1. What is a Wireless LAN (WLAN)?
Very simply, a WLAN is a wireless or radio frequency extension of a LAN. Some WLANs however, such as ad-hoc networks have no wired components. Generally these networks are based on the IEEE 802.11 protocol suite but can also consist of proprietary communication protocols.
YES! WLANs use much of the same technology (and even more in cases) that makes digital PCS phones secure. Spread spectrum and frequency hopping was originally developed for military use. The technology was designed to keep prying enemy ears from intercepting highly sensitive data. Both of these technologies are used in virtually all WLAN applications.
Besides making the radio link secure, the data is also encrypted for even more security if the radio link were ever ?tapped?. Different equipment manufacturers have implemented 40 bit, 64bit and 128 bit encryption. This initial attempt at security had some weaknesses, which were quickly identified.
New enhancements known as ?Wi-Fi Protected Access? (WPA) greatly improve the security of WLAN links. The two primary areas of improvements are in the areas of data encryption and user authentication.
The new encryption technique TKIP (Temporal Key Integrity Protocol) addresses all the known vulnerabilities of the previous WEP encryption technique by ?wrapping? a very secure protective layer over the existing WEP packets.
WEP had virtually no user authentication mechanism in it?s initial deployment. WPA coupled with another authentication technique EAP (Extensible Authentication Protocol) provides the mechanism for true authentication services. This not only authenticates the user at login, but also protects the user from accidentally joining an un-wanted rogue network, which may steal network credentials.
Additional layers of security can be supported through virtual private networks (VPN), radius servers, and other techniques.
3. Explain What do I need to make a WLAN work?
Basically all that is needed is a transmitting device, which connects to the Internet and operates in one of the unlicensed frequency bands, and a receiver (typically a PCMCIA card), which connects to your computer. But it?s not that easy?
There are many current products that have been designed with specific uses in mind. Some are very simple, and others very sophisticated. It?s sort of like asking what kind of computer does someone need? Well it really depends on what it?s being used for. Is it processing large amounts of data, maybe just used for surfing the web, possibly holding top-secret information! It?s obvious that the type of job dictates the type of equipment needed. Are you confused yet? Don?t worry! LBA has the expertise to help you decide what is the right system for your business application.
4. Explain Are all WLAN products interoperable?
All products that conform to IEEE 802.11 standards maintain some interoperability. Products that carry the Wi-Fi certification are tested to verify a base level of interoperability.
5. Can we import users from Active Directory?
The next release of LANwriter will provide this facility of connecting to an Active Directory server on the network for user management.
6. Explain How is LANwriter administered?
Administration of all aspects of LANwriter is done via a web browser from within the LANwriter application itself.
7. Explain What are the security features in LANwriter?
Every user is required to have a valid login account before using LANwriter to write data. User validation is against the WindowsXP security database of the computer hosting LANwriter. Users are of different kinds and there are ascending levels of security privileges. For eg. Admins have full control while Normal users can only compile data writing jobs and write them only after Approvers give approval. All data is cataloged and optionally archived to a spare Disk Drive before being written. This can be referred to at anytime to find out what data was written by any particular user for any particular job.
8. Explain Can LANwriter be used over the internet?
LANwriter being a browser-based application can be accessed over the internet if the LANwriter host is published as a virtual server behind your firewall. However this accessibility is best used for approving jobs remotely rather than for creating jobs which requires actual bulk file transfer over the network and cannot be done through the browser.
9. Explain Can we have too many APs and what is the impact?
We can absolutely have too many APs and this can actually be more troublesome than too few APs. When devices on the same channel are co-located without enough channel separation the result is wasted equipment and reduced performance.
LAN is a computer network that spans a relatively small area. Most LANs are confined to a single building or group of buildings. However, one LAN can be connected to other LANs over any distance via telephone lines and radio waves. A system of LANs connected in this way is called a wide-area network (WAN). Most LANs connect workstations and personal computers. Each node (individual computer) in a LAN has its own CPU with which it executes programs, but it also is able to access data and devices anywhere on the LAN. This means that many users can share expensive devices, such as laser printers, as well as data. Users can also use the LAN to communicate with each other, by sending e-mail or engaging in chat sessions.
11. Explain Is Setup, Configuration and Maintenance easy?
YES ! Setup is very easy. Even a lay computer user will be able to install LANwriter without any difficulty, thanks to the intelligent setup program that automatically installs the required system components and guides and prompts the user in a friendly way to input appropriate information as and when necessary. After the initial installation is done, the basic LANwriter setup may be further configured from any machine on the network via a web browser.
LANwriter is installed on a WinXPP workstation equipped with a CD-Burner, USB Ports for flash drives and connectivity to the Internet for FTP . A LAN user wanting to write a CD or transfer data to a pen drive or an FTP server, starts up the browser on his machine and points it to a web application running on the LANwriter sever, logs in and is guided along by the software in transferring files to the LANwriter workstation. He then creates a data transfer job and asks LANwriter to write the data to the chosen destination viz. CD, Pen drive or Ftp server. LANwriter executes the writing job in a queued manner and stores the information about the job in a database and safely archives the files to an archive location for future reference and reuse. LANwriter thus keeps a detailed record of the History of all data writing jobs and acts as a secure data publishing system for the enterprise.
13. Explain What is an Access Point (AP)?
An access point or AP is the infrastructure device that contains a wired network interface and one or more radio interfaces that bridges data between the air and the wire.
14. Explain What is NETBIOS and NETBEUI?
NETBIOS is a programming interface that allows I/O requests to be sent to and received from a remote computer and it hides the networking hardware from applications.
NETBEUI is NetBIOS extended user interface. A transport protocol designed by microsoft and IBM for the use on small subnets.
NETBIOS is a programming interface that allows I/O request to be send to and recieved from a remote computer and it hides the networking hardware from applications.
NETBEUI is a netBIOS extended user interface. A transport protocol designed by microsoft and IBM for the use on small subnets.
PING stands Packet Internet Gopher. This is a utility for ensuring connectivity between computers . ICMP protocol works behind this utility. Under it , sending node sends packets to destination node and reply is received if there is proper communication between two.
PING : Packet Internet Gropper
it's a diagnostic utility , which diagnose devices connectivity.
it use ICMP: Internet Control Messaging protocol to send echo requests ( usually 4 packets) and receive echo replies (4 packets)
16. Explain What are the different type of networking / internetworking devices?
Also called a regenerator, it is an electronic device that operates only at physical layer. It receives the signal in the network before it becomes weak, regenerates the original bit pattern and puts the refreshed copy back in to the link.
Bridges:
These operate both in the physical and data link layers of LANs of same type. They divide a larger network in to smaller segments. They contain logic that allow them to keep the traffic for each segment separate and thus are repeaters that relay a frame only the side of the segment containing the intended recipent and control congestion.
Routers:
They relay packets among multiple interconnected networks (i.e. LANs of different type). They operate in the physical, data link and network layers. They contain software that enable them to determine which of the several possible paths is the best for a particular transmission.
Gateways:
They relay packets among networks that have different protocols (e.g. between a LAN and a WAN). They accept a packet formatted for one protocol and convert it to a packet formatted for another protocol before forwarding it. They operate in all seven layers of the OSI model.
I Think Switches has left both layer 2 and 3. Bridges aren't used these days and it also work on data link layer and not on physical layer.
Switches (L2)
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It breaks collasion domain.Uses MAC address to communicate. Faster than bridges.
17. Explain What is difference between baseband and broadband transmission?
In the baseband transmission, the entire bandwidth of the cable is consumed by a single signal. In broadband transmission, signals are sent on multiple frequencies, allowing multiple signals to be sent simultaneously.
In baseband transmission we transmit digital signal without converting it into analog, here a low pass channel is used.
In broadband transmission we transmit digital signal by converting it into analog. here a band pass channel is used.
18. Explain how to create vlan?
VLAN is technology in which we can administratively assign different ports of same layer to switch to different subnetworks.
19. Explain What is local area network?
A local area network (LAN) is a computer network covering a small physical area, like a home, office, or small group of buildings, such as a school, or an airport.
Lan stands for local area network.A number of systems conneted in a physical connectivity in a limited geographycal location that is called lan.It provides full time connective.
