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Re: [ANCP] Comments on draft-ietf-ancp-framework-05.txt
On 10 Mar 2008, at 13:23, Stefaan DE CNODDER wrote:
>
> Hi Francois,
>
> Why would on-path CAC signaling query the NAS? Since it is on-
> path, it is already on the NAS, so it will never query the NAS?
All I am saying is that, in the case of on-path signaling, the NAS is
effectively queried by the on-path signaling itself.
I think we're in agreement.
Francois
>
> regards,
> Stefaan
>
>
> Francois Le Faucheur IMAP wrote:
>
>> Hello,
>> Please find below a few comments/suggestions on framework-05.
>> Francois
>> * under section 3.4.2: first bullet.
>> The following text has been added:
>> "The NAS may locally maintain available "video"
>> bandwidth on the Access Loop, and perform video bandwidth
>> accounting for the Access Loop. Upon receiving an Admission
>> Request from the AN, the NAS can check available "video"
>> bandwidth
>> before admitting or denying the multicast flow. In the
>> process,
>> the NAS may communicate with the Policy Server. For
>> unicast video
>> services such as Video on Demand (VoD), the Policy Server
>> may also
>> query the NAS, so that it can perform admission control for
>> the
>> unicast flow, and update the available video bandwidth
>> maintained
>> by the NAS.
>> "
>> Could we make this slightly more generic and replace the last
>> sentence with something like:
>> "For unicast video services such as Video on Demand (VoD), the
>> NAS may also be queried (by a Policy Server or via on-path CAC
>> signaling), so that it can perform admission control for the
>> unicast flow, and update the available video bandwidth maintained
>> by the NAS."
>> * section 3.4.2: 2nd bullet.
>> Similarly could we replace:
>> "For unicast video services the policy server may query the NAS
>> to perform admission control for the unicast flow, and update
>> the available video bandwidth maintained by the NAS."
>> by
>> "For unicast video services the NAS may be queried (by a policy
>> server or via on-path CAC signaling) to perform admission control
>> for the unicast flow, and update the available video bandwidth
>> maintained by the NAS."
>> * section 4.7.6
>> The last requirement in the section is intended to reflect the
>> "Spontaneous Admission Response" functionality described in
>> section 3.4.4.
>> As agreed, one scenario has been added to section 3.4.4 (ie where
>> the NAS is made aware of Join/Leave by other means than ANCP),
>> and this scenario needs to be reflected in section 4.7.6. I'd
>> suggest adding something like:
>> " o Upon receiving an Admission Response from the NAS
>> indicating that replication of a multicast flow is to start or
>> stop on a given access port of the AN, the AN must enforce this
>> decision whether a corresponding Admission Request was issued
>> earlier by the AN or not.
>> "
>> * section 4.7.6:
>> replace:
>> "the AN should support receiving ANCP messages from the NAS
>> containing conditional access information of multiple multicast
>> flows"
>> by
>> "the AN should support receiving ANCP messages from the NAS
>> containing conditional/admission access information of multiple
>> multicast flows"
>> * section 4.7.6
>> There is one requirement stating that
>> "the AN should support receiving ANCP messages from the NAS
>> containing conditional access information of multiple multicast
>> flows."
>> The details of such mechanism is largely left to the protocol
>> design team, which is fine.
>> But it may be useful to identify one additional associated
>> requirement on AN, allowing AN to tell NAS that there is no
>> longer any multicast flows joined (within the admitted set of
>> flows) so the corresponding bandwidth can be freed up (where CAC
>> is performed). This could read :
>> " o after receiving ANCP messages from the NAS containing
>> conditional access information of a set of multicast flows, the
>> AN should support using ANCP to notify the NAS when there is no
>> longer any multicast flows from that set joined for a
>> configurable time-out period."
>> *section 4.8.6:
>> replace:
>> "the NAS should support sending an Admission Response message
>> containing conditional access information of multiple multicast
>> flows"
>> by
>> "the NAS should support sending an Admission Response message
>> containing conditional/admission access information of multiple
>> multicast flows"
>> * section 4.8.6:
>> there needs to be a requirement here also for spontaneous
>> admission response. I would propose:
>> " o the NAS may support using ANCP to indicate to the AN that
>> replication of a multicast flow is to start or stop on a given
>> access port of the AN, without having received a corresponding
>> Admission Request earlier from the AN.
>> "
>> *section 4.8.6
>> I believe the WG agreed that the following text needs to be
>> confirmed on the list before it could stay in framework doc.
>> "
>> o The ANCP MUST allow the NAS, when replying to an AN
>> request, to
>> OPTIONALLY convey information on multiple multicast flows
>> sharing
>> the same conditional access rules. This allows the AN to take
>> autonomous decisions for these flows later on.
>> "
>> editorial suggestions:
>> ================
>> * Section 3.4:
>> Current text:
>> "The NAS can perform conditional
>> access and multicast admission control on IGMP joins, and create
>> replication state in the AN if the flow is admitted by the NAS."
>> Change:
>> replace "IGMP joins" by "joins"
>> Justification:
>> Joins/leaves may be communicated via IGMP or via some other means.
>> * section 3.4.2.2
>> replace:
>> "Otherwise, the Access Node would have to query the NAS for
>> Multicast Admission Control"
>> by:
>> "Otherwise, the Access Node would have to query the NAS for
>> Multicast Admission Control (as per Grey List behavior)"
>> Typos:
>> =====
>> * section 3.4.2:
>> s/as well as for other a set of multicast flows/as well as for a
>> set of multicast flows/
>> * in a few places: replace "lateron" by "later on"
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