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Sonet/SDH DWDM and ethernet


Rather a broad title i know. I am primarily an IP person and now need to get up to speed on some of the optical technologies.

I have done some reading around SONET, DWDM, Metro ethernet etc. but i am still struggling to understand a few basics i think.

I appreciate that Sonet/SDH can run over DWDM but i believe you can also run ethernet natively over DWDM.

If you were building a new optical network from scratch would you consider utilising SONET/SDH and if so what would be the reasoning behind it.

I guess where my confusion comes from is there is Ethernet over Sonet, Packet over Sonet etc. but are these technologies there simply because there is such a large installed base of Sonet/SDH or is there another reason eg. Sonet/SDH provide far more reliability for packet transfer with the ability to guarantee delays etc.

Any insights would be much appreciated



Re: Sonet/SDH DWDM and ethernet

1. Yes, take a deep dive into the ONS15454 documentation. We have been running gig/e over dwdm for about 5 years.

2. Yes, but for very specific uses. For example a metro based environment is well suited to sonet/dwdm topologies, Data center to data center links that require high capacity and recoverability (see the stuff on APS in sonet).

3. IMHO SONET provides the basis for branching into Ethernet over sonet etc...given the frame size, error correction, in band management its a great technology for High availability/Bandwidth. the ability to run ethernet keeps you from having to buy very expensive POS line cards.