On 4/13/09, Dylan Ebner <dylan.eb...@crlmed.com> wrote: > My point is, it is getting harder and harder to gurantee path divergence > and sometimes the redundancies need to be built into the workflow > instead of IT.
Actually, in many ways it's getting easier; now, you can sign an NDA with your fiber providers and get GIS data for the fiber runs which you can pop into Google Earth, and verify path separation along the entire run; you put notification requirements into the contract stipulating that the fiber provider *must* notify you and provide updated GIS data if the path must be physically moved, and the move deviates the path by more than 50 feet from the previous GIS data; and you put escape clauses into the contract in case the re-routing of the fiber unavoidably reduces or eliminates your physical run diversity from your other providers. In years past, trying to overlay physical map printouts to validate path separation was a nightmare. Now, standardized GIS data formats make it a breeze. "protected rings" are a technology of the past. Don't count on your vendor to provide "redundancy" for you. Get two unprotected runs for half the cost each, from two different providers, and verify the path separation and diversity yourself with GIS data from the two providers; handle the failover yourself. That way, you *know* what your risks and potential impact scenarios are. It adds a bit of initial planning overhead, but in the long run, it generally costs a similar amount for two unprotected runs as it does to get a protected run, and you can plan your survival scenarios *much* better, including surviving things like one provider going under, work stoppages at one provider, etc. Sometimes a little bit of paranoia can help save your butt...or at least keep you out of the hot seat. Matt
