There are some WIFI related terms that we hear almost daily but don’t have any idea about their meaning.
The following are some basic terms and concepts you’ll need to understand:
Standards and Drafts:
In most cases, when we refer to drafts and standards in this book, we’re referring to IEEE documents, such as IEEE 802.11b. The whole IEEE process for creating a standard is similar to what the US government goes through to change a bill into a law.
There are seven steps the IEEE implements in the standard-setting process:
securing sponsorship, requesting project authorization, assembling a Working Group, drafting the Standard, balloting (75% approval required), review committee, and last, the final vote.
This process usually takes at least 18 months to complete. Drafts are documents that describe that describe the rules by which vendors, developers, and manufacturers must comply when creating products for the identified technology; however, a draft is not the final version.
A draft is a version before the document becomes accepted as the standard. Drafts are like alpha or beta versions of software; the standard is the final version.
A standard may be altered or amended in the future, but not without majority voting consent of the members of that Working Group. Some amendments can amend both the standard and other amendments. Layer 1, layer 2, and layer 3 – these refer to the lowest layers of the OSI model.
The OSI model is a way to develop interoperable systems.
For networking systems, almost everything revolves around the OSI model.
In fact, there are four more layers of Layer 3
Starting with layer 3 (L3) and working down to layer 1 (L1), here are descriptions of what each layer does in regard to basic networking and wireless networking equipment.
Layer 3 –Network Layer:
- Layer 3 (L3) is the Network layer. This is where the network comes together.
- Upper layer applications exchange messages with layer 3.
- IP addressing and subnetting occur here.
- L3 is where you’ll find routers, wireless routers, and L3 switches (switches capable of routing packets).
- L3 and IP subnetting allow one network to talk to other networks, including the Internet. L3 exchanges packets with L2.
L2- The Data Link Layer:
Layer 2 is the Data Link layer or MAC.
- It is made of the Media Access Control (MAC) and the Logical Link Control (LLC) sub layers.
- L2 is where access points (APs), switches, and bridges exist. Devices use MAC addresses here.
- Devices in L2 can’t do routing; that’s left up to L3. L2 exchanges frames with L1.
L1 – The Physical Layer:
Layer 1 (L1) is the Physical layer or PHY. This is where all hardware and cabling fall. L1 exchanges electromagnetic representations of ones and zeros with the medium. Bits become electrons, photons (for fiber networks), or RF (for wireless networks).
To read more about OSI model click here.
The OSI model breaks down different functions and capabilities into seven separate layers. You can’t get to the bottom layer, without going through the other layers first.
The protocols that make each layer, or stack, interoperable, are referred to as the protocol stack.
Terms associated with IEEE 802.11 technologies:
IEEE 802.11b and .11g operate in the same frequency (2.4 GHz) and, since .11g is backward compatible with .11b, the two are often merged together as “802.11b/g” or “802.11bg.”
Sometimes you’ll even see “802.11abg” referring to the lower-layer technologies involved in Wi-Fi solutions: 802.11a and 802.11b/g.
Usage of Meters and Kilometers versus Feet and Miles:
Like many scientific communities, radio people primarily use the metric system when discussing range and distances.
Ham radio operators typically refer to the frequency ranges they are able to use in meter, centimeter, or millimeter terms.
For example, the 144-148MHz ham radio range is called the 2-meter ham band and the 50-54MHz range is called the 6-meter band.
These meter distances refer to the wavelength of the frequency.
A wavelength is a distance a radio wave travels at the time of one cycle. The metric system is more globally accepted than American standard measurements and, since RF is a solution used worldwide, you need to understand it in global terms
Clients are the combined hardware and software solutions that work together to help your computer; PDA, etc. get connected to the wireless network.
Some devices have embedded clients, like Windows XP®’s Wireless Zero Config or a Sony PSP®’s wireless client.
Other devices or operating systems get software installed either before or during the hardware install. You can’t just plug in a PC Card and expect everything to start working unless the system came preconfigured to do so.
The client software lets you configure the necessary parameters so your computer can connect. If security restrictions are enabled on the WLAN, you’ll have to configure them in the client software before being allowed to transmit data across the WLAN.
- This is basically the ability to get data across a communication link as fast as possible
- . A low latency connection for wireless layer 2 links is typically less than 150 milliseconds (ms).
- That means that your packets traverse the communication link in less than .15 of a second.
- This is most important in voice networks where humans can detect delays (drops) of 200ms or higher.
- Worse rates may be acceptable for cellular calls, but they are unacceptable for business IP telephony systems.
This is why it is important to have low latency in enterprise-capable wireless network solutions. SOHO, SMB, and Enterprise solutions.