RFC 3260 (rfc3260) - Page 2 of 10
New Terminology and Clarifications for Diffserv
Alternative Format: Original Text Document
RFC 3260 New Terminology and Clarifications for Diffserv April 2002
specifying classifier rules and any corresponding traffic profiles
and metering, marking, discarding and/or shaping rules which are to
apply...."
As work progressed in Diffserv (as well as in the Policy WG [6]), it
came to be believed that the notion of an "agreement" implied
considerations that were of a pricing, contractual or other business
nature, as well as those that were strictly technical. There also
could be other technical considerations in such an agreement (e.g.,
service availability) which are not addressed by Diffserv. It was
therefore agreed that the notions of SLAs and TCAs would be taken to
represent the broader context, and that new terminology would be used
to describe those elements of service and traffic conditioning that
are addressed by Diffserv.
- A Service Level Specification (SLS) is a set of parameters and
their values which together define the service offered to a
traffic stream by a DS domain.
- A Traffic Conditioning Specification (TCS) is a set of
parameters and their values which together specify a set of
classifier rules and a traffic profile. A TCS is an integral
element of an SLS.
Note that the definition of "Traffic stream" is unchanged from RFC
2475. A traffic stream can be an individual microflow or a group of
microflows (i.e., in a source or destination DS domain) or it can be
a BA. Thus, an SLS may apply in the source or destination DS domain
to a single microflow or group of microflows, as well as to a BA in
any DS domain.
Also note that the definition of a "Service Provisioning Policy" is
unchanged from RFC 2475. RFC 2475 defines a "Service Provisioning
Policy as "a policy which defines how traffic conditioners are
configured on DS boundary nodes and how traffic streams are mapped to
DS behavior aggregates to achieve a range of services." According to
one definition given in RFC 3198 [6], a policy is "...a set of rules
to administer, manage, and control access to network resources".
Therefore, the relationship between an SLS and a service provisioning
policy is that the latter is, in part, the set of rules that express
the parameters and range of values that may be in the former.
Further note that this definition is more restrictive than that in
RFC 3198.
Grossman Informational