Patent ID: 7929449

Claim:
A computer program product for determining a cause of a failure of a communication from a source device to a destination device, a preferred route from said source device to said destination device comprising a series of routers in a forward order, said program product comprising: a computer-readable, tangible storage device; first program instructions to determine one or more initial routers in said series in said forward order from said source device toward said destination device, a last of said initial routers in said forward order not designating a next router in said series in said forward order toward said destination device; second program instructions to determine said series of routers in a reverse order from said destination device toward said source device; third program instructions to identify a router in said series of routers in said reverse order which matches the last of said initial routers in said forward order, identify a next prior router from the matching router in said series of routers in said reverse order which should be designated by said last of said initial routers in said forward order as a next router in said forward order toward said destination device, and generate a notification as to which router said last of said initial routers should designate as its next router in said forward order toward said destination device; and wherein said first, second and third program instructions are stored on said computer-readable, tangible storage device.