There is a lot of talk about optical ethernet. Here is an excerpt from an article on DWDM. It appears that gigabit ethernet and Metro DWDM are a perfect match but not necessarily so for ordinary ethernet or fast ethernet. Lucent has an optical gigabit ethernet product and Nortel is about to announce one. It is interesting that companies would not necessarily have to replace or upgrade routers for optical access vis gigabit ethernet.
"Data services, specifically gigabit Ethernet, can be transmitted directly on a DWDM wave without intervening SONET equipment. Gigabit Ethernet is an optical technology so it can be transmitted directly at a significant cost savings. Also, at 1 gigabit per second (gbps), gigabit Ethernet does not fit neatly into any of the SONET multiplexes, being too big for OC-12 (622 megabits per seconds [mbps]) and too small for OC-48 (2.5gbps).
"Gigabit Ethernet manufacturers are producing what are, in effect, bit-rate-independent transponders for DWDM systems," says Mike Guess, vice president of engineering, IXC Communications Inc., Austin, Texas. "So you have a transponder that is not fixed to a SONET rate and is not looking for an OC-48 input, for example. It is looking just for an optical input and will clock its laser off whatever is the optical input."
However, Guess points out, the optical character that is so advantageous for gigabit Ethernet isn't there for the two other most common local area network (LAN) traffic data types, 100Base-T and 10Base-T, both of which are electrical. Also, DWDM is much more effective at high data rates, "and gigabit Ethernet is at the low end of what we consider high-speed nowadays," says Guess. Fujitsu has equipment that multiplexes 10Base-T streams for SONET. "You really need a combination of those two solutions [DWDM and new approaches to SONET] to make a data-friendly metro [DWDM] optical network."
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