Transcript Slide 1
Session 403 An Introduction to MST in Communication Manager Jeff Lusby Voice Architect MST - What Is It? • First developed as a tool for tracing external protocols like ISDN-PRI • External protocols supported in MST: ISDNPRI/BRI, ASAI, X.25, IP, CMS, CDR, PMS • Internal protocols (not much good to us as customers): CCMS, call vectoring, call tracing, hardware/software errors, and denial events Requirements and Uses • Must have a Release 2 or later Linux based CM server to decode the trace data • Requires that the login have maintenance permissions • Useful for isolating problems to the PBX, to a service provider, or to external equipment • Provides a detailed view of what happened and when it happened Configuring a Trace • • Configured via the SAT command change mst change mst default changes all fields back to default values Configuring a Trace • High-level MST configuration is done on page 1 of change mst • Dozens of y/n fields control various types of tracing: X.25, ISDN, CCMS, call trace, etc… • Configure various filters for the protocol(s) selected on the other pages of the form • Run Time Limit can turn off trace after the specified amount of time • Log Mst and Trace Analyzer must be set to Y in order to view the trace in the S8xxx Maintenance web interface (more on viewing the trace later) Configuring a Trace After setting the Trace Analyzer to Y you will see a WARNING at the bottom of the SAT screen regarding the Trace Analyzer. Configuring a Trace Configuring the MST trace to capture the signaling messages on an ISDN-PRI Dchannel is done on page 1 and 2 of the MST form. You enable ISDN-PRI on page 1 (don’t forget Log Mst and Trace Analyzer). Configuring a Trace Page 2 is used to define the ISDN-PRI Filter Data. The default for Port Type is b-channel so change the Port Type to d-channel, then enter the port location of the d-channel that you want to trace. Configuring a Trace • Port Type can also be set to H.323 • When the Port Type is changed some of the other fields will change as well • The Signaling Group Number for the IP Trunk Group is entered when tracing an H.323 Port Type Enabling the Trace • status mst prior to enabling a new trace, you may have messages left in the buffer from a previous trace (Avaya support) • Use clear mst to clear the buffer, then enable mst to start the trace Capturing a Trace Now that the trace is enabled it will collect all D-channel messages sent and received on the port defined in the MST screen. The trace will run until it is disabled and does not affect other command processing. Capturing a Trace The trace has been disabled by the command disable mst. To view the raw data use list mst but all that you will see are the hexadecimal bytes…. Analyzing a Trace So, how do you interpret this data? Analyzing a Trace Beginning with R2.x of Communication Manager the S8xxx servers have a built in trace analyzer that allows the hex to be converted to English (for the most part). The interpreted output is viewable from the maintenance web interface in the System Logs page found under Diagnostics. The “Communication Manager interpreted Message Tracer” is the log that will show the trace data. Analyzing a Trace In the event range section the field for Number of Lines: will default to 200, which is rarely enough. Just add a couple of zeroes. Analyzing a Trace Analyzing a Trace The first line of an interpreted message indicates whether the message is incoming or outgoing (from the CM perspective). • An incoming message has a double arrow pointing to the right (==>) on the first line 11:54:43.479 60 00003d17 ==> CALL_PROC crv 1_1a6a • An outgoing message has a single arrow pointing to the left (<--) on the first line 11:54:55.806 62 00003d17 <-- SETUP crv 0_1b5d Analyzing a Trace SETUP message from the PBX to T1 vendor, several fields of note are CALLING PARTY NUMBER and CALLED PARTY NUMBER. CALL_PROC followed by an ALERT message is the expected response from the service provider. When the Called Party answers a CONN message is sent, the PBX responds with a CONN_ACK. Analyzing a Trace Analyzing a Trace Analyzing a Trace Analyzing a Trace See you next year in Las Vegas May 22-26 for the 2011 International Conference