Figure One
Thick Ethernet Physical Topology

The cable type used for 10 Base-5 networks is a specialized form of RG-8 coaxial cable. This cable consists of a single central wire surrounded by a plastic insulation, which is in turn surrounded by four shields and an outside jacket. The resulting cable is nearly 1/2 inch in outside diameter, and is relatively heavy and inflexible. However, it is very resistant to external interferance.

A single 10 Base-5 segment may be up to 500 meters (1650 feet) in length and may have up to 255 nodes connected to it. Please note that each node must be at least 2.5 meters (8.25 feet) apart.

Long Distances Possible

10 Base-5 allows distances up to 500 meters (1650 feet). This makes it very useful as a "backbone" technology for wiring together multiple locations within a building without the use of repeaters.

Noise Immunity

Since 10 Base-5 uses a very heavily shielded cable, it can be used in electrically noisy environments which can cause other network types to fail.

Conceptually Simple

Since all devices on a 10 Base-5 network are simply chained together on a common coaxial cable, it is a simple matter to plan the routing of the cable. It is also easy to look at the diagram of the network and understand how a particular installation works.

Inflexible

10 Base-5 networks do not lend themselves well to installations where the setup of the network will change much after the initial installation. It can be very difficult to add or move a node once it is connected to the coaxial cable.

Fault Intolerant

Since 10 Base-5 uses a common physical cable to interconnect all the nodes, the failure of any part of the coaxial cable or any node has the ability to cause the entire network to go down.

Suceptible To Ground Loops

Ground loops are a notorious weakness of 10 Base-5. Basically, a ground loop occurs when a network cable is used to interconnect devices which are powered from different sources, and therefore a difference in voltage exists between two points on the network. The result is an electrical current flowing through the shields of the cable, which causes considerale noise to be introduced into the center conductor.

Very Difficult Troubleshooting

As mentioned above, a failure anywhere on a 10 Base-5 segment has the ability to drop the entire network. Troubleshooting such a failure can be extremely frustrating, as the only way to do it is to check each node and the cabling between them one at a time. This is very time consuming, and can be expensive if a company's entire business relies on the network to be up.

Today, the most common use for 10 Base-5 is as a "backbone" technology. Basically, a backbone is used to connect together multiple 10 Base-T hubs to create one large network, as depicted in Figure Two. Another common use is for connecting several distant devices to a central network.

Figure Two
Thick Ethernet Backbone