Some General Technology Information

Overview

Since I claim to provide Technology Services, this document discusses some of the technologies in use out there along with some of the nomenclature. There is a specific focus on Networking. Later I discuss some other technologies available to small businesses today.

Networking Technology

I have broken the discussion about Networking Technology into three sections:

Terminology

Network Categories

Transport Technologies

Terminology

Speed – Network speeds are typically given in Mbps (Mega bits per second). It takes about 8 bits to represent a letter or number (8 bits = 1 byte) so dividing that number by 10 is a good approximation of the MBps (Mega Bytes per second or million characters per second). Note that the difference is the capital “B” (byte) versus a lower case “b” (bit). So a 500K byte (character) document would take about 5 seconds to transfer on a 100Mbps connection.

Multipliers – in case it has been a while since you took physics or studied metric systems, here are the more common multiplier prefixes you will come across in networking:

G – giga – 1000 million (now that's big) – also know as a billion.

M – mega – a million times

K – kilo – a thousand times

Network Categories

From the smallest to the largest perspective, here are some buzzwords that describe networks and their definitions.

• PAN – Personal Area Network - Bluetooth– this is a very short distance technology similar to what you might get from a TV remote control (up to 30 feet). It is typically used for the connection from a computer to a PDA, cellphone, mouse, keyboard or printer. Typical transfer rates are 1 Mbps.
• LAN – Local Area Network. Used in homes, offices and buildings to connect computers that are in a relatively close proximity. Typical transfer rates are from 10 to 1000 Mbps. The most common today is 100 Mbps.
• MAN – Metropolitan area network. City wide (larger than a LAN, smaller than a WAN).
• WAN – Wide area networks. Used to connect sites over long distances (between cities, states or countries).

Transport Technologies

• Ethernet – the most common wired system using Cat5, Cat5e and now Cat6 cables for 10Mbps up to 1000 Mbps. Ethernet cabling can usually reach up to 100 meters (~300 feet).
• Fiber Channel – used for more specialized applications like high speed disk drives and long haul high speed networks. Extremely fast capability >1 Gbps
• Wireless LAN (Wi-Fi) – Wireless Fidelity comes in a few standard flavors and the vendors often enhance these standards with some flavor of their own.
• 802.11a – very uncommon (do not choose this).
• 802.11b – very common – 11 Mbps
• 802.11g – very common and overtaking 802.11b – 54 Mbps
• NetGear and Dlink Super G – 802.11g compatible but can achieve 108Mbps with other similar NetGear products. Linksys (Cisco) has a similar 72Mbps product.
• Mesh networks – peer to peer networks built on demand. For fire / rescue.
• Cellular – A cellular network connected using wireless “cells”. Each cell has a transmitter/receiver (cell tower) that communicates with the local clients (cell phones, laptops, PDA's, etc) in its cell. Each cell covers a 1-2 mile area or distances up to 10 or 20 miles in rural areas. Distance is limited by the power of the phone transmitter. Cell towers can communicate with other cell towers and the switched phone network to complete calls. As you move from one cell to another, the towers hand-off your call to another cell. This used to be a common reason for a dropped call, however, newer technology such as PCS has reduced this problem.
• Cable – Cable networks were originally designed only for television signals transmitted downstream. Due to the high bandwidth of the coaxial cable, the infrastructure was redesigned to incorporate upstream transmission and digital data traffic (as well as digital television traffic). Typical speeds are 1.5 – 3 Mbps downstream and 256K upstream. The downside here is that you share the bandwidth with your neighbors.
• DSL – The phone network using your local phone switching station (usually < 5 miles from your home) has become another mechanism for high speed data communications. DSL modems provide special signaling to get more out of your telephone wires than what the standard phone system uses. Typical speeds are 1.5 – 3 Mbps downstream and 256K-384Kbps upstream.
• Others - T1, T3, T4, X.25..

Security

Firewalls

A firewall is used to block network traffic. For instance, Windows XP comes with a Personal Firewall which blocks incoming traffic from the Internet. A firewall can also block traffic in the outgoing direction for the purpose of limiting connections to certain sites or certain types of traffic. Traffic can be blocked by source address or by traffic type (FTP, HTTP, SMTP, POP3, etc.)

Adware/Spyware/Virus Protection

Adware is software that is usually provided free of charge because it is funded by the (sometimes annoying) adds that it displays. Adware is a form of freeware (software provided free of charge). Proper Adware does not cause any malicious harm but provides an alternative way for funding software development costs (the advertiser pays the developer). It should be capable of being uninstalled leaving no remnants of itself.

Viruses are programs that find their way into your computer through malicious ways such as programs attached to emails that launch when you open them or programs embedded in WEB pages of malicious sites. They can also penetrate networks through security holes and bugs in server software such as Microsoft IIS, chat programs, etc. Viruses are malicious programs whose intention is to cause destruction or waste time.

Spyware are programs that are similar to viruses but whose intentions are to keep track of information or actions on your computer. They have the capability to monitor your keystrokes , scan files on the hard drive , snoop other applications, such as chat programs or word processors, install other spyware programs, read cookies , change the default home page on the Web browser , while consistently relaying this information back to the spyware author who will either use it for advertising and marketing purposes or sell the information to another party.

Yes, you should have Virus/Spyware protection and firewall software protection on your PC. If you have a broadband router connected to your cable modem or DSL router and your computer connects to the broadband router, then you can get away without the firewall, but you still need the virus and spyware protection.

Encryption

Encryption technology (not to be confused with compression which just makes data smaller) is used to secure information as it flows through a network or while it is on a storage device. Encryption technology is what enables secure Internet transactions to occur, although it does not guarantee that the person on the other end of the encrypted channel is going to do the right thing.

Internet Explorer (and other WEB browsers) will display a lock icon on the bottom of a WEB page that is using encrypted technology. It will also display a URL in the address bar that starts with https: instead of http:

VPN – Virtual Private Networks

A virtual private network is a connection that uses any network (such as the Internet) combined with encryption technology to provide a secure connection between two computers (or routers). Using a VPN connection, a user can access resources in your office network such as servers, file shares, printers, and software applications as if the computer they are sitting at is on the network.

Interesting Technologies

• Memory Key – A small semiconductor component that can have from 64Mbytes to 4 GB + of memory in a small device with no moving parts. This is the modern day floppy, but much faster and much more capacity.
• Remote Access – Windows remote access comes standard on Windows XP and Windows Server 2003 (all flavors). This technology provides you with the ability to securely connect to a different computer and control it with the keyboard and mouse of the computer you are sitting on and viewing the remote screen on your local computer. This is similar to a program that has been around for quite a while named “PCanywhere” but is more standard, powerful, and secure.
• Cellular wireless for laptop There are now PC cards available for laptops that connect any laptop computer to the Internet using the cellular network mentioned above. Just like cellphones, they work best outside, but provide speeds averaging 50-100+ Kbps (can you tell me how fast that is?) with peak speeds that can reach 200Kbps. That is better than the average dial-up but shy of the Wi-Fi and LAN speeds of today. Like everything else, they are getting faster and faster (and hopefully cheaper)!
• Network Video Cameras – There are digital surveillance cameras available today that plug right into your network and have WEB servers built into them that provide web access to the view of the camera. They can be used for health care, stores, residential security, etc. These cost around $300 for wireless (802.11b) versions. Test - Now how fast is that?