chapter3 datalink

Persistent Method

A rule for network devices that transmit immediately if the channel is free, and wait to transmit if busy.

Address Resolution Protocol (ARP)

A protocol that helps find the physical address (MAC address) of a device on a local network using its IP address.

ALOHA

An early method for multiple devices to share a communication channel, where devices transmit whenever they have data.

Bit Stuffing

A technique to prevent a specific bit pattern from appearing in the data by inserting an extra bit when needed.

Burst Error

A sequence of consecutive bits corrupted by noise or interference in a transmitted message.

Byte Stuffing

A technique similar to bit stuffing but for bytes, inserting an escape byte before a flag byte.

Carrier Sense Multiple Access (CSMA)

A set of rules where a device listens to the channel before transmitting.

CSMA with Collision Avoidance (CSMA/CA)

A type of CSMA where devices avoid collisions by signaling an intention to transmit.

CSMA with Collision Detection (CSMA/CD)

A type of CSMA that listens while transmitting to detect collisions.

Channelization

A technique that divides the bandwidth of a communication channel among multiple stations.

Codeword

The transmitted data unit including original data bits plus redundant bits for error detection.

Contention Method

A media access control method where multiple devices compete for access to the shared channel.

Controlled Access

A media access control method where access to the channel is managed by a central device.

Cyclic Redundancy Check (CRC)

An error detection code used to catch errors in digital networks by dividing data by a polynomial.

Data-Link Control (DLC)

Functions at the data-link layer managing the transmission of data frames between nodes.

Dataword

The original data bits before any error detection or correction bits are added.

Flag

A specific bit pattern marking the beginning or end of a data frame in a protocol.

Hamming Distance

The number of differing bit positions between two codewords, measuring their difference.

Interference

Unwanted signals that disrupt the quality of the intended signal.

Internet Protocol Control Protocol (IPCP)

A Network Control Protocol used by PPP to manage IP configuration on a link.

Links

Physical or logical pathways that connect network nodes.

Link Control Protocol (LCP)

A protocol used by PPP to manage point-to-point connections.

Media Access Control (MAC)

A sublayer defining how multiple devices can access a shared network medium.

Nodes

Devices connected to a network that can communicate with each other.

Nonpersistent Method

A transmission rule where a device waits a random time before sensing a busy channel again.

Parity-Check Code

An error detection method using an extra bit to ensure an even or odd count of 1s.

Point-to-Point Protocol (PPP)

A data-link layer protocol establishing direct connections between two nodes.

P-Persistent Method

A probabilistic transmission method where a device transmits with a probability 'p' if the channel is free.

Polling

A controlled access method where a central controller asks each device if it has data to transmit.

Pure ALOHA

The original ALOHA method where devices transmit whenever they have data, leading to high collisions.

Random-Access Method

A media access control method where any station can transmit without centralized control.

Reservation Method

A media access control method where stations reserve time slots before transmitting data.

Single-Bit Error

An error where only one bit is corrupted in a transmitted message.

Slotted ALOHA

An improvement over pure ALOHA where time is divided into slots for transmission.

Syndrome

The remainder from dividing a received codeword that helps identify errors.

Token-Passing Method

A controlled access method where devices transmit only when they possess a circulating token.