Jumbo frame

The term jumbo frames designated in the Ethernet data network non-standard and oversized frames.

For Ethernet, the data to be transmitted are grouped into frames. The default size for this is set at 1518 bytes in the IEEE 802.3 standard. Frames, which are longer than this value are called jumbo frames. Frequently, the term Maximum Transmission Unit (MTU) is used, but specifies the maximum unfragmented packet size in the higher network layer and Ethernet without Jumbo Frames 1500 bytes corresponds to ( 18 bytes is the overhead of an Ethernet frame without IEEE 802.1Q field).

For some special applications, jumbo frames can be useful, since the protocol overhead can be minimized. Since there is no standard for such frames, must be tested to see if all network elements such as switches, routers, etc. in a network with these jumbo frames can handle and if there is a speed advantage.

If compatibility is not given, it comes in the affected devices and network segments to Jabber, which is typically associated with a blockade of the data stream.

Areas of application

A typical application for Jumbo Frames is the transmission of large amounts of data, as is the case for example with the backup. This is intended to stress all components are reduced. Less headers must be produced, processed and transmitted and less checksums are calculated.

Another field of application is the rolling of the computational load on the Edge components or tunnel Edge of a network. The Edge component that couples the local to external networks must all packages from jumbo frames, leaving the local network, the MTU of the external destination network recode ( = fragment ). Although you can enjoy locally so the benefits that offer jumbo frames, but the communication to external networks is significantly more expensive.

Typically, additional bandwidth is consumed by the tunneling protocol. So is the MTU of the network to the header size of the Tunnelingprotokolls be reduced or the tunnel Edge must recode the frames either.

To simplify the use of jumbo frames, a dynamic determination of the maximum frame size can be made using the Path MTU Discovery.

Benefit

The benefit is debatable. In general, the transmission of jumbo frames over multiple hops as a last resort for the optimization should be considered. The entire network infrastructure hardware and software for the transmission of standard Ethernet frames with a size of 1518 bytes optimized (MTU 1500 bytes ). This applies Vorhaltespeicher ( buffer), the memory location ( cache ) and queues ( queues) the hardware and software components. Due to a difference in the frame size can cause a variety of impairments. An overall significantly slower processing of Ethernet frames can be the result.

Jumbo Frames support

Under Jumbo Frames Support Jumbo Frames support, or refers to the hardware support for jumbo frames. If this is not the case, the packets are ignored by the device itself, or deleted, and thus is not passed through the switch or router.