Cisco Systems RJ-45-to-AUX manual 375

B

backbone

A high−capacity infrastructure system that provides optimal transport on a LAN. Typically in a LAN, the data running from router to router, switch to switch, or switch to router is transported through a faster physical topology than the rest of the local area or virtual LAN devices. The physical cable is called the backbone.

BackboneFast

Initiated when a root port or blocked port receives an inferior BPDU from its designated bridge. It allows the secondary or backup port to immediately begin forwarding after a link fault with the root link. BackboneFast bypasses the MaxAge timer.

backplane

Similar to the motherboard in a PC. The backplane is the primary data/control bus located on a Cisco Catalyst switch. It interconnects all the modules inside the switch chassis.

bandwidth

The rated throughput capacity of a given network protocol or medium. base bandwidth

The difference between the lowest and highest frequencies available for network signals. The term is also used to describe the rated throughput capacity of a given network protocol or medium.

Basic Rate Interface (BRI)

An ISDN digital communications line that consists of three independent channels: two Bearer (or B) channels, each at 64Kbps, and one Data (or D) channel at 16Kbps. ISDN BRI is often referred to as 2B+D.

baud rate

The speed or rate of signal transfer. This term is named after French telegraphy expert J. M. Baudot.

binary

A Base 2 numbering system, characterized by 1s and 0s, used in digital signaling.

binding

The process of associating a protocol and a NIC.

bit

An electronic digit used in the binary numbering system. blackout

A total loss of electrical power. blocking architecture

A condition in which the total bandwidth of the ports is greater than the capacity of the switching fabric.

bridge

A device that connects and passes packets between two network segments that use the same communications protocol. Bridges operate at the Data Link layer of the OSI Reference Model. A bridge filters, forwards, or floods an incoming frame based on the MAC address of that frame.

Bridge Protocol Data Unit (BPDU)

A multicast frame generated by the switch that carries information about itself and changes in the network topology.

bridging address table

A list of MAC addresses kept by bridges and used when packets are received to determine which segment the destination address is on before sending the packet to the next interface or dropping the packet if it is on the same segment as the sending node.

broadband

A communications strategy that uses analog signaling over multiple communications channels. Broadband Interexchange Carrier Interconnect (B−ICI)

An interface that connects two ATM carriers. broadcast

A packet delivery system in which a copy of a packet is given to all hosts attached to the network. broadcast domain

In a none−switched network, all the devices that can receive a broadcast from one machine in the network sent on the physical wire. The broadcast domain is a segment not separated by a Layer 3

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