ProLiant BL p-Class GbE2 Interconnect Switch Application Guide

Troubleshooting tools 163
Troubleshooting tools
Introduction
This appendix discusses some tools to help you use the Port Mirroring feature to troubleshoot common network
problems on the HP ProLiant BL p-Class GbE2 Interconnect Switch.
Port Mirroring
The Port Mirroring feature on the GbE2 Interconnect Switch is very useful for troubleshooting any
connection-oriented problem. Any traffic in or out of one or more ports can be mirrored to a single monitoring
port to which a network monitor can be attached.
Port Mirroring can be used as a troubleshooting tool or to enhance the security of your network. For example, an
Intrusion Detection Service (IDS) server can be connected to the monitor port to detect intruders attacking the
network.
NOTE: The monitor port must be in the same VLAN as the mirrored port to ensure Port Mirroring works
correctly.
As shown in the following figure, port 19 is monitoring ingress traffic (traffic entering the GbE2 Interconnect
Switch) on port 23 and egress traffic (traffic leaving the GbE2 Interconnect Switch) on port 1. You can attach a
device to port 19 to monitor the traffic on ports 23 and 1.
Figure 28 Port Mirroring
This figure shows two mirrored ports monitored by a single port. Similarly, you can have one mirrored port to
one monitored port, or many mirrored ports to one monitored port. The GbE2 Interconnect Switch does not
support a single port being monitored by multiple ports because it supports only one monitored port configured
at a time.
Ingress traffic is duplicated and sent to the mirrored port before processing, and egress traffic is duplicated and
sent to the mirrored port after processing.