Netgear Router WGT624 V3 User Manual

							Reference Manual for the 108 Mbps Wireless Firewall Router WGT624 v3
Glossary-7
202-10090-01, April 2005
IP (Internet Protocol) address 
A 32-bit number that identifies each sender or receiver of information that is sent across the Internet. An IP 
address has two parts: an identifier of a particular network on the Internet and an identifier of the particular 
device (which can be a server or a workstation) within that network. 
ISO Network Model 
A network model developed by the International Standards Organization (ISO) that consists of seven 
different levels, or layers. By standardizing these layers, and the interfaces in between, different portions of 
a given protocol can be modified or changed as technologies advance or systems requirements are altered. 
The seven layers are: 
• Physical 
• Data Link 
•Network 
• Transport 
• Session 
• Presentation 
• Application 
The IEEE 802.11 Standard encompasses the physical layer (PHY) and the lower portion of the data link 
layer. The lower portion of the data link layer is often referred to as the Medium Access Controller (MAC) 
sublayer. 
MAC (Media Access Control) 
Every wireless 802.11 device has its own specific MAC address hard-coded into it. This unique identifier 
can be used to provide security for wireless networks. When a network uses a MAC table, only the 802.11 
radios that have had their MAC addresses added to that networks MAC table will be able to get onto the 
network. 
Mesh Networks 
Also called mesh topology, mesh is a network topology in which devices are connected with many 
redundant interconnections between network nodes. In a full mesh topology every node has a connection to 
every other node in the network. Mesh networks may be wired or wireless.  
						

							Reference Manual for the 108 Mbps Wireless Firewall Router WGT624 v3
-8Glossary
202-10090-01, April 2005
In a wireless mesh example, each of the spheres below represent a mesh router. Corporate servers and 
printers may be shared by attaching to each mesh router. For wireless access to the mesh, an access point 
must be attached to any one of the mesh routers. 
Multiple Input Multiple Output (MIMO)
MIMO refers to radio links with multiple antennas at the transmitter and the receiver side to improve the 
performance of the wireless link. 
NAT (Network Address Translation) 
A network capability that enables a houseful of computers to dynamically share a single incoming IP 
address from a dial-up, cable or xDSL connection. NAT takes the single incoming IP address and creates 
new IP address for each client computer on the network. 
Network name 
Identifies the wireless network for all the shared components. During the installation process for most 
wireless networks, you need to enter the network name or SSID. Different network names are used when 
setting up your individual computer, wired network or workgroup. 
NIC (Network Interface Card) 
A type of PC adapter card that either works without wires (Wi-Fi) or attaches to a network cable to provide 
two-way communication between the computer and network devices such as a hub or switch. Most office 
wired NICs operate at 10 Mbps (Ethernet), 100 Mbps (Fast Ethernet) or 10/100 Mbps dual speed. 
High-speed Gigabit and 10 Gigabit NIC cards are also available. See PC Card. 
PC card (also called PCMCIA) 
A removable, credit-card-sized memory or I/O (input/output) device that fits into a Type 2 PCMCIA 
standard slot, PC Cards are used primarily in PCs, portable computers, PDAs and laptops. PC Card 
peripherals include Wi-Fi cards, memory cards, modems, NICs, hard drives, etc. 
PCI adapter 
A high-performance I/O computer bus used internally on most computers. Other bus types include ISA and 
AGP. PCIs and other computer buses enable the addition of internal cards that provide services and features 
not supported by the motherboard or other connectors. 
Peer-to-peer network (also called Ad-Hoc in WLANs) 
A wireless or wired computer network that has no server or central hub or router. All the networked PCs are 
equally able to act as a network server or client, and each client computer can talk to all the other wireless 
computers without having to go through an access point or hub. However, since there is no central base 
station to monitor traffic or provide Internet access, the various signals can collide with each other, reducing 
overall performance. 
PHY 
The lowest layer within the OSI Network Model. It deals primarily with transmission of the raw bit stream 
over the PHYsical transport medium. In the case of wireless LANs, the transport medium is free space. The  
						

							Reference Manual for the 108 Mbps Wireless Firewall Router WGT624 v3
Glossary-9
202-10090-01, April 2005
PHY defines parameters such as data rates, modulation method, signaling parameters, transmitter/receiver 
synchronization, etc. Within an actual radio implementation, the PHY corresponds to the radio front end and 
baseband signal processing sections. 
Plug and Play 
A computer system feature that provides for automatic configuration of add-ons and peripheral devices such 
as wireless PC Cards, printers, scanners and multimedia devices. 
Proxy server 
Used in larger companies and organizations to improve network operations and security, a proxy server is 
able to prevent direct communication between two or more networks. The proxy server forwards allowable 
data requests to remote servers and/or responds to data requests directly from stored remote server data 
Range 
The distance away from your access point that your wireless network can reach. Most Wi-Fi systems will 
provide a range of a hundred feet or more. Depending on the environment and the type of antenna used, 
Wi-Fi signals can have a range of up to mile 
Residential gateway 
A wireless device that connects multiple PCs, peripherals and the Internet on a home network. Most Wi-Fi 
residential gateways provide DHCP and NAT as well. 
RJ-45 
Standard connectors used in Ethernet networks. Even though they look very similar to standard RJ-11 
telephone connectors, RJ-45 connectors can have up to eight wires, whereas telephone connectors have only 
four. 
Roaming 
Moving seamlessly from one AP coverage area to another with your laptop or desktop with no loss in 
connectivity. 
Rogue Access Point
Rogue AP is a term used to describe an unauthorized access point that is connected on the main home or 
corporate network or operating in a stand-alone mode (in a parking lot or in a neighbors building). Rogue 
APs, by definition, are not under the management of network administrators and do not conform to network 
security policies and may present a severe security risk. Ideally, it is best to have some type of WLAN 
system that does not allow rogue access points to easily be added to an existing WLAN. 
Router 
A device that forwards data packets from one local area network (LAN) or wide area network (WAN) to 
another. Based on routing tables and routing protocols, routers can read the network address in each 
transmitted frame and make a decision on how to send it via the most efficient route based on traffic load, 
line costs, speed, bad connections, etc.  
						

							Reference Manual for the 108 Mbps Wireless Firewall Router WGT624 v3
-10Glossary
202-10090-01, April 2005
Satellite broadband 
A wireless high-speed Internet connection provided by satellites. Some satellite broadband connections are 
two-way—up and down. Others are one-way, with the satellite providing a high-speed downlink and then 
using a dial-up telephone connection or other land-based system for the uplink to the Internet. 
Server 
A computer that provides its resources to other computers and devices on a network. These include print 
servers, Internet servers and data servers. A server can also be combined with a hub or router. 
Site survey 
The process whereby a wireless network installer inspects a location prior to putting in a wireless network. 
Site surveys are used to identify the radio- and client-use properties of a facility so that access points can be 
optimally placed. 
SSID (also called ESSID) 
A 32-character unique identifier attached to the header of packets sent over a WLAN that acts as a password 
when a mobile device tries to connect to the BSS. (Also called ESSID.) The SSID differentiates one WLAN 
from another, so all access points and all devices attempting to connect to a specific WLAN must use the 
same SSID. 
A device will not be permitted to join the BSS unless it can provide the unique SSID. Because an SSID can 
be sniffed in plain text from a packet, it does not supply any security to the network. An SSID is also 
referred to as a Network Name because essentially it is a name that identifies a wireless network. 
SSL (Secure Sockets Layer) 
Commonly used encryption scheme used by many online retail and banking sites to protect the financial 
integrity of transactions. When an SSL session begins, the server sends its public key to the browser. The 
browser then sends a randomly generated secret key back to the server in order to have a secret key 
exchange for that session. 
Subnetwork or Subnet 
Found in larger networks, these smaller networks are used to simplify addressing between numerous 
computers. Subnets connect to the central network through a router, hub or gateway. Each individual 
wireless LAN will probably use the same subnet for all the local computers it talks to. 
Switch 
A type of hub that efficiently controls the way multiple devices use the same network so that each can 
operate at optimal performance. A switch acts as a networks traffic cop: rather than transmitting all the 
packets it receives to all ports as a hub does, a switch transmits packets to only the receiving port. 
TCP (Transmission Control Protocol) 
A protocol used along with the Internet Protocol (IP) to send data in the form of individual units (called 
packets) between computers over the Internet. While IP takes care of handling the actual delivery of the 
data, TCP takes care of keeping track of the packets that a message is divided into for efficient routing 
through the Internet.  
						

							Reference Manual for the 108 Mbps Wireless Firewall Router WGT624 v3
Glossary-11
202-10090-01, April 2005
For example, when a web page is downloaded from a web server, the TCP program layer in that server 
divides the file into packets, numbers the packets, and then forwards them individually to the IP program 
layer. Although each packet has the same destination IP address, it may get routed differently through the 
network. At the other end, TCP reassembles the individual packets and waits until they have all arrived to 
forward them as a single file. 
TCP/IP 
The underlying technology behind the Internet and communications between computers in a network. The 
first part, TCP, is the transport part, which matches the size of the messages on either end and guarantees that 
the correct message has been received. The IP part is the users computer address on a network. Every 
computer in a TCP/IP network has its own IP address that is either dynamically assigned at startup or 
permanently assigned. All TCP/IP messages contain the address of the destination network as well as the 
address of the destination station. This enables TCP/IP messages to be transmitted to multiple networks 
(subnets) within an organization or worldwide. 
TKIP 
A security feature that is a WEP enhancement: Temporal Key Integrity Protocol and Message Integrity 
Check (MIC) is a modification of WEP to defend against known attacks (WEP+ four patches for key 
mixing, message integrity, rekeying, initialization vector protection) 
USB (Universal Serial Bus) 
A high-speed bidirectional serial connection between a PC and a peripheral that transmits data at the rate of 
12 megabits per second. The new USB 2.0 specification provides a data rate of up to 480 Mbps, compared to 
standard USB at only 12 Mbps. 1394, FireWire and iLink all provide a bandwidth of up to 400 Mbps. 
VoIP (Voice over IP) 
Voice transmission using Internet Protocol to create digital packets distributed over the Internet. VoIP can be 
less expensive than voice transmission using standard analog packets over POTS (Plain Old Telephone 
Service). 
VPN (Virtual Private Network) 
A type of technology designed to increase the security of information transferred over the Internet. VPN can 
work with either wired or wireless networks, as well as with dial-up connections over POTS. VPN creates a 
private encrypted tunnel from the end users computer, through the local wireless network, through the 
Internet, all the way to the corporate servers and database. 
War Chalking 
The act of making chalk marks on outdoor surfaces (walls, sidewalks, buildings, sign posts, trees) to indicate 
the existence of an open wireless network connection, usually offering an Internet connection so that others 
can benefit from the free wireless access. The open connections typically come from the access points of 
wireless networks located within buildings to serve enterprises. The chalk symbols indicate the type of 
access point that is available at that specific spot. 
There are three basic designs that are currently used: a pair of back-to-back semicircles, which denotes an 
open node; a closed circle, which denotes a closed node; a closed circle with a “W” inside, which denotes a  
						

							Reference Manual for the 108 Mbps Wireless Firewall Router WGT624 v3
-12Glossary
202-10090-01, April 2005
node equipped with WEP. Warchalkers also draw identifiers above the symbols to indicate the password that 
can be used to access the node, which can easily be obtained with sniffer software. 
As a recent development, the debate over the legality of warchalking is still going on. 
The practice stems from the U.S. Depression-era culture of wandering hobos who would make marks 
outside of homes to indicate to other wanderers whether the home was receptive to drifters or was 
inhospitable. 
War Driving 
War driving is the act of locating and possibly exploiting connections to wireless local area networks while 
driving around a city or elsewhere. To do war driving, you need a vehicle, a computer (which can be a 
laptop), a wireless Ethernet card set to work in promiscuous mode, and some kind of an antenna which can 
be mounted on top of or positioned inside the car. Because a wireless LAN may have a range that extends 
beyond an office building, an outside user may be able to intrude into the network, obtain a free Internet 
connection, and possibly gain access to company records and other resources. 
Some people have made a sport out of war driving, in part to demonstrate the ease with which wireless 
LANs can be compromised. With an omnidirectional antenna and a geophysical positioning system (GPS), 
the war driver can systematically map the locations of 802.11b wireless access points. 
WEP (Wired Equivalent Privacy) 
Basic wireless security provided by Wi-Fi. In some instances, WEP may be all a home or small-business 
user needs to protect wireless data. WEP is available in 40-bit (also called 64-bit), or in 108-bit (also called 
128-bit) encryption modes. As 108-bit encryption provides a longer algorithm that takes longer to decode, it 
can provide better security than basic 40-bit (64-bit) encryption. 
Wi-Fi (Wireless Fidelity) 
Another name for IEEE 802.11b. Products certified as Wi-Fi are interoperable with each other even if they 
are from different manufacturers. A user with a Wi-Fi product can use any brand of access point with any 
other brand of client hardware that is built to the Wi-Fi standard. 
Wi-Fi Alliance (formerly WECA – Wireless Ethernet Compatibility Alliance) 
The Wi-Fi Alliance is a nonprofit international association formed in 1999 to certify interoperability of 
wireless Local Area Network products based on IEEE 802.11 specification. Currently the Wi-Fi Alliance 
has 193 member companies from around the world, and 509 products have received Wi-Fi certification since 
certification began in March of 2000. The goal of the Wi-Fi Alliances members is to enhance the user 
experience through product interoperability (
www.weca.net). 
Wi-Fi Protected Access (WPA) 
WPA is a security technology for wireless networks that improves on the authentication and encryption 
features of WEP (Wired Equivalent Privacy). In fact, WPA was developed by the networking industry in 
response to the shortcomings of WEP. 
One of the key technologies behind WPA is the Temporal Key Integrity Protocol (TKIP). TKIP addresses 
the encryption weaknesses of WEP. Another key component of WPA is built-in authentication that WEP 
does not offer. With this feature, WPA provides roughly comparable security to VPN tunneling with WEP,  
						

							Reference Manual for the 108 Mbps Wireless Firewall Router WGT624 v3
Glossary-13
202-10090-01, April 2005
with the benefit of easier administration and use. This is similar to 802.1x support and requires a RADIUS 
server in order to implement. The Wi-Fi Alliance will call this, WPA-Enterprise. 
One variation of WPA is called WPA Pre Shared Key or WPA-PSK for short - this provides an 
authentication alternative to an expensive RADIUS server. WPA-PSK is a simplified but still powerful form 
of WPA most suitable for home Wi-Fi networking. To use WPA-PSK, a person sets a static key or 
passphrase as with WEP. But, using TKIP, WPA-PSK automatically changes the keys at a preset time 
interval, making it much more difficult for hackers to find and exploit them. The Wi-Fi Alliance will call 
this, WPA-Personal. 
Wi-Fi Protected Access and IEEE 802.11i Comparison 
Wi-Fi Protected Access will be forward-compatible with the IEEE 802.11i security specification currently 
under development by the IEEE. Wi-Fi Protected Access is a subset of the current 802.11i draft, taking 
certain pieces of the 802.11i draft that are ready to bring to market today, such as its implementation of 
802.1x and TKIP. These features can also be enabled on most existing Wi-Fi CERTIFIED products as a 
software upgrade. The main pieces of the 802.11i draft that are not included in Wi-Fi Protected Access are 
secure IBSS, secure fast handoff, secure de-authentication and disassociation, as well as enhanced 
encryption protocols such as AES-CCMP. These features are either not yet ready for market or will require 
hardware upgrades to implement. 
Wi-Fi Protected Access for the Enterprise 
Wi-Fi Protected Access effectively addresses the WLAN security requirements for the enterprise and 
provides a strong encryption and authentication solution prior to the ratification of the IEEE 802.11i 
standard. In an enterprise with IT resources, Wi-Fi Protected Access should be used in conjunction with an 
authentication server such as RADIUS to provide centralized access control and management. With this 
implementation in place, the need for add-on solutions such as VPNs may be eliminated, at least for the 
express purpose of securing the wireless link in a network. 
Wi-Fi Protected Access for Home/SOHO 
In a home or Small Office/ Home Office (SOHO) environment, where there are no central authentication 
servers or EAP framework, Wi-Fi Protected Access runs in a special home mode. This mode, also called 
Pre-Shared Key (PSK), allows the use of manually-entered keys or passwords and is designed to be easy to 
set up for the home user. All the home user needs to do is enter a password (also called a master key) in their 
access point or home wireless gateway and each PC that is on the Wi-Fi wireless network. Wi-Fi Protected 
Access takes over automatically from that point. First, the password allows only devices with a matching 
password to join the network, which keeps out eavesdroppers and other unauthorized users. Second, the 
password automatically kicks off the TKIP encryption process, described above. 
Wi-Fi Protected Access for Public Access 
The intrinsic encryption and authentication schemes defined in Wi-Fi Protected Access may also prove 
useful for Wireless Internet Service Providers (WISPs) offering Wi-Fi public access in hot spots where 
secure transmission and authentication is particularly important to users unknown to each other. The 
authentication capability defined in the specification enables a secure access control mechanism for the 
service providers and for mobile users not utilizing VPN connections.  
						

							Reference Manual for the 108 Mbps Wireless Firewall Router WGT624 v3
-14Glossary
202-10090-01, April 2005
Wi-Fi Protected Access in Mixed Mode Deployment 
In a large network with many clients, a likely scenario is that access points will be upgraded before all the 
Wi-Fi clients. Some access points may operate in a mixed mode, which supports both clients running 
Wi-Fi Protected Access and clients running original WEP security. While useful for transition, the net effect 
of supporting both types of client devices is that security will operate at the less secure level (WEP), 
common to all the devices. Therefore, organizations will benefit by accelerating the move to Wi-Fi Protected 
Access for all Wi-Fi clients and access points. 
WiMAX 
An IEEE 802.16 Task Group that provides a specification for fixed broadband wireless access systems 
employing a point-to-multipoint (PMP) architecture. Task Group 1 of IEEE 802.16 developed a 
point-to-multipoint broadband wireless access standard for systems in the frequency range 10-66 GHz. The 
standard covers both the Media Access Control (MAC) and the physical (PHY) layers. Ratification is 
expected in second half of 2004. 
Wireless Multimedia (WMM)
WMM (Wireless Multimedia) is a subset of the 802.11e standard. WMM allows wireless traffic to have a 
range of priorities, depending on the kind of data. Time-dependent information, like video, audio, or voice 
will have a higher priority than normal traffic. For WMM to function correctly, wireless clients must also 
support WMM. 
Wireless Networking 
Wireless Networking refers to the infrastructure enabling the transmission of wireless signals. A network 
ties things together and enables resource sharing. 
WLAN (Wireless LAN) 
Also referred to as LAN. A type of local-area network that uses wireless or high-frequency radio waves 
rather than wires to communicate between nodes.