HP 2910AL - Manual (Page 328)

Port Traffic Controls
Jumbo Frames
Troubleshooting
A VLAN is configured to allow jumbo frames, but one or more ports
drops all inbound jumbo frames.
The port may not be operating at 1 giga­
bit or higher. Regardless of a port’s configuration, if it is actually operating at
a speed lower than 1 gigabit, it drops inbound jumbo frames. For example, if
a port is configured for
Auto mode (speed-duplex auto), but has negotiated a
100 Mbps speed with the device at the other end of the link, then the port
cannot receive inbound jumbo frames. To determine the actual operating
speed of one or more ports, view the
Mode field in the output for the following
command:
show interfaces brief < port-list >
A non-jumbo port is generating “Excessive undersize/giant frames”
messages in the Event Log.
The switches can transmit outbound jumbo
traffic on any port, regardless of whether the port belongs to a jumbo VLAN.
In this case, another port in the same VLAN on the switch may be jumbo-
enabled through membership in a different, jumbo-enabled VLAN, and may
be forwarding jumbo frames received on the jumbo VLAN to non-jumbo ports.
Refer to “Outbound Jumbo Traffic” on page 13-16.
13-18