Subject: Integrated Services Working Group

From: braden (Bob Braden)
Date: Fri, 19 Nov 1993 12:14:16 -0800

As a result of the Wednesday evening BOF in Houston, given by Scott
Shenker and Dave Clark, this mailing list has been set up.:

   [email-masked]

("Integrated Services", crunched together)

Dave Clark has submitted the BOF minutes shown below to CNRI for the
IETF Proceedings.

Bob Braden

___________________________________________________________________

Minutes of the Real-time Packet Forwarding and Admission Control 
BOF.

The demand for multimedia communication and the success of IETF
audio/videocasts will soon create an urgent requirement for resource
reservation and control in the Internet.  From an architectural
viewpoint, this represents a new Internet service model.  Such a
service model should include, in an integrated fashion, both realtime
and link-sharing services along with the traditional best-effort
datagram services.  Research in DARTnet has developed (a) an integrated
service model for the Internet, and (b) a particular set of mechanisms
to realize this model.

To provide end-to-end service suitable for realtime applications, the
routers must all implement  the same service model, although there may
be alternative mechanisms.  We therefore propose that the service model
be standardized.  This BOF will describe the service model and the
realization, and suggest the service model as a candidate for Internet
standardization.

The session was opened by Scott Shenker, who noted that Bob Braden, one
of the BOF chairs, could not be present due to concerns about his home
in the current LA fires.

Scott delivered a talk on the necessity of explicit service models in
the Internet.  He described the taxonomy of service models that are
proposed in the related Internet Draft.  He stressed that this proposal
is not for a closed set of service models, but for a growing set of
explicit models.  He also mentioned dissenting opinions from the loyal
opposition, who would prefer an approach without explicit service
models or explicit service reservations.

Scott  then continued by presenting and discussing three 
fundamental questions.
1)  Why do we need a service model?  The answer is efficiency.  He 
    argued that implementing explicit mechanism is more effective than 
    expending bandwidth in improving overall service, and this 
    mechanism can only be introduced in the context of a model that 
    defines the objective of the mechanism. 
2) Should the service model be explicit or implicit? He advocated that 
    binding between application and service should be determined by 
    the application, outside the network, rather than internally to the 
    network.  
3) Is admission control necessary? He argued that, at least for heavy 
    users, occasional blocking is a much more economical approach than 
    vast over-provisioning.

He then took a straw poll, which, while informal, suggested that there 
was not wide dissention to his conclusions to the above questions.

A discussion of service models followed.  There was support for the 
concept of admission control.

David Clark then gave a talk on the way in which routers must be 
constructed in order to realize the service models discussed earlier. 
He used the guaranteed real time service as an example of 
behavioral characterization of router functionality.

More discussion followed.  It was observed that behavioral 
characterization of functionality is a very difficult intellectual 
problem, and that it was important that the community not get 
bogged down in this exercise. We must start to implement and 
deploy routers and get real experience at the same time we work 
towards a formal performance characterization.

It was observed that while the presentation had emphasized router 
requirements, there will also be a need for "subnetwork 
requirements" or "link level requirements". In the past, Internet has 
demanded relatively little of its subnet technology, but these QOS 
requirements will change that. ATM, in particular, must fit into this 
architecture in a harmonious way. 

The BOF ended at 9:30, due to exhaustion of all parties.  There was an 
informal assessment that a working group ought to be formed.