# Networking Issues

Networking Issues

Networks are of two types -

Wired and Wireless Most businesses use combination of both wired and wireless.

Media -

In a wired network this involves copper cables.

Over time, cables can become worn out or damaged and that is when shorts can happen.

Environment -

It is also important to use right kind of cable depending on what kind of network you are using.

For ex - If you are using copper cabling, it is important to recognize the environment around the cable because certain electronic equipment such as fans, fluorescent lights or AC can interfere with the copper media and therefore altering or reducing the strength of the signal which is known as attenuation.

Another factor us the length of the cable.

If the length of the cable exceeds maximum recommended length then this could also cause a problem.

If you are using wrong type of cable, this can also effect your network.

Ex - If you are using crossover cable when you should be using straight cable.

Wireless Factors -

Since the wireless devices operate using radio waves , the antenna is a big factor that can determine the range and speed of a signal.

Antenna Type -

Omni - directional antenna

This is the most common type of antenna.

This type of antenna transmits the signal in all directions.

So, every wireless device in all directions can pick up this signal as long as they are in range.

Directional Antenna -

In this type directs the signal in one direction and that direction is wherever you point the antenna to.

Interference -

There are also problems that can arise in a wireless environment and one these is interference.

Microwave ovens can cause interference and certain wireless devices can interfere with the wireless signal such as cellphone or bluetooth devices such as wireless keyboards or mouse.

The waves reproduced by these devices can alter the signal of the wireless networks.

A cordless phone is another device that can interfere with a wireless network and that is because a lot of cordless phone operate at a same frequency as wireless routers do which is at 2.4GHz.

There was a situation one time where a person was complaining that every time her phone rings, she will lose internet connection on her laptop and this was because her cordless phone and her wireless router were using the dame wireless channel.

So, to quickly resolved it, log into router’s configuration page and change the channel on her wireless signal which quickly solve the problem.

The structure of the building is another factor that is another factor that can affect a wireless signal.

Depending upon the structure of the building like concrete walls, window film and metal studs can only affect wireless signals.

So, you have to take care where you are placing your wireless router to avoid these issues.

You may have to test certain areas in your home or office to make sure that all your devices can use your wireless network.

Wrong Encryption -

Using the wrong type of encryption could also prevent wireless devices from joining your network.

For ex - If you are using a later wireless encryption method such as WPA2 on your wireless router but if you are using an older laptop that can only use WEP or WPA then that laptop wouldn’t be able to join the wireless network because you are using a later encryption method that your laptop cannot recognize.

Fiber Optics Issues -

Similar issues can happen in fiber optics networks also such as -

Signal loss or attenuation Wrong type of cable Wavelength mismatches Fiber type mismatches Dirty connectors Connector mismatches Exceeding bandwidth bending limit Exceeding cable length

DHCP -

Problems can also happen in DHCP.

For ex - What happen if the DHCP server was removed ?

If this were to happen and certain computers that have an expired ip address were not be able to renew their ip lease because there is no longer a DHCP server present so the computers won’t be able to access the network.

This will also effect when new computers are added.

They will not be able to access the network without an ip address.

It is important to remember that this is only the case if the computers were configured to obtain an ip address automatically.

This would have no effect if they were configured for a static ip.

In another scenario, what would happen if another DHCP server was added to the network.

It is important to remember if you are going to add another DHCP server to the network then it must be configured properly.

For ex - You have to make sure that two DHCP server do not give out the same ip address to a computer because all ip address must be unique.

And if the second DHCP server assigns an ip address that is already in use then ip address conflict will happen.

So, to avoid this, you must configure the address pool correctly.

DNS (Domain Name Service) -

Problems can also happen in DNS.

DNS resolves domain names to ip addresses.

A problem with DNS would result in web browsing issues using domain names.

To test DNS, try typing ip address instead of domain name.

Link LEDs (Light Emitting Diode) -

Link LEDs are very simple indicators that are used to tell us base information about a network device.

For ex - On a NIC, if you were to plug in a network cable, you would notice that the green LED would turn on.

The green LED is a link light which indicates a successful network connection.

However, if the LED does not light up after the cable is plugged in then this indicates a problem such as a bad cable or something like that.

The blinking yellow LED on the other hand indicates that there is network activity happening whether the blink rate is medium or slow, this indicates normal operation.

Physical Connectivity -

Check to see if your computer is connected to the network.

If it is, is the ink LED on the network card turned on or if the cable you are using good.

If you don’t see the link LED and if you know that cable is good, you might want to check the switch, is the switch turned on.

Check for lease cables as well.
