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HOME NETWORKING
MAC and IP Address
MAC
(Media Access Control) address is a hardware address for a networking device. For example, an Ethernet port in a laptop would have its own MAC address as well as the wireless card in the same laptop will have its own MAC address. The format of a MAC address is a sequence of six two-digits hexadecimal numbers separated by colons, for example, 00:2E:71:CF:A1:98
The format of an
IP
address is a 32-bit numeric address written as four numbers separated by periods. Each number can be zero to 255. For example, 192.200.78.155 could be an IP address. The same laptop mentioned in the example above would have its own local IP address that is assigned by the router. The router assigns each networked device a local IP address in the range of:
- 10.0.0.0 through 10.255.255.255 with subnet mask 255.0.0.0
- 172.16.0.0 through 172.31.0.0 with subnet mask 255.255.0.0
- 192.168.0.0 through 192.168.255.0 with subnet mask 255.255.255.0
The last one on the list (192.168.0.0 through 192.168.255.) is the most common. The protocol used to assign these numbers is called Dynamic Host Configuration Protocol (
DHCP
). No two device can have the same IP address or a conflict will occur when the router tries to send out data. Furthermore, your cable or DSL modem will assign a global IP address to your router. Therefore, any computer out on the internet will see one of the computers located on your LAN as the router’s IP address and not the local IP address.
A good analogy for MAC and IP address is to think of an apartment buildings street address as the IP address and the individual apartment numbers as MAC addresses.
Wireless Formats
In 1997, the Institute of Electrical and Electronics Engineers (
IEEE
) created the first
WLAN
(Wireless Local Area Network) standard. They called it 802.11. At a maximum bandwidth of 2 Mb/s, the original 802.11 protocol was pretty slow. The following formats emerged as technology developed:
- 802.11b
– Has a maximum bandwidth of 11 Mb/s (without extra manufacture’s technology such as Air Plus Extreme), and is located at the 2.4 GHz frequency range. Since this is a unregulated frequency range, interference can come from other appliances such as cordless phones and microwaves. However, 802.11b does have a long range.
- 802.11a
– Has a maximum bandwidth of 54 Mb/s (without extra manufacture’s technology such as Air Plus Extreme), and is located at the 5 GHz frequency range. The higher frequency allows more data throughput, but makes the signal more susceptible to loss from interference with walls and other objects. Therefore, the range is less than 802.11b.
- 802.11g
– is designed to take the best qualities of 802.11a (bandwidth) and 802.11b (range) and put them together. Therefore, 802.11g has a maximum bandwidth of 54 Mb/s (without extra manufacture’s technology such as Air Plus Extreme), and is located at the 2.4 GHz frequency range. Also, 802.11g is backwards compatible with 802.11b.
- Bluetooth
– is an alternate wireless technology to 802.11, but is mostly used for peripherals such as PDAs or wireless keyboards. It has a short range of only 30 feet and low bandwidth of 2 Mb/s.
A supplement to 802.11 protocols that allows faster bandwidths is called
MIMO
(Multiple Inputs Multiple Outputs) This technology is new and doesn’t have any standards so make sure it is backwards compatible to your current hardware.
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