Should i use jumbo packets

Because jumbo frames are larger than standard frames, fewer frames are needed and therefore CPU processing overhead is reduced. The frame size definition for jumbo frames is vendor-specific because jumbo frames are not part of the IEEE standard.

The most commonly used jumbo frame size is 9, bytes. For example, a 10Gbps switch generally needs to use Jumbo frames to provide Mbps. Most modern devices can handle Jumbo frames and switch between Jumbo and standard automatically, by default. This method applies when you have a local network of all modern devices or segment the network via virtual LAN and then manually set the MTU on each. The point is the use of fixed MTU is specific and only applies to particular cases.

And when applicable, it will improve the speed, but it can also hinder the performance when not. Likely because, again, this depends on specific situations. But the following is often true in my experience:. Unfortunately, what MTU value to use depends on the situation. Other times you need to disable it. There are just too many variables. Generally, which MTU value is the best depends on the receiving end — the one we typically have no control over.

You want to make sure the packet size is the best for the receiver. Use Spotlight for Terminal on a Mac. The command means: Send that remote device a packet of this size and see how it replies. And via the way it responds, we can determine the best packet size MTU value. The overhead still 22 bytes is between 0.

Past that, there is a super jumbo frame, which — you guessed it — is over bytes generally up to bytes. Not necessarily. There are three big reasons not to: not having jumbo frames enabled everywhere in the network, not having a standard for payload size, and increasing offload capabilities of network cards and CPUs.

Since jumbo frames are the exception to the rule, they are turned off by default on networking equipment and hosts. This immediately tells you there must be a problem with having them on by default.

Not only are jumbo frames turned off on all VLANs, but they are also dropped by default on all interfaces without manual changes. After that, the receiving device has to reassemble that fragmented frame and process the data.

This is fragmentation — the endpoint that has to store all those fragments long enough to reassemble the data and process it. Or said differently, jumbos waste less bandwidth on headers.

Reality check: that used to matter. Modems at 16 Kbps or whatever, yes. TCP offload and other driver techniques may alleviate the CPU burden of adding the packet headers and computing the checksum. Efficient driver coding e. Reason 3: My storage team or vendor told me they need jumbos for better performance.

Vendors have been claiming this for a while, and it may be true. Googling, I see articles that are all over the place. Jumbos have to be configured to a plan. You have to take re-routing STP changes or routing changes into account and set up jumbos consistently across every possible alternative path.

And then you have to look at every possible path between devices, check the actual MTU mark up a diagram , and look for inconsistencies.