ABR

Available Bit Rate - Information that is sent using a session and the network may guarantee some aspects of the bandwidth, latency, or jitter.

ACK

Acknowledge

ARP

Address Resolution Protocol - The TCP/IP protocol used to dynamically bind a high level IP address to a low-level hardware address. ARP is used only across a single physical network and is dependent on the hardware broadcast capability of the underlying network hardware. Although ARP is aware of IP, conceptually it resides in a lower layer than IP, and IP treats it as part of the functionality provided by the underlying hardware.

ASP

Application Service Provide - An operator of a server complex that provides the applications a thin client would use.

Boundary Point (BP)

A logical element that terminates a CableHome compliant network segment.

Bridge

A device that resides on a LAN and connects two LANs together.  It leans the addresses of devices on both sides of itself and will selectively forward protocol layer two packets between these ports.  It also forwards all broadcast packets between the two ports.

Cable modem (CM)

Client device for providing data over a cable TV network. Read all about it here.

CableHome

The CableLabs Home Networking Initiative.

CBR

Continuous Bit Rate - A rate that the network must sustain.

CIR

Committed Information Rate - The committed rate (in bits per second) at which the ingress access interface trunk interfaces, and egress access interface of a frame relay network transfer information to the destination frame relay end system under normal conditions. The rate is averaged over a minimum time interval Tc.

CLEC

Competitive Local Exchange Carrier

CMTS

Cable Modem Termination System. Central device for connecting the cable TV network to a data network like the internet. Normally placed in the headend of the cable TV system.

CPE

Customer Premises Equipment. Used to describe the PC and/or other equipment that the customer may want to connect to the cable modem.

CPE

Customer Premises Equipment. Used to describe the PC and/or other equipment, that the customer may want to connect to the cable modem.

DES

Data Encryption Standard - A mechanism to provide security for data using encryption.

DHCP

Dynamic Host Configuration Protocol. This protocol provides a mechanism for allocating IP addresses dynamically so that addresses can be reused. Often used for managing the IP addresses of all the cable modems in a cable plant and the PC's connected to the cable modems.

DLC

Digital Loop Carrier - In telephone communications, a technology that increases the              number of channels in the local loop by converting analog signals to digital and multiplexing them back to the end office.

DMT

Discrete MultiTone

DNS

Domain Name System - The DNS is a general purpose distributed, replicated, data query service.  The principal use is the lookup of host IP addresses based on host names.  The style of host names now used in the       Internet is called "domain name", because they are the style of names used to look up anything in the DNS.  Some important domains are: .COM (commercial), .EDU (educational), .NET (network operations), .GOV (U.S. government), and .MIL (U.S. military).

Most countries also have a domain. For example, .US (United States), .UK (United  Kingdom), .AU (Australia)

DOCSIS

Data Over Cable System Interface Specification.

The cable labs specification that allows interchangeable modems to be manufactured from several vendors.

EGP

Exterior Gateway Protocol - A protocol which distributes routing information to the routers which connect autonomous systems.

FCS

Frame Check Sequence - A number that is added onto a frame to detect if an error as occurred during transmission through the network.  It is also known as CRC (Cyclic Redundancy Check)

Gateway

The original Internet term for what is now called router or more precisely, IP router.  In modern usage, the terms "gateway" and "application gateway" refer to systems which do translation from some native format to another.

HFC

Hybrid fiber-coaxial (cable network). Older CATV systems were provisioned using only coaxial cable. Modern systems use fiber transport from the headend to an optical node located in the neighborhood to reduce system noise. Coaxial cable runs from the node to the subscriber. The fiber plant is generally a star configuration with all optical node fibers terminating at a headend. The coaxial cable part of the system is generally a trunk-and-branch configuration.

ICMP

Internet Control Message Protocol - An extension to the Internet Protocol.  It allows for the generation of error messages, test packets and informational messages related to IP.

IETF

Internet Engineering Task Force - The protocol engineering and development arm of the Internet.
It is a large and open international community, built on a voluntary basis, and its goal is to develop and define Internet protocols in order to contribute to the engineering and evolution of the Internet.

IGP

Interior Gateway Protocol - A protocol which distributes routing information to the routers within an autonomous system.  The term "gateway" is historical, as "router" is currently the preferred term.

IGP

Interior Gateway Protocol - A protocol which distributes routing information to the routers within an autonomous system.  The term "gateway" is historical, as "router" is currently the preferred term.

Internet

The global internet, that uses the TCP/IP protocol suite for interconnection atop different physical connection channels. The Internet provides universal connectivity and three levels of network services: unreliable, connectionless packet delivery IP and UDP; reliable, full duplex stream delivery TCP/IP; and application level services like e-mail that base on the first two.

internet

A collection of packet switching networks interconnected by routers along with the protocols that allow them to act logically as a single virtual network.

IP

Internet Protocol - The fundamental Internet protocol, used atop almost any physical network. Defines its basic transmitted unit of information, the IP datagram. Includes ICMP as an integral part.
IP is a connectionless, unreliable, best-effort packet delivery system.

ISP

Internet Service Provider

IUC

Interval Usage Code - A code that defines the usage of the packet/field.

LAN

Local Area Network - A data network intended to serve an area of only a few square kilometers or less.  Because the network is known to cover only a small area, optimizations can be made in the network signal protocols.

LLC

Logical Link Control - The part of the protocol that governs the assembling of data link layer frames and their exchange between data stations, independent of how the transmission medium is shared.

MAC layer

Media Access Control the Layer 2 protocol that allows packets to get on/off a LAN.

MAN

Metropolitan Area Network - A data network intended to serve an area approximating that of a large city. A popular example of a MAN is SMDS. 

MDCP

Media Device Control Protocol

MGCP

Media Gateway Control Protocol (Contains IPDC + SGCP)

MIB

Management Information Base - The set of parameters an SNMP management station can query or set in the SNMP agent of a network device (e.g. router).  Standard,       minimal MIBs have been defined, and vendors often have Private enterprise MIBs.  In theory, any SNMP manager can talk to any SNMP agent with a properly defined MIB. 

MIB

Management Information Base - The set of parameters an SNMP management station can query or set in the SNMP agent of a network device (e.g. router).  Standard,       minimal MIBs have been defined, and vendors often have Private enterprise MIBs.  In theory, any SNMP manager can talk to any SNMP agent with a properly defined MIB. 

MPEG

Motion Picture Experts Group - A body that set compression algorithms for video.

MSO

Multiple Service Operator. A cable TV service provider that also provides other services such as data and/or voice telephony.

NAT

Network Address Translation is a method by which IP addresses are mapped from one realm to another, in an attempt to provide transparent routing to hosts. It does this by translating the incoming IP address and port address on one Network side to another IP address/port address on the other side.

PDC

Internet Protocol Device Control (IP SS7), Level 3 Comm

PGRP

Peer Gatekeeper Routing Protocol

PPP

The Point-to-Point Protocol provides a method for transmitting packets over serial point-to-point links.

QAM

Quadrature Amplitude Modulation. A method of modulating digital signals using both amplitude and phase coding. Used for downstream and can be used for upstream.

QoS

Quality of Service

QPSK

Quadrature Phase-Shift Keying. A method of modulating digital signals using four phase states to code two digital bits per phase shift.

RARP

Reverse Address Resolution Protocol - A  TCP/IP  protocol a diskless station can use at startup to find its IP address. Derived from ARP. Superseded by BOOTP.

RFC

Request For Comments

The specification documents of the Internet protocol suite, as defined by the Internet Engineering Task Force IETF and its steering group the IESG.
The RFC Editor is the publisher of the all RFCs, and is located at the Information Sciences Institute  ISI of the University of Southern California USC.

RIP

Routing Information Protocol - A routing protocol.

Router

A system responsible for making decisions about which of several paths network (or Internet) traffic will follow.  To do this it uses a routing protocol to gain information about the network, and algorithms to choose the best route based on several criteria known as "routing metrics."  In OSI terminology, a router is a Network Layer intermediate system.

RSA

Rivest-Shamir-Adleman - A highly-secure cryptography method by RSA Data Security, Inc.  It uses a two-part key. The private key is kept by the owner; the public key is published.  Data is encrypted by using the recipient's public key, which can only be decrypted by the recipient's private key.

SAP

Session Admission Protocol

SDP

Session Device Protocol

SGCP

Simple Gateway Protocol (Bellcore, Cisco)

SIP

Session Initiation Protocol

SNMP

The Internet standard protocol developed to manage nodes on an IP network.

Switch

A device that moves a data between links based solely on its address.  It requires a process to establish a connection between the input port and the output port.  It is session aware and therefore will require the deactivation of the connection when completed.  It is a protocol layer two device.

TCP

Transmission Control Protocol - Reliable connection-oriented stream delivery service, one of the core internet protocols. Provides full-duplex connection with a possibility to shut it down one-way to form a simplex one between two machines on an internet. Allows efficient data transfer across networks of different kinds with different communication parameters, as well as different underlying communication protocols.
Most widely used in the Internet over IP, in which case it is often designated as TCP/IP. It provides the transport level in the TCP/IP protocol suite.

UBR

Unspecified Bit Rate - Information that is sent without being in a session and without guarantee of network delivery.

UDP

User Datagram Protocol - A datagram-oriented protocol above IP which includes a protocol port number for the source and the target, allowing to distinguish between different application programs on the source and target machine within the addressing scheme. It is as unreliable as the underlying IP, with the exception that it fixes a checksum field to control the transferred data integrity.

Upstream

The data flowing from the CM to the CMTS.

Upstream frequency

The frequency used to transmit data from the CM to the CMTS. Normally in the 5-42 MHz range for US systems and 5-65 MHz for European systems

URL

Uniform Resource Locators - A URL is a compact (most of the time) string representation for a resource available on the Internet.  URLs are primarily used to retrieve information using WWW.

UTC

Coordinated Universal Time - The international time standard (formerly Greenwich Meridian Time, or GMT). Zero hours UTC is midnight in Greenwich England, which is located at 0 degrees longitude.

VBR

Variable Bit Rate – A bit rate that has a periodic interval for transmission but provides different amounts of information at each interval.

VPN

Virtual Private Network