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How to configure jumbo frames on the EX series Ethernet switches



Article ID: KB11309 KB Last Updated: 18 Feb 2020Version: 6.0

Jumbo frames are Ethernet frames with more than 1,500 bytes of payload (Maximum Transmission Unit, MTU). Jumbo frames can carry up to 9,000 bytes of payload.

All Fast Ethernet switches and Fast Ethernet network interface cards support only standard-sized frames. However, many but not all, Gigabit Ethernet switches and Gigabit Ethernet network interface cards support jumbo frames.

Jumbo frames can be configured on the physical interfaces on the EX-series Ethernet switches.


Jumbo frames can be configured on the EX series Ethernet switches via 2 methods; the CLI (Command Line Interface) and J-Web interface.

Configuration using the CLI:

user@switch# set interfaces ge-0/0/0 mtu 9216      

(Maximum transmit packet size (256..9216))

Configuration using J-Web interface:

  1. Point your web browser to the management interface of the switch

  2. Log in to the EX series switch using the credentials you have provisioned.

  3. Once the Login is successful, you will be presented to the Dashboard page. Click the Configure Tab at the top.

  4. At this page, select the interface that needs to be enabled for jumbo frames.

  5. Click the 'Edit' button on the top right portion of the screen.

  6. Select Link options and set the MTU size to 9216. (Allowed values are 256 bytes - 9216 bytes)

Below are the steps on how to enable Jumbo frames on an aggregate interface on EX series switches

The following is the set of command to create a link aggregation bundle and enable jumbo frames:
{master:0}[edit interfaces ge-0/0/0]
user@switch# show
unit 0 {
    family ethernet-switching;

{master:0}[edit interfaces ge-0/0/0]
user@switch# delete unit 0

{master:0}[edit interfaces ge-0/0/0]
user@switch# show | compare
[edit interfaces ge-0/0/0]
unit 0 {
   family ethernet-switching;

user@switch# set chassis aggregated-devices ethernet device-count 4 >>>>4 LAG bundles can be created from 0-3
user@switch# set interfaces ge-0/0/40 ether-options 802.3ad ae0
user@switch# set interfaces ge-0/0/42 ether-options 802.3ad ae0
user@switch# set interfaces ae0 mtu 9200

Note: MTU can only be set on the bundle interface not on the child member.
Modification History:

2020-02-18: Article reviewed for accuracy; no changes required.

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