Wireless LAN@Home, Part I - Wi-Fi is Wining, Bluetooth and HomeRF are Fighting
25 April 2006Starting from year 2000, the installation base of broadband Internet connection at home is escalated. Statistic also shows that more and more family own more than one PC. Home LAN (local area network) is definitely and obviously the next consideration for those PCs.
When talking about connection, communication equipment and PC at home, it always involves wires, sockets, connectors, technical jargons and the works to put them together. Not mention the frustrations encountered to the non-computer-savvy people.
Just thinking about how many wires we have at home, there are phone lines, cable TV lines, speaker wires and of cause, power lines. If you did not build the house yourself, certainly once a while you need spend time for some do-it-yourself wiring works.
Another cable for PC?!
Now, let’s put the end of it.
The advancing of technology brings to market a wonderful breed of products that enable computers and even home appliances connection to each other, oh yes, wirelessly with reasonable cost. They are Wi-Fi, Bluetooth and HomeRF, weird names though.
In this article, I will focus on Wi-Fi because this technology is relatively mature and it is wining the competition. It also has a long list of products available from varieties of well-known vendors. Bluetooth, as a hot technology baby, is making the first set of steps all by itself and soon to be a hyper noise young adult. But seems it’s walking into a different area than Wi-Fi’s and claim as an owner: consumer electronics and home appliances. As for HomeRF, I announce it’s a loser.
Technical Background
The term “Wi-Fi” is used in place of IEEE 802.11b HR, as “Ethernet” is used instead of IEEE 802.3. So, if you are familiar with Ethernet already, it’s time to know Wi-Fi only because it will rule the LAN world in the near future.
Wi-Fi products are based on the IEEE 802.11b WLAN standard, which operates in the worldwide 2.4 GHz Industry, Science, and Medicine (ISM) band. The WECA (Wireless Ethernet Compatibility Alliance) is the nonprofit organization to certify interoperability of Wi-Fi products and to promote Wi-Fi as the global, wireless LAN standard across all market segments. It was formed in 1999, initially by 3Com, Cisco Systems, Intersil, and Lucent Technologies. Now there are more than 60 major network companies become member of WECA and the member base is growing.
Wi-Fi is aiming at both business and consumer market. It could be the replacement or extension of existing Ethernet based LAN.
If you a bit about modern network technology, you must know the seven (7) ISO layers. IEEE 802.11b, as Wi-Fi standard, is defined at the Physical (PHY) layer and Medium Access Control (MAC) sub-layer.
There are two major technology differences between wired and wireless Wi-Fi LAN. They are Network Topology and Radio Technology.
Network Topology
In wired LAN, topology is an essential architecture consideration. Ring (Token-Ring) or Bus (Ethernet), it was used to be a big question. Alone with Ethernet dominating the LAN world, there are more questions because topology also determine the connecting media. We have 1Base5 (UTP star topology), 10Base5 (tick coaxial bus topology), 10Base2 (thin coaxial bus topology), 10BaseT (UTP star topology), fiber (FDDI) and couple of others. There are different types of category for UTP, which replaced coaxial in most of local LANs.
In Wi-Fi wireless LAN (WLAN), I would say the topology concept is not significant any more. The only reason we still mention topology with WLAN is because it’s a big deal with Wi-Fi’s ancestor, Ethernet. When the air is the connection media, how would we talking about topology?
There are and will be many writings talking about the benefits of using wireless LAN in business or at home. But I think it’s saying all when you compare one breathes through a pipe that inserted into his noise and one breathes in the open air.
Radio Technology
We can eliminate the jargon Topology, but the core part of Wi-Fi is something not exists with Ethernet, the Radio Technology.
IEEE 802.11 defines two (2) radio technologies namely Direct Sequence Spread Spectrum (DSSS), and Frequency Hopped Spread Spectrum (FHSS). The details of these technologies are beyond this paper and my interests. It just always amazes me that there are such complex technologies that deal with invisible things in the air.
The Connection
As I mentioned above, there are no such thing called topology in Wi-Fi WLAN, but still, there are couple of unique equipments that you need to build a WLAN. It will be more involved and complicate when extending existing wired LANs in business area. But that can be taken care of by money. At home, with limited resource, things might be different. Fortunately, Wi-Fi is also a simple and flexible technology when apply it to a relatively isolate small area, home. That’s the beauty of Wi-Fi.
In WLAN, a group of connected computers is called Basic Service Set (BSS). In an isolate area such as home, a WLAN is sometimes called an Ad Hoc network. That is because there is not physical connecting between two computers. When one party of the connection is removed from home, the network is gone too. As always, there is a term for such network, Independent Basic Service Set (IBSS).
As illustrate in above diagram, there are three (3) components to form a computer WLAN. They are Access Point (AP), Station and Wireless Net Card.
Access Point (AP)
It is also called Internet/Network Gateway by some vendors. You only need it when you want to connect all you computer to outside network, say Internet. A BSS does not have to have an AP. When there is no AP in the WLAN, the IBSS is formed as peer-to-peer based connection. A BSS has a AP is said to be operating in the infrastructure mode.
Station
It’s a computer for a simple computer network. It could be any equipment connects to the WLAN wirelessly.
Wireless Net Card
To enable you computer join the wireless network, just like in wired LAN, you need a card plug into your computer. In this case, it’s card sending wireless signal.
That’s it. It’s hardly to say that you have a network set up since there is no wire, but you are definitely connected with just the above components.
The Concerns: Reliability, Security and Money
Everybody is worried about the cutting-edge technology would turning into bleeding-edge. Wi-Fi, as very young technology, is reliable enough for purchase consideration? I think it’s a yes.
WECA had setup a vigorous certification program to certify Wi-Fi products. They says that any product designated with a Wi-Fi logo has been qualified to assure interoperability between PC wireless LAN cards, devices and access points from different vendors. Such PC products include PCMCIA cards for notebooks, ISA and PCI cards for desktops, and Universal Serial Bus (USB) modules that can be used with either platform.
Companies whose products have received Wi-Fi-certification include 3Com, Cisco Systems, Compaq, Intel, Nokia, and Samsung.
Another issue, since your data will be send into the open air, is it secure? Well, security is always a double blade sword. One side, no matter what you do, you just can’t have enough it. On another side, there is cost.
IEEE 802.11 provides two security methods: authentication and encryption.
Authentication is the means by which one station is verified to have authorization to communicate with a second station in a BSS. In the infrastructure mode, authentication is established between an AP and each station. The encryption of Wi-Fi uses the RC4 PRNG algorithm from RSA Data Security, Inc.
For home usage, I think all above are secure enough for most of home network. If you truly believe resources and money will be spent to break into your WLAN and decrypt your data, and your data worth it, more money will help.
Now, the last issue, money. Currently, the cost of wireless card and AP is in the $150 - $400 range. Quite expensive comparing to Ethernet card. But the price will be decrease rapidly towards year-end while more Wi-Fi products brought to market every day.
Very soon, there will be no wire.
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