Hi, Baker:
It appears that a good amount discussion can be started to answer your questions (what has being discussed for the last couple of years in the ITU-T and TIPHON in particular). I am not trying to do so. Let me answer your questions summarizing the key points as follows:
1. Broadly, all applications can be considered in two categories: a. Real-time (e.g., audio, video [of H.323/SIP]) and b. Non-Real-time (e.g., data applications like file transfer, WWW, Mail, etc. - can a part of H.323/SIP).
The performance parameters of both real-time (audio, video) and non-real-time (data) traffic can be abstracted in an universal way that can be used by all applications (e.g., H.323, SIP, WWW, mail, etc).
However, the signaling messages used by each application are application-specific although the QOS parameters used by all of them still remain same (e.g., H.323 might use RAS/Q.931/Annex-G/H.245 signaling messages, SIP might use SDP).
The QOS signaling messages that use QOS parameters can be termed as the application layer QOS signaling messages and are sent on end-to-end basis and the values of those QOS parameters do not change no matter what may be the underlying transport networks (e.g., IP, ATM).
2. The network layer QOS signaling messages carried over the network may not be end-to-end significance. For example, an end-to-end path of an IP network may consist of RSVP, DiffServ, MPLS, and RSVP. So, the network layer QOS parameters may get translated between the source-destination path and may not remain the same what has been negotiated on end-to-end basis in the application layer (item 1).
The problems that are being addressed are as follows:
A. How to develop the end-to-end QOS signaling mechanisms in the application layer
B. How to relate the application layer QOS signaling to the network layer QOS signaling (e.g., RSVP, DifServ, MPLS, etc.) so that one-to-one consistency remain between the application and network layer QOS parameters.
Hope this may clarify some of your questions.
Best regards, Radhika R. Roy AT&T
-----Original Message----- From: Fred Baker [mailto:fred@cisco.com] Sent: Thursday, May 31, 2001 1:09 PM To: Roy, Radhika R, ALCTA Cc: Bob Braden; gratta@lucent.com; sob@harvard.edu; mankin@isi.edu; diffserv@ietf.org; iptel@lists.bell-labs.com; issll@mercury.lcs.mit.edu; megaco@fore.com; sip@lists.bell-labs.com; sipping@ietf.org; tsvwg@ietf.org; hiramatsu.yukio@lab.ntt.co.jp; rbuhrke@lucent.com; tsg11q8@ties.itu.ch; tsg11q9@ties.itu.ch; ITU-SG16@mailbag.cps.INTEL.COM Subject: RE: PROPOSED JOINT ACTIVITY ON A GENERIC PROTOCOL MECHANISM FOR E ND-TO-END QOS SERVICE CONTROL
At 06:08 AM 5/31/2001, Roy, Radhika R, ALCTA wrote:
All applications (e.g., H.323, SIP) uses signaling messages among its functional entities (e.g., terminal, agents, gatekeepers, proxies, gateways) for communications.
I'm not sure we're on the same planet. Please help me out here.
I can think of a few applications that have agents, gatekeepers, proxies, and gateways, mostly resulting from the imposition of firewalls or authentication systems, or from legacy applications like imitating the telephone system in a data network. The only one that *requires* any kind of gateway, to my knowledge, is H.323 teleconferencing, which represents a paltry fraction of traffic according to most current measurements. Anything else (75% of Internet traffic is http or FTP, most of the rest is mail, on private LANs applications like NFS are pretty common, and even SIP can be done without a gateway between consenting systems) could be hooked up in separate systems on a LAN and made to work without any such signalling at all.
Could you be more specific on what QoS signalling is required by the world wide web, mail, FTP, common ERP applications like ERP and PeopleSoft, calendaring, and so on? If not, could you be more specific about what "all" applications you have in mind?
And could you be more specific about what issues this proposal is addressing that have not already been addressed in de facto standards and deployed in operational systems? It would be very nice to understand what you are preparing to ask vendors to do, and whether operators are interested in deploying them.
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