topology

Network Topology

Common topologies:

Mesh

arbitrary point-to-point connectivity between stations (up to complete connectivity)

Adv: fast, no contention.

Dis: expensive (number of links and I/O ports required)

Star

Each station has one point-to-point link to central controller (hub).

Adv: less cabling than mesh (cheaper), one I/O port per station

Dis: vulnerable to single node (hub) failure, contention for hub

Tree

Variation of star; tree configuration where interior nodes are hubs and leaf nodes are stations

Adv: less vulnerable to hub failure, contention at central (root) hub reduced

Ring

Each station has two point-to-point links to adjacent stations.

Adv: cheap and easy cabling

Dis: vulnerable to single node or link failure

Bus

Single (backbone) multipoint link with stations tapped

Adv: cheap and easy to install, easy to add stations, least amount of cabling

Dis: vulnerable to backbone break, contention for link, can be difficult to add stations

(why is "adding stations" listed both under advantages and disadvantages?)

Transmission modes:

Simplex : signals flow one way through link (one way street)

Half-duplex: signals flow either way, but only one way at a time (railroad track)

Full-duplex: signals flow both ways simultaneously (highway)

(either separate paths, or partitioned channels)

Last reviewed: 19 January 2000

Peter Sanderson ( pete@csc.smsu.edu )