Backbone network

Global area network

A global area network (GAN) is a network used for supporting mobile communications across an arbitrary number of wireless LANs, satellite coverage areas, etc. The key challenge in mobile communications is handing off the user communications from one local coverage area to the next. In IEEE Project 802, this involves a succession of terrestrial WIRELESS local area networks (WLAN).^[5]

Metropolitan area network

Enterprise private network

An enterprise private network is a network build by an enterprise to interconnect various company sites, e.g., production sites, head offices, remote offices, shops, in order to share computer resources.

Sample EPN made of Frame relay WAN connections and dialup remote access.

[edit] Virtual private network

Sample VPN used to interconnect 3 office and Remote users

A virtual private network (VPN) is a computer network in which some of the links between nodes are carried by open connections or virtual circuits in some larger network (e.g., the Internet) instead of by physical wires. The data link layer protocols of the virtual network are said to be tunneled through the larger network when this is the case. One common application is secure communications through the public Internet, but a VPN need not have explicit security features, such as authentication or content encryption. VPNs, for example, can be used to separate the traffic of different user communities over an underlying network with strong security features.
A VPN may have best-effort performance, or may have a defined service level agreement (SLA) between the VPN customer and the VPN service provider. Generally, a VPN has a topology more complex than point-to-point.

[edit] Internetwork

An Internetwork is the connection of two or more private computer networks via a common routing technology (OSI Layer 3) using routers. The Internet is an aggregation of many internetworks, hence its name was shortened to Internet.

Types of networks based on physical scope

Common types of computer networks may be identified by their scale.

[edit] Personal area network

A personal area network (PAN) is a computer network used for communication among computer and different information technological devices close to one person. Some examples of devices that are used in a PAN are personal computers, printers, fax machines, telephones, PDAs, scanners, and even video game consoles. A PAN may include wired and wireless devices. The reach of a PAN typically extends to 10 meters.^[2] A wired PAN is usually constructed with USB and Firewire connections while technologies such as Bluetooth and infrared communication typically form a wireless PAN

[edit] Local area network

A local area network (LAN) is a network that connects computers and devices in a limited geographical area such as home, school, computer laboratory, office building, or closely positioned group of buildings. Each computer or device on the network is a node. Current wired LANs are most likely to be based on Ethernet technology, although new standards like ITU-T G.hn also provide a way to create a wired LAN using existing home wires (coaxial cables, phone lines and power lines).^[3]

Typical library network, in a branching tree topology and controlled access to resources

All interconnected devices must understand the network layer (layer 3), because they are handling multiple subnets (the different colors). Those inside the library, which have only 10/100 Mbit/s Ethernet connections to the user device and a Gigabit Ethernet connection to the central router, could be called "layer 3 switches" because they only have Ethernet interfaces and must understand IP. It would be more correct to call them access routers, where the router at the top is a distribution router that connects to the Internet and academic networks' customer access routers.
The defining characteristics of LANs, in contrast to WANs (Wide Area Networks), include their higher data transfer rates, smaller geographic range, and no need for leased telecommunication lines. Current Ethernet or other IEEE 802.3 LAN technologies operate at speeds up to 10 Gbit/s. This is the data transfer rate. IEEE has projects investigating the standardization of 40 and 100 Gbit/s.^[4]

[edit] Home area network

A home area network (HAN)is a residential LAN which is used for communication between digital devices typically deployed in the home, usually a small number of personal computers and accessories, such as printers and mobile computing devices. An important function is the sharing of Internet access, often a broadband service through a CATV or Digital Subscriber Line (DSL) provider. It can also be referred as Office area network(OAN).

[edit] Wide area network

A wide area network (WAN) is a computer network that covers a large geographic area such as a city, country, or spans even intercontinental distances, using a communications channel that combines many types of media such as telephone lines, cables, and air waves. A WAN often uses transmission facilities provided by common carriers, such as telephone companies. WAN technologies generally function at the lower three layers of the OSI reference model: the physical layer, the data link layer, and the network layer.

[edit] Campus network

A campus network is a computer network made up of an interconnection of local area networks (LANs) within a limited geographical area. The networking equipments (switches, routers) and transmission media (optical fiber, copper plant, Cat5 cabling etc.) are almost entirely owned (by the campus tenant / owner: an enterprise, university, government etc.).
In the case of a university campus-based campus network, the network is likely to link a variety of campus buildings including; academic departments, the university library and student residence halls.

Introduction to Mobile Telephone Systems-1G, 2G, 2.5G, and 3G Wireless Technologies and Services

Cellular, personal communication service (PCS), and third generation 3G mobile radio systems are all cellular wireless communication networks that provide for voice and data communication throughout a wide geographic area. Cellular systems divide ‘large geographic areas’ area into small radio areas (cells) that are interconnected with each other. Each cell coverage area has one or several transmitters and receivers that communicate with mobile telephones within its area.

The cellular system connects mobile radios (called mobile stations) via radio channels to base
stations. Some of the radio channels (or portions of a digital radio channel) are used for control
purposes (setup and disconnection of calls) and some are used to transfer voice or customer data
signals. Each base station contains transmitters and receivers that convert the radio signals to
electrical signals that can be sent to and from the mobile switching center (MSC). The MSC
contains communication controllers that adapt signals from base stations into a form that can be
connected (switched) between other base stations or to lines that connect to the public telephone
network. The switching system is connected to databases that contain active customers
(customers active in its system). The switching system in the MSC is coordinated by call
processing software that receives requests for service and processes the steps to setup and
maintain connections through the MSC to destination communication devices such as to other
mobile telephones or to telephones that are connected to the public telephone network.

When linked together to cover an entire metro area, the radio coverage areas (called cells) form a
cellular structure resembling that of a honeycomb. Cellular systems are designed to overlap each
cell border with adjacent cell borders to enable a “hand-off” from one cell to the next. As a
customer (called a subscriber) moves through a cellular system, the mobile switching center
(MSC) coordinates and transfers calls from one cell to another and maintains call continuity.

Key drivers for the mobile telephone market growth include new wireless technology (3G)
service availability and the replacement market for mobile phones with new capabilities such as
camera phones, color displays, and increased accessory capabilities.

Starting an Outreach Call Center Service

Even though the cost of telephone equipment and service can be steep, reaching out to customers by this method is invaluable to many business owners. Receiving a phone call gives a much more personal feel than a letter. Unfortunately, it’s becoming significantly harder for businesses to meet their financial obligations, so many are looking to outsource large volume calls to a professional service.
Today, there are also many businesses that need the services of a call center for a one-time event. For example, if a local business wants to have a special celebration, they may decide to use telephone calls to invite people. If you can provide the same service for less than it would cost the company, you might just be in business. In other cases, you might be able to find work catching up on the backlog of outgoing telephone calls that are normally managed by routine office staff.
For the most part, incoming and outgoing call centers perform similar tasks for a wide variety of companies. That said, the difference in who initiates the contact leads to a number of differences in how you will focus and structure each call. When you work in an outgoing call center, your conversations will be much more script-driven and you may be required to comply with a number of specific government regulations.

Description:

This book provides an introduction to the different types of private telephone systems, how they operate and common call processing features they offer. Private telephone systems are communication equipment and software that are owned, leased or operated by the companies that use these systems.
Private telephone systems are converting from company unique (proprietary) circuit switched systems to industry standard packet data voice (IP Telephony) systems. You will learn the basics of IP Telephony voice over Internet protocol (VoIP) and why it is so important to private telephone systems.
The fundamental parts of private telephone systems are described including telephone stations, local wiring, switching systems, and numbering plans are described and explained. The high growth market for private telephone systems and the key trends are covered providing you with an understanding of which system types are growing the fastest and how some systems are evolving to better compete in the industry.
Covered are the different types of private telephone systems. You will discover how multiline key telephone systems (KTS) operate and why they are converting from mechanical systems to automated electronic controlled networks. You will learn how automatic switching systems are used by private branch exchange (PBX) systems to provide features and services not offered by public telephone companies. Explained are the ways private telephone systems can be operated (hosted) by other companies (Hosted PBX/Centrex) and how these systems can provide services similar to PBX telephone systems. Discover how telephone systems can be combined with company information systems using computer telephony integration (CTI). You will learn how IP PBX (iPBX) systems operate and why IPTX is the fastest growing area in private telephone systems. You will learn some of the ways private telephone systems are adding wireless capabilities and industry standard wireless private branch exchange (WPBX) systems.
Important call processing features including distinctive ringing, call hold, call transfer, call pickup, line hunting and other features are described. Advanced private telephone system features are explained including automated attendant systems, automatic call distribution (ACD), Interactive voice response (IVR) and Voice mail (VM). A basic introduction to call centers is also included.