At 5:30 PM -0600 12/1/00, Brian E Carpenter wrote:
>Francis Dupont wrote:
>...
> > => just associate a QoS to a SPI and send the information (ie. how to
> > classify packets (addresses, ..., SPI) and the QoS) to the classifier
> > (which is by definition on-path).
>
>Wrong model. That requires signalling; diffserv doesn't have signalling.
>
>This works for RSVP as itojun explained, but it doesn't work for diffserv.
I'm getting confused. The Flow label is intended for intserv, so why
are you talking about subverting it (or the SPI) for diffserv?
If diffserv requires en-route inspection of the 5-tuple in order to set
the DSCP bits (and therefore you are trying to overload the Flow Label
with port semantics in order to avoid the cost of finding the ports),
that ought only to be done near the source edge (where parsing multiple
headers is less onerous), if at all, because of the ease with which one
could lie about one's port numbers to obtain better service. Are core
routers really going to provide different qualities of service to packets
based on an easily "forged" 8-bit integer?
I thought core routers classified packets for diffserv packets according
to the arrival interface and the arriving DSCP bits, *not* the 5-tuple.
Steve
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