Network Components
The term network refers to a collection of related things that are interconnected. In a computer network, a node is any computer, printer, or other electronic device that could potentially communicate with another. The connection between these devices, called a link, is any data transmission medium (like wires, infrared waves, or radio waves) shared by a set of nodes and used for communication among the nodes. Protocols are rules (or languages) that govern how devices on a network communicate with each other.
Here are some examples of network components:
Some products combine a number of these nodes, links, and protocols into a single physical device. When troubleshooting, you may be tempted to think of a base station, a computer, or even a hub as one node. Don't. An AirPort Extreme Base Station can act as an Ethernet switch, as a router, and as a DHCP server, and can provide wireless connectivity. Likewise, a PowerBook G4 can have multiple nodes, including analog modem, Ethernet port, and AirPort port. Network troubleshooting is easier if you think in terms of nodes instead of devices.
So, a network can be defined as a collection of nodes that are linked so that they all can communicate with one another and share resources. Network components include the electronic devices and the software used to communicate on the network, as well as the wires, cables, connectors, and other hardware devices that make the physical connections. This interconnectivity of network components can complicate troubleshooting, because you must consider user and network errors as well as software and hardware problems. This complication can be compounded by the fact that some types of errors may be related to network nodes and links that you may not have control over, or even access to (such as an ISP's equipment), so you may not always be able to locate and resolve all network issues without some help.
Identifying Network Components
Now that you have a language with which to organize your understanding of a given network, let's try practicing with some real-world customer scenarios.
A customer describes the following scenario:
“I have an iBook G4 with AirPort. When I'm in my classroom lab, I can't print to the lab inkjet printer, but I can print to the laser printer.”
At its most basic, you might fill in the network components table like this:
| Network | Node | Link | Protocol |
|---|---|---|---|
| LAN | iBook G4 | Ethernet cable | TCP/IP, Bonjour |
| Wireless | AirPort Extreme Card (inside iBook G4) | Radio waves | IEEE 802.11b, 802.11g |
| Inkjet printer | |||
| LAN | Laser printer |
Furthermore, you can speculate that the inkjet printer must be physically connected to something, possibly another computer or a wireless base station, and is therefore being shared over the classroom lab LAN. Likewise, the laser printer and base station must both be physically connected to something, probably an Ethernet switch or hub.
So, a more fleshed-out network components table might look like this:
Notice the distinction made between the facts that are known and the assumptions that are made. When you're troubleshooting, you should query the customer and, if possible, examine the actual network setup yourself to make sure of the information in each of these boxes.
Component Identification Exercise
For each of the following customer scenarios, fill out a network components table.
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Component Identification Exercise Answer Key
| A1: | Scenario 1:
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| A2: | Scenario 2:
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| A3: | Scenario 3:
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