230 ï GlossaryWAGO-I/O-SYSTEM 750Linux Fieldbus Coupler12 GlossaryBBitSmallest information unit. Its value can either be 1 or 0.Bit rateNumber of bits transmitted within a time unit.BootPthe bootstrap protocol is a protocol which specifies how system and networkinformation is to be transmitted from a server to work stations.BridgeA network bridge serves to transmit messages independent of the destinationof the message. It operates at the data link layer (layer 2) of the ISO/OSImodel.Bridges divide networks into segments which allows to increase the numberof nodes. Incomplete telegrams are removed. Telegrams are only sent if thenode's target address is in the connected segment. A bridge creates a database which contains all station addresses (MAC addresses). On the basis ofthis data, the bridge decides whether or not the received data packets areforwarded to another network segment. By and by, the bridge will be betterable to decide in which segment the data belongs. Today, switches are oftenused instead of bridges.BroadcastA message that is sent to all station connected to the network.BusLine for bit serial or bit parallel clocked data transfer. A bus for bit paralleldata transfer consists of address, data, control and supply bus. The width ofthe data bus (8, 16, 32, 64 bits) and its frequency are the determining factorsfor the data transmission speed. The width of the address bus limits thenetwork expansion.ByteBinary Yoked Transfer Element. A byte generally contains 8 bits.
