Vlan-Related Problems - HP ProCurve series 2500 Management And Configuration Manual

VLAN-Related Problems

Monitor Port. When using the monitor port in a multiple VLAN environ-
ment, it can be useful to know how broadcast, multicast, and unicast traffic
is tagged. The following table describes the tagging to expect.
Within Same
Tagged VLAN
as Monitor Port
Broadcast Tagged
Multicast Tagged
Unicast Flood Tagged
Unicast Not Untagged
to Monitor
Port
Unicast to Tagged
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".
Switch "X"
Port X-3
VLAN Port Assignment
Port VLAN_1 VLAN_2
X-3 Untagged Tagged
Figure 11-1. Example of Correct VLAN Port Assignments on a Link
Within Same Outside of
Untagged VLAN Tagged Monitor
as Monitor Port Port VLAN
Untagged Untagged
Untagged Untagged
Untagged Untagged
Untagged Untagged
Untagged N/A—Dropped
Link supporting VLAN_1
and VLAN_2
Port Y- 7
VLAN Port Assignment
Port VLAN_1
Y-7
Troubleshooting
Unusual Network Activity
Outside of
Untagged Monitor
Port VLAN
Untagged
Untagged
Untagged
Untagged
N/A—Dropped
Switch "Y"
VLAN_2
Untagged Tagged
11-9