HP 2910AL - Manual (Page 511)

Troubleshooting
Unusual Network Activity
TimeP, SNTP, or Gateway Problems
The Switch Cannot Find the Time Server or the Configured Gateway .
TimeP, SNTP, and Gateway access are through the primary VLAN, which in
the default configuration is the DEFAULT_VLAN. If the primary VLAN has
been moved to another VLAN, it may be disabled or does not have ports
assigned to it.
VLAN-Related Problems
Monitor Port. When using the monitor port in a multiple VLAN environ­
ment, the switch handles broadcast, multicast, and unicast traffic output from
the monitor port as follows:
■ If the monitor port is configured for tagged VLAN operation on the same
VLAN as the traffic from monitored ports, the traffic output from the
monitor port carries the same VLAN tag.
■ If the monitor port is configured for untagged VLAN operation on the same
VLAN as the traffic from the monitored ports, the traffic output from the
monitor port is untagged.
■ If the monitor port is not a member of the same VLAN as the traffic from
the monitored ports, traffic from the monitored ports does not go out the
monitor port.
None of the devices assigned to one or more VLANs on an 802.1Q­
compliant switch are being recognized.
If multiple VLANs are being used
on ports connecting 802.1Q-compliant devices, inconsistent VLAN IDs may
have been assigned to one or more VLANs. For a given VLAN, the same VLAN
ID must be used on all connected 802.1Q-compliant devices.
Link Configured for Multiple VLANs Does Not Support Traffic for One
or More VLANs.
One or more VLANs may not be properly configured as
“Tagged” or “Untagged”. A VLAN assigned to a port connecting two 802.1Q­
compliant devices must be configured the same on both ports. For example,
VLAN_1 and VLAN_2 use the same link between switch “X” and switch “Y”.
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