What is "Internetworking"?
Let’s make sure we have the horse before the cart. Multiple networks are required to be able to access the global Internet -- i.e. "internetworking" is required. The subject matter of this article is focused on one of these: it is called a "wireless local area network" (LAN). Specifically for this discussion, a local area network (LAN) is setup within a campground to enable the simultaneous access to an Internet Service Provider (ISP) by a number of RVs in a park. In other words, it is a LAN setup for use by a fairly large number of RVers using laptops or desktops from the comfort of their RVs, or virtually anywhere in the park, to be able to surf the web, send/receive e-mail, download/upload files, etc. Access to a LAN can be by a number of means but for this discussion it is by means of wireless technology. The reason for setting up the LAN is as noted to enable connection to the global Internet for accessing information (web sites, e-mail, etc.) and coming voice over Internet. This requires that the LAN interconnect with other networks (known as internetworking) that eventually lead to a connection to the global Internet through an ISP.
What is Wireless Networking?
At its most basic level, it is simply the replacement of a telephone wire with air. More accurately, it replaces the transmission of computer data over copper wires with transmission by radio frequency (RF) signals.
Most laptops have been manufactured since the later part of the 1990s with one or more slots on the side into which a card about 2 x 4 inches can be inserted. These were originally called PCMCIA cards. But thankfully that has been reduced to simply calling them "PC cards". There are PC cards for a number of purposes such as inputting digital photo files from a digital camera, cell phone connection, Ethernet network connection via cable, and most recently the wireless network card. The PC wireless card contains 1-milliwatt (mw) RF transmitter and an antenna. This form factor thus protrudes from the computer slot an inch or so to accommodate these capabilities.
PC wireless cards broadcast to and receive from a device called an Access Point (commercial applications) or Residential Gateway ("RG") (for home networks). The Access Point is a hardware device, which receives and transmits data by RF to and from the laptop. The RG purchased for a home would normally come with capability to use either an Ethernet cable or a standard phone jack to be able to connect to another computer or the telephone company. A standard telephone cable is run from the RG to a telephone jack in the home. When the RG receives a request wirelessly from your laptop to get data or access a web site it automatically dials the number you have preprogrammed into it for your ISP. Thus one can roam around the home or outside in the yard to a certain degree and stay connected to your ISP. RF signals can pass through walls and around other obstructions; although some obstructions will either limit or cause total loss of the RF signal. The less physical obstructions the better the signal strength that can be maintained and is a direct correlation to speed of service available.
In commercial applications such as campgrounds Access Points would be used. Access Points with up to 100 mw of RF power can range up to 1000 feet in non-obstructed areas and can be used in multiple numbers in overlapping patterns to create a seamless pattern covering a large area, such as a campground. The Access Points are normally wired by an Ethernet cable to a computer which is set up to allow multiple simultaneous internet connections. (For more detailed discussion of operation the more detailed description of "How Does A Wireless Network Work?") and is in turn wired to some sort of high-speed bandwidth service such as xDSL (a number of types of DSL are available and x simply denotes the general service) using standard telephone wiring or a satellite service such as Hughes Direcway. The DSL line or satellite connects the computer to the ISP. A satellite may be necessary when a park is beyond the maximum service distance of DSL or telephone line conditions are poor. DSL rates are not guaranteed but are dependent upon the line conditions present. The equipment determines the conditions at time of each connection and then sets a rate ranging from 32Kbps to 6.4 Mbps* (see definitions below). The service normally provided is asynchronous and thus labeled ADSL. This means that the rate of download is much faster than upload. In fact, the upload is generally 32Kbps to 640 Kbps vs. downloads of 32 Kbps to 6.4 Mbps. The relatively slower upload speed is not generally a problem with consumer use of the service, because downloads are likely to be graphic intensive web sites or large data downloads while uploads are likely to be short instructions such as requesting the web site. Satellite service is asynchronous as well. Downloads of 400-1500 Kbps vs. uploads of 64Kbps.
What constitutes a wireless network?
I have mentioned above the hardware aspect of wireless computing, i.e. the use of a PC wireless card (or a network adapter in case of desktop) and an Access Point. Wireless network design comes in several flavors. Two modes of connection exist in the wireless environment -- Peer to Peer and Infrastructure. Infrastructure mode is the one used in campgrounds and will be discussed below.
Infrastructure mode means that each wireless client computer (laptop/desktop) associates itself with an Access Point via RF signal transmission in the 2.4GHz* range. (This is the same frequency range used by such more familiar devices as your home hand held remote telephone receiver and microwave oven.) This is the mode in use today in RV parks, offices, homes, hotels, airports, coffeehouses, ad infinitum. The Access Point then serves two purposes. It forms the bridge to Internet connectivity for these computers and/or it enables the communication between these client machines while acting as a hub, thus permitting them to be able to share files and printers.
As mentioned above, wireless technology design is radio frequency based. The design of these wireless devices is therefore governed by the Institute of Electrical and Electronic Engineers (IEEE) specification called 802.11. At present, 802.11b is the specification to which most devices conform; it covers a bandwidth capability of 11Mbps. However, the 11 Mbps is not available to a user unless you’re the only person on the air. It is a shared resource. The use of multiple AP’s in a park increases the available bandwidth since each AP can provide the 11Mbps. It’s successor 802.11g, which will provide a bandwidth of up to 54 Mbps, is just beginning to show up in devices for sale but hasn’t been officially released at this writing. However, there appears to be little risk in purchasing these devices and if one is in the market for wireless components one would be well advised to look at 802.11g; it should be backward compatible to 802.11b if that is of concern. Note: 802.11a devices are just emerging as well. These devices are for corporate networks and operate at 5GHz and are not compatible with 802.11b or 802.11g, both of which are at 2.4GHz. A second important point is to realize that the LAN speed far exceeds the best ADSL speeds. The best ADSL speed being 6.4 Mbps vs. the 802.11b LAN of 11Mbps. So, while communication between computers on the LAN can go at 11Mbps, the speed out to the Internet is much more restrictive. Said otherwise, the campground's DSL connection will be the weakest link in terms of what the RVer ultimately sees as the "speed" of his or her wireless internet service.
When purchasing wireless equipment, one should make sure that the equipment bears the logo shown below which indicates it has been tested by an independent lab tasked with assignment to certify operability between the various suppliers of equipment.
What about Security (Privacy)?
Install a wireless PC card into your laptop PCMCIA slot and you are in the RF broadcasting business. How far is dependent upon the environment. Clear line of sight outdoors may be as far as several hundred feet as noted above. Because 802.11b transmissions cannot be picked up by simple scanners or receivers, this has mislead many users into thinking their information is secure. However, anyone driving along in a car with a PC wireless card installed in their laptop may use the wireless network connection software, or a special software such as one called NetStumbler, to pick up any existing wireless signal and access the transmitting computer though the open network. In fact, a geocachhing-like sport, called "war driving", has emerged involving people driving or walking in residential neighborhoods or business districts trying to lock on to open networks and access private data or just take advantage of a free Internet service. At a recent Las Vegas electronic trade show, a group of attendees decided to test the area to see how simple or difficult it might be to find open networks. The answer was not difficult at all. They found literally hundreds of open networks. The existing security in 802.11b specification is weak; but if applied will at a minimum make these folks job tougher. This security is called Wired Equivalent Privacy (WEP). Turning on WEP to require an encryption key is step one. It is also highly desirable to install a firewall such as the top rated Zone Alarm that can be downloaded free.
Tom has written an article on this web site about how easily he was able to connect at Buckhorn Lake RV Park in TX. Tom uses Apple MacIntosh laptops. Apple Mac laptops have had built in wireless capability for some time. This capability involves software as well as hardware. An antenna is incorporated into the case and is therefore not visible. Apple trade named this capability "Airport", but for all practical purposes it is identical to the PC card capability described above. Toshiba has recently introduced a laptop (Satellite Pro 6100 series) with 802.11b capability as well as 802.11a. (Again, 802.11a is a corporate specification running at 5 GHz and thus not compatible with 802.11 b or 892.11g which operate at 2.4GHz)
More importantly the market place is driving software solutions for making a painless connection to a wireless network. Wireless networks are being deployed at a furious pace and for users to be able to take advantage of this capability and make it an economically viable business for those deploying the infrastructure the connection process must be made virtually transparent. Business Week (April 7, 2003) had an item on a company named PCTEL, which is providing a product to Dell Computer; that was described as “software (that) lets users move freely, from one wireless network to another”.
Bottom line seems to be that those of us with older non-Mac laptops will have several possible routes to follow. We may be able to connect to a park LAN by setting our TCP/IP properties to obtain IP automatically and using the user name and password provided by the park or the parks LAN provider as discussed in Tom’s article. A second method may require some manual changes in these properties using instructions provided by the park. (Note – These type of changes may require the insertion of your operating system disc at some point in the install process so it’s a good idea to take it with you.) Finally, it may be that one can look forward to a day when some software company sees a market for ease of use software to access LAN’s for existing hardware and brings a product to market to do just that. (Ever the optimist)
Definitions
GHz Pronounced "gigahertz" (a measure of frequency in cycles per second)
G = giga = 1 billion = 1,000,000,000
Hz = Hertz
Kbps Pronounced as "kilobits per second" Connection Speed
K = Kilo = 1 thousand = 1,000 bps = bits per second
Mbps Pronounced as "megabits per second" Connection Speed
M = Mega =1,000,000 bps
Bit A single digit in computers either a 1 or 0.