Ring network

Ring network

A ring network is a network topology in which each node connects to exactly two other nodes, forming a circular pathway for signals - a ring. Data travels from node to node, with each node handling every packet.

Because a ring topology provides only one pathway between any two nodes, ring networks may be disrupted by the failure of a single link. A node failure or cable break might isolate every node attached to the ring. FDDI networks overcome this vulnerability by sending data on a clockwise and a counterclockwise ring: in the event of a break data is wrapped back onto the complementary ring before it reaches the end of the cable, maintaining a path to every node along the resulting "C-Ring". 802.5 networks -- also known as IBM Token Ring networks -- avoid the weakness of a ring topology altogether: they actually use a "star" topology at the "physical" layer and a Multistation Access Unit to "imitate" a ring at the "datalink" layer.

Many ring networks add a "counter-rotating ring" to form a redundant topology. Such "dual ring" networks include Spatial Reuse Protocol, Fiber Distributed Data Interface (FDDI), and Resilient Packet Ring.

Advantages

*Very orderly network where every device has access to the token and the opportunity to transmit
*Performs better than a star topology under heavy network load
*Can create much larger network using Token Ring
*Does not require network server to manage the connectivity between the computers

Disadvantages

*One malfunctioning workstation or bad port in the MAU can create problems for the entire network
*Moves, adds and changes of devices can affect the network
*Network adapter cards and MAU's are much more expensive than Ethernet cards and hubs
*Much slower than an Ethernet network under normal load

Misconceptions

* "Token Ring is an example of a ring topology." 802.5 (Token Ring) networks do not use a ring topology at layer 1. As explained above, IBM Token Ring (802.5) networks "imitate" a ring at layer 2 but use a physical star at layer 1.
* "Rings prevent collisions." The term "ring" only refers to the layout of the cables. It is true that there are no collisions on an IBM Token Ring, but this is because of the layer 2 Media Access Control method, not the physical topology (which again is a star, not a ring.) Token passing, not rings, prevent collisions.
* "Token passing happens on rings." Token passing is a way of managing access to the cable, implemented at the MAC sublayer of layer 2. Ring topology is the cable layout at layer one. It is possible to do token passing on a bus (802.4) a star (802.5) or a ring (FDDI). Token passing is not restricted to rings.

Other topologies

*Star network
*Bus network
*Mesh network
*Tree network
*Hypertree network


Wikimedia Foundation. 2010.

Игры ⚽ Нужно решить контрольную?

Look at other dictionaries:

  • ring network — noun (computing) One forming a closed loop of connected terminals • • • Main Entry: ↑ring …   Useful english dictionary

  • ring network —    A network topology in the form of a closed loop or circle, with each node in the network connected to the next. Messages move in one direction around the system. When a message arrives at a node, the node examines the address information in… …   Dictionary of networking

  • ring network — žiedinis tinklas statusas T sritis automatika atitikmenys: angl. ring network vok. ringförmiges Netz, n; Ringnetz, n rus. кольцевая сеть, f pranc. réseau annulaire, m …   Automatikos terminų žodynas

  • ring network — žiedinis tinklas statusas T sritis informatika apibrėžtis ↑Tinklas, kurio ↑mazgai (kompiuteriai) sujungti ratu. Duomenys siunčiami žiedu iš vieno mazgo į kitą gretimą mazgą viena kryptimi. Mazgas, gavęs duomenis, patikrina, kam jie skirti. Jeigu… …   Enciklopedinis kompiuterijos žodynas

  • ring network —    A network topology with decentralized control in which messages are passed around the ring from node to node until they reach their designation or address; most use the token passing access method …   IT glossary of terms, acronyms and abbreviations

  • Ring Network —   A point to point network where every node is connected to two other nodes (thus forming a circle) …   International financial encyclopaedia

  • Token Ring network —    IBM s implementation of the token ring network architecture, which uses a token passing protocol transmitting at 4 or 16Mbps. Using standard telephone wiring, a Token Ring network can connect a maximum of 72 devices; with shielded twisted pair …   Dictionary of networking

  • token-ring network —    A LAN with a ring structure that uses token passing to regulate traffic on the network and avoid collisions.    On a token ring network, the controlling network interface card generates a token that controls the right to transmit. This token… …   Dictionary of networking

  • token ring network — estafetinis žiedinis tinklas statusas T sritis informatika apibrėžtis ↑Žiedinis tinklas, kuriame duomenų srautą reguliuoja ↑estafetės paketas. Tinkle būna tik vienas estafetės paketas, suteikiantis teisę duomenis siųsti tik tuo metu jį turinčiam… …   Enciklopedinis kompiuterijos žodynas

  • token ring network —    1. A LAN access method that uses the token passing technology in a physical ring.    2. A LAN access method from IBM that conforms to the IEEE 802.5 token ring standard …   IT glossary of terms, acronyms and abbreviations

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”