Re: [RE] Stream identification at the MAC SAP
Title: Re: [RE] Stream identification at the MAC SAP
Richard can fill you all in, if you are really interested, but the real reason 802.9 didn’t go anywhere had more to do with it’s intended market: as a high-performance link for telephone systems. Its isochronous services were limited to muxing standard telephone ISDN channels on top of 10Mbit Enet. It was an OK idea at the time, but since the isoch services depended on PBX support it was a very odd hybrid system. PBX companies did not embrace it, so the world ended up with two parallel wiring systems: one for telephones and one for the LAN. The telephone systems, being highly centralized, were not amenable to the kind of incremental growth that the LAN part of the universe (to get a significant telephone network upgrade, an enterprise had to buy a whole new PBX, a rather expensive proposition).
Oddly enough, with Residential Ethernet (at least the way some of us have been envisioning it), you could really toss the PBX out the window without losing any quality of service.
Anyway, it’s unfortunate that 802.9 is sometimes called an isochronous LAN, because it never was. It was, instead, a hybrid LAN/Telephone network, an entirely different beast.
On 11/11/04 5:36 PM, "Matt Squire" <MSquire@HATTERASNETWORKS.COM> wrote:
So, there was a bunch of work on trying to make isochronous LANs in the IEEE, and now all of that work is in hibernation and not in use.
Maybe that says something.
- Matt
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Michael D. Johas Teener
http://public.xdi.org/=Michael.Johas.Teener - PGP ID 0x3179D202
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