Ch. 7 Key Terms

Data Link layer term describing a device connected to a network.

Connection of devices on a common media.

AKA network segment

Group of devices associated by the arrangement of a hierarchical addressing scheme.

Devices share common network portion of their Layer 3 addresses.

Part of a computer network that every device communicates with using the same physical medium.

Can be extended by hubs or repeaters.

Network Interface Card

Computer Hardware - used for LANs

Allows a computer to connect to a networking cable it can then send and receive data over the cable at the direction of the computer.

Logical Link Control

IEEE 802.2 standard that defines the upper sublayer of the Ethernet Layer 2 specifications (and other LAN standards).

Media Access Control

Lower of the two sublayers of the IEEE standard for Ethernet.

Defined by 802.3

Indicates whether the performance of a device, attached to a particular type of LAN can be accurately predicted (determined).

EX: Token Ring, LANs

Carrier Sense Multiple Access

Media access method in which transmitting node listens for a signal on the media before transmitting.

Will wait to transmit if a signal is detected.

Signal on a medium used to support the transmission of data.

• Data is "carried" over the medium by modulation
• (combining data signal w/ carrier signal)

(Ethernet)

Results of two nodes transmitting simultaneously.

Causes damage to signals requiring them to be retransmitted.

Carrier Sense Multiple Access / Collision Avoid

Mechanism used to regulate the transmission of data onto a network medium.

Device requests right to send in order to avoid collisions.

Used in 802.11 WLANs

When communication can only be transmitted in one direction at one time.

One station receives what the other transmits and must wait till completion to send the response.

Communication that allows transmission and receipt at the same time.

No collisions!

Arrangement of the nodes in a network and the physical connections between them.

Representation of how media is used to connect the devices.

Map of the devices on a network representing how the devices communicate with each other.

Logical connection between two devices in which the frames are passed between the devices.

Independent of the physical structure and may be established through multiple physical devices.

Access method used with some LANs

Devices access media in a controlled manner managed by a small frame called a token.

Devices can only send when they have claimed the token.

Cycle Redundancy Check

Type of hash function (one-way encryption) that is used to produce small, fixed-size checksum of a block of data, such as a packet or a computer file.

CRC is computed & appended before transmission/storage and verified by the recipient to confirm nothing was changed during transmission.

Retransmission delay used with CSMA/CD when a collision occurs.

Forces each sender that detected the collision to delay a random amount of time before attempting to retransmit.

Association Identity

Number used in the 802.11 header to specify the session between a wireless client and the access point.

Address Resolution Protocol

Method for finding a host's hardware address (MAC) from its IPv4 Network Layer address.