VoIP Performance Management and Optimization: Managing VoIP Networks

Chapter Description

To ensure voice quality and to optimize media delivery over the IP, it is crucial to properly plan, design, implement, and manage the underlying network. This chapter discusses what are the best practices for planning media deployment over IP networks.

Using the Trace/Syslogs Logs for Deep Analysis

Syslogs or Trace logs contain information that was typically used during deep debugging and root cause analysis sessions. There is lot of valuable information embedded in the Syslogs, which if tapped, on a real time basis can take the VOIP network monitoring to another level. It allows for creating in-depth view of the network elements.

The basic idea is to stream the Syslogs to a dedicated server for deep analysis, where a continuous process should be introduce to parse the Syslogs for key trends. Key exercises that need to be performed are:

1. Identify systemic metrics that can be tracked through the logs.
2. Identify frequent service affecting issues which can be tracked through logs.
3. Capture frequency of the systemic metrics.
4. Lastly group the metrics into functional buckets, thus allowing for easier functional debugging and tracking.

Figure 6-4 captures a table highlighting some key metrics that are captured from the CISCO Softswitch BTS 10200. These metrics are basically derived from the log text. Each piece of text acts as signature for the metric. The Syslog is periodically parsed for these signatures. The signatures would then map to event types, based on their criticality. They could fall into an ERROR or a WARNING category. These events can then trigger traps or other notifications to monitoring systems.

Sample key metrics from CISCO Softswitch Trace logs

Log text	Possible Severity	Explanation
MGW admin state not allow subscriber maint request	Error	Cannot perform maintenance request( administrative and diagnostic module related)
ANM_process state_waitcrxresp Connection failed event type	Error	Announcement connection failed (Announcement Manager)
Failed SRV lookup and A record lookup while attempting add port and Domain name	Error	DNS issue for softsw_tsap_addr. BTS could not resolve domain name during a an audit of the SIP table.
KA timer expired for aggrIdx	Error	Cops protocol(BTS to CMTS) related error. Keep-alive timer expired for AGGR.

These metrics should be used for tracking overall system health through periodic summary reports along side with triggered event notifications.

The smart analysis of the Syslogs allows the service provider to develop an extra layer monitoring which might not be covered through the typical alarm notification functionality and may even drive towards improving the reported alarms.