Response to your communication on Ethernet Traffic Parameters

["Adrian Farrel" <adrian@olddog.co.uk>]

Hi Jim,

In August the OIF sent CCAMP a communication about the use of the Ethernet
Traffic parameters described in
http://www.ietf.org/internet-drafts/draft-ietf-ccamp-ethernet-traffic-parameters-00.txt

The communication asked a specific question:

"One concern was expressed during the discussion in our meeting: the
proposed format contains a switching granularity subfield that defines
whether port or frame granularity switching is used, and there were comments
that it is not the granularity of switching that needs to be specified, but
the portion of the frame that is considered in forwarding. These are the
Ethernet layers defined by IEEE standards that the OIF is considering. For
example, we are currently looking at both Ethernet Private Line and Ethernet
Virtual Private Line. In the latter case, switching is performed based on
the VLAN identifier value, however the frame is still what is switched. We
believe the terminology used in the new Tspec format may warrant further
consideration in CCAMP."

We agree, when frame-based switching is being applied it is important for an
implementation to know what constitutes the label within each received
frame. Without this knowledge, it is (of course) impossible to correctly
switch the frames. However, it is not the job of the traffic parameters
(i.e. the TSpec) to convey this information.

Label type information is conveyed in the Generalized Label Request object.
Specifically, the switching type is used to indicate what type of switching
is required, although in many cases the label type should be obvious from
the context of the TE link.

The CCAMP working group is open to the specification of values for inclusion
in the Generalized Label Request to identify different Ethernet frame
switching paradigms, but please note that there are currently no Ethernet
frame switching types defined as acceptable by the IEEE. When the IEEE has
defined suitable data plane profiles, the CCAMP working group will be happy
to accept work that clarifies how signaling should be used.

Regards,
Adrian Farrel and Deborah Brungard
CCAMP Working Group Co-Chairs