Re: [RE] Stream identification at the MAC SAP
Title: Re: [RE] Stream identification at the MAC SAP
To add something
such as a stream identifier that is the same across the MACs, the place to
do it is 802.1 rather than 802.2. It could be done with a type field (which
identifies this as a stream header) followed by one or more fields to identify
the stream. I haven't seen enough to determine that this is necessary or
desireable, but if it is then it should be done in 802.1 not 802.2.
Pat
See comments below...
Just an opinion, but ...
- None of the higher layer services running on
ethernet/802(anything)/IP have any idea what to do with isochronous data ...
so it is not surprising that there are no service parameters that deal with
this.
[Bill Shvodian] I don't think that is quite true. RSVP can be
used to reserve bandwidth for a stream. From rfc 2205: "An
RSVP session is defined by the triple: (DestAddress, ProtocolId [,
DstPort])." This information could be used to identify an isochronous
strream.
- At the guts of ResE, I expect we will need a unique
EtherType to indicate an isochronous packet, just like you do for MAC
control frames.
[Bill Shvodian] Identifying it as isochronous is
one thing. Identifying which stream is another. You may
have two video streams and multiple audio streams between two
nodes, but since the reservations and treatment may be different depending
on the type of stream.
- I expect there will have to be a NEW service
interface for isochronous data (yet another reason for this to be done in
802.3). This might look just like the existing MA-UNITDATA.request, except
with scheduling parameter(s).
[Bill Shvodian] I agree. I
just wish that 802.2 had agreed to make the change so that ALL 802
standards would use the same defined parameters, rather than having one
for RE, one for 802.11e, one for 802.15.3, etc, etc.