multicast flows with respect to a 
mobile host to be managed (e.g., subscribed, received and/or 
transmitted) using multiple endpoints multicast-enabled entities."

Additionally, we revised "motivation" part as follows:

--> "Motivation: The motivation of this requirement is to consider 
multicast early in the design process so that solutions can be developed 
to overcome performance issues in multicast distribution scenario avoid 
network inefficiency issues in multicast traffic delivery. The multicast 
solution may should therefore avoid having multicast-capable access 
routers being restricted to manage restricting the management of all IP 
multicast traffic relative to a host via a single endpoint, which would 
lead to the problems described in PS1 and PS6 through a dedicated 
interface on multicast-capable routers.

>
> 21) Section 4.7
>
>            problems described in PS1 and PS6.
>
> o For readability I would add references to relevant Sections as
>    well e.g. "..describer in Section 4.1 PS1 and in Section .."
>
### Comments on 21) ###

SF_ Following your suggestion:
--> "This requirement addresses the problems PS1 in Section 4.1. and PS8 
in Section 4.7."

Best regards,
Sérgio

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