UBR

The term is quite a versatile abbreviation for different things, depending on the perspective it is used in. This article will however not deal with all those meanings as they lay outside the realm of the networking world, hence, this article only explains the term with respect to the networking world perspective. The term UBR stands for Unspecified Bit Rate in the networking world. It is also referred to as a Class D quality of service, which is used in the allocation of the bandwidth in the ATM, along with four other services that are used in the allocation of ATM bandwidth. This article will however, not take in to the account the work done by those other four services and will deal with UBR only.

The Unspecified Bit Rate is that ATM bandwidth allocation service, which fails to guarantee a throughput levels at all and along with that it does not allocate bandwidth specifically of a certain size for its functions unlike the CBR, that is, it makes use of the available bandwidth to perform its function. Due to these reason the UBR service is rated as the Class D service in the ATM technology of bandwidth allocation. The most common UBR is seen in the places where the data that is to be transmitted or sent to the destination is not that much important and can tolerate delays, as the data sent through this service cannot attain high speeds and is often prone to delays, if there is no bandwidth available for the UBR to transmit the data.

Along with the delays in the transmission of data through the UBR, another problem also occurs, that is, cell loss often takes place when the data is being transmitted, which result in the loss of bit of information from the data.