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Showing posts from August, 2012

Wireless Network Routers

A wireless router integrates a wireless access point with an Ethernet switch and an Ethernet router. The integrated switch connects the integrated access point and the integrated Ethernet router internally, and allows for external wired Ethernet LAN devices to be connected as well as a (usually) single WAN device such as a cable modem or DSL modem. A wireless router advantageously allows all three devices (mainly the access point and router) to be configured through one central configuration utility, usually through an integrated web server. However one disadvantage is that one may not decouple the access point so that it may be used elsewhere.

Token passing

In Token Ring another access method is used, called Token Passing.

With Token Passing, a small message, called a token, constantly circulates around the ring. If the token is marked as free, the host that receives the ”free” token can transmit its data and mark the token as busy. All the hosts along the ring receive the data and the busy token, until the host that sent the original message sets the token free again.

Right now the token is with host B, and it is marked free. Let’s say that host B wants to send data to host D. B sets the token to busy and adds its data. The host C has now received the token and the data, but since C is not the receiver it just passes on the token and the data into the ring.

The host D receives the data and sets the token to copied. The token and the data are then
passed on into the ring.

The host A just passes on the token and the data. The host B sees that the data has been received in a proper way by D. B therefore deletes the data and sets the token …

Fiber To Home

Fiber-To-The-Home (FTTH)

"How Fiber to the Home Works"FTTH In an FTTH (Fiber-to-the-Home)system, glass fiber cables go directly from the Internet backbone to the user’s premises, using high-speed pulses of light to transport information. Fiber-optic cables have large bandwidth (speeds greater than 2.5 gigabits per second).

More and more, both traditional phone companies and start-up companies are installing FTTH to deliver broadband services, particularly in areas with new residential and commercial construction. Companies with older copper networks are, in some cases, overlaying copper-wired networks with new FTTH systems, then removing the old networks. Two types of FTTH architectures are currently used: Pointto- point and passive optical network (PON).

Point-to-point providers install an optical transceiver in the provider’s central office for each customer. Fiber-optic cable then connects the central offi ce to the customer’s premises, much like a telephone line. PON is a …