End-of-Life (EoL)

Enable Jumbo Frames on the VM-Series Firewall

By default, the maximum transmission unit (MTU) size for packets sent on a Layer 3 interface is 1500 bytes. This size can be manually set to any size from 512 to 1500 bytes on a per-interface basis. Some configurations require Ethernet frames with an MTU value greater than 1500 bytes. These are called jumbo frames.
To use jumbo frames on a firewall you must specifically enable jumbo frames at the global level. When this is enabled, the default MTU size for all Layer 3 interfaces is set to a value of 9192 bytes. This default value can then be set to any value in the range of 512 to 9216 bytes.
After setting a global jumbo frame size it becomes the default value for all Layer 3 interfaces that have not explicitly had an MTU value set at the interface configuration level. This can become a problem if you only want to exchange jumbo frames on some interfaces. In these situations, you must set the MTU value at every Layer 3 interface that you do not want to use the default value.
The following procedure describes how to enable jumbo frames on a firewall, set the default MTU value for all Layer 3 interfaces and to then set a different value for a specific interface.
  1. Enable jumbo frames and set a default global MTU value.
    1. Select
      Device
      Setup
      Session
      and edit the Session Settings section.
    2. Select
      Enable Jumbo Frame
      .
    3. Enter a value for
      Global MTU
      .
      The default value is 9192. The range of acceptable values is: 512 - 9216.
    4. Click
      OK
      .
      A message is displayed that informs you that enabling or disabling Jumbo Frame mode requires a reboot and that Layer 3 interfaces inherit the
      Global MTU
      value.
    5. Click
      Yes
      .
      A message is displayed to inform you that Jumbo Frame support has been enabled and reminds you that a device reboot is required for this change to be activated.
    6. Click
      OK
      .
    7. Click
      Commit
      .
  2. Set the MTU value for a Layer 3 interface and reboot the firewall.
    The value set for the interface overrides the global MTU value.
    1. Select
      Network
      Interfaces
      .
    2. Select an interface of the Layer3
      Interface type
      .
    3. Select
      Advanced
      Other Info
      .
    4. Enter a value for
      MTU
      .
      The default value is 9192. The range of acceptable values is: 512 - 9216.
    5. Click
      OK
      .
    6. Click
      Commit
      .
    7. Select
      Device
      Setup
      Operations
      and select
      Reboot Device
      .

Recommended For You