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To: c. carlson who wrote (175)	3/7/2000 8:05:00 PM
From: kumar	Read Replies (1) \| Respond to of 620

100 time/sec : slow/fast ? I am told by people more knowledgeable than me : "... Current optical switches use mechanical relays or stepper motors to either move mirrors or to physically move a (relatively) large optical spreader to a new location. It is very archaic and slow. Typical optical switches can require settling times of up to a second. So hundreds/sec. is impressive compared to that. ..."

To: c. carlson who wrote (175)	3/8/2000 9:53:00 AM
From: MCF	Read Replies (1) \| Respond to of 620

c.carlson, Hey thanks for the explanation.Sounds like hundreds of times a second is slow,even with densely packed packets in frame relay or ATM.It was also my understanding that the analog(light wave) does not need to be converted from analog to digital for re-routing ,offering high throughput through the switch.That is about the extent of my background on the subject.Does anyone out there know who Cisco uses for fibre based component supply,JDSU?MRVC?ETEK? anyone got any data? Thanks Surf@60

To: c. carlson who wrote (175)	3/8/2000 7:21:00 PM
From: Vijay Mehta	Read Replies (2) \| Respond to of 620

>>I plead ignorance on this subject, but hundreds of times >>a second sounds too slow. I live in a world where I am >>used to hearing 400MHZ or 500MHZ. >>Can anyone who knows something about this subject tell me >>what hundreds of times a second means for this technology?? Actually, I think these core optical switches will be used in the backbone of the internet by large service providers. Today, they use SONET/SDH rings where re-provisioning and re-routing customer data takes 3 to six months. This is the issue that all-DWDM all-optical networks are solving. Some folks like Sycamore, Monterey Networks (now Cisco) solve it by software. To be able to change routes houndred times a second means that this switch can be deployed more in the edges of the network. Think of it this way: in the core of the network, there are a few major interchanges you need to get to, so fewer routes and longer-life routes. You don't need to change routes that often. As your network expands to larger size by including more of the edges, you need to change routes based on traffic more often. Vijay

To: c. carlson who wrote (175)	3/11/2000 1:18:00 AM
From: George Dawson	Read Replies (1) \| Respond to of 620

Hundreds of times per second is relatively fast compared with some public information on existing photonic switches. For example, these products describes a connection times of 50-150ms: starswitch.com tellium.com I have not been able to find information on Lucent's products on their web site or in their technical journal. According to IEEE Computer magazine Lucent and Tellium will release all optical switches in the near future and Lucent, Monterey Networks, Sycamore Networks, and Tellium will release all optical routers this year. Hundreds of time per second seems fast compared with this information, but the sample is admittedly small. With regard to the speed of a typical LAN or SAN optoelectronic switch these connection or switching times are relatively slow - but these seem to be versions that are very early in the technology. For comparison, these connection times are comparable to latencies of second generation fibre channel switches or later generation ATM switches. George D.