Media Gateway Control Protocol (MGCP) and Call Associated Signaling (CAS)
Session Description Protocol (SDP)
Simple Client Control Protocol (SCCP)
Session Initiation Protocol (SIP)
Advantages of Cisco VLT Use
Here are some of the advantages of Cisco VLT use:
Messages are displayed in tabular form.
You can display messages for a particular call (as identified by its call reference) or for all calls that involve a particular device IP address, direction (send or receive), protocol, command, message, or channel.
You can display messages for calls with specified criteria.
You can display messages by call reference; each message contains the show timestamp, protocol, calling number, and called number.
You an display messages for calls whose device IP address, direction (send or receive), protocol, command, message, call reference, or channel contains a text string.
Analysis with Cisco VLT
Open the trace file with Cisco VLT. Here is a tabular display of the traces with Timestamp / Call Ref / Protocol / Calling and Called numbers:
Traces can be analyzed with display set as:
Raw: This displays the trace as it is in the file.
Simple translation: This display rearranges the text and provides a simple translation.
Detailed: This displays the text and also provides a detailed explanation for the display.
Here is a sample screenshot of the Raw display of the trace:
Here is a display of the same text with a Detailed explanation:
Here is a Detailed explanation of the SDP parameter and its interpretation: