Troubleshooting traffic mirroring
Cause
If mirrored traffic does not reach the configured remote destination (endpoint) switch or remote exit port, check the
following configurations:
• If the destination for mirrored traffic is on a different VLAN than the source, routing must be correctly
configured along the path from the source to the destination.
• All links on the path from the source switch to the destination switch must be active.
CAUTION: A mirroring exit port should be connected only to a network analyzer, IDS, or other
network edge device that has no connection to other network resources. Configuring a mirroring exit
port connection to a network can result in serious network performance problems, and is strongly
discouraged by HPE.
Interface monitoring features
You can designate monitoring of inbound and outbound traffic on ports and static trunks. This allows the
monitoring of individual ports, groups of contiguous ports, and static port trunks.
The switch monitors network activity by copying all traffic inbound and outbound on the specified interfaces to the
designated monitoring port, to which a network analyzer can be attached.
If a tagged packet arrives on a monitored port, the packet will remain tagged when it goes out a monitored port
even if that port is configured as untagged. If the packet is untagged, it will remain untagged going out the monitor
port. The monitor port state (tagged or untagged) does not affect the tagging of the packet. However, egress
mirroring does not reflect the tagged or untagged characteristic to the mirror port, instead it reflects the tagged or
untagged characteristic of the mirror port.
NOTE: When both inbound and outbound monitoring is done, and IGMP is enabled on any VLAN,
you may get two copies of IGMP packets on the monitored port.
NOTE: VLANs and port trunks cannot be used as a monitoring port.
The switch can monitor static LACP trunks, but not dynamic LACP trunks.
It is possible, when monitoring multiple interfaces in networks with high traffic levels, to copy more
traffic to a monitor port than the link can support. In this case, some packets may not be copied to
the monitor port.
Configuring port and static trunk monitoring (Menu)
This procedure describes configuring the switch for monitoring when monitoring is disabled. (If monitoring has
already been enabled, the screens will appear differently than shown in this procedure.)
1. From the console Main Menu, select:2. Switch Configuration... 3. Network Monitoring Port
2. In the Actions menu, press [E] (for Edit).
3. If monitoring is currently disabled (the default) then enable it by pressing the Space bar (or [Y]) to select Yes.
4. Press the down arrow key to display a screen similar to the following and move the cursor to the Monitoring
Port parameter.
5. Use the Space bar to select the port to use for monitoring.
Chapter 15 Monitoring and Analyzing Switch Operation 303
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