Available Bit Rate
Encyclopedia
Available Bit Rate is a service used in ATM
networks when source and destination don't need to be synchronized. ABR does not guarantee against delay or data loss
. ABR mechanisms allow the network to allocate the available bandwidth
fairly over the present ABR sources. ABR is one of five service categories defined by the ATM Forum for use in an ATM Network.
The network switch
es use locally available information to determine the explicit allowable rates or relative rate (increase/decrease) for the source. The newly calculated rates are then being sent to the sources using Resource Management records (RM-cells). RM-cells are generated by the source and travel along the data path to the destination and sent back. ABR sets a Minimum Cell Rate (MCR) and a Peak Cell Rate (PCR). When transfers exceed the PCR, cells are dropped.
Many implementers consider ABR to be overly complex, and its adoption has been modest.
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Asynchronous Transfer Mode
Asynchronous Transfer Mode is a standard switching technique designed to unify telecommunication and computer networks. It uses asynchronous time-division multiplexing, and it encodes data into small, fixed-sized cells. This differs from approaches such as the Internet Protocol or Ethernet that...
networks when source and destination don't need to be synchronized. ABR does not guarantee against delay or data loss
Data loss
Data loss is an error condition in information systems in which information is destroyed by failures or neglect in storage, transmission, or processing. Information systems implement backup and disaster recovery equipment and processes to prevent data loss or restore lost data.Data loss is...
. ABR mechanisms allow the network to allocate the available bandwidth
Bandwidth (computing)
In computer networking and computer science, bandwidth, network bandwidth, data bandwidth, or digital bandwidth is a measure of available or consumed data communication resources expressed in bits/second or multiples of it .Note that in textbooks on wireless communications, modem data transmission,...
fairly over the present ABR sources. ABR is one of five service categories defined by the ATM Forum for use in an ATM Network.
The network switch
Network switch
A network switch or switching hub is a computer networking device that connects network segments.The term commonly refers to a multi-port network bridge that processes and routes data at the data link layer of the OSI model...
es use locally available information to determine the explicit allowable rates or relative rate (increase/decrease) for the source. The newly calculated rates are then being sent to the sources using Resource Management records (RM-cells). RM-cells are generated by the source and travel along the data path to the destination and sent back. ABR sets a Minimum Cell Rate (MCR) and a Peak Cell Rate (PCR). When transfers exceed the PCR, cells are dropped.
Many implementers consider ABR to be overly complex, and its adoption has been modest.
External links
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