FortiWLC – Appendix


Captive Portal and Fortinet Connect Deployment Recommendations

These are the deployment recommendations.

DNS Entry

It is mandatory to enter the DNS while creating internal DHCP profile.

External Portal IP Configuration

If a NAT device is located between the controller and the Fortinet Connect, the IP address with which Fortinet Connect sees the controller should be configured under Device > RADIUS Clients page in Fortinet Connect Admin portal (http://<fortinetconnect-ip-address>/admin) . Select the RADIUS client and enter the controller IP address in the Client tab. The Fortinet Connect Automatic Setup then configures the controller correctly and ensures that the correct controller IP address is configured on Fortinet Connect.

Remember Me settings

In the Portal Settings step of the Guest Portal configuration wizard, if you choose to enable

Remember Credentials, then select “Initially attempt to use a cookie, if this fails try the MAC address” option. This removes the dependency on the client’s browser and security settings.

SmartConnect Certificate download

In the Certificates step of the Smart Connect Profile Wizard, ensure that you select the complete certificate chain of your uploaded certificate. If all certificates in the chain (from root to server) have been uploaded, then selecting the server certificate will automatically select the entire certificate chain.

  • To upload the server certificates, go to Server > SSL Settings > Server Certificate
  • To upload rest of the chain, go to Server > SSL Settings > Trusted CA Certificates

Captive Portal and Fortinet Connect Deployment Recommendations

IP Prefix Validation

In a situation where a station with an IP address from a different subnet connects to the controller, it can result in various network issues including outage. A new field, IP Prefix Validation is added to the ESS Profile and Port Profile configuration page. When enabled, stations with different subnet are prevented from connecting to the controller. By default, IP Prefix Validation in ESS Profile is ON and in Port Profile it is OFF.

IP Prefix Validation must be disabled if the ESS profile is used for RAC.

IP Prefix Validation

A Glossary

This glossary contains a collection of terms and abbreviations used in this document. A B C D E F G H I J K L M N O P Q R S T U V W X Y


10BaseT An IEEE standard (802.3) for operating 10 megabits per second (Mbps) Ethernet networks (LANs) over twisted pair cabling and using baseband transmission methods.
100baseT A Fast Ethernet standard (802.3u) that allows up to 100 Mbps and uses the CSMA/CD LAN access method.
3DES Triple Des. A Data Encryption Standard (DES) that uses three 64-bit encryption key, and therefore is three times longer than that used by DES.
802.11 802.11, or IEEE 802.11, is a radio technology specification used for Wireless Local Area Networks (WLANs). 802.11 defines the mobile (wireless) network access link layer, including 802.11 media access control (MAC) and different Physical (PHY) interfaces. This standard defines the protocol for communications between a wireless client and a base station as well as between two wireless clients.

The 802.11 specification, often called Wi-Fi, is composed of several standards operating in different radio frequencies, including the 2.4 GHz (802.11 b and g) and 5 GHz (802.11a) unlicensed spectrums. New standards are emerging within the 802.11 specification to define additional aspects of wireless networking.

802.11a A supplement to 802.11 that operates in the 5 GHz frequency range with a maximum 54 Mbps data transfer rate. The 802.11a specification offers more radio channels than the 802.11b and uses OFDM. The additional channels ease radio and microwave interference.
802.11b International standard for wireless networking that operates in the 2.4 GHz frequency range (2.4 GHz to 2.4835 GHz) and provides a throughput of up to 11 Mbps. This common frequency is also used by microwave ovens, cordless phones, medical and scientific equipment, as well as Bluetooth devices.



802.11e An IEEE specification for providing Quality of Service (QoS) in 802.11 WLANs. 802.11e is a supplement to the IEEE 802.11 and provides enhancements to the 802.11 MAC layer supplying a Time Division Multiple Access (TDMA) construct and error-correcting mechanisms that aid delay-sensitive applications such as  and video.
802.11g Similar to 802.11b, this standard operates in the 2.4 GHz frequency. It uses OFDM to provide a throughput of up to 54 Mbps.
802.11i Supports the 128-bit Advanced Encryption Standard (AES) and Temporal Key Integrity Protocol (TKIP) along with 802.1X authentication and key management features for increased WLAN security capabilities.
802.11j Provides enhancements to the current 802.11 standard to support the 4.9GHz – 5GHz band for operations in Japan.
802.11k Due for ratification in 2005, the 802.11k Radio Resource Management standard will provide measurement information for access points and switches to make Wireless LANs run more efficiently.
802.11n An emerging standard aimed at providing greater than 100 Mbps of throughput in a wireless environment.
802.11r A specification under development to improve a wireless client’s ability to roam across wireless networks.
802.16 A specification for fixed broadband wireless metropolitan access networks (MANs) that uses a point-to-multipoint architecture. The standard defines the use of bandwidth between the licensed 10GHz and 66GHz bands and between the 2GHZ and 11GHz (licensed and unlicensed) frequency ranges. 802.16 supports very high bit rates for a distance of approximately 30 miles.


Wireless LAN security implementation that uses port-based authentication between an operating system and the network access device, meant to increase security in user authentication by using RADIUS, Extensible Authentication Protocol (EAP), and LDAP.
AAA authentication, authorization, and accounting (triple A). An IP-based system for providing services to ensure secure network connections for users. The system requires a server such as a RADIUS server to enforce these services.
access point A device that is managed by a controller and that allows stations such as cellular phones or laptops to communicate wirelessly with the Wireless LAN System.
accounting Services that track the resources a user session uses such as amount of time logged on, data transferred, resources, etc. Accounting services are typically used for billing, auditing, analysis, etc.



ACL Access Control List. A list kept by the controller to limit access of station to the WLAN. The ACL can be a permit, deny, or RADIUS Server list of MAC addresses of the NIC device within the station. An ACL is controller by the configured state, either enabled or disabled.
AES Advanced Encryption Standard. An encryption standard that uses a symmetric encryption algorithm (Rijndael). AES was chosen by the National Information and Standards Institute (NIST) as the Federal Information Processing Standard (FIPS).
Air Traffic


Fortinet technology that exercises a high degree of control over all transmissions within a wireless network. Unlike superficially similar technologies from other vendors, Air Traffic Control technology coordinates uplink and downlink transmissions on a single 802.11 channel in such a manner that the effects of co-channel and adjacent channel interference are eliminated and all access points on a network can share a single radio channel. It also load balances traffic across channels when using Channel Layering, ensuring that each channel
ATS Access Transaction Station. Alternative term for access point.
attenuation The reduction of RF signal strength due to the presence of an obstacle, such as a wall or person. The amount of attenuation caused by a particular object will vary depending upon its composition.
authentication The process of identifying a user, usually based on a username and password, but can also be a MAC address.


The process of granting or denying a user access to network resources once the user has been authenticated through the username and password.
backbone The central part of a large network that links two or more subnetworks and is the primary path for data transmission for a large business or corporation. A network can have a wired backbone or a wireless backbone.
bandwidth The amount of transmission capacity that is available on a network at any point in time. Available bandwidth depends on several variables such as the rate of data transmission speed between networked devices, network overhead, number of users, and the type of device used to connect PCs to a network. It is similar to a pipeline in that capacity is determined by size: the wider the pipe, the more water can flow through it; the more bandwidth a network provides, the more data can flow through it. Standard 802.11b provides a bandwidth of 11 Mbps; 802.11a and 802.11g provide a bandwidth of 54 Mbps. These are the raw capabilities of the network. Many things conspire to reduce these values, including protocol overhead, collisions, and implementation inefficiencies.
base station A term in cellular networking that refers to a radio transmitter/receiver that maintains communications with mobile radiotelephone sets within a given range (typically a cell site).


bps bits per second. A measure of data transmission speed over communication lines based on the number of bits that can be sent or received per second. Bits per second-bps-is often confused with bytes per second-Bps. 8 bits make a byte, so if a wireless network is operating at a bandwidth of 11 megabits per second (11 Mbps or 11 Mbits/sec), it is sending data at 1.375 megabytes per second (1.375 MBps).
bridge A product that connects a local area network (LAN) to another local area network that uses the same protocol (for example, wireless, Ethernet or token ring). Wireless bridges are commonly used to link buildings in campuses.
BSC Base Station Controller. Manages radio resources and controls handoff between cells. May also contain the transcoder for compressing/uncompressing  between cellular network and the Public Switched Telephone Network (PSTN).


Basic Service Set Identifier is a means of uniquely identifying an access point, usually intended for machine use rather than human use. A 48-bit Ethernet MAC address is used to identify an 802.11 wireless service. In a Virtual Cell, all same-channel APs may appear to have the same BSSID, thus virtualizing the network from the client’s perspective. When Virtual Ports are used, each client sees a different BSSID, appearing to get its own private AP. See also ESSID.
Co-channel Interference Radio interference that occurs when two transmitters use the same frequency without being closely synchronized. Legacy wireless systems cannot achieve this kind of synchronization, so access points or cell towers that transmit on one channel must be spaced far apart. The result is coverage gaps that must be filled in with radios tuned to another channel, resulting in an inefficient and complex microcell architecture. Air Traffic Control technology avoids cochannel interference by tightly synchronizing access point transmissions, enabling that adjacent APs to use the same channel.
Channel Bonding The combination of two non-overlapping 20 MHz. channels into a single 40 MHz. channel, doubling the amount of data that can be transmitted in a given time but halving the number of available channels. Along with MIMO, it is a key innovation in the 802.11n standard.
Channel Layering Wireless LAN architecture in which several Virtual Cells are located in the same physical space but on non-overlapping channels, multiplying the available capacity. This additional capacity can be used for redundancy or to support higher data rates or user density. It can be enabled through multiple radios on one AP or by using multiple AP close together, so the total capacity is limited only be the number of non-overlapping channels available.
Channel Reuse A pattern in which different APs can use the same channel. In microcell networks, such APs need to be placed far apart to avoid co-channel interference, meaning that contiguous coverage requires multiple channels. In networks using Air Traffic Control technology, the same

channel can be reused throughout the network, meaning that only one channel is required and others are left free for other purposes.

CHAP Challenge Handshake Authentication Protocol. An authentication protocol that defines a three-way handshake to authenticate a user. CHAP uses the MD5 hash algorithm to generate a response to a challenge that can be checked by the authenticator.
CLI Command-line interpreter. On a controller and other units, this is similar to a command shell for giving instructions.
client Any computer connected to a network that requests services (files, print capability) from another member of the network.


Clients are end users. Wi-Fi client devices include PC Cards that slide into laptop computers, mini-PCI modules embedded in laptop computers and mobile computing devices, as well as USB radios and PCI/ISA bus Wi-Fi radios. Client devices usually communicate with hub devices like access points and gateways.
collision avoidance A network node characteristic for proactively detecting that it can transmit a signal without risking a collision.
controller A device that is responsible for configuring and integrating the access points in a WLAN.
CSMA-CA CSMA/CA is the principle medium access method employed by IEEE 802.11 WLANs. It is a “listen before talk” method of minimizing (but not eliminating) collisions caused by simultaneous transmission by multiple radios. IEEE 802.11 states collision avoidance method rather than collision detection must be used, because the standard employs half duplex radiosradios capable of transmission or reception-but not both simultaneously.


A method of managing traffic and reducing noise on an Ethernet network. A network device transmits data after detecting that a channel is available. However, if two devices transmit data simultaneously, the sending devices detect a collision and retransmit after a random time delay.
dBm A measurement of relative power (decibel) related to 1 milliwatt (mW).
Denial of Service (DoS) A condition in which users are deliberately prevented from using network resources.
DES Data Encryption Standard. A symmetric encryption algorithm that always uses 56 bit keys. It is rapidly being replaced by its more secure successor, 3DES.
DHCP A utility that enables a server to dynamically assign IP addresses from a predefined list for a predefined time period, limiting their use time so that they can be reassigned. Without DHCP, IP addresses would have to be manually assigned to all computers on the network. When

DHCP is used, whenever a computer logs onto the network, it automatically is assigned an IP address.

DNS A program that translates URLs to IP addresses by accessing a database maintained on a collection of Internet servers. The program works behind the scenes to facilitate surfing the Web with alpha versus numeric addresses. A DNS server converts a name like to a series of numbers like Every website has its own specific IP address on the Internet.


Various technology protocols for high-speed data,  and video transmission over ordinary twisted-pair copper POTS (Plain Old Telephone Service) telephone wires.
EAP Extensible Authentication Protocol. An extension to PPP. EAP is a general protocol for authentication that also supports multiple authentication methods, such as token cards, Kerberos, one-time passwords, certificates, public key authentication and smart cards. IEEE 802.1x specifies how EAP should be encapsulated in LAN frames.
EAP-TLS Extensible Authentication Protocol with Transport Layer Security. EAP-TLS supports mutual authentication using digital certificates. When a client requests access, the authentication server responds with a server certificate. The client replies with its own certificate and also validates the server certificate. The certificate values are used to derive session encryption keys.
EAP – TTLS Extensible Authentication Protocol with Tunneled Transport Layer Security. EAP-TTLS uses a combination of certificates and password challenge and response for authentication within an 802.1X environment. TTLS supports authentication methods defined by EAP, as well as the older Challenge Handshake Authentication Protocol (CHAP), Password Authentication Protocol (PAP), Microsoft CHAP (MS-CHAP), and MS-CHAPV2.
encryption key An alphanumeric (letters and/or numbers) series that enables data to be encrypted and then decrypted so it can be safely shared among members of a network. WEP uses an encryption key that automatically encrypts outgoing wireless data. On the receiving side, the same encryption key enables the computer to automatically decrypt the information so it can be read.
enterprise A term that is often applied to large corporations and businesses. The enterprise market can incorporate office buildings, manufacturing plants, warehouses and R&D facilities, as well as large colleges and universities.
ESSID Extended Service Set Identifier (ID). The identifying name of an 802.11 wireless network, which is a string of up to 32 characters that is intended to be viewed by humans. When you specify an ESSID in your client setup, you ensure that you connect to your wireless network rather than another network in range.

A set of access points can share an ESSID. In this case, a station can roam among the access points.



International standard networking technology for wired implementations. Basic 10BaseT networks offer a bandwidth of about 10 Mbps. Fast Ethernet (100 Mbps) and Gigabit Ethernet (1000 Mbps) are becoming popular.
FCC Federal Communications Commission. The United States’ governing body for telecommunications law.
firewall A system that secures a network and prevents access by unauthorized users. Firewalls can be software, hardware or a combination of both. Firewalls can prevent unrestricted access into a network, as well as restrict data from flowing out of a network.



Term coined by analyst firm Gartner to describe a wireless LAN system in which the controller governs handoffs, such as one utilizing Virtual Cells. This is contrasted with third generation (micro-cell architecture) systems, in which the controller is only responsible for managing access points and clients must decide for themselves when to initiate a handoff. Second generation systems lacked a controller altogether and were designed for standalone operation, whereas the first generation used proprietary, non-802.11 systems.
gain The ratio of the power output to the power input of an amplifier in dB. The gain is specified in the linear operating range of the amplifier where a 1 dB increase in input power gives rise to a 1 dB increase in output power.


In the wireless world, a gateway is an access point with additional software capabilities such as providing NAT and DHCP. Gateways may also provide VPN support, roaming, firewalls, various levels of security, etc.
Handoff The transfer of a link from one access point to another as a client moves through a network. In legacy microcell networks, Wi-Fi clients are responsible for handoff, meaning that the quality of the link and the overall network performance is dependent on each client’s implementation of 802.11 roaming algorithms. In Virtual Cell and Virtual Port networks, the network itself governs handoffs as clients remain connected to a single virtual AP.
hub A multiport device used to connect PCs to a network via Ethernet cabling or via Wi-Fi. Wired hubs can have numerous ports and can transmit data at speeds ranging from 10 Mbps to multigigabyte speeds per second. A hub transmits packets it receives to all the connected ports. A

small wired hub may only connect 4 computers; a large hub can connect 48 or more. Wireless hubs can connect hundreds.



The international unit for measuring frequency, equivalent to the older unit of cycles per second. One megahertz (MHz) is one million hertz. One gigahertz (GHz) is one billion hertz. The standard US electrical power frequency is 60 Hz, the AM broadcast radio frequency band is 535-1605 kHz, the FM broadcast radio frequency band is 88-108 MHz, and Wireless 802.11b LANs operate at 2.4 GHz.
IP number Also called an IP address. A 32-bit binary number that identifies senders and receivers of traffic across the Internet. It is usually expressed in the form nnn.nnn.nnn.nnn where nnn is a number from 0 to 256.
identitybased networking A concept whereby WLAN policies are assigned and enforced based upon a wireless client’s identity, as opposed to its physical location. With identity networking, wireless devices need only authenticate once with a WLAN system. Context information will follow the devices as they roam, ensuring seamless mobility.
IEEE Institute of Electrical and Electronics Engineers. ( A membership organization that includes engineers, scientists and students in electronics and allied fields. It has more than 300,000 members and is involved with setting standards for computers and communications.
IEEE 802.11 A set of specifications for LANs from The Institute of Electrical and Electronics Engineers (IEEE). Most wired networks conform to 802.3, the specification for CSMA/CD based Ethernet networks or 802.5, the specification for token ring networks. 802.11 defines the standard for Wireless LANs encompassing three incompatible (non-interoperable) technologies: Frequency Hopping Spread Spectrum (FHSS), Direct Sequence Spread Spectrum (DSSS) and Infrared. WECA’s focus is on 802.11b, an 11 Mbps high-rate DSSS standard for wireless networks.
infrastructure mode A client setting providing connectivity to an AP. As compared to Ad-Hoc mode, whereby PCs communicate directly with each other, clients set in Infrastructure Mode all pass data through a central AP. The AP not only mediates wireless network traffic in the immediate neighborhood, but also provides communication with the wired network. See Ad-Hoc and AP.
IP Internet Protocol. A set of rules used to send and receive messages at the Internet address level.
IP telephony Technology that supports , data and video transmission via IP-based LANs, WANs, and the Internet. This includes VoIP ( over IP).
IP 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.

IPSec                       IPSec is a security protocol from the Internet Engineering Task Force (IETF) that provides authentication and encryption. IPsec, which works at Layer 3, is widely used to secure VPNs and wireless users. Some vendors, like Airespace, have implemented special WLAN features that allow IPsec sessions to roam with clients for secure mobility.

ISDN A type of broadband Internet connection that provides digital service from the customer’s premises to the dial-up telephone network. ISDN uses standard POTS copper wiring to deliver , data or video.

ISO network A network model developed by the International Standards Organization (ISO) that consists of model 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.




LAN                          Local Area Network. A system of connecting PCs and other devices within the same physical proximity for sharing resources such as an Internet connections, printers, files and drives. When Wi-Fi is used to connect the devices, the system is known as a Wireless LAN or WLAN.

LDAP Lightweight Directory Access Protocol. A set of protocols for accessing information directories conforming to the X.500 standard.




Lightweight Access Point Protocol. A proposed specification to the International Engineering Task Force (IETF) created to standardize the communications protocol between access points and WLAN system devices (switches, appliances, routers, etc.). Initial authors include Airespace and NTT DoCoMo. See CAPWAP
MAC Medium Access Control. This is the function of a network controller that determines who gets to transmit when. Each network adapter must be uniquely identified. 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 network’s MAC table will be able to get onto the network.
Man in Middle (MiM) An attack that results from the interception and possible modification of traffic passing between two communicating parties, such as a wireless client and Access Point. MIM attacks succeed if the systems can’t distinguish communications with an intended recipient from those with the intervening attacker.
Mbps Million bits (megabits) per second.
MIC Message Integrity Check. MIC is part of a draft standard from IEEE 802.11i working group. It is an additional 8 byte field which is placed between the data portion of an 802.11 (Wi-Fi) frame and the 4 byte ICV (Integrity Check Value) to protect both the payload and the header. The algorithm which implements the MIC is known as Michael.
Microcell Wireless architecture in which adjacent APs must be tuned to different, non-overlapping channels in an attempt to mitigate co-channel interference. This requires complex channel planning both before the network is built and whenever a change is made, and uses spectrum so inefficiently that some co-channel interference still occurs, especially at 2,4 GHz. Microcell architectures were common in 2G cell phone systems and legacy wireless LAN systems. They are not used in 3G cellular networks or in wireless LAN systems that use Air Traffic Control, as these allow all access points to share a single channel.
mobile professional A salesperson or a “road warrior” who travels frequently and requires the ability to regularly access his or her corporate networks, via the Internet, to post and retrieve files and data and to send and receive e-mail.


The process or condition in which radiation travels between source and receiver via more than one propagation path due to reflection, refraction, or scattering.
NAT NetwOrk Address Translation. A system for converting the IP numbers used in one network to the IP numbers used in another network. Usually one network is the internal network and one

network is the external network. Usually the internal IP numbers form a relatively large set of IP numbers, which must be compressed into a small set of IP numbers for the external 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.


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.
OFDM Orthogonal Frequency Division Multiplexing. A modulation technique for transmitting large amounts of digital data over a radio wave. OFDM splits the radio signal into multiple smaller signals that are transmitted in parallel at different frequencies to the receiver. OFDM reduces the amount of crosstalk in signal transmissions. 802.11a uses OFDM.
Overlay Network


A dedicated network of radio sensors that are similar to access points but do not serve clients, scanning the airwaves full time for security or management issues. Overlay networks lack the flexibility of AP-based scanning, as radios cannot be redeployed between scanning and client access. They also lack deep integration with the main wireless network, necessary for realtime management and intrusion prevention.
Partitioning Virtualization technique in which a single resource is divided up into virtual resources that are then dedicated to a particular application. Examples include the virtual machines in server virtualization, virtual disk drives in SANs and Virtual Ports in Fortinet’s Wireless LAN Virtualization. The main advantages of partitioning are control and isolation: Each application or user can be given exactly the resources that it  needs, protecting them from each other and ensuring that none consumes more than its allocated share of resources. In a wireless context, it makes a wireless LAN behave more like a switched Ethernet port.
Pooling Virtualization technique in which multiple physical resources are combined into a single virtual resource. Examples include the multiple disk drives in a virtual storage array, the multiple CPUs in a modern server and the multiple access points in a Fortinet Virtual Cell. The main advantages of pooling are agility, simplified management and economies of scale: Resources can be moved  between applications on demand, reducing the need for over-provisioning and freeing applications or users from dependence on a single piece of limited infrastructure.


PC card A removable, credit-card-sized memory or I/O 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 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.
PDA Smaller than laptop computers but with many of the same computing and communication capabilities, PDAs range greatly in size, complexity and functionality. PDAs can provide wireless connectivity via embedded Wi-Fi Card radios, slide-in PC Card radios, or Compact Flash Wi-Fi radios.
PEAP Protected Extensible Authentication Protocol. An extension to the Extensible Authentication Protocol with Transport Layer Security (EAP-TLS), developed by Microsoft Corporation. TLS is used in PEAP Part 1 to authenticate the server only, and thus avoids having to distribute user certificates to every client. PEAP Part 2 performs mutual authentication between the EAP client and the server.
peer-to-peer network 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 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.
plenum The ceiling plenum is the volume defined by the area above the back of the ceiling tile, and below the bottom of the structural slab above. Within this plenum is usually found a combination of HVAC ducts, electrical and electronic conduits, water pipes, traditional masking sound speakers, etc. Networking equipment needs to be plenum rated to certify that it is suitable for deployment in this area.
PoE Power over Ethernet. A technology defined by the IEEE 802.3af standard to deliver dc power over twisted-pair Ethernet data cables rather than power cords. The electrical current, which enters the data cable at the power-supply end and comes out at the device end, is kept separate from the data signal so neither interferes with the other.
POTS Plain Old Telephone Service. Standard analog telephone service (an acronym for Plain Old Telephone Service).


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.


Public Switched Telephone Network. The usual way of making telephone calls in the late 20th century, designed around the idea of using wires and switches. Perhaps to be supplanted by  Over IP in the 21st century.


Quality of Service. A set of technologies for managing and allocating Internet bandwidth. Often used to ensure a level of service required to support the performance requirements of a specific application, user group, traffic flow, or other parameter. Defined within the service level are network service metrics that include network availability (uptime), latency and packet loss.
RADIUS Remote Authentication Dial-In User Service. A service that authorizes connecting users and allows them access to requested systems or services. The Microsoft ISA server is a RADIUS server.
range How far will your wireless network stretch? 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.
RC4 algorithm The RC4 algorithm uses an Initialization Vector (IV) and a secret key to generate a pseudorandom key stream with a high periodicity. Designed by RSA Security, RC4 is used in WEP and many other transmission protocols including SSL.
RF Radio Frequency. The type of transmission between a Wireless LAN access point and a wireless client (e.g., laptop, PDA, or phone). Wireless LANs can use RF spectrum at either 2.4 GHz (IEEE 802.11b or IEEE 802.11g) or 5 GHz (IEEE 802.11G).
RFID Radio Frequency ID. A device that picks up signals from and sends signals to a reader using radio frequency. Tags come in many forms, such as smart labels that are stuck on boxes; smart cards and key-chain wands for paying for things; and a box that you stick on your windshield to enable you to pay tolls without stopping. Most recently, active 802.11 RFID tags are being deployed in enterprise environments to provide more consistent tracking across farther distances than traditional passive devices.
RF fingerprinting In an enterprise WLAN scenario, RF fingerprinting refers to creating a blueprint of a building’s RF characteristics, taking into account specific wall and design characteristics such as attenuation and multipath. This information is compared to real-time information collected by APs for

802.11 location tracking. By taking RF characteristics into account, RF fingerprint is the most accurate method of wireless device tracking available today.

RF prediction The process of predicting WLAN characteristics, such as throughput and coverage area, based upon imported building characteristics and sample WLAN design configurations.
RF triangulation A common method used for 802.11 device tracking whereby 3 or more Access Points compare RSSI information to triangulate in on a device’s location. While easy to implement, RF triangulation does not account for multipath, attenuation, and other RF characteristics that may affect receive sensitivity, making it less accurate than RF fingerprinting.
roaming The process that takes places as a client moves between the coverage areas of different APs, necessitating a handoff. In microcell Wi-Fi networks, roaming can be a complex procedure that risks dropped connections and drags down network performance, as the client is forced to decide when to disconnect from one AP and search for another. In networks using Virtual Cell and Virtual Port technology, the infrastructure controls roaming, automatically connecting each client to the optimum AP.
rogue Access Point An AP that is not authorized to operate within a wireless network. Rogue APs subvert the security of an enterprise network by allowing potentially unchallenged access to the enterprise network by any wireless user (client) in the physical vicinity.
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 no loss in connectivity.
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.
RSA A public-key algorithm developed in 1977 and named after its inventors, Rivest, Shamir, and Adleman. RSA, currently owned by RSA Data Security, Inc., is used for encryption, digital signatures, and key exchange.
RSN Robust Security Network. A new standard within IEEE 802.11i to provide security and privacy mechanisms in an 802.11 wireless network. RSN leverages 802.1x authentication with Extensible Authentication Protocol (EAP) and AES for encryption.


Received Signal Strength Indication. The measured power of a received signal.
scanning The process of checking the airwaves for rogue access points or attackers.  Scanning APs are typically implemented as an Overlay Network, as most APs can not scan and serve traffic at

the same time. Fortinet’s APs are able to scan the airwaves and serve clients simultaneously, eliminating the need for an overlay.  Fortinet’s single-channel architecture improves accuracy when scanning for intruders, as all APs are able to detect signals from all clients.

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.

Single Channel

Term sometimes used to describe a network in which all access points operate on the same channel, such as one using Virtual Cell technology. Single channel operation is more spectrally efficient than a microcell architecture and necessary for the use of Virtual Cells and network-controlled handoff. Single Channel improves security by making intrusion detection easier and location tracking more accurate, as every AP automatically receives transmissions from every client within range. It also enables the RF Barrier to function with as little as one radio, because only one channel needs to be blocked from outside access.

SIP Session Initiation Protocol. SIP is a protocol for finding users, usually human, and setting up multimedia communication among them, typically a VoIP phone call.
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. Wireless LAN System WLANs are optimized to not require a site survey.
spectral efficiency The ratio of data rate to radio spectrum usage. A Virtual Cell is much more spectrally efficient than a microcell architecture, as the microcells consume at least three non-overlapping channels to provide the coverage that a Virtual Cell offers with just one.
SSID A 32-character unique identifier attached to the header of packets sent over a WLAN that acts as a name 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.
ssh Secure SHell. A terminal-emulation program that allows users to log onto a remote device and execute commands. It encrypts the traffic between the client and the host.
SSL Secure Socket 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.


station Devices such as cellular phones or laptops that need to communicate wirelessly with the Meru Wireless LAN System and do so through access points.
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.
subnet mobility The ability of a wireless user to roam across Access Points deployed on different subnets using a single IP address.
supplicant A wireless client that is requesting access to a network.


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. 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 user’s 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 Temporal Key Integrity Protocol. An enhancement to the WEP encryption technique that uses a set of algorithms to rotate session keys for better protection. TKIP uses RC4 ciphering, but adds functions such as a 128-bit encryption key, a 48-bit initialization vector, a new message integrity code (MIC), and initialization vector (IV) sequencing rules.


USB 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.


Universal Time Coordinated. Also known as Greenwich Mean Time. The time is not adjusted for time zones or for daylight savings time.
Virtual Cell Proprietary wireless LAN architecture in which multiple access points are pooled into a single, virtual resource. To the client, APs are indistinguishable because they all use the same BSSID and radio channel . Because clients remain connected to the same virtual AP as they move through a network, no client-initiated handoffs are necessary. Instead, the network itself automatically routes all radio connections through the most appropriate AP. This maximizes bandwidth, simplifies network management and conserves radio spectrum for scalability and redundancy.
Virtual Port An enhancement to the Virtual Cell architecture which partitions the network so that each client device has its own private network with a unique BSSID. From the client’s perspective, it gets its own dedicated AP to which it remains connected no matter where it travels in the network. Like a switched  Ethernet port, the Virtual Port eliminates latency, jitter and contention for bandwidth as there is only ever one client on each port. Unlike an Ethernet port, it can be personalized to fit each user or device, giving the network control over client behavior with no proprietary client-side software or extensions necessary.
VoFI ( over

Wi-Fi) or VoWLAN ( over Wireless


 over IP links that run over a wireless network. VoIP does not usually require high data rates, but it stresses wireless networks in other ways by demanding low latencies and smooth handoffs. In addition, no 802.11n phones yet exist, as most handsets are too small to accommodate MIMO’s multiple antennas  spaced a wavelength apart. This means that 802.11n networks running VoFI must have a way to deal with 802.11b/g clients.
VLAN Virtual LAN. A logical grouping of devices that enables users on separate networks to communicate with one another as if they were on a single network.
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 user’s computer, through the local wireless network, through the Internet, all the way to the corporate servers and database.


WAN                        Wide Area Network. A communication system of connecting PCs and other computing

devices across a large local, regional, national or international geographic area. Also used to distinguish between phone-based data networks and Wi-Fi. Phone networks are considered WANs and Wi-Fi networks are considered Wireless Local Area Networks (WLANs).

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 104-bit (also called 128-bit) encryption modes. As 104-bit encryption provides a longer key that takes longer to decode, it can provide better security than basic 40-bit (64-bit) encryption.

Wi-Fi                        Brand name for wireless LANs based on various 802.11 specifications. All products bearing the Wi-Fi logo have been tested for interoperability by the Wi-Fi Alliance, an industry group composing every major 802.11 client and infrastructure vendor.

WLAN                      Wireless LAN. Also referred to as LAN. A type of local-area network that uses high-frequency radio waves rather than wires to communicate between nodes.

WME                        Wireless Multimedia Extension. The Wi-Fi Alliance’s standard for QoS based upon the Enhanced Distribution Coordination Function (EDCF), which is a subset of the IEEE 802.11e specification.

WNC                        Wireless Network Controller. Alternative term for controller.

WSM                        Wi-Fi Scheduled Media. The Wi-Fi Alliance’s emerging standard for QoS that is based upon the HCF portion of the 802.11e standard, which dedicates bandwidth segments to specific data types. WSM is going to have less of a focus in the enterprise space than its WME counterpart.

WPA                        Wi-Fi Protected Access. The Wi-Fi Alliance put together WPA as a data encryption method for 802.11 Wireless LANs. WPA is an industry-supported, pre-standard version of 802.11i utilizing the Temporal Key Integrity Protocol (TKIP). WPA will serve until the 802.11i standard is ratified in the third quarter of 2003.


X.509                         Created by the International Telecommunications Union Telecommunication Standardization

Sector (ITU-T), X.509 is the most widely used standard for defining digital certificates.

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