Kenneth,
I believe I have addressed this issue with you before, but for clarification, OC-192, OC-48, etc are transmission bit rates. OC-192 is approximately 10 Gibabits per second, which is close to 10G Ethernet. Ethernet protocol operates in bit rate multiples of ten. The SONET protocol on the other hand establishes the OC-x bit rates at multiples of four, ie 16, 48, 192, 768. However the SONET protocol is independent of the hardware as the SONET protocol is used with legacy SONET equipment, and DWDM as well. The latter rapidly taking market share from the former.
I wouldn't get too disheartened over this issue as most journalists and industry pundits fail to recognize the differences as well. It is easy to confuse protocols and hardware with similar tags.
To put things in perspective legacy SONET equipment uses a pair of fibers, one for transmission the other for reception, at the various bit rates described above. However, Ciena's DWDM uses a single fiber with multiple channels transmitting in a bidirectional mode. Ciena is offering up to 160 channels at 10G each, and this will double by year end, and double again next year. I believe Nortel's DWDM requires a pair of fibers which effectively reduces the bandwith by 50%.
The overall transmission rate is the product of the number of channels times the bit rate times the number of fibers. SONET OC-192 using a pair of fibers has an effective bit rate of 5 Gbits per fiber, whereas the Ciena 160 channel DWDM OC-192 system has an effective bit rate of 1600 Gbits/sec per fiber, all at overall lower capital equipment cost, lower operating cost, much smaller foot print, and much easier provisioning.
Now you know why legacy SONET gear sales are registering zero growth. It is no contest. And Ciena is perfectly positioned to benefit from this changing landscape that it originally painted back in 1995.
The best is yet to come.
Jack Hutchison |
