Chapter 2

Describe Personal Computer Memory Card International Association (PMCIA) cards/PC Card

- A credit card-sized peripheral that slides into a slot on a laptop computer can add additional functionality to the laptop, much like a card can be inserted into the bus expansion slot on a desktop computer - Defines 3 form factors for 3 types of PC cards. All 3 card types are the same length (85.6 mm) and width (54 mm) and use the same 68-pin connector. The cards only differ in their thickness * Pg. 48 details length, width, thickness, and typical uses of PC card types

Describe CompactFlash (CF)

- A small form factor (43 x 36 x 3.3 mm for Type I, and 43 x 36 x 5 mm for Type II) card that is generally used as a mass storage device format for portable electronic devices - Used as a storage medium for digital cameras for several years, although it is being replaced by smaller cards - Primarily designed for use in personal digital assistant (PDA) devices

Describe the IEEE 802.11 standard

- A standard for WLANs operating at 1 and 2 Mbps - Specified that wireless transmission could occur in one of two ways: via infrared light OR radio waves (preferred)

Describe the IEEE 802.11n-2009 standard

- An updated version of the IEEE 802.11-2007 standard that was intended to usher in the next generation of WLAN technology - It includes the following improvements over previous standards: 1. Speed (data rate of up to 600 Mbps) 2. Coverage area (double the indoor range and triple the outdoor range) 3. Interference (uses different frequencies to reduce interference) 4. Security (requires the strongest level of wireless security)

Describe Mesh Access Points

- Each mesh access point communicates wirelessly with the next closest mesh access point. Dozens—or even hundreds—of mesh access points can communicate between themselves to create a wireless mesh network (WMN) - Only one mesh access point must be physically connected to the wired network; all the other mesh access points transparently connect, or hop, through each other to reach the mesh access point with the wired connection. This arrangement allows for multiple inter- connected paths through which the signal can reach the mesh access point that is connected to the wired network

Describe Residential WLAN gateways

- Entry point into the wireless network from the Internet. However, most vendors instead choose to label their products as "wireless broadband routers." - Complemented by new software functions that simplify the management and functionality of these devices. For example, Windows 7 added two significant wireless functions to its operating system. One function, Windows Connect Now, or WCN, is a solution for home networking and SOHOs. (WCN is not intended for enterprises.) A Windows 7 computer can scan the airwaves for a newly installed WCN capable device, such as an AP. When the device is detected, the user can simply enter a personal identification number (PIN) from the hardware device - The second wireless function added to Microsoft Windows 7 is the wireless Hosted Net- work. This feature has two parts: the virtualization of the physical wireless NIC into multiple virtual wireless NICs (called Virtual WiFi) and a software-based wireless access point (SoftAP) that uses a designated virtual wireless NIC. The wireless Hosted Network allows users to extend the functionality of their portable laptop computer. For example, a user could set up her computer to create a wireless network so that other users can quickly share documents wirelessly between multiple computers. Another function allows a laptop's network connection to be shared by other computers and devices. For example, a user could connect her computer to the Internet and then turn her computer into an AP that shares the Internet connection with other wireless laptop devices, much like a hardware AP

Describe Power over Ethernet (PoE)

- Instead of receiving power directly from an alternating current (AC) electrical outlet, direct current (DC) power is delivered to the AP through the unused wires in a standard unshielded twisted pair (UTP) Ethernet cable that connects the AP to the wired network - Eliminates the need for installing electrical wiring and makes mounting APs more flexible - The current PoE standard is IEEE 802.3at-2009 - There are 2 common approaches: 1. PoE-enabled Ethernet Switch 2. PoE Injectors

Describe Lightweight Access Points

- Lighter version of standard APs, in that it does not contain the management and configuration functions found in autonomous access points; instead, these features are contained in a central device known as a wireless LAN controller (WLC), or wireless switch - The WLC is the single device that can be configured and then these settings are automatically distributed to all lightweight access points - Centralized

Describe Enterprise Encryption Gateways

- Provides encryption and authentication services for a wireless network - Typically resides between the wireless network and the wired network and serves as the entry point to the wired network - Its purpose is to relieve an AP from the burden of encryption and authentication - Also serves the reverse function, decrypting traffic as it arrives from the WLAN - Can even authenticate devices on the WLAN and approve or deny their access into the wireless network

Describe the IEEE 802.11b standard

- Revisited version of IEEE 802.11 since 2 Mbps speeds were deemed too slow - It serves as an amendment to 802.11 and adds two higher speeds: 5.5 Mbps and 11 Mbps to the original 802.11 standard of 1 Mbps and 2 Mbps - Supports wireless devices (officially known as a station or STA) that are up to 250 feet apart - As wireless devices are moved farther apart, the rate at which the data is transmitted between devices will decrease (radio waves decrease in power over distance). Other factors that impact transmission include the number of wireless devices and type of obstruction between devices

Describe the IEEE 802.11a standard

- Sister version of 802.11b standard, which specifies a maximum rated speed of 54 Mbps and also supports 48, 36, 24, 18, 12, 9 and 6 Mbps transmissions using a different set of radio wave frequencies than 802.11b - Came into the market later than 802.11b due to technical issues and high cost - Devices who use this standard cannot use complementary metal oxide semiconductor (CMOS), which is the semiconductor used in 802.11b WLANs - Achieves higher speeds than 802.11b, but at the cost of distance. Devices who use this standard can be no more than 100 feet apart

Describe the IEEE 802.11g standard

- Updated version of 802.11b and 802.11a, also known as the "best of both worlds" - Preserves the stable and widely accepted features of 802.11b, but increase the data transfer rates to those similar to 802.11a - Supports a maximum data speed of 54 Mbps, with lesser speeds of 48, 36, 24, 18, 12, 9, and 6 Mbps - Specifies that devices operate in the same radio frequency as IEEE 802.11b and not the frequency used by 802.11a - Can support devices that are up to 350 feet apart

What are the 2 basic functions of an Access Point (AP)?

1. Act as the base station for the wireless network 2. Act as a bridge between wireless and wired networks

Currently no standards exist for WMNs. The IEEE 802.11 TG subgroup "s" started work on developing standards in 2003 and is still working on the project. In the interim, over 70 competing WMN routing protocols are available. These protocols differ over?

1. Algorithm 2. Management data vs. transmit data 3. Number of radios

What are the 3 major parts of an Access Point (AP)?

1. An antenna and a radio transmitter/receiver to send and receive wireless signals 2. Special bridging software to interface wireless devices to other devices 3. A wired network interface that allows it to connect by cable to a standard wired network

What are the 3 types of Access Points (APs)?

1. Autonomous access points 2. Lightweight access points 3. Mesh router access points

What are the advantages of Radio Waves?

1. Can penetrate objects like walls and allow the wireless user to be mobile 2. Travel longer distances (compared to infrared) and can be used outdoors as well as indoors 3. Can travel at much higher speeds than infrared transmissions * Preferred method for wireless LANs

List all Small Form Factor Cards:

1. CompactFlash (CF) 2. Secure Digital (SD)

What are the 2 terms used for measuring wireless network speeds?

1. Data rate 2. Throughput

What are the 3 sources of Standards?

1. De facto standards 2. De jure standards 3. Consortia-created standards

What are the 4 standards for wireless LANs?

1. IEEE 802.11 2. IEEE 802.11b 3. IEEE 802.11a 4. IEEE 802.11g * These have been combined and implemented into 802.11-2007

Remote wireless bridges have significant differences from APs or wireless workgroup bridges. These differences include:

1. Increased power 2. Direction antenna 3. Special software

What are some of the advantages of Standards?

1. Interoperability 2. Competition 3. Lower costs 4. Protection

What are the limitations of infrared wireless systems?

1. Lack of mobility (directed transmissions require an obstruction-free line of sight path) 2. Limited range 3. Confined to indoor use 4. Slow transmission speed (no higher than 4 Mbps)

What are the advantages to using mesh access points to create a Wireless Mesh Network (WMN)?

1. Low-cost installation 2. Large coverage area 3. Easy-to-change coverage area 4. Can be installed in areas without wired infrastructure 5. Self-configuring WMN 6. Self-healing WMN 7. Fast installation

List all Internal Cards:

1. PCI 2. PCI-e 3. Mini-PCI 4. Mini-PCI-e

List all Large Form Factor Cards:

1. PCMIA (Personal Computer Memory Card International Association Card)/PC Card 2. CardBus 3. ExpressCard

What are the 2 types of connections remote wireless bridges support?

1. Point-to-Point (PtP—two buildings are connected) 2. Point-to-Multipoint (PtMP—multiple buildings are connected)

A remote wireless bridge can function in one of four different mode:

1. Root mode 2. Nonroot mode 3. Repeater mode 4. Access point mode

Wireless NICs for laptops are available as?

1. Type II PC Cards 2. CardBus 3. ExpressCards

What is 802.11-2007?

A combination of standards and amendments that have been concentrated into a single standard. It includes the following: 1. IEEE 802.11-1999 2. IEEE 802.11a-1999 3. IEEE 802.11b-1999 4. IEEE 802.11d-2001 5. IEEE 802.11g-2003 6. IEEE 802.11h-2003 7. IEEE 802.11i-2004 8. IEEE 802.11j-2004 9. IEEE 802.11e-2005

What is a Bridge?

A device that is used to connect two network segments, even if those segments use different types of physical media (such as wired and wireless connections)

What is a Gateway?

A network device that acts as an entrance to another network. There are two types: 1. Enterprise Encryption Gateways 2. Residential WLAN gateways

What is a Secure Digital Input Output (SDIO) device?

A variation of an SD card, which is a combination of an SD card and an input/output (I/O) device such as a wireless NIC. It was primarily designed for use in PDA devices

What is the Wireless Zero Configuration (WZC) service?

A wireless connection management utility that operates as a Windows service and interacts with the client hardware NIC drivers. It automatically determines which wireless network to connect to based on default settings and preferences set by the user. It was replaced by WLAN AutoConfig since it had security weaknesses and limited functionality

Explain 802.11g's mixed mode

Although both 802.11b and 802.11g devices can function together on the same wireless network, the presence of any 802.11b device will cause the network to decrease its data rate to only 802.11b speeds

What is a CardBus?

An enhanced type of PC card that is a 32-bit bus in the PC Card form factor. It includes a bus mastering feature, which allows a controller on the bus to talk to other devices or memory without going through the CPU

What is a Secure Digital (SD) card?

Another small form factor (32 mm 24 mm 2.1 mm) card that started as a portable storage device for digital cameras and PDAs

What is an Ad Hoc Wireless Mesh Network?

Another type of wireless mesh network where instead of mesh access points communicating with each other, wireless client devices like laptop computers act as the relay station for signals to and from the AP, with the signal hopping through the wireless clients

Why is Lower Costs an advantage of Standards?

Competition results in lower costs for both users and manufacturers. When several vendors make similar products based on the same standards, they compete against each other on the price, which in turn makes the product less expensive for users. Competition also results in lower costs for manufacturers. Because standards have been established, manufacturers do not need to invest large amounts of capital in research and development. This reduces start-up costs as well as the amount of time required to bring a product to market. Also, manufacturing to standards encourages manufacturers to deploy mass-production techniques and economies of scale to keep production costs low, with savings that in turn are passed on to users

WLANs are based on what standards?

De Jure Standards

What are De Facto Standards?

Despite the name, they are not standards, but instead are common practices that the industry follows for various reasons (such as ease of use, tradition, or what the majority of users choose to do). They are established by success in the market

Infrared transmissions can either be?

Directed or Diffused

WLAN standards are set by the...

Institute of Electrical and Electronics Engineers (IEEE). There currently is one wireless LAN standard, IEEE 802.11-2007, and one significant amendment, 802.11n-2009

Most laptop computers today come with a wireless Mini-PCI or Mini-PCI-e network interface card installed because?

Laptop computers do not have full-size PCI or PCI-e slots

One of the limitations of consortia is?

Membership is not always be open to everyone who wants to participate

The hardware that a desktop or laptop client computer needs to send and receive data on a wired network is called a?

Network interface card (NIC) or client network adapter

What are De Jure Standards?

Official standards that are controlled by an organization or body that has been entrusted with that task

What are Consortia-created standards?

One of the complaints against de jure standards is the amount of time it takes for a standard to be completed. In reaction to this, consortia sometimes take on the task of creating standards. Consortia are usually industry-sponsored organizations that want to promote a specific technology. The goal of consortia is to develop a standard that promotes a specific technology in a short period of time

Explain 802.11g's B-only mode

Only 802.11b devices are recognized and 802.11g devices are ignored

Explain 802.11g's G-only mode

Only 802.11g devices are recognized and 802.11b devices are ignored

Why is PCI being replaced with PCI Express (PCI-e)?

PCI-e has a high-speed point-to-point serial bus replacement of the older shared parallel PCI bus architecture

Desktop computers typically have one or more ____ expansion slot inside the computer to make it possible to add devices to the system

Peripheral Component Interconnect (PCI)

A ____ is a small, inexpensive device that can inject power into an Ethernet cable. These injectors can be endspan devices (such as a network switch enabled to provide power on each port) or a midspan device, which is connected inline to each end device and adds power to the line. Using PoE injectors, a standard, non-PoE-enabled Ethernet switch can be used to supply the data while the PoE injector provides the power. Positioned between the switch and the end device, the PoE injector is connected to both the switch and end device. Typically PoE injectors can provide power to a single cable (single port PoE injectors) or to multiple cables simultaneously (multiport PoE injectors)

PoE injector

A ____ can contain embedded PoE technology, called power sourcing equipment, or PSE, that provides both electrical power and data. Nothing more must be done other than connecting the device to the switch with an Ethernet cable. End devices that can support PoE send the switch an authenticated PoE signature that indicates that they do support this technology, which helps prevent damage to other equipment. Once the switch knows that the device is PoE compliant it sends power along one pair of unused wires in the cable. In addition, the switch will discontinue the power when the PoE device is disconnected

PoE-enabled Ethernet switch

Early NICs were separate cards that had one edge connected to the expansion slot of the computer's bus (the subsystem for transferring data between the system's components), while the ____ connection on the other end provided access for a cable connection

RJ-45

Why is Interoperability an advantage of Standards?

Standards ensure that devices from one vendor will function with those from other vendors. Devices that are not based on standards often cannot interoperate with similar devices from other vendors

Why is Protection an advantage of Standards?

Standards help protect the user's investment in equipment. It is not uncommon for a proprietary vendor to phase out a product line, leaving a business that purchased the equipment with two choices: continue to use the now-obsolete system with escalating costs for supplies and technical support, or discard the legacy system and buy a new system. Both choices are costly. Standards, however, can help create a migration path for equipment upgrades. Newer standards are generally backward compatible or at least provide a means of migrating to equipment based on the newer standards at a minimal cost

Why is Competition an advantage of Standards?

Standards serve to create competition. If a vendor creates a new device without regard to current standards, then it automatically owns the specifications for the device; the vendor might even take out a patent on the device. This makes it virtually impossible for another vendor to produce the same device; thus, competition among multiple vendors selling the same device is impossible. From the point of view of the consumer, standards are desirable because they encourage competition. Any vendor can create a device based on a recognized standard. In order to compete, vendors will add additional features to their products, thus increasing the overall value for users

What is Throughput?

The measure of how much actual data can be sent per unit of time across a network. Throughput is often used to measure the amount of data actually sent across a network in a real world setting. If two 802.11 devices are 30 feet (10 meters) apart, the throughput may only be 5.5 Mbps

What is ExpressCard?

The technology that is replaced PC card and CardBus. It is designed to deliver higher-performance modular expansion in a smaller size. There are two standard ExpressCard form factors: the ExpressCard/34 module (34 mm 75 mm) and the ExpressCard/54 module (54 mm 75 mm). Both formats are 5 mm thick (the same as the Type II PC Card) yet 10.6 mm shorter than a PC Card

What is Data Rate?

The theoretical maximum rated speed of a network. For example, the data rate for IEEE 802.11b is 11 Mbps. However, the data rate is only theoretical. Due to a variety of factors, a network rarely achieves its stated data rate

What are Autonomous Access Points?

These devices are considered autonomous, or independent, because they are separate from other network devices and even other autonomous access points. They have the intelligence required to manage wireless authentication, encryption, and other functions for the wireless client devices that they serve. Because everything is self-contained in these single devices they are also called fat access points

In ____, a remote wireless bridge functions as a normal AP only and does not communicate with other remote wireless bridges; instead, it only communicates with wireless client devices such as laptop computers

access point mode

Standard APs are known as ____?

autonomous access points

A wireless mesh network (WMN) that connects mesh access points for the purpose of sharing an Internet connection is also known as a ____?

backhaul wireless mesh network

A ____ relies on reflected light. The emitters on diffused transmissions have a wide-focused beam instead of a narrow beam and are pointed at the room's ceiling, which serves as the reflection point. When the emitter transmits an infrared signal, the signal bounces off the ceiling, expanding (called diffusing) to filling the room. The detectors—pointed at the same reflection point—can then pick up the reflected signal

diffused transmission

A ____ requires that the emitter and detector be directly aimed at one another in a line of sight (LoS) path

directed transmission

If someone wants to To transmit a 1 via infrared transmission, an ____ (a device that transmits a signal) increases the intensity of the current and sends a pulse using infrared light. At the receiving end, a detector (a device that receives a signal) senses the higher intensity pulse of light and produces a proportional electrical current

emitter

Infrared transmissions send data by the ____ of the infrared light wave instead of turning the light off and on

intensity

In ____ mode, a remote wireless bridge can transmit only to a bridge that is in root mode. Although some remote wireless bridges in nonroot mode can also be configured as an AP to simultaneously communicate with a remote wire- less root bridge and wireless clients, this is discouraged for security purposes.

nonroot

A ____ connects two or more networks together that are separated by a longer distance. They are used to connect networks between different buildings

remote wireless bridge

In order to enhance the signal strength between buildings, another remote wireless bridge may be positioned between two other bridges. This bridge then functions in ____

repeater mode

WLANs were designed to...

replace or supplement a wired local area network (LAN)

In ____, a remote wireless bridge can communicate only with other bridges that are not in root mode. When in root mode, the remote wireless bridge is called a root bridge. There must be one (and only one) root bridge in a PtP or PtMP configuration, and it cannot communicate with another root bridge or a wireless client

root mode

A ____ may be thought of as a model that is used for comparison

standard

A ____ performs the same functions as a wired NIC with one major exception: there is no external cable RJ-45 connection. In its place is an antenna (sometimes embedded into the adapter) designed to send and receive signals through the airwaves

wireless client network interface card adapter

A ____ is used to connect a wired network segment to a wireless network segment

wireless workgroup bridge