In most cases, network problems can be resolved without assistance from any
outside technical support. However, some problems may seem to be too elusive
and professional help is required. This is when Cisco Systems Technical
Assistance Center (TAC) should be utilized.

It is
suggested the following be completed before calling Cisco (TAC):
- Have the service contract number ready. TAC will ask for it.
- Have a diagram of the network, or the affected portion of the network. Make
sure all IP addresses and associated network masks or prefix lengths are
listed.
- List the steps already taken and their results compiled for the TAC
engineer.
- If the problem appears to be with only a few routers (fewer than four),
capture the output from show tech command from these
routers.
Dial-in or Telnet access also helps considerably in effective problem
resolution.