The Collision domain is a part of an Ethernet network, all nodes of which compete for a common shared transmission medium and, therefore, each node of which can create a conflict with any other node in this part of the network.
In other words, a network segment having a common channel layer of the OSI model in which only one subscriber can transmit a frame . The delay in the propagation of frames between stations , or the simultaneous start of transmission causes collisions that require special processing and reduce network performance.
The more nodes in this segment, the higher the likelihood of collisions. Switches are used to separate the collision domain.
The concept exists regardless of the applicable physical layer standard .
Content
- 1 Network Devices and Collision Domain
- 2 Terminology
- 3 See also
- 4 notes
- 5 Sources
Network Devices and Collision Domain
Network devices running on the link layer of the OSI model can extend or limit the collision domain.
The following options are possible:
- OSI first-level devices ( hubs , repeaters ) only relay any signal coming from the transmission medium and extend the collision domain.
- OSI second-level devices ( bridges , switches ) share a collision domain.
- The collision domain is separate when connected to the switch port in half-duplex mode , or when connecting point-to-point two network adapters ; full duplex collisions are absent.
Terminology
- Propagation delay is the transmission time of the time segment, the so-called slotTime, equal to 512 bits for speeds up to 100 Mbit / s and 4096 bits for speed 1000 Gbit / s [1] , during which a collision can occur. It is determined by the speed of the signal along the wire and the transmission rate. For Ethernet 10 Mbit / s, the propagation delay is 51.2 ΞΌs, for 100 Mbit / s it is 5.12 ΞΌs. Most network equipment only controls transmission collisions during the propagation delay.
- Belated collision - a collision that occurred after a propagation delay. Such collisions are not detected by most network equipment and result in frame loss.
- The diameter of the collision domain is the maximum delay in signal propagation between any two stations . It is usually defined in units of time and corresponds to twice the transmission time of the minimum frame length for a given type of Ethernet. D = 2 * <minimum frame length> * 0.1 ΞΌs
See also
- Broadcast Domain
Notes
- β IEEE 802.3 β’ -2012 - Section One PDF format . - The Institute of Electrical and Electronics Engineers, Inc., 2012. - P. 74.96. - ISBN 973-07381-7312-2.
Sources
- Brian Hill Complete Cisco Reference = Cisco: The Complete Reference. - M .: "Williams" , 2007. - S. 1088. - ISBN 0-07-219280-1 .
- Olifer V.G., Olifer N.A. Computer networks. Principles, technologies, protocols: Textbook for universities. 3rd ed. - SPb. : ZAO Publishing House "Peter", 2006. - S. 958.