Configuring Jumbo Frames Support on a NetScaler Appliance

To enable the NetScaler appliance to support jumbo frames, you set the MTU to more than 1500 on interfaces or LA channels, and on VLANs on which you want the NetScaler appliance to support jumbo frames.

Points to consider before setting the MTU of interfaces, LA channels, or VLANs on a NetScaler appliance

1. Jumbo frames are not supported on NetScaler MPX 15000 and MPX 17000 Platforms.
2. When you create an LA channel, the channel takes the MTU of the first bound interface if no MTU is specified for the channel.
3. The MTU for a channel is propagated to all the bound interfaces.
4. When an interface is bound to the channel whose MTU is different from the interface’s MTU, the interface goes onto the inactive list.
5. When you change the MTU of a member interface, the interface goes onto the inactive list.
6. When an interface is unbound from the channel, the interface retains the MTU value of the channel.
7. You can set the MTU for an interface, channel, or VLAN to a value in the range of 1500-9216.
8. You cannot set the MTU on the default VLAN. The NetScaler appliance uses the MTU of the interface through which it receives or sends data from or to the default VLAN.

9. For TCP based traffic on a load balancing configuration on a NetScaler appliance, MSSs are set accordingly at each end point for supporting jumbo frames:

   • For a connection between a client and a load balancing virtual server on the NetScaler appliance, the MSS on the NetScaler appliance is set in a TCP profile, which is then bound to the load balancing virtual server.
   • For a connection between the NetScaler appliance and a server, the MSS on NS1 is set in a TCP profile, which is then bound to the service representing the server on the NetScaler appliance.
   • By default, a TCP profile nstcp_default_profile is bound to all TCP based load balancing servers and services on the NetScaler appliance.
   • For supporting jumbo frames, you can either change the MSS value of the TCP profile nstcp_default_profile, or create a custom TCP profile and set its MSS accordingly, and then bind the custom TCP profile to the desired load balancing virtual servers and services.
   • The default MSS value of any TCP profile is 1460.

NetScaler command line procedures

To set the MTU of an interface by using the NetScaler command line:

At the command prompt, type:

• set interface <id> -mtu <positive_integer>
• show interface <id>

Example:

> set interface 10/1 –mtu 9000
Done

To set the MTU of a channel by using the NetScaler command line:

At the command prompt, type:

• set channel <id> -mtu <positive_integer>
• show channel <id>

Example:

> set channel LA/1 –mtu 9000
Done

To set the MTU of a VLAN by using the NetScaler command line:

At the command prompt, type:

• add vlan <id> -mtu <positive_integer>
• show vlan <id>

Example:

> set vlan 20 –mtu 9000
Done

NetScaler GUI procedures

To set the MTU of an interface by using the NetScaler GUI:

Navigate to System > Network > Interfaces, open the interface, and set the Maximum Transmission Unit parameter.

To set the MTU of a channel by using the NetScaler GUI:

Navigate to System > Network > Channels, open the channel, and set the Maximum Transmission Unit parameter.

To set the MTU of a VLAN by using the NetScaler GUI:

Navigate to System > Network > VLANs, open the VLAN, and set the Maximum Transmission Unit parameter.