Configuring jumbo frame operation

Overview

Determine the VLAN membership of the ports or trunks through which you want the switch to accept inbound jumbo traffic. For operation with GVRP enabled, refer to the GVRP topic under “Operating Rules”, above.
Ensure that the ports through which you want the switch to receive jumbo frames are operating at least at gigabit speed. (Check the Mode field in the output for the show interfaces brief <PORT-LIST> command.)
Use the jumbo command to enable jumbo frames on one or more VLANs statically configured in the switch. (All ports belonging to a jumbo-enabled VLAN can receive jumbo frames.
Execute write memory to save your configuration changes to the startupconfig file.

Viewing the current jumbo configuration

Syntax

show vlans

Lists the static VLANs configured on the switch and includes a Jumbo column to indicate which VLANs are configured to support inbound jumbo traffic. All ports belonging to a jumbo-enabled VLAN can receive jumbo traffic.

Listing of static VLANs to show jumbo status per VLAN

Syntax

show vlans ports<PORT-LIST>

Lists the static VLANs to which the specified ports belong, including the Jumbo column to indicate which VLANs are configured to support jumbo traffic.

Entering only one port in PORT-LIST results in a list of all VLANs to which that port belongs.

Entering multiple ports in PORT-LIST results in a superset list that includes the VLAN memberships of all ports in the list, even though the individual ports in the list may belong to different subsets of the complete VLAN listing.

Example

If port 1 belongs to VLAN 1, port 2 belongs to VLAN 10, and port 3 belongs to VLAN 15, executing this command with a PORT-LIST of 1 - 3 results in a listing of all three VLANs, even though none of the ports belong to all three VLANS. (See Listing the VLAN memberships for a range of ports.)

Listing the VLAN memberships for a range of ports

Syntax

show vlans vid

Shows port membership and jumbo configuration for the specified vid . (See Listing the port membership and jumbo status for a VLAN.)

Listing the port membership and jumbo status for a VLAN

Enabling or disabling jumbo traffic on a VLAN

Syntax

vlan vid jumbo

no vlan vid jumbo

Configures the specified VLAN to allow jumbo frames on all ports on the switch that belong to that VLAN. If the VLAN is not already configured on the switch, vlan vid jumbo also creates the VLAN.

A port belonging to one jumbo VLAN can receive jumbo frames through any other VLAN statically configured on the switch, regardless of whether the other VLAN is enabled for jumbo frames.

The [no] form of the command disables inbound jumbo traffic on all ports in the specified VLAN that do not also belong to another VLAN that is enabled for jumbo traffic. In a VLAN context, the command forms are jumbo and no jumbo.

(Default: Jumbos disabled on the specified VLAN.)

Configuring a maximum frame size

You can globally set a maximum frame size for jumbo frames that will support values from 1518 bytes to 9216 bytes for untagged frames.

Syntax

jumbo max-frame-size size

Sets the maximum frame size for jumbo frames. The range is from 1518 bytes to 9216 bytes. (Default: 9216 bytes)


	NOTE: The jumbo `max-frame-size` is set on a GLOBAL level.

Configuring IP MTU


	NOTE: The following feature is available on the switches covered in this guide. `jumbos` support is required for this feature. On switches that do not support this command, the IP MTU value is derived from the maximum frame size and is not configurable.

You can set the IP MTU globally by entering this command. The value of max-frame-size must be greater than or equal to 18 bytes more than the value selected for ip-mtu. For example, if ip-mtu is set to 8964, the max-frame-size is configured as 8982.

Syntax

jumbo ip-mtu size

Globally sets the IP MTU size. Values range between 1500 and 9198 bytes. This value must be 18 bytes less than the value of max-frame-size.

(Default: 9198 bytes)

Viewing the maximum frame size

Use the show jumbos command to display the globally configured untagged maximum frame size for the switch, as shown in the following example.

(HP_Switch_name#) show jumbos

 Jumbos Global Values

  Configured : MaxFrameSize : 9216   Ip-MTU : 9198
  In Use     : MaxFrameSize : 9216   Ip-MTU : 9198

Operating notes for maximum frame size

When you set a maximum frame size for jumbo frames, it must be on a global level. You cannot use the jumbo max-frame-size command on a per-port or per-VLAN basis.
The original way to configure jumbo frames remains the same, which is per-VLAN, but you cannot set a maximum frame size per-VLAN.
Jumbo support must be enabled for a VLAN from the CLI or through SNMP.
Setting the maximum frame size does not require a reboot.
When you upgrade to a version of software that supports setting the maximum frame size from a version that did not, the max-frame-size value is set automatically to 9216 bytes.
Configuring a jumbo maximum frame size on a VLAN allows frames up to max-frame-size even though other VLANs of which the port is a member are not enabled for jumbo support.

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