MTU

MTU may refer to:

MT-55

The MT-55A (Slovak: Mostný tank) is an armoured vehicle-launched bridge (AVLB) tank, manufactured by ZTS Martin in Slovakia. The AVLB is based on a T-55A medium tank chassis, with the turret detached and replaced by a special bridge launching equipment.

The MT-55A was produced for the armies of the Warsaw Pact (including the Soviet Army), as well as for export clients.

Design and development

The MT-55A was designed and produced by ZTS Martin from 1962 (the former Czechoslovakia was one of the countries that build the T-54/55 series under licence). The development phase ended in 1967 after which five pre-series vehicles were built. Series production started in 1969.

The transformed T-55A chassis differs only by the arrangement of the compartments in the hull. The bridge tank is proposed for an easy and swift crossing of antitank barriers (trenches) and other obstacles with the purpose of facilitating the passage of mechanised and tank units.

The bridge initiating equipment is controlled by a system of hydraulic cylinders; the allocation of hydraulic oil can be controlled both manually by mechanical levers and automatically. The pressure of the liquid is provided by high-pressure piston pumps motorized by the tank engine. All mechanisms of the MT-55A used for laying and recovering the bridge can be controlled by the crew from inside the tank with the hatch covers closed.

Maximum transmission unit

In computer networking, the maximum transmission unit (MTU) of a communications protocol of a layer is the size (in bytes or octets) of the largest protocol data unit that the layer can pass onwards. MTU parameters usually appear in association with a communications interface (NIC, serial port, etc.). Standards (Ethernet, for example) can fix the size of an MTU; or systems (such as point-to-point serial links) may decide MTU at connect time.

A larger MTU brings greater efficiency because each network packet carries more user data while protocol overheads, such as headers or underlying per-packet delays, remain fixed; the resulting higher efficiency means an improvement in bulk protocol throughput. A larger MTU also means processing of fewer packets for the same amount of data. In some systems, per-packet-processing can be a critical performance limitation.

However, this gain is not without a downside. Large packets occupy a slow link for more time than a smaller packet, causing greater delays to subsequent packets, and increasing lag and minimum latency. For example, a 1500-byte packet, the largest allowed by Ethernet at the network layer (and hence over most of the Internet), ties up a 14.4k modem for about one second.