Specifications

© 2006 Cisco Systems, Inc.
All rights reserved.
Product Features 2-29
NAM / Traffic Analyzer v3.5 Tutorial
© 2006 Cisco Systems, Inc. All rights reserved.
Product Features 2-29
NAM / Traffic Analyzer v3.5 Tutorial
Data Center
Cisco
CallManager
Cluster
Access
Distribution
Core
Internet
Deploy NAMs at
critical points in your
network near the
Cisco CallManager
as well as near
phones and
aggregation points.
Deploy NAMs at
critical points in your
network near the
Cisco CallManager
as well as near
phones and
aggregation points.
NAM
NAM
NAM
NAM
NAM
NAM
NetFlow Data Export
to remote NAM
NAMs could be either NAM-
1/2 or NM-NAM depending
on network equipment
NAMs could be either NAM-
1/2 or NM-NAM depending
on network equipment
Planning for NAM Deployment
Voice Monitoring
Planning for NAM Deployment
Voice Monitoring
Deployment for VoIP problems
Performance monitoring of voice applications is critical because voice traffic is much more sensitive to
certain fluctuations in network performance than data. For example, voice traffic cannot tolerate variable
delays in the delivery of packets in the same way that data can. Users, who’ve come to expect the high
quality of voice transmission, will be able to discern this variation in delay, known as jitter. Proactively
monitoring voice applications will enable you to deliver high-quality voice services before users experience
any degradation. After you isolate the source or location of the delay, you can then implement quality-of-
service (QoS) policies to ensure better performance.
To monitor voice traffic, NAMs should be deployed at various points in the network: in switches at the access
layer that connect users with IP phones to the network; in distribution layer switches that connect access
layer switches to the Cisco Call Manager, and perhaps in routers at branch offices. Perhaps the most useful
placement of a NAM for voice monitoring is near the Cisco CallManager Cluster. Monitoring network access
to the Cisco CallManager will provide a rich source of information about the performance of the voice
system. This instrumentation strategy will help you identify performance problems such as jitter and packet
loss for all IP calls.
Other NAM features can also be used to gather statistics on voice applications. RMON can be used to collect
protocol statistics on protocols such as Skinny Call Control Protocol (SCCP), H323, Media Gateway Control
Protocol (MGCP), and Session Initiation Protocol (SIP). You can also gather response-time statistics on
voice applications. Again, alarms can be defined to notify you when voice packet loss or jitter signals the
degradation of voice application performance. In addition, you can configure the NAM to provide reports on
users and call statistics for troubleshooting or other purposes.