Frame Relay is a data transfer technology that was originally represented a further development of X.25. Many operators now offer frame relay connections as a cheaper alternative to a leased line. In Europe, the base stations of the GSM network that receive the radio signals from mobile phones and reconciled to the fixed network via Frame Relay are often connected for example.
Frame Relay or X.25 multiplexes as the Datex -P network, the data streams of different transmission or receiving stations according to the statistical point of a line and supported speeds between 56 kbit / s and 45 Mbit / s Frequently Frame Relay is a guaranteed transfer rate ( CIR Committed Information Rate ) and a short-term exceeding of the transmission rate (EIR of Excess Information Rate ) offered.
The greatest improvement in contrast to X.25 is to support higher bandwidths. X.25 was originally developed for the transmission of data over telephone lines, which rarely better error rates than 1:10,000 have (that is, less than 1 bit in error on 10,000 transmitted bits have ). Therefore has X.25 complex mechanisms for the correction of errors and retransmission of data blocks. Frame Relay does not have these mechanisms.
One common feature with X.25 is that Frame Relay is a connection-oriented normally. For each participant their own virtual connection is established. However, so-called point-to- multipoint connections are also possible.
Frame Relay is an effective data transmission technology for data streams, which have a constant bit rate such as digitized speech. For data transfers with highly varying traffic profile, also for multimedia it is not particularly well suited. Nevertheless, it is often used on long-haul routes for connecting LANs because of the low cost. The error rate is then but in overload situations clearly noticeable.
Frame relay is designed to allow for efficient utilization of existing technical resources. The provider can offer all our customers a total of more transmission capacity than is available to him, as most customers do not always take advantage of 100 percent of their " line ". In some market segments Frame Relay got a bad reputation because of that - because some vendors in total sold significantly more bandwidth than they actually was available.
Frame Relay is increasingly replaced by ATM, and products that are based on IP. Especially increasingly take over virtual private networks and MPLS networks as a cheaper alternative as more broadband market segment of Frame Relay.
Format of data units
The data frame is a frame relay is structured as follows:
The Address field contains the connection identifier traffic parameters for the treatment of congestion situations ( flow control) and is structured as follows:
Information on the address field:
- Computer Networks
- Network protocol
- Communication technology