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General FAQ
General FAQ
What is Hot Spot ?
For users of Notebook or portable PC equipped with wireless lan device, a Hot Spot is an area where companies providing Internet connection and virtual private network (VPN) access from a given location, in wireless condition. For example, a traveller with a portable PC with a wireless lan device on board can look up a local hot spot (access point), contact it, and get connected through its network to reach the Internet and their own company remotely with a secure and mobile connection.
How to analize antenna distance between two buildings?
Most installers are using one of a few things to analize the distance between buildings: Light meter, GPS, Binoculars Most installers will do their best with binoculars and then get their portable PC to 'peak' the signal (move the antenna around a little until they have the highest signal level). This allows them to maximize their signal. In a wireless LAN with 802.1X, a user (known as the supplicant) requests access to an access point (known as the authenticator). The access point forces the user (actually, the user's client software) into an unauthorized state that allows the client to send only an EAP start message. The access point returns an EAP message requesting the user's identity. The client returns the identity, which is then forwarded by the access point to the authentication server, which uses an algorithm to authenticate the user and then returns an accept or reject message back to the access point. Assuming an accept was received, the access point changes the client's state to authorized and normal traffic can now take place.
The authentication server may use the Remote Authentication Dial-In User Service (RADIUS), although 802.1X does not specify it.
Is 802.11g compatible with 802.11b standard?
The most recently approved IEEE standard for wireless local area networks (WLANs), 802.11g offers wireless transmission over relatively short distances at up to 108 megabits per second (Mbps theorical) compared with the 11 megabits per second of the 802.11b (Wi-Fi) standard. Like 802.11b, 802.11g operates in the 2.4 GHz range and is thus compatible with it.
What is SSID Broadcast?
This is a function performed by an Access Point that transmits its name so that wireless stations searching for a network connection can 'discover' it. It's what allows your wireless adapter's client manager program or Windows XP's built-in wireless software to give you a list of the in-range Access Points.
The ability to disable SSID broadcast essentially makes your Access Point invisible unless a wireless client already knows the SSID, or is using tools that monitor or 'sniff' traffic from an AP's associated clients.
What is 802.11d Standard?
802.11d is supplementary to the Media Access Control (MAC) layer in 802.11 to promote worldwide use of 802.11 WLANs. It will allow access points to communicate information on the permissible radio channels with acceptable power levels for user devices. The 802.11 standards cannot legally operate in some countries; the purpose of 11d is to add features and restrictions to allow WLANs to operate within the rules of these countries.
How WPA (Wi-Fi Protection Access) works?
WPA stands for Wi-Fi Protected Access which is a specification of standards-based, interoperable security enhancements that strongly increase the level of data protection and access control for existing and future wireless LAN systems. Designed to run on existing hardware as a software upgrade, Wi-Fi Protected Access is derived from and will be forward compatible with the upcoming IEEE 802.11i standard. When properly installed, it will provide wireless LAN users with a high level of assurance that their data will remain protected and that only authorized network users can access the network.
What is WDS?
WDS (Wireless Distribution System) is a Wireless Access Point mode that enables wireless bridging in which WDS APs communicate only with each other only (without allowing for wireless clients or stations to access them), and/or wireless repeating in which APs communicate both with each other and with wireless stations (at the expense of half the throughput).
What is AES (Advanced Encryption System)?
Advanced Encryption System. A symmetric key encryption technique which replace the commonly used DES standard. It was the result of a worldwide call for submissions of encryption algorithms issued by NIST in 1997 and completed in 2000. The winning algorithm, Rijndael, was developed by two Belgian cryptologists, Vincent Rijmen and Joan Daemen. AES provides strong encryption in various environments: standard software platforms, limited space environments, and hardware implementations.
What is 802.11b?
802.11b, or IEEE 802.11b, is a standard that has been developed by the IEEE (Institute of Electrical and Electronic Engineers), http://standards.ieee.org. The IEEE is an international organization that develops standards for hundreds of electronic and electrical technologies. The organization uses a series of numbers, like the Dewey Decimal system in libraries, to differentiate between the various technology families. The 802 committee develops standards for local and wide area networks (LANs and WANs). For example, the 802.3 committee develops standards for Ethernet-based wired networks, the 802.15 group develops standards for personal area networks, and the 802.11 committee develops standards for wireless local area networks (LAN).802.11 is then further divided: 802.11b, or Wi-Fi, is a standard for wireless LANs operating in the 2.4 GHz spectrum with a bandwidth of 11 Mbps. 802.11a is a different standard for wireless LANs operating in the 5 GHz frequency range with a maximum data rate of 54 Mbps. Another draft standard, 802.11g, is for WLANs operating in the 2.4 GHz frequency but with a maximum data rate of 54 Mbps (108 turbo mode theorical). Other task groups are working on enhanced security (802.11i), spectrum and power control management (802.11h), quality of service (802.11e), etc.
How do I use my portable PC when I am traveling?
Just find a Wireless Hot Spot or wireless network to which you can connect. These networks are becoming common in cities and towns worldwide — Internet cafes and coffee shops are popping up everywhere! — as well as in public areas like airports, hotels and convention centers or anywhere people gather. Some wireless Hot Spot networks require you to manually configure your access connection; others work with your Wireless radio to automatically log on. In addition, many large businesses and universities are providing wireless access to visitors and guests at their locations.
Sometimes there is no difference; sometimes there is a big difference. There is no official definition of what a gateway is. Many manufacturers call their wired broadband modem/router connections gateways. However, in general, a wireless gateway is an access point with NAT routing and DHCP server. An access point is a wireless gateway without NAT routing and DHCP server. An access point essentially functions as an extension from an existing wired network to a community of users with wireless laptops and desktop computers.
Most homes and small offices use wireless gateways because they need the NAT routing and DHCP server that enables them to share a single Internet connection among all the computers in the home or office. Most enterprises and large businesses use access points, not gateways, because their wired network (their "backbone") already has NAT and DHCP server supplied by an industrial strength router or hub.
Many access points also have extra network management and advanced user functions and security capabilities built into them. Gateways may also offer specialized security functions like firewalls.
In general, access points and gateways do the same thing: they function as base stations connecting various wireless laptops and desktop computers, ensuring that wireless data gets shared and transmitted among them as needed.
Why do I need to know what NAT and DHCP are?
NAT stands for Network Address Translation and enables your Wi-Fi gateway to share a single Internet connection among all the computers in your home or business. DHCP (Dynamic Host Configuration Protocol) is what enables your network to use TCP/IP to connect the different components. There are various networking protocols. See Windows Networking Tips and Techniques.
Most Wi-Fi gateways for homes and small businesses provide both NAT and DHCP. In general, if you are setting up a stand-alone wireless network, you want NAT and DHCP. If you are adding a wireless gateway to an existing wired network, you probably want to turn off the NAT and DHCP functions built into your wireless gateway and have it function as a wireless access point.
How do I add Wireless Lan to my desktop computer?
You can use either an external adapter like a USB Wireless Client Device adapter or an internal Wireless Lan PC card. An external USB radio plugs into your desktop computer's USB jack. To use an internal solution, you need to open up your desktop computer and insert a Wireless PCI card in either a PCI bus slot or an ISA bus slot.
Can I use Wireless Lan radio lan with my Apple Macintosh?
Yes. You have two options. Most newer Macintosh Power PCs, G3s and G4s have a slot or USB port where you can connect any RB-LINK Wireless Lan Client device or AP. If you didn't order it when you bought your Apple computer, you can still buy the module and put it in yourself — installation is very simple. If you have an older Mac laptop with a PC Card slot, you can choose from all RB-LINK products who make Apple-compliant PC Card radios. USB adapters for Apple are also available.
Once you have the correct PC Card radio, you need a gateway or access point to talk to. You can use any RB-LINK access point , it will talk to your Apple.
Many access points and gateways now use a web-based setup routine. That means as long as you have an Internet browser on your computer, you can set up the access point.
Once set up and configured, a network consisting of combined Apple and Windows computers and access points will work together. Of course, unless you are running an emulator program, you won't be able to run Windows programs on your Apple computer and vice versa. However, your Wireless Lan network devices will talk to each other and enable you to share an Internet connection and transfer files among the various computers.
How do I make my wireless network secure?
Wireless security is important, and RB-LINK wireless networks can enable WPA, a sophisticated encryption technology that protects data flowing between Wireless radios and access points. Make sure you enable it on your network. Some of our access points or gateways also provide access control function to restrict access to your Wireless Lan network.
Will my microwave oven or cordless phone interfere with my Wireless lan network?
Microwave ovens and many cordless phones operate in the 2.4 GHz spectrum, the same radio spectrum used by 802.11b radio wireless networks. That means they can cause interference — but in most instances this will just slow down the Wireless connection; it won't stop transmission or break the connection. To reduce interference, you can move a 2.4 GHz cordless phone away from your Wireless equipped computer or base station. Interference usually only happens with older microwave ovens. You can also try changing the channel on which your Wireless network operates.
Can an external antenna be attached to RB-LINK Access Point? How far would that extend the data transmission distance?
Yes, additional external antenna can be attached to RB-LINK Access Point, Router, and Bridges. The distance increase would depend on antenna output power.
Is RB-LINK AP and Bridge sealed for outdoor use?
Yes, RB-LINK AP and Bridges are equipped with protection for all type weather conditions.
What are the differences between RB-LINK High Power Wireless LAN card and normal Wireless LAN card found in the market?
Higher transmission power, sending signals of 20 dbm (600 meters). Smart Antenna, Auto-Switch feature for indoor/outdoor use, and diversity.
How can I find the IP address of my computer?
To find the IP address of my computer, please click on your operating system for instructions.
· Windows 95, 98, and ME
· Windows 2000 and XP
· Macintosh 8.x and 9.x
· Macintosh OS X
· Linux
Windows 95, 98, and ME
Step 1 Click on Start, then click on Run.
Step 2 The Run Dialogue Box will appear. Type winipcfg in the window as shown then click OK.
Step 3 The IP Configuration window will appear, displaying your Ethernet Adapter Information.
Select your adapter from the drop down menu.
If you do not see your adapter in the drop down menu, your adapter is not properly installed.
Step 4 After selecting your adapter, it will display your IP address, subnet mask, and default gateway.
Step 5 Click OK to close the IP Configuration window.
Windows 2000 and XP
Step 1 Click on Start and select Run.
Step 2 Type cmd then click OK.
Step 3 From the Command Prompt, enter ipconfig. It will return your IP address, subnet mask, and default gateway.
Step 4 Type exit to close the command prompt.
Macintosh 8.x and 9.x
Step 1 Click on the Apple Menu>Control Panels>TCP/IP.
Step 2 Select your ethernet adapter from the Connect Via drop-down menu.
Step 3 Under Setup, select Using DHCP Server from the Configure drop-down menu, if connecting to a router DHCP server. This is the most common setting when using a router. In this configuration, your computer will be automatically assigned an IP address by the router.
Step 4 You must reboot your computer to "renew" your IP address.
Macintosh OS X
Step 1 Click on Apple Menu>System Preferences>Network>TCP/IP.
Linux
Step 1 At the command line type /sbin/ifconfig and you will get a listing of information. Your IP is shown after inet addr.
What is NAT?
NAT stands for Network Address Translator. Basically, each NAT box has a table consisting of pairs of local IP addresses and globally unique addresses, by which the box can "translate" the local IP addresses to global address and vice versa. Simply put, it is a method of connecting multiple computers to the Internet (or any other IP network) using one IP address.
With proper configuration, multiple users can access the Internet using a single account via the NAT device.
What is DHCP and what does it do?
Short for Dynamic Host Configuration Protocol, a communication protocol that dynamically or automatically assigns IP addresses to devices located on the network. With DHCP a device can have different IP address every time it connects to a network. DHCP also supports static and dynamic IP addresses on the same network.
DHCP uses the concept of a "lease" or amount of time that a given IP address will be valid for a computer. The lease time can vary depending on how long a user is likely to require the Internet connection at a particular location. It´s especially useful in education and other environments where users change frequently. Using very short leases, DHCP can dynamically reconfigure networks in which there are more computers than there are available IP addresses.
What is a VPN?
Short for Virtual Private Network. A VPN allows two or more private networks to be connected publicly. This is done by creating a securely encrypted tunnel. This will allow users to exchange critical information remotely and a way to manage their network.
What is a MAC address?
The MAC (Media Access Control) address is a networking device´s unique hardware number. This allows for networking devices to identify each other on the network, whether it be on a private LAN or on the Internet.
The MAC address is a 12 digit Hexadecimal number;
· A-F
· 0-9
Note: A Mac address can also be referred to as a Physical Address, Hardware Address or Ethernet Address.
· How do I find the MAC/Adapter Address in Windows 98 or Windows Me?
· How do I find the MAC/Adapter Address in Windows NT, 2000 and XP?
· Macintosh
What is PPTP?
Point-Point Tunneling Protocol (PPTP) is the technology that creates a Virtual Private Network (VPN). PPTP is to insure that messages are transmitted from one private network to another. Users can dial into their corporate network via the Internet with PPTP.
What is an Access Point?
An access point is a bridging device for connecting a wired and wireless network together. Access points are typically wireless routers or stand-alone devices that plug into an Ethernet hub, switch, or router.
What is WPA?
WPA, or Wi-Fi Protected Access, is a Wi-Fi standard that was designed to improve the security features of WEP (Wired Equivalent Privacy). The technology is designed to work with existing Wi-Fi products that have been enabled with WEP (i.e., as a software/firmware upgrade to existing hardware).
The 2 major improvements over WEP:
· Improved data encryption through the Temporal Key Integrity Protocol (TKIP). TKIP scrambles the keys using a hashing algorithm and, by adding an integrity-checking feature, ensures that the keys haven’t been tampered with.
· User authentication, which is generally missing in WEP, through the extensible authentication protocol (EAP). WEP regulates access to a wireless network based on a computer’s hardware-specific MAC address, which is relatively simple to be sniffed out and stolen. EAP is built on a more secure public-key encryption system to ensure that only authorized network users can access the network.
* It should be noted that WPA is an interim standard that will be replaced with the IEEE’s 802.11i standard upon its completion.
What is SSID?
SSID, or Service Set Identifier, is the workgroup name of your Wireless Network. All devices (Access Points, Wireless Routers, and Wireless Network Adapters) must all have the same SSID to communicate on the Wireless Network.
· You can use up to 32 letters and/or numbers.
· Do not use spaces, dashes, slashes, or other non-alphanumeric characters.
· The SSID is CaSe-SenSiTiVe.
it is recommended to change your SSID. Since the SSID is transmitted, do not use personal information. The SSID has nothing to do with security, it simply is a name for your wireless network.
What is Infrastructure?
Infrastructure: An 802.11 network in which wireless devices communicate with each other by first going through an Access Point (AP) or wireless router.
What is Ad-hoc mode?
Set of 802.11b wireless stations that communicate directly with one another without using an access point or any connection to a wired network.
What is WEP?
WEP stands for Wired Equivalent Privacy. It is based on the IEEE 802.11 standard and uses the RC4 encryption algorithm. Enabling WEP allows you to increase security by encrypting data being transferred over your wireless network.
When WEP encryption is enabled, there are up to four options*: 64-bit and 128-bit. 64-bit is the same as 40-bit WEP. The lower level of WEP encryption uses a 40-bit (10 character) "secret key" (set by the user), and a 24-bit "initialization vector" (not under user control). So lower level 40 and 64 bit WEP cards are equivalent in encryption strength and compatibility.
* 802.11B supports 64 and 128-bit encryption, 802.11B+ (enhanced) supports 64, 128, and 256-bit encryption, 802.11G support 64 and 128-bit, and 802.11A supports 64, 128, and 152-bit encryption.
Note: WEP does not stand for Wireless Encryption Protocol.
What is a Switch?
A switch connects all computer LAN connections into one device like a hub. Unlike hubs, switches can run at full-duplex mode. This means that the computer and switch can both transmit and receive simultaneously. The biggest difference between a switch and a hub is that when a computer transmits a digital signal to a hub, it’s then sent to all ports attached to that hub, whereas a switch will send it only to the specific port where the destination MAC address is located.
A firewall is a system that is designed to prevent unauthorized access to private computers or networks. Firewalls can be implemented in hardware or software. All data entering or leaving the computer must pass through the firewall. The purpose of a firewall is to allow the data you want to get through, like the web sites you ´re looking at, or your email or the network games you are playing, while keeping hackers out.
Routers use NAT which will act as a firewall. You cannot "turn the firewall off". A way to allow traffic in from the internet is to open ports or enable DMZ to allow all traffic to 1 computer. Would the information be intercepted while transmitting on air?
WLAN features two-fold protection in security. On hardware side, as Direct Sequence Spread Spectrum technology, it has the inherent security feature of scrambling. On software side, WLAN series offer the encryption function (WEP) to enhance security and Access Control. Users can set it up depending on their needs.
What is PPPoE?
PPPoE stands for Point-to-Point Protocol over Ethernet. It is a non-standard method of connecting to your ISP to gain an IP address. It relies upon a software client that is provided by the ISP. An IP address is required to gain a connection to the Internet.
What is Web-based Manangement?
A device (hubs, switches, routers, or wireless access points) with an embedded web-based (hypertext) interface allows users to manage the hub from anywhere on the network through a standard browser such as Netscape Navigator or Microsoft Internet Explorer. The web-browser acts as a universal access tool and can communicate directly with the device using HTTP protocol.
To access your device, open your web browser and enter the IP address of the device (192.168.0.1 for example). Please refer to your manual or quick installation guide for the IP address.
What is the maximum number of nodes which can be supported in Infrastructure mode? How about Ad-Hoc mode?
In theory, in Infrastructure mode, a maximum of 2048 wireless nodes can be supported. In ad-hoc mode, a maximum of 256 wireless nodes can be supported. Please keep in mind that ad-hoc mode has additional overhead and the more nodes which are used, the lower the amount of available bandwidth will be. For applications which are bandwidth intensive, such as games and multimedia, 6 to 8 nodes would be optimum in achieving adequate network performance.
What is Firmware?
Software (programs or data) that has been written onto read-only memory (ROM). Firmware is a combination of software and hardware. ROMs, PROMs and EPROMs that have data or programs recorded on them are firmware.
What is OFDM?
Orthogonal Frequency Division Multiplexing, an FDM modulation technique for transmitting large amounts of digital data over a radio wave. OFDM basically splits the radio signal into multiple smaller sub-signals that are then transmitted simultaneously at different frequencies to the receiver. OFDM reduces the amount of cross talk in signal transmissions. 802.11a and 802.11g
WLAN technology uses OFDM.What is a VLAN?
Virtual Local Area Networks (VLANs) are a logical grouping of network users and resources connected to defined ports on the switch. A VLAN looks like, and is treated like, its own subnet. By using virtual LANs, you’re no longer confirmed to physical locations. A VLAN can be created by location, function, and department regardless of where the resources or users are located.
What is IEEE 802.11 standard ?
The IEEE 802.11 specification is a wireless LAN standard developed by the IEEE committee in order to specify an "over the air" interface between a wireless client and a base station or Access Point, as well as among wireless clients. The IEEE created the specification but they do not certify equipment, WECA certifies wireless LAN products.
What is DSSS? What is FHSS? And what are their differences?
Frequency hopping spread spectrum (FHSS) uses a narrowband carrier that changes frequency in a pattern that is known to both transmitter and receiver. Properly synchronized, the net effect is to maintain a single logical channel. To an unintended receiver, FHSS appears to be short-duration impulse noise.
Direct-sequence spread-spectrum (DSSS) generates a redundant bit pattern for each bit to be transmitted. This bit pattern is called a chip (or chipping code). The longer the chip, the greater the probability that the original data can be recovered. Even if one or more bits in the chip are damaged during transmission, statistical techniques embedded in the radio can recover the original data without the need for retransmission. To an unintended receiver, DSSS appears as low power wideband noise and is rejected (ignored) by most narrowband receivers. Most wireless LAN vendors have been adopting DSSS technology after considering the trade off between cost and performance,
Would the information be intercepted while transmitting on air?
WLAN features two-fold protection in security. On the hardware side, to an unintended receiver, DSSS appears as low power wideband noise and is rejected (ignored) by most narrowband receivers. On the software side, WLAN series offer the encryption function (WEP) to enhance security and Access Control. Users can set it up depending on their needs.
What is Auto-Negotiation?
Auto-Negotiation is a mechanism that takes control of the cable when a connection is established to a network device. Auto-Negotiation detects the various modes that exist in the device on the other end of the wire, and advertises it own abilities to automatically configure the highest performance mode of interoperation. Auto-Negotiation acts like a rotary switch that automatically switches to the correct technology, such as 10BASE-T, 100BASE-TX, 100BASE-T4, or a corresponding Full Duplex mode. Once the highest performance common mode is determined, Auto-Negotiation passes control of the cable to the appropriate technology and becomes transparent until the connection is broken.
What is Spread Spectrum ?
Spread Spectrum technology is a wideband radio frequency technique developed by the military for use in reliable, secure, mission-critical communications systems. And Spread-Spectrum is designed to trade off bandwidth efficiency for reliability, integrity, and security. In other words, more bandwidth is consumed than in the case of narrowband transmission, but the trade off produces a signal that is, in effect, louder and thus easier to detect, provided that the receiver knows the parameters of the spread-spectrum signal being broadcast. If a receiver is not tuned to the right frequency, a spread-spectrum signal looks like background noise. There are two main alternatives, Direct Sequence Spread Spectrum (DSSS) and Frequency Hopping Spread Spectrum (FHSS).