Collision domain

	Email		Print
	Bookmark		Link

Collision domain

A collision
Collision (telecommunications)

In telecommunication, the term collision has the following meanings:# In a data transmission system, the situation that occurs when two or more demands are made simultaneously on equipment that can handle only one at any given instant....
domain is a physical network segment

Network segment

A network segment is a portion of a computer network wherein every device communicates using the same physical layer. Devices that extend the physical layer, such as repeaters or network hubs, are also considered to extend the segment....
where data packets can "collide" with one another for being sent on a shared medium, in particular in the Ethernet

Ethernet

Ethernet is a family of Data frame-based computer networking technologies for local area networks . The name comes from the physical concept of the Luminiferous aether....
term used to describe a network scenario wherein one particular device sends a packet on a network segment, forcing every other device on that same segment to pay attention to it.

A group of Ethernet or Fast Ethernet devices in a CSMA

Carrier Sense Multiple Access

Discussion

Ask a question about 'Collision domain'

Start a new discussion about 'Collision domain'

Answer questions from other users

Full Discussion Forum

Encyclopedia

Network segment

Ethernet

Carrier Sense Multiple Access

Carrier Sense Multiple Access is a probabilistic Media Access Control protocol in which a node verifies the absence of other Network traffic before Transmission on a shared Transmission medium, such as an electrical bus, or a band of the electromagnetic spectrum....
LAN that are connected by repeaters and compete for access on the network. This situation is typically found in a hub environment where each host segment connects to a hub that represents only one collision domain and only one broadcast domain

Broadcast domain

A broadcast domain is a logical division of a computer network, in which all node s can reach each other by broadcasting at the data link layer....
. Only one device in the collision domain may transmit at any one time, and the other devices in the domain listen to the network in order to avoid data collisions. Collisions decrease network efficiency; if two devices transmit simultaneously, a collision occurs, and both devices must retransmit at a later time.

The basic strategy goes like this:

A computer listens on the cable to see if another computer is transmitting, which is indicated by a voltage change on the cable. If busy, the computer waits and listens.

When the cable is not busy, a computer attempts to transmit.

Another computer may attempt to transmit at the same time, which causes a collision.

Both computers that attempted to transmit must back off, wait a random period of time (else they would immediately collide again), and then attempt to transmit again.

Computers on the network detect collisions by looking for abnormally changing voltages. Signals from multiple systems overlap and distort one another. Overlapping signals will push the voltage above the allowable limit. This is detected by attached computers, which reject the corrupted frames (called runts

Runts

Runts are Candy sold by Nestl? under their The Willy Wonka Candy Company brand. First seen on the market in 1982, they are fruit flavored candies in the shape of their respective fruits....
).

Collision domain

See also