Cisco Catalyst 4500 Series, Software Configuration Manual

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Catalyst 4500 Series Switch, Cisco IOS Software Configuration Guide - Cisco IOS XE 3.9.xE and IOS 15.2(5)Ex
Chapter 1 Product Overview
Management Features
Cisco IOS Mediatrace and Performance Monitor
Cisco IOS Mediatrace helps to isolate and troubleshoot network degradation problems by enabling a
network administrator to discover an IP flow's path, dynamically enable monitoring capabilities on the
nodes along the path, and collect information on a hop-by-hop basis. This information includes, among
other things, flow statistics; utilization information for incoming and outgoing interfaces, CPUs, and
memory; as well as any changes to IP routes or the Cisco IOS Mediatrace monitoring state.
For details, see the following URLs:
http://www.cisco.com/en/US/docs/ios-xml/ios/media_monitoring/configuration/15-1sg/mm-pasv-mon.
html
http://www.cisco.com/en/US/docs/ios-xml/ios/media_monitoring/configuration/xe-3sg/mm-pasv-mon.
html
http://www.cisco.com/en/US/docs/ios/media_monitoring/command/reference/mm_book.html
http://www.cisco.com/en/US/docs/ios-xml/ios/media_monitoring/configuration/15-1sg/mm-mediatrace
.html
http://www.cisco.com/en/US/docs/ios-xml/ios/media_monitoring/configuration/xe-3sg/mm-mediatrace
.html
Configuration guidelines for Cisco IOS Mediatrace and Performance Monitor include the following:
•
Video monitoring is supported only on physical ports.
Limitations for Cisco IOS Mediatrace and Performance Monitor on a Catalyst 4500 series switch include
the following:
•
Both features can only be configured to monitor ingress traffic.
• Packets cannot be monitored by both CEure and the rxSPAN session with encapsulation. The
first-applied configuration takes precedence.
•
Not all packets received by an interface can be monitored. After a packet is received by an ingress
interface, it might be either unable to make a forwarding decision or dropped at various stages
because of configured security features (like IP Source Guard). The switch attempts to monitor
packets close to the switch, but only those that are not dropped before the input classification stage
can be monitored.
• CPU utilization is impacted when you monitor a high traffic rate. After the internally-determined
threshold is crossed, monitored packets are dropped although the original packet is forwarded in
hardware intact. Starting with Release IOS XE 3.3.0SG and IOS 15.1(1)SG, monitored packets
might be dropped if any of the following apply:
–
The packet rate exceeds 512 PPS per flow.
– The aggregated bandwidth of the monitor traffic exceeds 10Mbps.
–
Resources are insufficient to enqueue a new monitored packet.
When monitored packets are dropped, the monitor event will be set to TRUE if the flow record
contains collect monitor event . If one minute passes with no new drops, the monitor event is set to
FALSE but is not reflected in the output of the show performance monitor status until the new
monitor interval starts.
monitor event is a global flag. This means that any packet drops that would trigger "monitor event"
be set to TRUE for all monitored flows at that monitor interval. If a metric depends on the collection
of continuous packets, the accuracy of that metric might be impacted when a
monitor event is TRUE.