How do I decide when to use jumbo frames with Direct Connect?

Last updated: 2020-02-18

How do I decide when to use jumbo frames with AWS Direct Connect?

Resolution

By sending out jumbo frames instead of standard Ethernet frames, you can send more data with the same amount of overhead. However, jumbo frames aren't compatible with all configurations. Follow the guidance below to confirm that jumbo frame is appropriate for your use case.

Confirm jumbo frame compatibility with your configuration

  • AWS Managed VPN doesn't support jumbo frames. If the same route is advertised over DX and AWS Managed VPN, then 1500 MTU is used.
  • Public and Transit virtual interfaces don't support jumbo frames. Jumbo frames are supported only on private virtual interfaces attached to a virtual private gateway or a DX gateway.
  • Confirm that all nodes support jumbo frames, including the router, switch, and end devices (such as network cards). The Amazon Elastic Compute Cloud (Amazon EC2) instances in your VPN must also support jumbo frames. Otherwise, network performance could decrease, because incompatible devices are likely to drop or fragment frames.
  • Jumbo frames apply only to propagated routes from DX. If you add static routes to a route table that point to your virtual private gateway, then traffic routed through the static routes is sent using 1500 MTU.
  • If two virtual interfaces advertise the same route but use different MTUs, then 1500 MTU is used for both virtual interfaces.

Confirm jumbo frame compatibility with DX partners and DX port owners

  • If your DX connection is provided by a DX partner, confirm that the port is compatible with jumbo frames.
  • If a DX port is owned by another AWS account, ask the port owner to enable jumbo frames on the port. The port owner can do this by modifying the MTU on an existing virtual Interface or creating a new virtual interface with 9001 MTU.

Configure your jumbo frames

If you determine that jumbo frames are compatible with your use case, then you can set the MTU of your private virtual interface. Be sure that all network devices in the path between the two hosts are configured to use the same MTU.