Subject: [Diffserv] Diffserv charter revision

From: Brian E Carpenter <[email-masked]>
Date: Thu, 15 Jun 2000 10:43:14 -0500

Here is a routine update to the diffserv WG charter, at Scott's request.
The changes are:
1. replaced BA by PDB according to the recent terminology consensus.
2. adjusted milestone dates.

Thanks

   Brian
---------------
Description of Working Group: 

There is a clear need for relatively simple and coarse methods of providing
differentiated classes of service for Internet traffic, to support various types of
applications, and specific business requirements. The differentiated services approach to
providing quality of service in networks employs a small, well-defined set of
building blocks from which a variety of aggregate behaviors may be built. A small
bit-pattern in each packet, in the IPv4 TOS octet or the IPv6 Traffic Class octet, is
used to mark a packet to receive a particular forwarding treatment, or per-hop behavior,
at each network node. A common understanding about the use and
interpretation of this bit-pattern is required for inter-domain use, multi-vendor
interoperability, and consistent reasoning about expected aggregate behaviors in a
network. Thus, the Working Group has standardized a common layout for a six-bit field of
both octets, called the 'DS field'. RFC 2474 and RFC 2475 define the
architecture, and the general use of bits within the DS field (superseding the IPv4 TOS
octet definitions of RFC 1349). 

The Working Group has standardized a small number of specific per-hop behaviors (PHBs),
and recommended a particular bit pattern or 'code-point' of the DS
field for each one, in RFC 2474, RFC 2597, and RFC 2598. No more PHBs will be
standardized until all the current milestones of the WG have been satisfied and
the existing standard PHBs have been promoted at least to Draft Standard status. 

The WG has investigated the additional components necessary to support differentiated
services, including such traffic conditioners as traffic shapers and packet
markers that could be used at the boundaries of networks. There are many examples of
these in the technical literature. 

The WG will define a general conceptual model for boundary devices, including traffic
conditioning parameters, and configuration and monitoring data. It is expected
that a subset of this will apply to all diffserv nodes. The group will also define a MIB
and a PIB for diffserv nodes, and an encoding to identify PHBs in protocol
messages. It will document issues involving diffserv through tunnels. 

The WG will develop a format for precisely describing various Per-Domain Behaviors 
(PDBs). A PDB is a collection of packets with the same codepoint, thus receiving the 
same PHB, traversing from edge to edge of a single diffserv network or
domain. Associated with each PDB are measurable, quantifiable characteristics which 
can be used to describe what happens to packets of that PDB as they cross the
network, thus providing an external description of the edge-to-edge quality of 
service that can be expected by packets of that PDB within that network. A PDB is
formed at the edge of a network by selecting certain packets through use of 
classifiers and by imposing rules on those packets via traffic conditioners. The
description of a PDB contains the specific edge rules and PHB type(s) and 
configurations that should be used in order to achieve specified 
externally visible characteristics. 

In addition to defining a format for PDB descriptions, specific descriptions of PDBs that
can be constructed using the standard PHBs will be developed and reviewed
by a design team prior to informational or standards track publication. 

The group will continue to analyze related security threats, especially theft of service
or denial of service attacks, and suggest counter-measures. 

The group will not work on: 

o mechanisms for the identification of individual traffic flows 

o new signalling mechanisms to support the marking of packets 

o end to end service definitions 

o service level agreements 

Goals and Milestones:

Feb 00     Publish draft of format for PDB descriptions (done, using old term "BA")
 
Feb 00     Solicit PDB descriptions (done)
 
Mar 00     Meet at Adelaide IETF to review tunnels draft, discuss initial PDB
descriptions (done)

July 00    Finalize model and MIB drafts, submit to IESG
 
July 00    Finalize tunnels draft, submit to IESG

Aug 00     Finalize PIB draft, submit to IESG

Aug 00     Finalize PDB format draft, submit to IESG

Aug 00     Meet at Pittsburgh IETF to finalize initial PDB descriptions, submit to IESG

Dec 00     Meet at San Diego IETF to close any open issues, make WG dormant

_______________________________________________
diffserv mailing list
[email-masked]
http://www1.ietf.org/mailman/listinfo/diffserv
Archive: http://www-nrg.ee.lbl.gov/diff-serv-arch/