Digital Network Topologies
The classic network topologies associated with digital networks are shown here, with comments:
Star network topology:
This is the latest in digital networking from the 1970's. Note the central failure point at the "Waco" location. - If anything goes wrong there, nobody can talk to anybody else, period.
Some personalities are attracted by the idea of a 'central control point', even at the cost of having an inefficient, fragile network that cannot really be depended upon when the chips are down.
Today, Star networks generally only exist in home networks ( wired and wireless ) where several computers share a single network connection through a switch or router.
Ring network topology:
The Ring network topology is a giant leap forward from a Star network, in that any single network node or location can be lost without taking down the rest of the network. - They will still be able to communicate.
If more that one node goes down, however, it is possible to fragment a Ring network so that not all remaining nodes can 'talk' to all of the others.
Semi-Meshed network topology:
This is the gold standard of digital networking today. It is the networking model that the internet is modeled upon, representing a big step forward from Star or Ring networks, both in its ability to lose one or more nodes and keep right on going, and in the increased speed the multiple connections allow.
Amateur Packet Radio utilizes the Semi-Meshed network topology, which goes far in explaining how some of the larger Packet networks can lose several nodes and continue to function in a useful manner.
Note: Of the major Packet networks, only one ever experienced total failure, leaving no trace of its existence behind... This was the TexNet Packet network that once covered parts of Texas and two other states with more than 90 nodes. TexNet did not utilize the Semi-Meshed network topology, but instead was built upon the obsolete Star model. - As one would expect, when the central control of TexNet went down, so did the entire network - in very short order.
Fully-Meshed network topology:
This design goes one step further than the Semi-Meshed network topology by providing a direct connection between each node to each other node in the network. Too expensive and complicated for large-scale use, this designs usefulness is limited to smaller networks that must be very secure and very fast.
It is doubtful that anything beyond a few small-scale government and corporate applications of a fully-meshed network topology are in use, anywhere.
Last edited by N5PVL; 12-03-2010 at 01:13 AM.
73 DE Charles, N5PVL
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