Medianet Reference Guide - Cisco

Cisco Network Analysis Module
Chapter 6
Medianet Management and Visibility Design Considerations
Figure 6-5
Example of WS-SVC-NAM-2 Traffic Analyzer Chassis Interface Statistics
From a medianet management perspective, these statistics can be used for high-level troubleshooting of
traffic crossing the particular chassis, because even small rates of packet discards or interface errors can
result in degraded video quality. Note, however, that the interface statistics alone cannot be used to
determine whether video traffic is being discarded, because packet discards can be occurring only within
a particular switch port queue that may or may not hold video traffic. However, as is discussed in Router
and Switch Command-Line Interface, page 6-35, many router and switch platforms can show drops
down to the level of individual queues within the CLI.
If mini-RMON port statistics are enabled, the WS-SVC-NAM-2 provides slightly more information
regarding the types of errors encountered per interface, including undersized and oversized packets,
Cyclic Redundancy Check (CRC) errors, fragments, jabbers, and collisions. Figure 6-6 provides an
example showing port statistics on the uplink ports of a Cisco Catalyst 6500 switch.
Figure 6-6
Example of W-SVC-NAM-2 Traffic Analyzer Chassis Port Statistics
The port statistics can also provide information regarding the amount multicast traffic crossing the
interfaces. When viewed as current rates, the NAM port statistics show the number of multicast
packets/second seen by the interface. These can be graphed in real time as well, or viewed as cumulative
data. The port statistics do not show current rates in terms of bits/second or bytes/seconds for multicast
data, which would be useful for determining bandwidth provisioning for multicast traffic. However, the
design engineer can still gain some visibility into the amount of multicast traffic crossing a particular
interface on the Cisco Catalyst 6500 through the WS-SVC-NAM-2 port statistics.
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Medianet Reference Guide
OL-22201-01