Diffserv Codepoint Field - 3Com 3C15500 - Network Director User Manual

DiffServ Codepoint
Field
The DiffServ Codepoint field, defined in the IETF (Internet Engineering
Task Force) RFC 2474, allows information about the quality of service
requirements of a packet to be carried with the packet as it traverses the
network.
There are no restrictions on what any of the codepoint values mean as it
is the choice of the network manager or the network management tool
to decide the local meanings, although there are recommended uses for
some of the values. The codepoint meanings can extend beyond simple
traffic priority to more precise specifications such as latency and jitter
requirements.
Information about the field, its use and the recommended values are
available in the IETF RFCs listed in
Table 102 RFC Definitions
RFC Number Title
RFC 2474 Definition of the Differentiated Services Field (DS Field) in the IPv4
and IPv6 Headers
RFC 2475 An Architecture for Differentiated Services
RFC 2597 Assured Forwarding PHB Group
RFC 3246 An Expedited Forwarding PHB
RFC 3247 Supplemental Information for the New Definition of the EF PHB
RFC 3260 New Terminology and Clarification for DiffServ
All of these RFCs are freely available from the IETF website:
http://www.ietf.org/
The RFCs listed in Table 102
DiffServ. Additional RFCs can be located on the Differentiated Services
Working Group's page on the IETF website.
As the DiffServ codepoint field is only present in IP packets, this restricts
the use of this marking mechanism to IP packets only. This means that the
information about the importance of non-IP traffic cannot be conveyed
from a complex classification device to a simple classification device using
this marking mechanism.
Useful Information and References
Table 102.
do not include all of the RFCs relevant to
653