Filed under: The Success in Service S aelection Board(SSB) interview
Dear friends,
I like to add my experiences about my first interview for Indian Indian Air Force at mysore held from 12 th of April 2008. I am very honored to write this post from my interview place. When I reached mysore railway station on 11th april around 10 O’ clock in the night I was very eager to know what will be going on the very first day. I was supposed to report at the Prepaid Autobooth which is in the railway station of mysore on next morning.
So, I took a bed in the retiring room in the railway station. As it was the first time when I am staying in a place where I do not know anyone I was little eager to know how I am going to manage. Then when I entered to the retiring room I could find some of the persons who have been already there for the same purpose which I had came for. And also, I found the retiring room was very neat. The bath rooms were are also clean. That’s were I got the first confidence. Then I slept and was ready at the prepaid auto booth at 6:45 Am. Exactly at 7 O’ clock the uniformed persons from IAF came to receive us and they boarded our luggages in the trucks and we got boarded in the van after verification of our call up letters. There were around 32 persons who got boarded in the van.
We reached the IAF station at 7:30 Am. We were verified for our identification and taken into a big conference hall. There we were welcomed by the Psychologist with warm wishes. Then our doubts were clarified regarding the filling up of Personnel Information Questions and the percentage of marks. They are received with our journey tickets for TA. So, many of us are little hungry and little tired since some of them had overnight travel. We were given Tea and Bread which quenched our hunger.
Then some of the persons were called in to have Phase one tests where, others who have completed their Phase one were waiting outside the hall. Then we had our tests and the results of phase one have been announced. I am also one of the person who got selected. It was one of stepping stone in my life and the first stepping stone in the SSB.
It was 2 O’ clock. We got our luggages and kept near our rooms. We were taken for lunch at the Dining Hall. There we had a lunch with a fruit and Dall with rice. It was wonderful environment to have lunch in such a place. There I founded spoon and I had no idea to use that.
Now, we are given rooms for our accommodation for the next four days for further tests and interviews. In our hall there were around 10 beds and nine candidates are given accommodation. In the room we were provided with all facilities like bed with bed sheets, pillows with cover even, we are asked to bring light bedding. We had lockers and stands to dry our clothes. We are given addition table fans, mosquito destroyers which I am not aware or imagined which I will have such a facility. We were given instructions about our facilities and our expected behaviors and our time schedules. In the evening we had another psychological test. The day 1 ended smoothly.
The day 2, We had tea at 5:30 in the early morning and got ready at 7 O’ clock as we are instructed to do so. I was supposed to have the personnel interview at 10:30 in the morning. I dressed up and got ready, I had interview in a charming manner. The interview panned made to feel comfortable for making me to perform better in which the software companies or others do not follow. I was questioned about my interests, hobbies, opinion of my parents, friends, neighbors, and class mates about me. It lasted up to one hour. I enjoyed very much..
Finally i got conference out.. sad but need to accept it…
Filed under: Computer Science
Both offer advantages to the home and small business customer
This tutorial will help you understand the practical differences between DSL and cable modem networking. While similar in many respects, DSL and cable Internet services differ in several fundamental ways.
DSL and Cable – Comparison and Contrast
When evaluating cable and DSL services, you should consider the following:
- Speed (advantage – Cable): Cable boasts faster speed than DSL Internet in theory. However, cable does not always deliver on the promise in everyday practical use.
Read more – DSL vs Cable – Speed Comparison
- Popularity (advantage – Both): In the U.S., cable Internet enjoys significantly greater popularity than DSL, although DSL has been closing the gap recently.
Outside the U.S., DSL continues to hold the edge. Both dominate the rest of the competition with millions of subscribers to each.
Read more – DSL and Cable Modem Subscribers – U.S.
Customer Satisfaction (advantage – DSL): Even if a technology is popular, customers may be unhappy with it whether due to cost, reliability or other factors. Indeed, in the U.S. cable services generally rate lower than DSL in customer surveys.
Read more – DSL vs Cable Customer Satisfaction – U.S.
Security (advantage – Both): Cable and DSL implement different network security models. Historically, more concerns have existed with cable security, although cable providers have definitely taken steps to improve security over the past few years. It’s likely both DSL and cable are “secure enough” for most people’s needs.
Filed under: Computer Science
Here’s How:
1. Verify the current local IP address of your router. Home broadband routers are manufactured to use a default address such as 192.168.0.1, 192.168.1.1, or 192.168.2.1. If you are unsure of your router’s default IP address, or if you have changed the default previously, follow these instructions:
2. Verify your computer is connected to the router either via an Ethernet cable or wirelessly association with the router. In either case, ensure your computer possesses a valid IP address.
3. Open a Web browser window and request a connection to the router using its local IP address. For example, type http://192.168.1.1/ in the browser’s address bar to request a connection to a router using the IP address 192.168.1.1.
4. If the browser request is successful, you will be connected to the router and prompted for the administrative login (username and password) information. Enter the administrative login information to authenticate yourself to use the router’s admin screens. Broadband routers contain default usernames and passwords when first installed. Consult your router’s documentation if you need to know the default login information.
5. If the browser request returns an error message, your computer is likely not connected to the router. You may need to perform additional troubleshooting to establish a connection. Try the following procedures and repeat step 3 above as needed to resolve any connection problems:
a. Reboot (power off and on) your router
b. Temporarily disable your network firewall
c. Reset your router to factory defaults (consult the manufacturer’s documentation)
Tips:
1. If this is the first time you are connecting to a wireless router for admin work, consider using a wired Ethernet link rather than a Wi-Fi link. Your Ethernet connection will keep working even if you haven’t finished configuring or accidentally break the Wi-Fi settings.
What You Need:
- Wireless router
- Computer with Web browser
Filed under: Computer Science
- reposition your router (or access point) to avoid obstructions and radio interference. Both reduce the range of WiFi network equipment. Common sources of interference in residences include brick or plaster walls, microwave ovens, and cordless phones. Additionally, consider changing the WiFi channel number on your equipment to avoid interference.
- upgrade the antenna on your router (or access point). WiFi antennas on most wireless base stations can be removed and replaced with more powerful ones.
- add another access point (or router). Large residences typically require no more than two APs, whereas businesses may employ dozens of APs. In a home, this option requires connecting your primary wireless router (access point) to the second one with Ethernet cable; home wireless routers and/or APs don’t normally communicate with each other directly.
- add a bi-directional WiFi signal amplifier to wireless devices as needed. A WiFi signal amplifier (sometimes called “signal booster”) attaches to a router, access point or Wi-Fi client at the place where the antenna connects. Bi-directional antennas amplify the wireless signal in both transmit and receive directions. These should be used as WiFi transmissions are two-way radio communications.
- add a WiFi repeater. A wireless repeater is a stand-alone unit positioned within range of a wireless router (access point). Repeaters (sometimes called “range expanders”) serve as a two-way relay station for WiFi signals. Clients too far away from the original router / AP can instead associate with the WLAN through the repeater.
Filed under: Computer Science
This article will discuss two different methods for testing application compatibility with Windows Vista.
One of the largest barriers to upgrading to Windows Vista is that of application compatibility. Many applications that ran flawlessly under Windows XP are either problematic, or will not run at all in Windows Vista. As such, it is imperative that you test for application compatibility before upgrading to Vista.
There are two primary methods of performing an application compatibility test. One method is geared primarily toward smaller companies and home users, while the other method is intended for use in enterprise class environments. Because everyone’s needs are different, I will show you both techniques.
The Windows Vista Upgrade Advisor
The tool of choice for smaller organizations (or for home users) is the Windows Vista Upgrade Advisor. The Windows Vista Upgrade Advisor is a simple (but effective) tool that is designed to test to see if a PC is ready to be upgraded from Windows XP to Windows Vista.
Although this tool is intended for smaller organizations, do not let that fool you. The tool does a very effective job of making sure that the system in question is adequately prepared for the upgrade. Using the tool simply involves downloading it, running the Setup Wizard, performing a scan, and looking at the results.
You can download the Windows Vista Upgrade Advisor directly from the Microsoft Web site. The tool will run on any version of Windows XP, so long as it is 32-bit. Once the tool has been downloaded, simply double click on the file that you have downloaded to run the Setup wizard. Setup is extremely simple.
Once Setup is complete, you must run a system scan to check the PC’s Vista compatibility. Pretty much any product that requires you to scan a system (anti virus, disk repair program, etc.) requires you to sit and wait while the scan completes. This tool does require you to wait for about five minutes for the scan to complete, but the wait is not a complete waste of your time, because the tool gives you information about the differences between the various versions of Vista during your wait.
When the scan completes, you will see a summary screen. Notice at the top of the screen that the first piece of information that you are given is a definitive answer as to whether or not the computer can run Vista.
The lower portion of this screen provides you with some basic information regarding Vista’s system requirements, the computer’s hardware devices, and applications installed on the system. As you can see in the figure, this machine met all of the necessary system requirements, but there were a few hardware devices for which the tool had no compatibility information. Clicking the See Details button (in the Device section) displays a screen showing which devices the tool had no information on. Had there been device compatibility issues, those would have appeared on this screen as well.
The bottom portion of this screen contains a section on application compatibility. . the Windows Vista Upgrade Advisor has identified some problems with some of the applications installed on this machine. Clicking the See Details button (in the rograms section) causes the utility to display the screen.
As you can see in the figure, the Windows Vista Upgrade Advisor displays the name, vendor, and version number for each application that has Vista compatibility issues. The utility also displays a summary of the action that is required in regard to the application. In this particular screen shot, it appears as though the required action message is completely generic, but that is not the case. I have had this screen to tell me that if I uninstall an application prior to the upgrade, I will be able to reinstall it after the upgrade with no issues. The point is that the utility does not just display the same message for every application.
Just as the Windows Vista Upgrade Advisor displays applications known to have compatibility problems, it also displays a list of applications that are guaranteed to be compatible with Vista
If you look toward the top of the screen shown in Figure C, you will notice that the compatibility report is tabbed. This allows you to switch back and forth between system, device and application compatibility information. Notice that the tab on the right is a task list. If you click the Task List tab.
Notice in the figure that the Task List displays the tasks that need to be completed prior to upgrading to Vista. The Task list also displays any tasks that you will have to do after Vista is installed. Again, the messages shown in the figure look generic, but the Task List really is worth paying attention to, because it does occasionally tell you something important that you need to do. For example, the Task List may tell you that you need to reinstall an application after the upgrade is complete.
Why Not Use the Windows Vista Upgrade Advisor in the Enterprise?
As you can see, the Windows Vista Upgrade Advisor is a great tool. That being the case, you might be wondering why you cannot use this tool in an enterprise environment. The reason why this tool is not suitable for larger organizations is because scans must be performed individually on each machine. There is no way to automate system scans or to compile a report that displays the scan results of every workstation in the organization.
One thing to keep in mind is that the Windows Vista Upgrade Advisor provides you with exactly the same information as Microsoft’s enterprise class solution (Business Desktop Deployment 2007). The real value of Windows Vista Upgrade Advisor is its simplicity. The Business Desktop Deployment 2007 tool is effective for deploying Vista to large numbers of workstations, but takes a lot of work to configure. As you have seen, there is absolutely no configuration necessary for running the Windows Vista Upgrade Advisor. Therefore, my advice would be that if you have fewer than 100 PCs in your organization then you are probably better off manually testing workstation compatibility by using Windows Vista Upgrade Advisor. For organizations with more than 100 PCs, you should normally use Business Desktop Deployment 2007 to assist you with the upgrade.
Filed under: Computer Science
Wireless and Antenna Terms
Wireless routers, access points, and adapters send and receive radio wave signals through antennas. The antenna is hidden inside adapters, but on routers and access points there’s a visible antenna. Radio waves can be focussed like a lightbulb. And like a light, some materials reduce or stop radio waves. While light focused from several lights is brighter and makes it easier to see, several antennas in the same area cause interference — the radio signals will be muddy and confused.
Your goals in optimizing power are:
- Avoid obstacles.
- Avoid interference.
- Increase signal strength. Power affects how far an antenna radiates.
- Use the equipment in places it’s most powerful and most sensitive.
Antennas don’t radiate equally in every direction. Just as the base of a lightbulb blocks light, and just as a light can be focussed by a reflector, so an antenna signal may be blocked and focused. Since people cannot see radio waves, you’ll rely on testing and trial-and-error to get an idea of where antennas “shine” most brightly. An adapter’s antenna is important, but the most powerful and sensitive antennas are on routers, access points, and detachable external antennas.
The focus of an antenna is either omni-directional antenna or directional. “Omnis” are used in most home products, they radiate horizontally all around, but are weaker upward or downward. When visible, these antennas are usually a rod a few inches long. A directional antenna radiates strongly in a limited direction. It is a flat panel or a dish. These are used for point-to-point transmissions (where two antennas are focused directly at each another). These need a line of sight between them, and preferably a large open space around the main beam.
When you are near antennas you’ll still get a signal, even if you are out of the direction of its strongest signals. But when further away, you have to be in the direction the beam is the most powerful and unobstructed to receive it.
One final concept before you go to the above links is interference. Interference is a signal — one you don’t want — at the same frequency as the one you’re using. Interference comes from devices such as microwave ovens, cell phones, 2.4 GHz cordless phones, and copy machines. Interference is also caused when your own wireless signals are bounced off reflecting objects. Objects may partly or completely absorb signals, reflect them, bend them, or let them pass right through. Metal and water (including the water in people!) absorb or reflect signals. Air, wood, and glass tend to let signals pass with weakening. And when outdoors, plants and the weather may cause interference.
Improving Wireless Range: Choosing the Best Locations
This describes moving equipment, positioning antennas, and avoiding obstacles. When optimizing your existing equipment, consider:
- Placing antennas in a good location, at a good angle.
- Avoiding physical things that block signals.
- Reducing the interference from other things that transmit radio waves.
Before starting adjustment, make sure that antennas and cables are securely fastened!
If your network has more than a couple wireless devices, before you move things, decide which wireless devices are transmitting the heaviest load. These links are important to optimize. NETGEAR products have automatic data rate fallback, which allows increased distances without losing connectivity. It also means that devices that are further away are inherently slower. Therefore the most critical links in your network are those where the traffic is high, and the distances are great. Optimize those, first. The ones that are least important are links that have little, occasional traffic, and which have a strong signal strength.
Picking Good Locations for Antennas
- Antennas should be in line-of-sight of one another, where possible. Put your face next to one antenna, to find whether the other is visible.
- Place high, and clear of obstructions as practical.
- Keep antennas 2 feet from metal fixtures such as sprinklers, pipes, metal ceiling, reinforced concrete, metal partitions. (However, antennas on roofs do not necessarily give the best results. )
- Keep away from large amounts of water such as fish tanks and water coolers.
- Antennas transmit weakly at the base, where they connect. So don’t expect good reception from the bottom of a router or access point.
- For multi-story buildings, placing antennas at 45 degrees (diagonally) or 0 degrees (straight out parallel to the floor) may be most effective.
Reducing Interference
Avoid windows unless communicating between buildings. (Windows let in interference from the outside world.)
Place antennas away from various electromagnetic noise sources, especially those in the 2400 – 2500 MHz frequency band. Common noise-creating sources are:
- Computers and fax machines (place wireless equipment no closer than 1 foot)
- Copying machines, elevators and cell phones (no closer than 6 feet)
- Microwave ovens (no closer than 10 feet)
Improving Wireless Range: Tuning Equipment
Using the best channels has a big effect on network performance. Your goal is to choose settings that avoid interference from other networking and radio frequency equipment. (If you have 802.11a or 802.11a/g, channel selection is less important, skip to “Reducing Wireless Network Traffic”.)
f you have a simple home network, and aren’t close to neighbors with wireless equipment, you may be lucky enough just to choose between many channels that work well.
Complications arise when:
- You want much better coverage than you’re getting.
- You use multiple access points or wireless routers. (Then you’ll probably be using more than one channel.)
- You aren’t the only person nearby running a wireless network.
Simple Spacing of Channels
As explained in Improving Wireless Range: Overview, improving signal strength is not like adding more lights to get a brighter living room. Devices that transmit powerfully — such as routers, access points, and cell phone base stations — confuse one another. It’s necessary to distance them and to have them use different channels.
For 802.11b and 802.11g, there are 11 channels for wireless equipment (13 channels in Europe). In the simple situation where there’s little interference, you can choose any channel that works for you. When there is interference from wireless networks that overlap with one another, each network should use one of the non-overlapping channels: 1, 6, or 11 (1, 7, 13 in Europe). Then, 3 networks can use the same space with minimum interference. If you can’t do that, choose channels as widely spaces as possible.
What If a Channel I Want to Use Has Too Much Noise (Interference)?
If your neighbor has a wireless network, it wouldn’t be surprising that they are already using channel 1 and channel 11. Unfortunately, you can’t completely avoid interference just by using other channels. Wireless protocols 802.11b and 11g only have 3 non-overlapping channels. Therefore when 4 or more channels are used in the same area, the level of interference can increase notably. If you and your close neighbor both have a router and a wireless access point, for example — which makes a total of four powerful transmitters — both of you will have a certain amount of interference.
If there’s a severe problem, a practical and sociable thing is to talk to your neighbors using wireless networks that can be seen when you scan. Together, you can choose optimal channels for your respective networks. You’ll want your own channels at least 5 apart. So, for example, you could use channels 1 and 8, and your neighbor could use 5 and 11.
You may be able to place routers and access points further away inside your homes. After all, the kinds of physical barriers that reduce your transmission range also reduce the signal that your neighbor doesn’t want to see.
If you can use a directional antenna, or an antenna cable to shift an antenna, that can help you both. See the articles on antenna selection.
Reducing Wireless Network Traffic
When there’s noise, your network performance drops, so one approach is not to stop the noise, but to reduce the amount of network data being transmitted.
In a noisy environment, it may be useful to keep part of your network wired. If Ethernet cabling isn’t an option, consider NETGEAR’s Powerline products — using existing home wiring instead of cables.
When SSID Broadcast is turned on, it’s easiest for equipment to find the strongest signal. However this also causes network overhead. When the SSID is broadcast, your neighbor’s equipment may keep a record of it, and automatically try to connect several times a second; this can cause significant performance reduction. So where there are close networks, turn off SSID Broadcast, and change the default SSID.
Turning off WEP and WPA may increase network throughput, but exposes your network to hackers. This is not recommended, except for testing purposes.
Improving Wireless Range: Choosing the Right Equipment
This article is useful:
- To compare how various wireless devices should be used, or
- If Choosing the Best Locations and Tuning Your Equipment don’t get the performance you want, or
- You want a big improvement immediately at a reasonable cost.
The cheaper solutions are first, followed by more expensive, but very powerful ones. A network with more than a few computers may benefit from a combination of approaches.
I. A New Router
II. A Second Router as a Wireless Access Point
III. Powerline
IV. An Access Point
V. An Antenna
VI. A Site Survey
I. A New Router
Replace your existing router with a better one. This is recommended if your router is a couple years old. A new router will probably double your coverage in a single area.
Advantages
- Making the change is likely to be simple. New NETGEAR routers come with wizards that make basic installation easy, and will probably fit with your existing network with few other changes.
- The newest NETGEAR routers are excellent values.
- New routers such as the WPN824 RangeMax can deal with tricky wireless environments without any tuning at all.
Disadvantages
- May require you to also buy new adapters to get all the router benefits.
- Isn’t best for difficult environments with spotty coverage, or for covering large areas such as entire buildings.
II. A Second Router to use as a Wireless Access Point
With this solution you disable features of a wireless router, leaving the wireless transmitter working. This configuration uses an existing wired or wireless router. Here’s a sample configuration.
Advantages
- Low cost. With an inexpensive router, this is the cheapest solution.
Disadvantages
- NETGEAR provides no free support at all for this.
- NETGEAR routers are not designed for this purpose, so configuration, behavior, features, and performance may not be as expected. Problems may include no DHCP passthrough and stopping access point roaming.
- Only suitable for small, moderately loaded networks. E.g., not good for running a game server or a database server.
- Can be slightly difficult to configure.
III. Powerline
Instead of networking through the air, or through Ethernet cables, Powerline uses the existing electrical wires in your walls. See Powerline FAQ.
Advantages
- Fairly low cost.
- Excellent solution in difficult RFI environments, since Powerline signals don’t go through the air.
- Good security for casual users.
- Powerline can easily be moved in a house. No reconfiguration is needed, units can be plugged in where and when you want.
- Doesn’t require continuous wireless coverage, just an available electrical plug.
- Works nicely with wireless technology to cover “blind spots”.
Disadvantages
- Powerline performance is not limited by RFI, but it is limited by noisy power. As with wireless, it’s difficult to know exactly how well Powerline will work until you try it.
- Powerline is often not suitable for businesses, dorms, and hotels. See Assessing Powerline for Business Environments.
IV. An Access Point
Dedicated access points have better performance and features than routers that are used as access points (see above).
Advantages
- Can cover an area far distant from your wireless router, without having to cover all the area in between.
- Potentially excellent LAN performance, especially with careful configuration and placement.
- Advanced security features.
- Access points are covered by NETGEAR’s free support policy.
Disadvantages
- Business access
- Using access points in repeater mode does not result in the best performance.
- Configuration is more complicated than other solutions.
V. Antennas
Antennas can provide great power. NETGEAR antennas and boosters are available in the United States that transmit for miles. Less powerful antennas may still cover an entire building.
Advantages
- Antennas give excellent throughput over large continuous areas.
- Antennas are available for outdoor, as well as indoor use.
- Antennas are often the most practical solution for networking between buildings.
Disadvantages
- Antennas must be connected to equipment specifically designed for them. This adds to cost.
- A site survey may be needed before installation. (See below.)
- Antennas may require professional installation. This adds to cost.
- In thunderstorms, connections may be slow or temporarily interrupted. Critical networking or networking in areas of frequent storms may require other network connections as a backup.
- Regulations in all countries limit how antennas can be used.
VI. A Site Survey
A site survey is a study of your environment, your network, and your computing needs. Self-help site survey software is available, but a complete evaluation requires a professional. For a network of more than a few computers, plan on using 1-2 hours of help in the range of $100-$150 / hour. For all but small networks using the cheaper approaches described above, the amount spent will be saved by avoiding buying wrong equipment, or equipment that isn’t cost-effective in your situation. These professionals are found online or in the Yellow Pages under “Radio Communication Equipment”.
Improving Wireless Range: Testing
Test as little or as thoroughly as you like. When making changes, you’ll want to test to see how you’ve improved. When you test, use your actual environment. For example, test at home while others use computers, talk on cell phones, and run the microwave.
Start with the cheapest and fastest test:
See If It Works
If the network works, and you’re satisfied with the performance, don’t do anything else. If it seems like it’s working, it is.
To Test Coverage Using the NETGEAR Utility
Each wireless device has a software utility monitoring signal strength and transmission. Most have a meter that reads green, yellow or red. (One adapter has bullets from 8 to 0, instead.) When the meter is green, then that device is getting a strong signal and good throughput. As you move further away from the router or access point, the signal strength drops to yellow. As the signal gets weaker, throughput automatically is adjusted downward, but the connection is maintained. Eventually, you move so far away that the meter turns red: at that point you will have throughput and connection problems.
You can get a idea of where signal is strong by walking around and seeing where it’s green, yellow or red. In fact, this is a technique used by NETGEAR in testing.
To Test Whether Two Transmitters are Too Close
The closer two routers or access points using the same channel are, the more they interfere with each other’s signal. Take an adapter plugged into a laptop, and establish a connection with a router or access point. Then move to within 6 feet (2 meters) of the router or access point’s antenna. Scan the network for available signals. If you can see any other router or access point that is using the same channel, then you should either:
- Move the routers or access point further apart.
- Turn off one of the routers or access points.
- Change the channel of one of the routers or access points.
To Test For Packet Loss
This test is good to run while someone else is setting the position of the antenna for you.
The throughput meter gives an accurate measure of how much traffic is on your network, but does not show how much traffic is being lost and which must therefore be retransmitted. When packets are frequently dropped — for example in a very noisy environment — it puts a burden on your network. A small amount of packet loss on an Ethernet network is acceptable (1% or 2%). However, if there is several percent loss, or there are periods of several seconds of packet loss, then you should optimize your network.
Test packet loss using ping. (For other information, including how to interpret other ping results, see Testing Connections with Ping.)
1. On a Windows computer, type Start > Run > cmd. The cmd.exe window appears.
2. At the command prompt (the flashing cursor), type ping IPAddress -t, where “IPAddress” is replaced by the LAN address of the router, access point, or adapter you transmitting to. So your command would look something like this: ping 192.168.0.2 -t.
3. Press Enter. Now, every second, the device you are on will ask the remote device to respond to it.
4. When a packet is lost, the words “Request Timed Out” are displayed.
5. Press Control and the C key at the same time to end the test. The test concludes with a summary of all the packets lost.
6. Close the cmd.exe window whenever you choose.
6. Use Professional Help
Professionals have specialized equipment and experience that can be used to set up very effective networks. This is especially attractive for setting up wireless networks in large buildings or large outdoor areas. A professional can:
- Draw up a “site survey” map that identifies sources of noise and obstructions.
- Test the effectiveness of an existing wireless network.
- Make recommendations about equipment purchase.
- Make recommendations about equipment location and configuration.
- Make recommendations about how to mitigate noise sources.
- Do the actual equipment installation for you.
These professionals can be found online or in the Yellow Pages under “Radio Communication Equipment”.
Filed under: Computer Science
WiMAX (Worldwide Interoperability for Microwave Access) is the IEEE 802.16 standards-based wireless technology that provides MAN (Metropolitan Area Network) broadband connectivity. WiMAX is an Air Interface for Fixed Broadband Wireless Access Systems, also known as the IEEE WirelessMAN air interface. WiMAX-based systems can be used to transmit signals as far as 30 miles. So far, WiMAX can offer a solution to what is normally called the “last-mile” problem by connecting individual homes’ and business offices’ communications.
Cable/DSL Broadband Access
Currently, there are cable and DSL broadband access services in the marketplace. But, their practical limitations in features and deployment have prevented them from reaching many potential broadband Internet customers. The wired broadband connection provided by cable and DSL is an all-consuming and expensive process. A large number of areas throughout the world currently are not able to access broadband connectivity. Traditionally, DSL can only reach about 18,000 feet (three miles) from the central office switch, and this limitation means that many urban and suburban locations may not be served by DSL connectivity. The limitation of cable is that many older cable networks have not been equipped to offer a return channel, and converting and deploying these networks to support high-speed broadband can be expensive.
Wireless Standards
Drawing on hundreds of experts in the telecommunications industry, the IEEE has established a collection of wireless standards that include IEEE 802.15, also known as Bluetooth, for the Personal Area Network (PAN); IEEE 802.11, also known as WiFi, for the Local Area Network (LAN); 802.16 for the Metropolitan Area Network (MAN), and IEEE 802.20 for the Wide Area Network (WAN).
Unlike WiFi, WiMAX’s range is typically measured in miles rather than feet. The main distinction of the difference between the two standards means that WiFi is focused on a local-area networking (LAN) technology and that WiMAX is a MAN technology.
The 802.16d standard of extending 802.16 supports three physical layers (PHYs). The mandatory PHY mode is 256-point FFT Orthogonal Frequency Division Multiplexing (OFDM). The other two PHY modes are Single Carrier (SC) and 2048 Orthogonal Frequency Division Multiple Access (OFDMA) modes. By the way, the corresponding European standard—the ETSI HiperMAN standard—defines a single PHY mode identical to the 256 OFDM modes in the 802.16d standard.
Why WiMAX?
WiMAX covers a couple of different frequency ranges. Basically, the IEEE 802.16 standard addresses frequencies from 10GHz to 66GHz. The 802.16a specification, which is an extension of IEEE802.16, covers bands in the 2GHz-to-11GHz range. WiMAX has a range of up to 30 miles with a typical cell radius of 4–6 miles.
WiMAX’s channel sizes range from 1.5 to 20MHz as well, and offer a WiMAX-based network the flexibility to support a variety of data transmitting rates such as T1 (1.5Mbps) and higher data transmitting rates of up to 70Mbps on a single channel that can support thousands of users. This flexibility allows WiMAX to adapt to the available spectrum and channel widths in different countries or licensed to different service providers.
WiMAX supports ATM, IPv4, IPv6, Ethernet, and VLAN services. So, it can provide a rich choice of service possibilities to voice and data network service providers. In addition, WiMAX provides an ideal wireless backhaul technology to connect 802.11 wireless LANs and commercial hotspots with the Internet.
The WiMAX-based solution is set up and deployed like cellular systems using base stations that service a radius of several miles/kilometers. The most typical WiMAX-based architecture includes a base station mounted on a building and is responsible for communicating on a point to multi-point basis with subscriber stations located in business offices and homes. The customer premise equipment (CPE) will connect the base station to a customer as well; the signal of voice and data is then routed through standard Ethernet cable either directly to a single computer, or to an 802.11 hot spot or a wired Ethernet LAN.
WiMAX-based solutions include many other advantages, such as robust security features, good QoS (Quality of Service), and mesh and smart antenna technology that will allow better utilization of the spectrum resources. Also, the WiMAX-based voice service can work on either traditional Time Division Multiplexed (TDM) voice or IP-based Voice, also known as Voice over IP (VoIP).
WiMAX Connectivity and Solutions
WiMAX allows equipment vendors to create many different types of IEEE802.16-based products, including various configurations of base stations and customer premise equipment (CPE). WiMAX also allows the services provider to deliver many types of wireless access services. The WiMAX can be used on a variety of wireless broadband connections and solutions:
- “Last Mile” Broadband Access Solution—Metropolitan-Area Networks (MAN) connections to home and business office, especially in those areas that were not served by cable or DSL or in areas where the local telephone company may need a long time to deploy broadband service. The WiMAX-based wireless solution makes it possible for the service provider to scale-up or scale-down service levels in short times with the client request.
- Backhaul networks for cellular base stations, bypassing the Public Switched Telephone Network (PSTN); the cellular service providers can look to wireless backhaul as a more cost-effective alternative. The robust WiMAX technology makes it a nice choice for backhaul for enterprises such as hotspots as well as point-to-point backhaul solutions.
- Backhaul enterprise connections to the Internet for WiFi hotspots. It will allow users to connect to a wireless Internet service provider even when they roam outside their home or business office.
- A variety of new business services by wireless Internet service provider.
Who Are Working on WiMAX?
The WiMax Forum is a non-profit organization formed in 2001 by Nokia Corp. and Ensemble Communications Inc., etc. Right now, the WiMAX Forum has more than 110 members of equipment, semiconductor suppliers, and services providers such as Alcatel, AT&T, Fujitsu, Intel, Nortel, Motorola, SBC and Siemens, and so forth. The WiMax Forum aims to support wireless metropolitan-area networking products based on IEEE 802.16, like the Wi-Fi Alliance has done for wireless LANs and IEEE 802.11. The WiMAX Forum has most recently been working to promote the adoption of IEEE 802.16-compliant equipment, certification, and interoperability testing. In 2003, Intel Corp. became a major supporter of the WiMax Forum.
In order to bring interoperability into MAN, the WiMAX Forum is focusing its efforts on establishing a baseline protocol that allows equipment and devices from multiple vendors to interoperate and that also provides a choice to buy equipment and devices from different suppliers.
Currently, there are no WiMax-certified products yet available in the market, but the race is already on. At the Intel Developer Forum in September 2004, Intel showed off its first samples of a WiMAX chipset that has been named Rosedale. Intel is planning to offer WiMax transmitters by 2005, and expects to ship WiMax devices for the home and office to take off by 2006. Also, Intel hopes that notebooks will begin to incorporate WiMAX technology during 2006, and by 2007, handsets for mobility will be available. Intel has already signed up Proxim and Alcatel to develop WiMAX base-station and CPE (Customer Premises Equipment) kits. Fujitsu Microelectronics America Inc. in early 2005 expects to introduce a new WiMAX-based single-chip solution for deployment in base stations and subscriber stations as well; the product integrates both PHY and MAC functionality. Siemens Information and Communication Mobile also plans to build complete WiMAX-based solutions for establishing fixed, broadband speed metropolitan area wireless radio networks.
Filed under: Computer Science
WiMax (802.16e) is a newer standard of wireless networking designed to provide the last mile of high speed internet access to the end user. Some people would call Wimax WiFi on steroids but this would be to broad of an assessment. Wifi was and still will be used in LAN environments for the foreseeable future. WiMax was designed to provide (MAN) Metropolitan Area Access, to homes and businesses.
WiMax base stations will have the ability to provide approximately 60 businesses with T1 access and hundreds of homes with DSL/Cable speed access…in theory. Engineers are stating that WiMax has the capability of reaching 30 Miles but real world testing has shown 4-8 mile working radius.
WiMax (MAN) deployments are similar to a WiFi network. First the ISP would have their T3 or higher access. The ISP would then use line of sight antennas (Bridges) to connect to towers that would distribute the non line of sight signal to (MAN) residential/business clients.
WiMax line of sight antennas operate at a higher Frequency up to 66mhz. Distribution antennas do not have to be in the line of sight with their clients. Non – line of sight towers operate on a range similar to WiFi . WiMax can operate right next to cell phone towers with no interference.
WiMax networks are similar to Wifi in deployment. The Wimax Base station/Tower will beam a signal to a WiMax Receiver. Similar to a WiFi access point sending a signal to a laptop. As far as I can tell laptops will be shipping with Wimax receivers in 2006.
QOS (Quality of Service) is an major issue with WiMax because of the number of people accessing a tower at once. Some would think that a tower could be easily overloaded with a lot of people accessing it at once. Built into the WiMax standard is an algorithm that when the tower/base station is nearing capacity then it automatically will transfer the user to another WiMax tower or cell. Unlike a Wifi clients who have to kind of fight to stay associated with a given access point; WiMax will only have to perform this hand shake at the MAC level the first time they access the network.
WiMax is designed for building a network infrastructure when the environment or distance is not favorable to a wired network. Also, WiMax is a cheaper and quicker alternative than having to lay wire. Third world countries will greatly benefit from deploying WiMax networks. WiMax can handle virtually all the same protocols Wifi can including VOIP. African countries are now going to start deploying WiMax networks instead of cell phone networks. Disaster zones can also utilize WiMax giving them the ability to distribute crisis information quickly and cheaply.
Militaries are already using wireless technology to connect remote sites. Logistics will be simplified with the ease of tracking with RF technologies. WiMax can also handle Webcams and streaming video which would give commanders eyes on target capability. Just imagine if planes were able to drop preconfigured self deploying WiMax antennas in strategic areas giving troops real time battlefield intel. Armed with wireless cameras, drones and a GPS one soldier would truly be an Army of One.
As WiMax is deployed in more areas theory and real life capabilities of WiMax will come to light. The differences between WiMax and Wifi are simple. Think of a WiMax network as an ISP with out wires, with the signal providing your internet access to your business/ home. Wifi will be used within in your LAN for the near future.
Filed under: Terrorism by Pakistan
Terrorism and insurgency are the unending battles India has been fighting since Independence.
In the first part of his analysis on terrorism, B Raman discussed its causes, the distinctions between religious and non-religious terrorist groups and their sources of funding and their sanctuaries.
Today, he explains how most Indian Muslims have refused to fall prey to the gambits of Pakistan-backed terrorist organisations.
Pakistan has been the main source of arms, ammunition and training for religious terrorist groups which operated in the Punjab in the past and for those which are operating presently in J&K and other parts of India. The training is given by the ISI, either directly or through religious fundamentalist and pan-Islamic jihadi organisations, in various makeshift camps located in PoK, the Northern Areas (Gilgit and Baltistan) and the North-West Frontier Province.
Before September 11, 2001, the ISI had located the training camps of the Pakistani jihadi organisations, which are members of the IIF, in Afghan territory, but have since shifted them to PoK and the Northern Areas. Five Pakistani jihadi organisations are members of bin Laden’s IIF — HUM, Harkat-ul-Jihad-al-Islami, Lashkar-e-Toiba, Jaish-e-Mohammad and Lashkar-e-Jhangvi. The first four operate in India. LEJ, which is an anti-Shia organisation, operates only in Pakistan.
Under US pressure, President Musharraf has banned the activities of LET, JEM and LEJ in Sindh, Punjab, the NWFP and Balochistan, but not in PoK, the Northern Areas and the Federally-Administered Tribal Areas. The activities of HUM and HUJI, which are closest to Pakistan’s military-intelligence establishment, have not been banned anywhere.
In a recent judgement against some Pakistani doctors accused of providing sanctuaries and medical assistance to Al Qaeda members, the Pakistani supreme court pointed out that the Pakistan government has not, till now, declared Al Qaeda a terrorist organisation and banned its activities in Pakistan as required under the Anti-Terrorism Act.
The role of Pakistani mercenaries
Between 1989 and 1993, terrorism in J&K was mainly due to the activities of indigenous Kashmiri organisations. When they were unable to succeed, the ISI started infiltrating trained jihadi cadres of the Pakistani pan-Islamic organisations, who had fought against the Soviet troops in Afghanistan in the 1980s, into J&K for beefing up indigenous organisations. Since 1999, the Pakistani jihadi organisations have taken over the leadership of the anti-government of India movement and have been operating in Indian territory under the guise of Kashmiris.
As already mentioned above, out of the 46 suicide terrorist attacks reported since 1999, 44 have been by Pakistanis belonging to these jihadi organisations. The principal leaders of these organisations are Pakistani Punjabis and the majority of their cadres are Pakistani nationals.
These Pakistani jihadi organisations project J&K as the gateway to India and say that, after ‘liberating’ J&K from the control of the Hindus, they will ‘liberate’ the Muslims in other parts of India and set up two more independent ‘homelands’ for Muslims — one in north India and the other in south India. As part of this long-term aim, they have been setting up clandestine cells in other parts of India and have launched some major operations such as the attack inside the Red Fort in New Delhi in January 2001, the attack on the Indian Parliament in December, 2001, and the attack on Hindu worshippers in a temple in Gandhinagar, Gujarat, in September 2002.
There have also been a number of terrorist incidents in other parts of India such as the attack on the security guards outside the US consulate in Kolkata in January 2002, the four explosions in Mumbai in 2002-03 — the latest on March 13, 2003, killed 12 innocent train passengers — and the explosion in a Hindu religious place in Hyderabad last year.
The role of Al Qaeda in India
Till now, Al Qaeda’s Arab members have not operated in Indian territory. Some Arabs were arrested in J&K during counter-terrorism operations, but they were members of Pakistani pan-Islamic jihadi organisations and not of Al Qaeda as such. However, HUM, HUJI, LET and JEM, the Pakistani jihadi organisations which are members of bin Laden’s IIF along with Al Qaeda and the Taliban, have been responsible for most of the religious terrorist incidents in J&K and other places in India.
The impact of Bin Laden & Al Qaeda on the Indian Muslim community
India has a little over 140 million Muslims — the second largest Muslim community in the world after Indonesia. Only a very small section of the community has taken to terrorism due to various grievances and instigation by the ISI and Pakistan’s religious, fundamentalist and jihadi organisations.
The overwhelming majority of Indian Muslims are loyal, law-abiding citizens. They have not allowed their anger against the Indian government or the Hindus for any reason to drive them into the arms of terrorist organisations. India has the most modern, peaceful and forward-looking Muslim community in the world.
If one keeps J&K aside, the following factors are significant:
During the 1980s, over 6,000 Muslims from different parts of the world went to Afghanistan to join the Afghan Mujahideen groups in their fight against the Soviet troops. Not a single Indian Muslim joined them.
There are hundreds of Muslims from various parts of the world undergoing jihad training in Pakistan’s various madrasas. But there are no reports of any Indian Muslims studying there.
bin Laden’s IIF has 13 member-organisations from different parts of the world — five of them are from Pakistan. Not a single Indian Muslim organisation — not even from J&K — has joined the IIF.
When the US started its air strikes on Al Qaeda and the Taliban training camps in Afghan territory on October 7, 2001, there were demonstrations by Muslims in many parts of the world. There was hardly any demonstration in India.
After the US-led coalition started its war on terrorism in Afghanistan, hundreds of Muslims from many countries went to Pakistan and Afghanistan to join the Taliban and Al Qaeda in their fight against the coalition troops. There were no Indian Muslims among them.
At its detention centres at Gauntanamo Bay in Cuba, Diego Garcia and Bagran in Afghanistan, the US has been interrogating hundreds of Muslims from different countries caught helping Al Qaeda in Afghanistan. There is not a single Indian Muslim amongst them.
As many foreign Muslims, if not more, come to India for higher education as they go to Pakistan. Those studying in Pakistan go back to their countries as terrorists, narcotics smugglers or other law-breakers. There was only one instance of a Palestinian, who studied in India, taking to terrorism after he returned to his country in 1992. Foreign Muslim students studying in India go back to their countries as constructive citizens –bureaucrats, academics, IT experts, etc. President Hamid Karzai of Afghanistan, who is the toast of the world today for his courage, vision and modern outlook, is a product of the Indian education system.
These factors show bin Laden and his Al Qaeda have had little impact on the Muslim community in India. The Indian Muslims, including the aggrieved sections of the Kashmiris, have kept away from them. The attempts of the Pakistani pan-Islamic jihadi organisations to rally the support of the Indian Muslims in the name of bin Laden have, thus far, been unsuccessful.
India’s domestic counter-terrorism policies
India’s counter-terrorism policies are based on the following principles:
A genuine and well-functioning democracy, good governance, responsiveness to public grievances, effective policing and economic development are the best antidotes to terrorism.
India has not allowed the intimidatory violence of terrorism to come in the way of the electoral process. In the 1990s, elections were held in Punjab at the height of terrorist violence. Elections were held in J&K in September last year despite instructions from the ISI to the Pakistani jihadis to disrupt the process. Foreign diplomatic missions in New Delhi were encouraged to send their observers to the state to satisfy themselves that the elections were free and fair. All of them have certified this. Elections to the Nagaland assembly were held last month.
The government has not allowed terrorists to disrupt the economic development of the affected areas. Even at the height of terrorism, Punjab continued to be the granary of India, producing a record wheat crop year after year. In J&K, the fall in revenue due to a decline in foreign tourists arrival is being sought to be remedied by encouraging greater domestic tourism.
In the 1990s, when terrorists prevented the holding of examinations in Srinagar, the government flew the students to Jammu at its cost to take the examination.
When they prevented businessmen from the rest of India from going to the valley to purchase their requirements of handicrafts and dry fruits, the government flew the vendors to New Delhi to enable them to dispose of their stocks.
The government has announced many packages for the economic development of the affected areas and has been trying to implement them despite the terrorist violence.
The government has refused any kind of concessions to terrorists resorting to intimidation tactics such as hijacking, hostage-taking, etc.
The government has refused to hold talks with terrorists until they give up violence, but began to search for a political solution through talks once the terrorists give up violence.
In the 1970s, a large section of the Naga hostiles and the Mizo National Front gave up violence and entered into talks with the government, which led to a political solution. But the National Socialist Council of Nagaland, led by Isaac Swu and T Muivah, has been holding on without reaching an agreement. It has, however, been observing a cease-fire for the last two years and holding talks with the government.
The government is maintaining an open mind to suggestions coming from all sections of J&K for improving the political and administrative set-up. It has recently appointed former home secretary N N Vohra to enter into a dialogue with all the elected representatives of the state on their demand for greater autonomy.
India’s external counter-terrorism policies
India has been the victim of Pakistan-sponsored terrorism since the 1950s. In those years, Pakistan’s ISI had supported the insurgent/terrorist groups in India’s northeast region and provided them sanctuaries, training, arms and ammunition in the Chittagong Hill Tracts of the then East Pakistan. India’s anxiety to stop this played an important role in its assistance to the people of East Pakistan to liberate themselves.
Since 1980, the ISI has been providing sanctuaries, training, arms and ammunition in Pakistan to religious terrorist groups operating in Punjab, J&K and other parts of India. It is also infiltrating the mercenaries of the Pakistani pan-Islamic jihadi organisations into India to promote cross-border terrorism.
India has taken up this issue with the US since 1992 and wants Pakistan declared a State sponsor of international terrorism under US laws and have punitive action taken against it. In 1993, the Clinton administration placed Pakistan on a watch list of suspected State sponsors of international terrorism for six months and forced Nawaz Sharif, who was then in power, to sack Lieutenant General Javed Nasir, then ISI’s director-general, and other senior officers. This did not have any effect on the use of terrorism by the ISI.
Since 9/11, Pakistan’s military-intelligence establishment has been collaborating with the US in taking action against Al Qaeda elements posing a threat to US nationals and interests. But it has not taken any action against cross-border terrorism directed against India and to destroy terrorist infrastructure in PoK and the Northern Areas.
After the attack by terrorists belonging to LET and JEM on the Indian Parliament in December 2001, India mobilised and deployed its Army on the border in response to public pressure for action against the terrorist infrastructure in Pakistani territory. In response to appeals from the US, UK and other friendly governments, India refrained from action against Pakistan. Under US pressure, Pakistan banned LET and JEM, but not HUJI and HUM, and arrested some of their leaders and cadres. They have since been released.
US officials themselves admit Pakistan has not implemented its assurances to the US that it would put a stop to cross-border terrorism in J&K. Despite this, the US is reluctant to act against Pakistan because of its cooperation in assisting the US in neutralising Al Qaeda elements who have taken shelter in Pakistan.
India has made it clear that there will be no question of any talks with Pakistan on the normalisation of bilateral relations till it stops cross-border terrorism, winds up the terrorist infrastructure in its territory and gives up the use of terrorism as a weapon against India.
India has also been greatly concerned over the use of Bangladesh territory by religious and non-religious terrorists operating against India. The non-religious terrorist groups continue to enjoy sanctuaries in the CHT. Of the religious terrorist organisations, HUJI has an active branch in Bangladesh. Some Al Qaeda elements, who escaped into Pakistan from Afghanistan, have found their way into Bangladesh, where they have been given shelter by HUJI.
There is active complicity between the ISI and its counterpart in Dhaka in this matter. The Bangladesh authorities have not been co-operating with India in taking effective action against the large-scale illegal immigration into India. However, keeping in view the otherwise good relations with Bangladesh, India has been trying to have these problems sorted out bilaterally at the political and diplomatic levels. But the progress so far has been disappointing.
Filed under: Computer Science
Netgear Wireless Router Setup and Security
The use of wireless routers and access points have become more frequent. If you do plan on setting up a wireless router it is your responsibility to properly configure and secure your wireless router for both your own personal privacy and overall network stability. On this page you will find instructions on how to properly setup your wireless router.
Netgear WGR614 54Mbps Wireless Router
1. Begin setup of your Netgear Wireless Router by first reading the instructions in the included manual, and following their guidelines for plugging in and initializing the access point. The first few steps in this guide should coincide with the information found in the manual, however we will follow up with important information on how to secure your wireless access point.
2. After powering up the router, use an ethernet cable to connect your computer to one of the ports on it marked 1 through 4. Next open a web browser window on the connected computer and type http://192.168.1.1 into the address bar and press enter. This will take you to the Netgear Smart Wizard welcome page, click OK to begin the configuration. The router will attempt to detect the type of connection you have and the next message you receive should be Dynamic IP (DHCP) Detected, click Next once you see this.
3. Next you will enable the wireless capability of your router. In the dropdown box for the region where you are located select United States from the list. On this screen you should also change the Wireless Network Name (SSID) from its default value to something unique so that your Base Station will not be confused with another. Click Next.
4. You should now see a message confirming that your connection is working and wireless is enabled. However, your are not secured yet. Read the notes and click Done. Then direct your browser to http://www.routerlogin.net to continue the configuration. A window will pop up prompting you for your login and password, enter admin for the username and password for the password, then click OK.
1. Once you have logged in you will see the main configuration page (shown above). Now click on the Wireless Settings at the left of the page. In order to password protect your wireless network select the WEP (Wired Equivalent Privacy) option under the Security Options and then under the Security Encryption (WEP) section that appears, select 128 bit next to Encryption Strength. Choose a password between 6 and 8 characters and type it into the Passphrase box under the Security Encryption (WEP) Key heading. Then click Generate. Finally click Apply. You may also select WPA encryption, however not all network cards support this, so check your documentation first.
2. Next look for the Advanced section heading on the left side of the page and click on this Wireless Settings section. Disable the SSID broadcast option by unchecking the second box in this section and then click on the Setup Access List button.
3. On this page (seen below) check the box to Turn Access Control On and click on the Apply button to save this setting.
4. Now click on the Add button, this will display a Wireless Card Entry heading. This is where you will choose a name and enter a MAC Address, also known as Physical Address, for each computer that you will be using to connect to your wireless network. If you don’t know how to get this information follow the steps here. Once you have finished, click the Apply button.
1. Finally click on the Set Password link on the left of the page under the Maintenance heading. Change the default password for accessing your wireless router setup pages by first typing the old one, password, into the appropriate field and then entering a new one into the New Password field and confirming it. This should be a different password than the one you setup for WEP encryption, but should also be at least 6 to 8 characters in length. Click the Apply button.
2. Your Netgear Wireless Router is now secure.