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Canon 802.11g 54M WLAN User Manual

Page 66

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802.11g 4-Port Wireless LAN Broadband Router

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software or a special piece of hardware built specifically to act as a firewall. In most

circumstances, a firewall is used to prevent unauthorized Internet users from accessing

private networks or corporate LAN’s and Intranets.

A firewall watches all of the information moving to and from your network and analyzes

each piece of data. Each piece of data is checked against a set of criteria that the

administrator configures. If any data does not meet the criteria, that data is blocked and

discarded. If the data meets the criteria, the data is passed through. This method is called

packet filtering.

A firewall can also run specific security functions based on the type of application or type of

port that is being used. For example, a firewall can be configured to work with an FTP or

Telnet server. Or a firewall can be configured to work with specific UDP or TCP ports to

allow certain applications or games to work properly over the Internet.

Firmware

Program that is inserted into programmable read-only memory (programmable read-only

memory), thus becoming a permanent part of a computing device.

Fragmentation Threshold Value

Indicates how much of the network resources are devoted to recovering packet errors. The

value should remain at its default setting of 2,432. If you experience high packet error rates,

you can decrease this value but it will likely decrease overall network performance. Only

minor modifications of this value are recommended.

Fragmentation

Breaking a packet into smaller units when transmitting over a network medium that cannot

support the original size of the packet.

IEEE

The Institute of Electrical and Electronics Engineers

IEEE 802.11b/g standard

The IEEE 802.11b/g Wireless LAN standards subcommittee formulates standards for the

industry. The objective is to enable wireless LAN hardware from different manufacturers to

communicate.

Infrastructure Mode

A client setting provides connectivity to an Access Point. As compared to Ad-Hoc mode

where PCs communicate directly with each other, clients set in Infrastructure mode all pass

data through a central Access Point. The Access Point not only mediates Wireless network

traffic in the immediate neighborhood but also pro-vides communication with the wired

network. An integrated wireless and wireless and wired LAN is called an Infrastructure