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Ethernet standards specify what constitutes a valid network. Remember that when you stay within the standards that were set, your network will operate with few, if any, errors. The three most common things that create network problems are incorrect cabling, overpopulation of the network (node count), and overextended network cabling distance.
You will want to refer to the diagrams under "Keeping Your Network Valid" later in this document. Two diagrams are presented; a valid network operating within standards, and an invalid network that has exceeded Ethernet standards. Initial planning of your network, or expanding your network following these standards, will keep your network running more efficiently. The basic rules to follow are outlined in this section.
Three Important Network Considerations
- Wiring
Consider the wiring or cabling you are using for your network. The wrong quality or type for your network can cause network difficulty.
- Count
Consider the number of nodes you are attaching to your network. Too many nodes within a workgroup, or too many hubs within a network without segmenting them with a switch, will cause frequent collisions and errors on your network.
- Distance
Consider the distance between the nodes on your network. If the overall distance of your network exceeds Ethernet standards it will cause timing errors that will slow down your network.
Helpful Tips
- Each computer connected to the network requires a Network Adapter Card.
- The easiest and most popular Ethernet topology is the star topology, which is required when using 10BASE-T cabling.
- A 10BASE-T Ethernet network uses Category 3 or 5 twisted-pair cable with RJ-45 connectors on each end.
- With 10BASE-T wired networks, a maximum of 5 wiring segments is allowed between any connected computer within the LAN. Lay out your network on paper and count each wiring segment to verify compliance. See "Keeping Your Network Valid" below to see how to expand your network and stay in compliance.
- 10 Mbps hubs can be connected together using Category 3 or 5 twisted-pair cable. Computer-to-switch or computer-to-hub distance must not exceed 100 meters (328 feet).
- 100 Mbps connections can be connected using Category 5 twisted-pair cable. Computer-to-switch or computer-to-hub distance must not exceed 100 meters (328 feet).
- Switches and hubs can also be connected through a backbone using 10BASE 2 thin coax cable with BNC connectors. Maximum backbone length must not exceed 185 meters (602 feet).
- Two LAN segments can be connected together using a bridge.
- Fast Ethernet 100BASE-TX wired networks can have only 2 wiring segments between any connected computer within the LAN. See "Keeping Your Network Valid" below to see how to expand your network.
- A backbone counts as one segment. Connected segments count separately.
- Any switch placed within the LAN starts the count over, thereby allowing expansion of the network while maintaining Ethernet specifications.
- A switch is a key element in being able to expand your network and still maintain compliance. Improperly segmenting or overpopulating your network will cause collisions and poor network performance.
Other things can occasionally go wrong too. So, if you've determined that none of the above items are causing a problem, call your network equipment manufacturer to help determine where to look next.
Keeping Your Network Valid
This is a valid network even though there are five hubs, because a switch is in the key location to keep this network valid.
In this example, the valid wire count between computers A and B is only 3. Here's why. Instead of another hub, a switch has been added to the network. The switch starts the count over, which keeps the count within standards. A switch or bridge must follow two connected hubs. If all hubs on this network were fully populated with directly connected computers, it would contain 40 computers with more room to grow. This switch currently directly connects three hubs, but could grow to directly connect up to eight hubs, while still maintaining standards.
Below is an invalid network that contains only five hubs. However, in this example, the wiring count between computer A and B is 6, violating Ethernet standards. Here is why;
Following two connected hubs, no switch or bridge is installed. The wiring count exceeds five causing delayed and weak signals from computer A to computer B. Even though it is a smaller network than the first example, it has already exceeded Ethernet standards.
This applies to:
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