Editing Network segment

{{Short description|Portion of a computer network}}
{{Use American English|date = March 2019}}
{{Use dmy dates|date=May 2025}}

A '''network segment''' is a portion of a [[computer network]]. The nature and extent of a segment depends on the nature of the network and the device or devices used to interconnect end stations.<ref>{{cite web |url=http://www.linfo.org/network_segment.html |title=Network Segment Definition |date=2 October 2005 |access-date=2010-09-03}}</ref>

==Ethernet==
According to the defining [[IEEE 802.3]] standards for [[Ethernet]], a network segment is an ''electrical connection'' between networked devices using a [[shared medium]].<ref>{{citation |section=1.4.318 |quote=segment: The medium connection, including connectors, between Medium Dependent Interfaces (MDIs) in a CSMA/CD local area network. |publisher=IEEE |title=802.3-2008 Part 3: Carrier sense multiple access with Collision Detection (CSMA/CD) Access Method and Physical Layer Specifications |date=26 December 2008}}</ref> In the original [[10BASE5]] and [[10BASE2]] Ethernet varieties, a segment would therefore correspond to a single coax cable and all devices tapped into it. At this point in the evolution of Ethernet, multiple network segments could be connected with [[repeater]]s (in accordance with the [[5-4-3 rule]] for 10 Mbit Ethernet) to form a larger [[collision domain]].

With [[twisted-pair Ethernet]], electrical segments can be joined using repeaters or [[repeater hub]]s as can other varieties of Ethernet. This corresponds to the extent of an [[OSI layer 1]] network and is equivalent to the collision domain.<ref>{{cite web |url=http://www.linktionary.com/s/segment.html |title=Segment (Network) |access-date=2010-09-03}}</ref><ref>{{cite web |url=http://compnetworking.about.com/od/networkdesign/l/bldef_segment.htm |title=Segment |access-date=2010-09-03}}</ref> The 5-4-3 rule applies to this collision domain.

Using [[network switch|switches]] or [[network bridge|bridges]], multiple layer-1 segments can be combined to a common [[layer-2]] segment, i.e. all [[node (networking)|nodes]] can communicate with each other through [[MAC address]]ing or [[broadcasting (networking)|broadcasts]]. A layer-2 segment is equivalent to a [[broadcast domain]]. Traffic within a layer-2 segment can be separated into virtually distinct partitions by using [[VLAN]]s. Each VLAN forms its own logical layer-2 segment.

==IP==
A [[layer-3]] segment in an [[IP network]] is called a [[subnetwork]], formed by all nodes sharing the same network prefix as defined by their IP addresses and the network mask.<ref>{{cite web |url=http://www.inetdaemon.com/tutorials/networking/lan/define_network_segment.shtml |title=What is a Network Segment? |access-date=2010-09-03}}</ref> Communication between layer-3 subnets requires a [[router (computing)|router]]. Hosts on a subnet communicate directly using the layer-2 segment that connects them. Most often a subnetwork corresponds exactly with the underlying layer-2 segment but it is also possible to run multiple subnets on a single layer-2 segment.

==References==
{{reflist}}

{{DEFAULTSORT:Network Segment}}
[[Category:Ethernet]]
[[Category:Network architecture]]