4finger and Frank -
Thanks for the dialogue on Metro Service Providers: it opens up an area of activity that I am trying to study, but which seems to elude categorization.
My limited understanding of the subject reduces it to this: it seems to me that the problems of optical switching are such that it can only be performed at a higher level: at the wavelength level, on fiber. Switching occurs by (lambda?), not content: is that correct? I'm assuming that such switching can occur because data is 'pre-sorted' before it is inserted into an appropriate wavelength.
If I'm understanding what I'm reading correctly, the problems of reading packet header information, and switching packets, cannot be done at the optical level: it is o-e [-o], or, the data stream itself must be routed to a slower network, where the necessary switching, and transfer, continues, perhaps with re-insertion of old data, or insertion of new data, into an optical stream, or to substreams of slower, dedicated data, such as video, or voice.
I'm still trying to figure out how such switching would occur in an Ethernet sub-network, though SONET seems a little clearer. The extension of optical networks, in the Metro model, ending with FTTH, seems prohibitively difficult: how can content information possibly be switched at optical speeds? FTTH, a concept I once threw around with abandon, now seems laden with huge obstacles.
I realize that I have opened a constellation of subjects here. Frank, can you suggest any books that would get me
started (at least)? I am particularly interested in an overview of existing network architectures, switching and routing, and how future optical networks might evolve/coexist with legacy networks.
TIA
Best regards,
Jim |
