Subject: FW: SIP DiffServ (was RE: [SIP] Minutes of SIP Security task for ce in Adelaide)

From: "Sinnreich, Henry" <[email-masked]>
Date: Sat, 20 May 2000 13:25:56 +0000

Sorry for the resend - there were typos. Henry

>The real question is to define a mechanism that allows the 
>health of the network to be assessed in some sort of 
>meaningful way so that this knowledge may be made available to the UAC.

The model in <sinnreich-sip-qos-osp> actually deals with this problem.
Upon failure of the RSVP request, the telephony endpoint can alert the user:
"QoS cannot be provided, would you like to proceed with the call?".

The awareness of the originating SIP server, though not explicitly
discussed, can also be dealt with by the model.

We have shown that the transit networks providing DiffServ to the edge
networks, have to police the ingress traffic, to make sure that the
premium QoS traffic injected does not exceed the SLS. This job is done by
the border routers in the transit networks.

The border router can alert the edge router in the access network when
excess traffic is being passed, and this could be also used to alert the
bandwidth and policy manager in the access network. The policy manager will
refuse to authorize new requests for QoS enabled voice calls coming from
application servers, including the SIP server. The SIP server will therefore
know...

Please let me know if there are any weaknesses in the model, as shown in the
diagrams and call flows.
http://ietf.org/internet-drafts/draft-sinnreich-interdomain-sip-qos-osp-01.t

Henry

>-----Original Message-----
>From: Dean Willis [mailto:[email-masked]]
>Sent: Friday, May 19, 2000 5:35 PM
>To: Michael Thomas
>Cc: IETF SIP
>Subject: RE: SIP DiffServe (was RE: [SIP] Minutes of SIP Security task
>force in Adelaide)
>
>
>
>Ah. The networkstatus-aware proxy is effectively advising the 
>SIP user of congestion in the DiffServ network. Kind of like 
>those radio announcers that say "Highway 18 is shut down again 
>-- please use surface streets or just stay home".
>
>The real question is to define a mechanism that allows the 
>health of the network to be assessed in some sort of 
>meaningful way so that this knowledge may be made available to the UAC.
>
>--
>Dean
>
>
>
>> -----Original Message-----
>> From: Michael Thomas [mailto:[email-masked]]
>> Sent: Thursday, May 18, 2000 4:32 PM
>> To: Dean Willis
>> Cc: IETF SIP; Michael Thomas
>> Subject: SIP DiffServe (was RE: [SIP] Minutes of SIP 
>Security task force
>> in Adelaide)
>> 
>> 
>> Dean Willis writes:
>>  > Consider it in an aggregation model, like a donut. The chewy 
>> outside parts of the donut are controlled by IntServ. Traffic 
>> leaps across the DiffServ donut-hole only if the heuristic 
>> process thinks (IE, is reasonably sure) that there is 
>adequate bandwidth.
>> 
>>    OK, but I still don't see what that has to do
>>    with proxies. That sounds like something an
>>    edge router would do before it admits diffserv
>>    traffic into the diffserv core. Proxies are even
>>    more clueless because they never see the actual
>>    traffic patterns.
>> 
>> 		Mike
>> Hfæj)bz	b²Ô^>X¬¶ÆÞ-YZnÇ(sm§ÿåSËlmée*¦ìr?¿(tm)¨¥(tm)©ÿ-+-SwèþÈ©
>

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