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Re: [AVT] Revised text of the proposal for describing the functionality of Rate Adaptation



Please see inline.

 

Zeev

 

-----Original Message-----
From: VAN CAENEGEM Tom [mailto:Tom.Van_Caenegem at alcatel-lucent.be]
Sent: Monday, March 30, 2009 7:28 AM
To: Peilin YANG; Bill Ver Steeg (versteb); Ali C. Begen (abegen); Zeev Vax
Cc: Roni Even; Tom Taylor; Ye-Kui Wang; avt at ietf.org
Subject: RE: Revised text of the proposal for describing the functionality of Rate Adaptation

 

Hi Peilin,

 

Thanks for your comments. For those that concern editorial stuff, I have no comments back.

I have comments on three of your suggested modification items, as explained below.

Kind regards

Tom

 

 

Item 1) RMS-I message

 

You wrote:

"In the RMS-I message, the present values of Response include 0,1 and 2. The value of 0 indicates that the rapid synchronization request has been rejected. Nevertheless, in the RMS-I message there is not a field to indicate a rejected reason. In my point of view, tt is easier for RR to understand the rejected reason if there is a field of reason. What's more, it is convenient to make statistics report.

 

The following Figure is my proposal.  (..) "

 

TOM : in any case the message formats will be revised to describe parameters as much as possible and/or useful by means of(optional) TLV fields. I believe Bill will make a proposal soon.

I think the "cause of rejection" may be such a TLV field, when the RS indeed rejects the Burst Request. However, I think that may well be a vendor-specific field (for which we need a "type" classifier), as there are many reasons why a request is not honored, but to list them would IMO be out of scope of this draft. So, the question is: do we define a Type for a TLV extension that we call e.g. "reason of rejection" or do we just stick to a Type that only means " vendor specific". I think in both cases, an RR and a RS of a different vendor will not understand each-other, so we may well make it very generic and only define a TLV "type" that means " vendor specific"

 

[Zeev Vax] We still need to discuss the exact balance between TLV and fixed fields.

 

 

 

Item 2) Section 6.2: Message flows

 

   3.  Updated Request: The RR MAY send a new RMS-R message with a different

       valule of the field Max Receive Bitrate. The RS MAY use this updated

       bitrate for sending the burst, or refine the value and use the refined

       value for sending the burst. In any of the cases, the RS MAY send an

       RMS-I to indicate the bitrate being used. In case the RS receives

       multiple RMS-R messages at the same time, the latest RMS-R message,

       as indicated by the value of the MSN field in the RMS-R message, MUST

       be used, and other RMS-R messages SHOULD be discarded.

 

TOM: I suggest to delete " In case the RS receives

       multiple RMS-R messages at the same time, the latest RMS-R message,

       as indicated by the value of the MSN field in the RMS-R message, MUST

       be used, and other RMS-R messages SHOULD be discarded."

[Zeev Vax] I agree with Tom, and his comment is align with what we agreed in the last meeting. Any following RMS-R message might be used by the RS, but it is only recommendation.

 

This is because an RS may not support the feature of flexible burst rate adaptation under control of the RR. Hence in that case its implementation may be such that it classifies incoming RMS-R based on version number and internal state. When the RS  has already an active thread for a certain RR and certain SSM (a pending or active burst request) , the RS can simply drop any new RMS-R (with a higher message sequence number) transmitted by that specific RR for that specific ssm.

 

 

 

 

Item 3) Section on RMS-R message (section 7.1)

 

      Message Sequence Number (8 bits) :  During rapid synchronization,

      the RMS-R message(s) may be sent more than once.  The first RMS-R

      message SHALL have an MSN value of 0. If a new information is conveyed

      in a new RMS-R message, the MSN value SHALL be incremented by one.

 

TOM: an RMS-R message may also be sent multiple times with the same information for redundancy purposes. For that reason, I suggest we have instead of " If a new information is conveyed in a new RMS-R message, the MSN value SHALL be incremented by one ", we are more specific and align with the phrasing as used for the RMS-I message:

"This value SHALL NOT be changed if the same RMS-R message is sent to the same RS multiple times for redundancy purposes. If a new information is conveyed in a new RMS-R message, the MSN value SHALL be incremented by one"

 

[Zeev Vax] Both sound reasonable to me

 

 

 

-----Original Message-----

From: Peilin YANG [mailto:yangpeilin at huawei.com]

Sent: maandag 30 maart 2009 13:20

To: Bill Ver Steeg (versteb); Ali C. Begen (abegen); VAN CAENEGEM Tom; zeevvax at microsoft.com

Cc: Roni Even; Tom Taylor; Ye-Kui Wang

Subject: Revised text of the proposal for describing the functionality of Rate Adaptation

 

Dear Bill, Ali, Tom and Zeev,

 

I added some revised text of the proposal for describing the functionality of Rate Adaptation for the Burst. Please see the attached file. The revised text mainly involves in a new step 3, part of step 1, "7.1. RMS Request" and Figure 3 depicts an example of messaging flow.

I am very glad to disucss it with you. In the attachment file it also includes a little revision. Please see if not suitable for revison.

 

In addition, I think, the following suggestions also need to be discussed. 

 

1) IGMP

 

In the draft like the following text it only describes the IGMP based on IPv4.

 

"When a receiver wishes to join the same multicast session, instead of simply issuing   an Internet Group Management Protocol (IGMP) [RFC3376] Join message, it sends a request to the feedback target address for the session asking for the Reference Information. "

 

Do you think it is necessary to consider MLD protocol based on IPv6 in the document as follows?

 

"When a receiver wishes to join the same multicast session, instead of simply issuing   an Internet Group Management Protocol (IGMP) [RFC3376] or Multicast Listener Discovery (MLD) [RFC 3810] Join message, it sends a request to the feedback target address for the session asking for the Reference Information. "

 

2) RMS-I message

 

In the RMS-I message, the present values of Response include 0,1 and 2. The value of 0 indicates that the rapid synchronization request has been rejected. Nevertheless, in the RMS-I message there is not a field to indicate a rejected reason. In my point of view, tt is easier for RR to understand the rejected reason if there is a field of reason. What's more, it is convenient to make statistics report.

 

The following Figure is my proposal. 

 

      0                   1                   2                   3

      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     |      MSN      |   Response    |      Reason   |     Rsvd.     |

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     |        Extended RTP Seqnum of the First Burst Packet          |

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     |                   Earliest IGMP Join Time                     |

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     |               Rapid Synchronization Duration                  |

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     |                       Max Burst Bitrate                       |

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

 

        Figure 5: FCI field syntax for the RMS Information message

 

3) "an/the RTP Receiver" and "a/the Receiver"

In the document there are many "an/the RTP Receiver" and "a/the Receiver". Do you think it is necessary to keep these terms to be consistent throughout the document?  I revised them as "an/the RTP Receiver" in the revised proposal text.

 

4) "the burst", "a/the unicast burst", "an/the RTP burst" and "the RTP unicast burst"

In the document there are many "the burst", "a/the unicast burst", "an/the RTP burst" and "the RTP unicast burst". Do you think it is necessary to keep these terms to be consistent throughout the document?  I revised them as "a/the unicast burst" in the revised proposal text.

 

5) "joining the multicast session" and "joining the multicast group"

In the document there is only one "joining the multicast group". I modified "joining the multicast group" to "joining the multicast session"

 

6) The description of "Updated Responses" of step 3 In the document there is a general description for "Updated Responses" as follows. When I discussed with our development enginerrs, as on-native english speakers they said it is not completely clear to how to implement it.

 

  "3.  Updated Responses:  RS may send more than one RMS-I messages,

       e.g., to update the burst bitrate information when the bitrate is

       adapted and/or to signal RR in real time to join the SSM session."

 

They said the original text from the draft - draft-levin-avt-rtcp-burst-00 is easier to understand.

So I suggest to add a little description example at the end of the sensence.

 

The following text is my proposal. The last sensence is largely extracted from the draft - draft-levin-avt-rtcp-burst-00 

 

  "3.  Updated Responses:  RS may send more than one RMS-I messages,

       e.g., to update the unicast burst bitrate information when the bitrate is

       adapted and/or to signal RR in real time to join the SSM session; to notify

       RR to join the multicast session when the unicast burst catches up with

       the original multicast session."

 

Regards,

Peilin

 

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----- 邮件 -----

发件人: "Bill Ver Steeg (versteb)" <versteb at cisco.com>

日期: 星期五, 三月 27, 2009 上午3:43

: RE: Hi Bill and all,

收件人: Peilin YANG <yangpeilin at huawei.com>, "Ali C. Begen (abegen)" <abegen at cisco.com>, Tom.Van_Caenegem at alcatel-lucent.be, zeevvax at microsoft.com, Ye-Kui Wang <yekuiwang at huawei.com>

抄送: Roni Even <ron.even.tlv at gmail.com>, Tom Taylor <tom.taylor at rogers.com>, "Dave Oran (oran)" <oran at cisco.com>, avt at ietf.org

 

> Peilin-

>

> I think we made good progress on the draft. We also have some other

> folks looking at how the rate adaptation interacts with the rest of

> the signaling. Hopefully we will be able to cleanly incorporate rate

> adaptation into the protocol. If you have some suggested text in that

> area, that would be great.

>

> Bill VerSteeg

>

> -----Original Message-----

> From: Peilin YANG [mailto:yangpeilin at huawei.com]

> Sent: Wednesday, March 25, 2009 8:07 PM

> To: Bill Ver Steeg (versteb); Ali C. Begen (abegen);

> Tom.Van_Caenegem at alcatel-lucent.be; zeevvax at microsoft.com; Ye-Kui Wang

> Cc: Roni Even; Tom Taylor; Dave Oran (oran); avt at ietf.org

> Subject: Hi Bill and all,

>

> Hi Bill and all,

>

> Thank you very much for concerning Huawei's draft.

> I am sorry I haven't participated the SF meeting because I haven't got

> an American Visa this time.

>

> YK told me an informal result of break session yesterday.

> Now I am considering the revised text for describing the functionality

> of Rate Adaptation for the Burst to the common converging solution and

> other possible contributing text.

>

> Regards,

>

> Peilin

>

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> HUAWEI, which is intended only for the person or entity whose address

> is listed above. Any use of the information contained here in any way

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> reproduction, or dissemination) by persons other than the intended

> recipient(s) is prohibited. If you receive this email in error, please

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