HP ProCurve 2610-24, Management And Configuration Manual

Page: 216 / 464

Port Status and Basic Configuration
Jumbo Frames
Jumbo-Enabled VLAN
VLAN 10
Non-Jumbo VLAN
VLAN 20
Port 3 belongs to both VLAN 10 and VLAN 20.
Jumbo packets received inbound on port 3 can be
forwarded out the Non-Jumbo ports 4, 5, and 6.
1 5 2
3
4 6
Figure 10-12. Forwarding Jumbo frames Through Non-Jumbo Ports
Jumbo frames can also be forwarded out non-jumbo ports when the jumbo
frames received inbound on a jumbo-enabled VLAN are routed to another,
non-jumbo VLAN for outbound transmission on ports that have no mem­
berships in other, jumbo-capable VLANs. Where either of the above
scenarios is a possibility, the downstream device must be configured to
accept the jumbo traffic. Otherwise, this traffic will be dropped by the
downstream device.
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 switch can transmit outbound jumbo traf­
fic on any port, regardless of whether the port belongs to a jumbo VLAN. In
this case, another port in the same VLAN 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 10-23.
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