On Aug 13, 2009, at 3:41 PM, Paul Timmins wrote:
Mark R Lindsey wrote:
On Aug 13, 2009, at 12:46 PM, Kenny Sallee wrote:
* redundancy for CLEC In the case of a site fault, the remaining site would detect the fault and assume full control. It's critically important in these designs that the two call control servers have connectivity that's the most reliable part;...
It sounds like for the entire effort and cost of this, there's still a SPOF, not to mention it requires you always augment at 45% or lower so if you lose one server, you don't block.
Good point; I was imprecise. You must certainly have redundant paths between your two SS7-attached call control servers. And there are voip platforms that support this fully. This "dual brain" fault occurs when BOTH of your redundant links between your SS7-attached call control servers are dead. You are also correct that you you engineer so that any one component in a fault-tolerance pair can support all of the load. But that's a familiar refrain in systems design: we do that with SS7 link members (neither link may exceed 50% utilization) and with our RAID-1 arrays (two disks, filled to 50% the cumulative capacity). Mark R Lindsey lindsey at e-c-group.com http://e-c-group.com/~lindsey +12293160013