Interpacket gap

In computer networking, the interpacket gap (IPG), also known as interframe spacing, or interframe gap (IFG), is a pause which may be required between network packets or network frames. Depending on the physical layer protocol or encoding used, the pause may be necessary to allow for receiver clock recovery, permitting the receiver to prepare for another packet (e.g. powering up from a low-power state) or another purpose. It may be considered as a specific case of a guard interval. Ethernet devices must allow a minimum idle period between transmission of Ethernet packets. A brief recovery time between packets allows devices to prepare for reception of the next packet. While some physical layer variants literally transmit nothing during the idle period, most modern ones continue to transmit an idle pattern signal. The standard minimum interpacket gap for transmission is 96 bit times (the time it takes to transmit 96 bits of data on the medium). The time is measured from the end of the frame check sequence of one frame to the start of the preamble for the next. During data reception, some interpacket gaps may be smaller due to variable network delays, clock tolerances (all speeds), and the presence of repeaters (10 Mbit/s only). Some manufacturers design adapters transmitting with a smaller interpacket gap for slightly higher data transfer rates. That can lead to data loss when mixed with standard adaptors. For Fibre Channel, there is a sequence of primitives between successive frames, sometimes called interframe gap as well. The minimum sequence consists of six primitives, IDLE|IDLE|R_RDY|R_RDY|IDLE|IDLE. Each primitive consists of four channel words of 10 bits each for 8b/10b encoded variants (1–8 Gbit/s), equivalent to four data bytes.

À propos de ce résultat

Cette page est générée automatiquement et peut contenir des informations qui ne sont pas correctes, complètes, à jour ou pertinentes par rapport à votre recherche. Il en va de même pour toutes les autres pages de ce site. Veillez à vérifier les informations auprès des sources officielles de l'EPFL.

Concepts associés (9)

Séances de cours associées (3)

Interpacket gap

Ethernet frame

In computer networking, an Ethernet frame is a data link layer protocol data unit and uses the underlying Ethernet physical layer transport mechanisms. In other words, a data unit on an Ethernet link transports an Ethernet frame as its payload. An Ethernet frame is preceded by a preamble and start frame delimiter (SFD), which are both part of the Ethernet packet at the physical layer. Each Ethernet frame starts with an Ethernet header, which contains destination and source MAC addresses as its first two fields.

Ethernet physical layer

The physical-layer specifications of the Ethernet family of computer network standards are published by the Institute of Electrical and Electronics Engineers (IEEE), which defines the electrical or optical properties and the transfer speed of the physical connection between a device and the network or between network devices. It is complemented by the MAC layer and the logical link layer. The Ethernet physical layer has evolved over its existence starting in 1980 and encompasses multiple physical media interfaces and several orders of magnitude of speed from 1 Mbit/s to 400 Gbit/s.

Chaîne sans fil: Modulation et bruit COM-405: Mobile networks

Explore la modulation sans fil, les effets sonores, la propagation multipathe et les caractéristiques des canaux dans la communication sans fil.

Canal sans fil : effets multi-voies et modulation COM-405: Mobile networks

Explore l'impact des effets multi-voies, des techniques de modulation et des caractéristiques des canaux sur la communication sans fil.

Protocoles MAC sans fil : CSMA et Aloha COM-405: Mobile networks

Explore les protocoles MAC sans fil tels que CSMA et Aloha, en discutant de leur fonctionnement, des défis et des solutions pour améliorer l'efficacité.