Organizational Connection Options

Contents

• Audience and Objectives 
• About this document
• Review. 

• Overview
• Types of TCP/IP Networks 
• Current Network Types
• Internet connection points
• VPN

• Internet service providers (ISP) 
• Role
• Virtual domain
• Proxy server
• Co-location

• Audience Issues 
• Types of audiences
• Connection types
• Issues of bandwidth

The connectivity needs of organizations are similar in many to those of individuals, but they differ in volume and the need for reliability. See module NG10c "Internet Connection Options" for details on general connectivity options.

Organizations may also need to have an internal communications network, and when they span large areas, things can get trickier. In this module, we'll look at the ways organizations connect, their relations to Internet Service Providers (ISPs) and issues that arise from differences in audiences.

Overview of Current Network Types 

Local Area Network (LAN)

• Ethernet is dominant on the wires. Speed: 10 megabits per second (10 Mb/sec) is common; 100 Mb/sec preferred
• Wireless networks: 
• via radio frequency (RF)
• via infrared (IR)

Wide Area Network (WAN)

• World-wide; theoretically could extend to interplanetary space. 

Other network terms

• PAN: a Personal Area Network connects devices attached to an individual, such as music devices with headsets, or sensors with eyeglass displays. The most commonly used protocol for PANs is Bluetooth.
• DAN: Domestic Area Networks connect devices in a home or moderate sized building. In addition to computers, DANs can be used to connect security, environment, lighting, and video monitoring systems, as well as various communication and control devices. DANs mainly use IEEE 802.11 protocols, though some use Bluetooth and others use powerline signalling, which transmits over ordinary AC electrical wires.
• MAN: a Metropolital Area Network connects users and devices on a city-wide scale. These could be personal computers or devices used to monitor and manage traffic, public safety, highway or utility crews in a given area. At the time of this writing (mid-2005) several wireless protocols are being deployed, but no single standard has emerged as dominant.

An internet

• Any network designed to bridge two or more other networks

The Internet

• The TCP/IP based, public-access network of networks that spans the globe 

An intranet

• A TCP/IP based, private LAN 
• May give insiders access to the Internet
• Does not allow access from the Internet

A virtual private network (VPN)

• A connection between networks which uses the Internet but is secured from outside snooping or interference
• Has the span of a WAN and the privacy of a LAN or intranet

Internet Connection Points 

Point of Presence (POP)

• POPs provide a local phone number for customers to call
• Each POP has a bank of modems
• Behind each modem is a wide-area network connection to give customers access to the ISP's servers.

Network Access Point (NAP)

Virtual Private Networks 

Why?

What?

A VPN is a connection between networks which uses the Internet but is secured from outside snooping or interference by use of a secure "tunnel". The tunnel is actually a protocol that encrypts packets and sends them "wrapped" in normal Internet packets.

Four needs must be met in setting up a VPN:

1. Authentication: how to I know the message came from the person it says it came from?
2. Access control: how do we keep outsiders out?
3. Confidentiality: how do we keep outsiders from knowing what we're saying— but also, how do we keep our "tunnel" secret, so outsiders won't know where its endpoints are?
4. Data integrity: how do we make sure outsiders don't tamper with our messages?

How?

Why?

Certain types of business groups, for example what are known as "vertical systems," are often close partnerships between different divisions or corporations. These may need to communicate rapidly and securely, and sometimes using the public Internet infrastructure through a VPN doesn't meet the needs.

For example, in closely linked manufacturing processes, real-time monitoring and control over long distances may be necessary. This can't be done reliably over the public Internet infrastructure, because heavy traffic or other problems may prevent critical packets from reaching their destinations in time to control a process safely.

Another instance where an extranet may be used is when security is absolutely critical, as in some government and military "command and control" networks. In this case, the motiviation may be the added security of not sharing public infrastructure, where even though they are encrypted, the packets are out of the control of the authorities.

What?

An extranet is a private network that uses Internet protocols and the public telecommunication system to securely share part of a business's information or operations with suppliers, vendors, partners, customers, or other businesses.

How?

The organizations that need to set up the extranet usually lease communication lines from long-distance communications providers, though they may actually need to lay cable themselves. Both these options are quite expensive, so they aren't normally used unless the expense can be justified on security or financial grounds. The protocols used are the normal Internet protocols, but they are transmitted without interference from other Internet traffic.