Curtis,
Touché! (sorta)
What is it they say about a hammer seeking nails? I think that we are all guilty of that principle, at times. Read on.
You're absolutely correct re: overhead bytes in the SONET header, these are not read in the optical domain. Granted. At least not at this time, so in this semantic matter I concede. But that only speaks to the electrical states of SONET, not the photonic ones. And granted, if I were more thorough in my earlier comments I would have made the distinctions, but I did not. Concession goes to Curtis on elecrical attributes.
But this hammer's focus has been primarily on the optical, more so at least than the on the electrical. I've since reactivated the other monitor on my radar setup. I should have included both all along.
Nevertheless, the data flows riding over those lambdas do, more often than not, to date, consist of SONET/SDH containers, and must be rated for such in the optical domain, as well as the elecrical where such capabilities actually do exist (such as in ODCs), which was the intent behind the point I was making.
The optical rating hasn't anything to do with overhead bytes or reading headers, rather it has to do with meeting the optical parameters which are in many ways dictated by the OC level to be used. (Even if ports satisfy a multitude of line rates.)
Such things as spectrum allocation on the dwdm grid plan, power intensity and receive sensitivity, Optical Overhead signaling used for Network Management, as opposed to regular SONET NMS bytes which are purely electrical, interface connector types, distance limitations per type of strand/mode used, dispersion handling capabilities, etc. The OPTICAL, or photonic level, components of SONET, NOT the electrical ones.
Your observation brings up a good point, however, which I also stated earlier on in a previous message in this discussion, wherein I stated in reply #827 (shown edited).
I stated:
"I would suggest that the popular misuse of the lexicon surrounding the marketecture of this space has become so pervasive at this point that... we are giving full credence to their new meanings... whilst we attempt to rationalize what they actually mean and what's actually going on... we tend to entirely ignore, sometimes simply forget, the fact that we are actually using.."
To wit, I concede my semantic infraction at the electrical state, but not the optical, and thank you for highlighting the difference.
[It actually does depend on how granular you want to take it. This in some ways demonstrates the power of the marketecture and reinforces what I sated earlier in quotes above. For example, I read specifications on DWDM network elements made by any number of vendors which stipulate OC-48, OC-192 configuration options. But we know better, of course, that this only defines the optical handling, which highlights the main point of this discussion all along.
An extension of the dwdm-based OADM, I should add, being the SONET-enabled Optical Digital Cross-connects (ODCs), such as those made by TLAB and ALA do, in fact, perform the o-e conversions necessary to read those overhead bytes, if my memory serves me correct.]
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Re: SRP, thanks for the update.
"You seem to know quite a bit about it."
Not really, not as much as I should at this stage. I was intrigued it during some presentations I'd reviewed about a year ago, in its earlier stages. I've more recently been re-introduced to it, and plan on learning more. Right now I'm only speculating as to its ultimate potential and future implications, even as they might affect the outcome of some of the issues we've discussed here.
Thanks again for adding value to this discussion.
Frank (always looking for finishing nails) |
