Troubleshooting guide

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Cisco Broadband Local Integrated Services Solution Troubleshooting Guide
OL-5169-01
Chapter 4 Troubleshooting with Call Flows
Voice Quality Problems
Dropped Calls
Dropped calls occur when a call is terminated prematurely. Dropped calls can be the result of a gateway
resetting or a circuit problem. Use a protocol analyzer to determine which side is hanging up the call,
and trace call flows to isolate where the problem is occurring.
Codec Mismatch
If a customer gets a reorder tone when going off-hook, it could be the result of codec disagreement
between endpoints. Verify that both endpoints support at least one common codec (for example, G.711).
If not, you need to use transcoders.
Dial Plans
A Dial Plan is a list of numbers (and groups of numbers) that tells the call agent which devices to send
calls to when a certain string of digits is collected. It is analogous to a static routing table in a router. Be
sure that your dial plan concepts, basic call routing, and planning have been carefully considered and
properly configured before trying to troubleshoot a potential dial plan problem.
Consider the following questions when troubleshooting dial plan problems:
• What Directory Number (DN) is originating the call?
• What is the number that is being dialed? Note if and when callers are receiving a secondary dial tone
at any stage. What do callers hear after all the digits have been entered (re-order, fast-busy)? Do they
receive progress tones before they expect to hear anything? Make sure callers wait at least 10
seconds after entering the last digit, since they may have to wait for the interdigit timer to expire.