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North American Network Operators Group Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical Re: Sonet protection usage
> Think about it -- are they really provisioning two circuits, leaving > one available as a backup? Of course not! I think you missed on of my points, which was APS on the trib side of the ADM, only a small mention of APS on the network side. If you can't figure out whether you've two circuits sitting there you've got bigger problems... > This may be a useful feature for voice circuits, where most of the > capacity sits idle most of the time. It's worse than useless for data. Again, I think you're missing the application wrt it residing on the trib side of the ADM -- to protect against router failures -- continuing to use the same network portion (i.e. the expensive portion) of the connection. > APS was designed to protect against the failure of the electronics > for a single fiber in a cable. Often, a dozen other circuits are > "protected" by a single APS. It's a ripoff. Perhaps in your experience, though I can argue quite the contrary, especially when your company owns the the transmission facilities. Though again, I was referring primarily to local protection against router failure on the trib side of the ADM. > Of course, the usual failure mode is backhoe fade, not electronics. > In which case, that APS circuit was cut along with the rest. Of course, backhoes don't normally work inside PoPs, which is the application of APS I was referring to. Routers do fail though (often more than links), and APS has been demonstrated to work relatively well for protecting against such failures. > For transoceanic links, diverse APS is even more unlikely, and unless > you are paying serious money, you won't be a priority over the other > hundred customers that are sharing that APS circuit. Not on the trib side, when protecting against router failures. > Diverse links _are_ the only _real_ protection. You might even get > what you pay for.... And in the short term, you at least get twice > the bandwidth Again, APS w/two local links to an ADM sufficiently protect against a local router failure. -danny
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