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Re: [EFM] EFM Requirements

Talking about voice transport...

At 20:09 20/08/01 -0400, Matt Squire wrote:
>So what.  At the Ethernet level a packet has priority.  Someone has
>classified this packet as important.  Therefore, the network should do
>what it can to not discard the packet and to give it a relatively low
>latency.  The packet can be carrying voice, video, or my mother's secret
>lasagna recipe - I don't care.  I've been told its important - the
>application is irrelevant.

I must make sure that we are talking about the same Ethernet here. Ethernet 
by itself has no priority mechanism. A bunch of proprietary schemes were 
created, and some standard work was done, but I'm not aware of any widely 
deployed, complete, standards-based, solution for prioritization on the 
Ethernet level. I'm happy to be proved wrong, though, as it would be 
something really nice to have.

Now, if EFM will have the mechanisms to tag packets as important 
(non-discardable, low latency, and so on), then you're right. You are 
simply mapping IP QoS over Ethernet. But even then, the standard group has 
some work to do, to make sure that the prioritization mapping is done the 
right way.

>The point is that the Ethernet layer has no additional work to do to
>carry voice.  Therefore the requirements for transporting voice need not
>be singled out - there are none.

As I said, this is not granted - at least as far as I know. You have 
pointed out that there are several ways to carry voice; in my opinion, some 
of them will need specific provisions in the standard. If we can map 
everything to standard features of the Ethernet, then you're right, and we 
have nothing to worry.

Carlos Ribeiro
CTBC Telecom