Glossary A - C

AIS (Alarm Indication Signal) - One of the OAM function types used for fault management (see also CC, RDI).

ANSI - American National Standards Institute.

ASCII (American Standard Code for Information Interchange) - A seven-level code (128 possible characters) used for data transfer.

ATM (Asynchronous Transfer Mode) - A standard (ITU) implementation of cell relay, which is a packet switching technique using packets (cells) of a fixed length. It is asynchronous in the sense that the recurrence of cells containing information from an individual user is not periodic. ATM is used for transmission of integrated services, broadband switching and multiplexing with high-performance and cost-effectiveness under certain QoS guarantees.

Backhaul - Transporting traffic between distributed sites (typically access points) and more centralized points of presence. See Cellular Backhaul.

Bandwidth - The range of frequencies passing through a given circuit. The greater the bandwidth, the more information can be sent through the circuit in a given amount of time.

Best effort - A QoS class in which no specific traffic parameters and no absolute guarantee are provided. Best effort includes UBR and ABR.

Bit - The smallest unit of information in a binary system. Represents either a one or zero (“1” or “0”).

Bit Interleaving/Multiplexing - A process used in time division multiplexing where individual bits from different lower speed channel sources are combined (one bit from one channel at a time) into one continuous higher speed bit stream.

bps (Bits Per Second) - A measure of data transmission rate in serial transmission.

Bridge - A device interconnecting local area networks at the OSI Data Link Layer, filtering and forwarding frames according to media access control (MAC) addresses.

Bridging - Interconnecting local area networks at the OSI Data Link Layer, filtering and forwarding frames according to media access control (MAC) addresses.

Broadband - Wideband technology capable of supporting voice, video and data, possibly using multiple channels.

Byte - A group of bits (normally 8 bits in length).

Carrier Ethernet- Carrier Ethernet is a ubiquitous service based on standardized equipment and protocols providing seamless connectivity between high speed Ethernet-based LANs and WANs. Carrier Ethernet is characterized by industry-defined attributes for service level agreements, provisioning, system-wide management, and carrier-class OAM. Originally implemented in the core network, Carrier Ethernet is now being extended to the edge and access segment.

Carrier Ethernet deployment- Carrier Ethernet deployment is picking up pace as Ethernet becomes a widely-accepted, carrier-grade service suite, however, it depends on service providers’ ability to cost-effectively overcome two key challenges: The diversity of existing access and transport networks, and the need to meet user expectations for SLA accountability.

Central Office (CO) - Telephone company switching office. This is where you would find the local telco switch that connects to your telephone.

Channel - A path for electrical transmission between two or more points. Also called a link, line, circuit or facility.

Channelized T1/E1 - T1 or E1 service that is divided into individual 64 kbps channels (or channels that are multiples of 64 kbps such as a 256 kbps channel made from four 64 kbps channels), as opposed to unchannelized service, which uses the entire bandwidth of the T1 (1.544 Mbps) or E1 (2.048 Mbps). Channelized T1 or E1 lines can consist of switched lines with in-band signaling or leased lines.

CIR (Committed Information Rate) - A term used in Frame Relay, which defines the information rate that the network is committed to provide to the user, under any network conditions.

Circuit Emulation - A connection over a virtual circuit-based network providing service to the end users that is indistinguishable from a real point-to point, fixed-bandwidth circuit. Services based on circuit emulation (Circuit Emulation Services or CES) offer traditional TDM trunking (at n x 64 kbps, fractional T1/E1, T1/E1 or T3/E3) over a range of transport protocols, including ATM, Internet Protocol (IP), MPLS and Ethernet.

Circuit Emulation Service - New technology for offering circuit emulation services over packet-switched networks. The service offers traditional TDM trunking (at n x 64 kbps, fractional E1/T1, E1/T1 or E3/T3) over a range of transport protocols, including Internet Protocol (IP), MPLS and Ethernet.

CO (Central Office) - Telephone company switching office. This is where you would find the local telco switch that connects to your telephone.

CPE (Customer Premises Equipment) - Generally refers to communications equipment located at the customers' premises for use with communication service providers' services. In some cases, these are customer-owned or leased; in other cases, these are the property of the service provider.

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