Extreme Networks ExtremeWare 7.7, Command Reference Manual

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configure ip-mtu vlan
ExtremeWare 7.7 Command Reference Guide 257
configure ip-mtu vlan
configure ip-mtu <number> vlan <vlan name>
Description
Sets the maximum transmission unit (MTU) for the VLAN.
Syntax Description
Default
The default IP MTU size is 1500.
Usage Guidelines
Use this command to enable jumbo frame support or for IP fragmentation with jumbo frames. Jumbo
frames are Ethernet frames that are larger than 1522 bytes, including 4 bytes used for CRC. Both
endstations involved in the transfer must be capable of supporting jumbo frames. The switch does not
perform IP fragmentation or participate in MTU negotiation on behalf of devices that do not support
jumbo frames.
When enabling jumbo frames and setting the MTU size for the VLAN, keep in mind that some network
interface cards (NICs) have a configured maximum MTU size that does not include the additional
4 bytes of CRC included in a jumbo frame configuration. Ensure that the NIC maximum MTU is at or
below the maximum MTU size configured on the switch. Frames that are larger than the MTU size
configured on the switch are dropped at the ingress port.
If you use IP fragmentation with jumbo frames and you want to set the MTU size greater than 1500, all
ports in the VLAN must have jumbo frames enabled.
For MPLS modules:
Fragmentation is based on either the minimum value of the configured MPLS IP
MTU size or the configured IP MTU size for the egress VLAN.
Example
The following command sets the MTU size to 1500 for VLAN sales :
configure ip-mtu 1500 vlan sales
The following command increases the MTU size on the MPLS VLANs to accommodate the MPLS shim
header:
configure ip-mtu 1550 vlan vlan1
History
This command was first available in ExtremeWare 6.2.
This command was added to the Summit “ e ” series of switches in ExtremeWare 7.2e.
number Specifies the
IP MTU
value. Range is from 1500 to 9194.
vlan name Specifies a VLAN name.