Configuring MTU Parameters for vRouter Interfaces


Support for IPv4 and IPv6 addresses requires configuring the MTU parameter differently for each type of IP address. By default MTU is set at 1500 for the VNICs. For IPv4 addresses, the Maximum Transmission Unit (MTU) the range is to 68 to 9216, but the range for IPv6 addresses is 1280-9216. However, Netvisor One displays the MTU range as 68-9216 which is supported by IPv4 addresses. But if you configure an IPv6 interface with an MTU value outside of the 1280-9216 for IPv6 addresses, Netvisor One returns an error.


In the case of interfaces configured with IPv4 and IPv6 addresses (dual-stack), Netvisor One limits the MTU range to 1280-9216. The following special rules apply to dual-stack interfaces:

 

  • If you configure the MTU option for a vRouter interface with an IPv6 address using the command, vrouter-interface-create, Netvisor One performs a range check to ensure the MTU value is within 1280-9216.


  • If you configure the MTU option for a vRouter interface using the vrouter-interface-modify command, Netvisor One performs a check for IPv6 addresses, and then performs a range check for 1280-9216.


  • If you add an IPv6 address with the command, vrouter-interface-ip-add, Netvisor One performs a range check to ensure the MTU of the VNIC interface is within 1280-9216.


  • If you configure a hardware vRouter, Netvisor One propagates the MTU value to the switch interface, so the MTU values are in the switch ASIC.