Star network: Difference between revisions

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{{Short description|Computer network topology}}

[[Image:NetworkTopology-Star.png|thumb|Star network layout]]

{{About|the network topology|the interbank network|STAR (interbank network)|the television network|Star Television Network|other uses|Starnet (disambiguation){{!}}Starnet}}

{{Redirect|Hub and spokes architecture|the network of alliances in the Asia-Pacific region|San Francisco System}}

{{Use American English|date=January 2020}}

[[File:Star Topology.png|thumb|Star topology in use in a network]]

A '''star network''' is an implementation of a [[spoke–hub distribution paradigm]] in [[computer network]]s. In a star network, every [[host (network)|host]] is connected to a central [[hub (network science)|hub]]. In its simplest form, one central hub acts as a conduit to transmit messages.<ref>{{citation

'''Star networks''' are one of the most common [[computer network]] [[Network topology|topologies]]. In its simplest form, a star network consists of one central [[Network switch|switch]], [[Network hub|hub]] or computer which acts as a conduit to transmit messages. If the central node is ''passive'', the originating node must be able to tolerate the reception of an echo of its own transmission, delayed by the two-way transmission time (i.e. to and from the central node) plus any delay generated in the central node. An ''active'' star network has an active central node that usually has the means to prevent echo-related problems.

| last1 = Roberts | first1 = Lawrence G.

| last2 = Wessler | first2 = Barry D.

| contribution = Computer network development to achieve resource sharing

| doi = 10.1145/1476936.1477020

| ___location = New York, NY, USA

| pages = 543–549

| publisher = ACM

| title = AFIPS '70 (Spring): Proceedings of the May 5–7, 1970, spring joint computer conference

| year = 1970| s2cid = 9343511

}}</ref> The star network is one of the most common [[Network topology|computer network topologies]].

==Network==

The star topology reduces the chance of network failure by connecting all of the systems to a central node. When applied to a bus-based network, this central hub rebroadcasts all transmissions received from any peripheral node to all peripheral nodes on the network, sometimes including the originating node. All peripheral nodes may thus communicate with all others by transmitting to, and receiving from, the central node only. The failure of a transmission line linking any peripheral node to the central node will result in the isolation of that peripheral node from all others, but the rest of the systems will be unaffected.

The hub and hosts, and the transmission lines between them, form a [[graph (discrete mathematics)|graph]] with the [[star (graph theory)|topology of a star]]. Data on a star network passes through the hub before continuing to its destination. The hub manages and controls all functions of the network. It also acts as a [[repeater]] for the data flow. In a typical network the hub can be a [[network switch]], [[Ethernet hub]], [[wireless access point]] or a [[router (computing)|router]]

The star topology reduces the impact of a transmission line failure by independently connecting each host to the hub. Each host may thus communicate with all others by transmitting to, and receiving from, the hub. The failure of a transmission line linking any host to the hub will result in the isolation of that host from all others, but the rest of the network will be unaffected.<ref>{{cite web|url=http://searchnetworking.techtarget.com/dictionary/definition/what-is-star-network.html# |title=Star Network |publisher=TechTarget |access-date=2014-06-24}}</ref>

Strictly speaking only networks that use switches have a true star topology. If the network uses a hub, the network topology has the physical appearance of a star, but is actually a [[Bus_network|bus]].

The star configuration is commonly used with [[twisted pair cable]] and [[optical fiber]] cable. However, it can also be used with [[coaxial cable]] as in, for example, a [[video router]].

== Advantages ==

== Advantages and disadvantages ==

* Good performance.

* Easy to set up and to expand.

* Any non-centralised failure will have very little effect on the network, whereas on a ring network it would all fail with one fault.

* Easy to detect faults

* Data Packets are sent quickly as they do not have to travel through any unnecessary nodes.

== Disadvantages =Advantages===

* If one node or its connection fails, it does not affect the other nodes.<ref name="teach-ict.com">{{Cite web|title = Teach-ICT OCR GCSE Computing - computer network topologies, bus network, ring network, star network|url = http://teach-ict.com/gcse_computing/ocr/215_communications_networking/network_topologies/miniweb/pg4.htm |website = teach-ict.com |archive-url=https://web.archive.org/web/20151222163638/http://teach-ict.com/gcse_computing/ocr/215_communications_networking/network_topologies/miniweb/pg4.htm |archive-date = 2015-12-22}}</ref>

* Devices can be added or removed without disturbing the network.

*Works well under heavy load.

*Appropriate for a large network.

===Disadvantages===

* Expensive to install

* Expensive due to the number and length of cables needed to wire each host to the central hub.<ref name="teach-ict.com" />

* Extra hardware required

* The central hub is a [[single point of failure]] for the network.

* If the hub/switch fails the entire system is affected.

* Each device needs a separate cable connection to the central hub, leading to higher cable usage.

* The number of devices is limited by the capacity of the central hub.

== See alsoReferences ==

{{reflist}}

*[[Bus network]]

*[[Ring network]]

*[[Mesh network]]

*[[Tree and hypertree networks]]

[[Category:{{Network topology]]topologies}}

[[Category:Network topology]]

[[de:Topologie (Rechnernetz)#Stern-Topologie]]

[[es:Red en estrella]]

[[fr:Réseau en étoile]]

[[id:Topologi bintang]]

[[pl:Topologia gwiazdy]]

[[pt:Rede em estrela]]

[[ru:Звезда (топология компьютерной сети)]]

[[ta:விண்மீன் வலையமைப்பு]]

[[zh:星型网]]