Applications of Mesh networks

Mesh networks may involve either fixed or mobile devices. The solutions are as diverse as communication needs, for example in difficult environments such as emergency situations, tunnels and oil rigs to battlefield surveillance and high speed mobile video applications on board public transport or real time racing car telemetry. A significant application for wireless mesh networks is VoIP. By using a Quality of Service scheme, the wireless mesh may support local telephone calls to be routed through the mesh. For example, miner safety has improved with VOIP phones communicating over a mesh network.

Some current applications:
U.S. military forces are now using wireless mesh networking to connect their computers, mainly ruggedized laptops, in field operations. It enables troops to know the locations and status of every soldier or marine, and to coordinate their activities without much direction from central command. Video Clip
Electric meters now being deployed on residences transfer their readings from one to another and eventually to the central office for billing without the need for human meter readers or the need to connect the meters with cables.[citation needed]
The laptops in the one laptop per child program use wireless mesh networking to enable students to exchange files and get on the Internet even though they lack wired or cell phone or other physical connections in their area.

The 66-satellite Iridium constellation operates as a mesh network, with wireless links between adjacent satellites. Calls between two satellite phones are routed through the mesh, from one satellite to another across the constellation, without having to go through an earth station. This makes for a smaller travel distance for the signal, reducing latency, and also allows for the constellation to operate with far fewer earth stations that would be required for 66 traditional communications satellites.

Marlon Guerrero

17810603

C.A.F

http://en.wikipedia.org/wiki/Wireless_mesh_network#Applications

Wireless mesh Architecture

Wireless mesh architecture is a first step towards providing high-bandwidth network over a specific coverage area. Wireless mesh architectures infrastructure is, in effect, a router network minus the cabling between nodes. It's built of peer radio devices that don't have to be cabled to a wired port like traditional WLAN access points (AP) do. Mesh architecture sustains signal strength by breaking long distances into a series of shorter hops. Intermediate nodes not only boost the signal, but cooperatively make forwarding decisions based on their knowledge of the network, i.e. perform routing. Such an architecture may with careful design provide high bandwidth, spectral efficiency, and economic advantage over the coverage area.

Example of three types of wireless mesh network:
Infrastructure wireless mesh networks: Mesh routers form an infrastructure for clients.
Client wireless mesh networks: Client nodes constitute the actual network to perform routing and configuration functionalities.
Hybrid wireless mesh networks: Mesh clients can perform mesh functions with other mesh clients as well as accessing the network.

Wireless mesh networks have a relatively stable topology except for the occasional failure of nodes or addition of new nodes. The traffic, being aggregated from a large number of end users, changes infrequently. Practically all the traffic in an infrastructure mesh network is either forwarded to or from a gateway, while in ad hoc networks or client mesh networks the traffic flows between arbitrary pairs of nodes.

Marlon Guerrero

17810603

C.A.F

http://en.wikipedia.org/wiki/Wireless_mesh_network#Architecture

Wireless mesh network

A wireless mesh network (WMN) is a communications network made up of radio nodes organized in a mesh topology. Wireless mesh networks often consist of mesh clients, mesh routers and gateways. The mesh clients are often laptops, cell phones and other wireless devices while the mesh routers forward traffic to and from the gateways which may but need not connect to the Internet. The coverage area of the radio nodes working as a single network is sometimes called a mesh cloud. Access to this mesh cloud is dependent on the radio nodes working in harmony with each other to create a radio network. A mesh network is reliable and offers redundancy. When one node can no longer operate, the rest of the nodes can still communicate with each other, directly or through one or more intermediate nodes. The animation below illustrates how wireless mesh networks can self form and self heal. Wireless mesh networks can be implemented with various wireless technology including 802.11, 802.16, cellular technologies or combinations of more than one type.

A wireless mesh network can be seen as a special type of wireless ad-hoc network. It is often assumed that all nodes in a wireless mesh network are immobile but this need not be so. The mesh routers may be highly mobile. Often the mesh routers are not limited in terms of resources compared to other nodes in the network and thus can be exploited to perform more resource intensive functions. In this way, the wireless mesh network differs from an ad-hoc network since all of these nodes are often constrained by resources.

The principle is similar to the way packets travel around the wired Internet — data will hop from one device to another until it reaches its destination. Dynamic routing algorithms implemented in each device allow this to happen. To implement such dynamic routing protocols, each device needs to communicate routing information to other devices in the network. Each device then determines what to do with the data it receives — either pass it on to the next device or keep it, depending on the protocol. The routing algorithm used should attempt to always ensure that the data takes the most appropriate (fastest) route to its destination.

Marlon Guerrero

17810603

C.A.F

http://en.wikipedia.org/wiki/Wireless_mesh_network

Wireless community network

Wireless community networks or wireless community projects are the organizations that attempt to take a grassroots approach to providing a viable alternative to municipal wireless networks for consumers.

Because of evolving technology and locales, there are at least four different types of solution:
Cluster: Advocacy groups which simply encourage sharing of unmetered internet bandwidth via Wi-Fi, may also index nodes, suggest uniform SSID (for low-quality roaming), supply equipment, dns services, etc.
Mesh: Technology groups which coordinate building a mesh network to provide Wi-Fi access to the internet
WISP: A mesh that forwards all traffic back to consolidated link aggregation point(s) that have centralized access to the internet

WUG: A wireless user group run by wireless enthusiasts. An open network not used for the reselling of internet. Running a combination of various off the shelf WIFI hardware running in the license free ISM bands 2.4 GHz/5.8 GHz

Certain countries regulate the selling of internet access, requiring a license to sell internet access over a wireless network. In South Africa it is regulated by ICASA They require that WISP's apply for a VANS or ECNS/ECS license before being allowed to resell internet access over a wireless link. The cluster and mesh approaches are more common but rely primarily on the sharing of unmetered residential and business DSL and cable Internet. This sort of usage might be non-compliant with the Terms of Service (ToS) of the typical local providers that deliver their service via the consumer phone and cable duopoly. Wireless community network sometimes advocate complete freedom from censorship, and this position may be at odds with the Acceptable Use Policies of some commercial services used. Some ISPs do allow sharing or reselling of bandwidth.

Marlon Guerrero

17810603

C.A.F

http://en.wikipedia.org/wiki/Wireless_community_network

Uses of Wireless

Wireless networks have continued to develop and their uses have grown significantly. Cellular phones are part of huge wireless network systems. People use these phones daily to communicate with one another. Sending information overseas is possible through wireless network systems using satellites and other signals to communicate across the world. Emergency services such as the police department utilize wireless networks to communicate important information quickly. People and businesses use wireless networks to send and share data quickly whether it be in a small office building or across the world.

Another important use for wireless networks is as an inexpensive and rapid way to be connected to the Internet in countries and regions where the telecom infrastructure is poor or there is a lack of resources, as in most developing countries.

Compatibility issues also arise when dealing with wireless networks. Different components not made by the same company may not work together, or might require extra work to fix these issues. Wireless networks are typically slower than those that are directly connected through an Ethernet cable.

A wireless network is more vulnerable, because anyone can try to break into a network broadcasting a signal.Many networks offer WEP - Wired Equivalent Privacy - security systems which have been found to be vulnerable to intrusion. Though WEP does block some intruders, the security problems have caused some businesses to stick with wired networks until security can be improved. Another type of security for wireless networks is WPA - Wi-Fi Protected Access. WPA provides more security to wireless networks than a WEP security set up. The use of firewalls will help with security breaches which can help to fix security problems in some wireless networks that are more vulnerable.

Marlon Guerrero

17810603

C.A.F

http://en.wikipedia.org/wiki/Wireless_network#Uses

Types of wireless connections

Wireless PAN

Wireless Personal Area Networks (WPANs) interconnect devices within a relatively small area, generally within reach of a person. For example, Bluetooth provides a WPAN for interconnecting a headset to a laptop. ZigBee also supports WPAN applications. Wi-Fi PANs are also getting popular as vendors have started integrating Wi-Fi in variety of consumer electronic devices. Intel My WiFi and Windows 7 virtual Wi-Fi capabilities have made Wi-Fi PANs simpler and easier to set up and configure.

Wireless LAN

A wireless local area network (WLAN) links two or more devices using a wireless distribution method (typically spread-spectrum or OFDM radio), and usually providing a connection through an access point to the wider internet. This gives users the mobility to move around within a local coverage area and still be connected to the network.
Wi-Fi: Wi-Fi is increasingly used as a synonym for 802.11 WLANs, although it is technically a certification of interoperability between 802.11 devices.
Fixed Wireless Data: This implements point to point links between computers or networks at two locations, often using dedicated microwave or laser beams over line of sight paths. It is often used in cities to connect networks in two or more buildings without physically wiring the buildings together.

Wireless MAN

Wireless Metropolitan area networks are a type of wireless network that connects several Wireless LANs.

WiMAX is the term used to refer to wireless MANs and is covered in IEEE 802.16d/802.16e.

Wireless WAN

wireless wide area networks are wireless networks that typically cover large outdoor areas. These networks can be used to connect branch offices of business or as a public internet access system. They are usually deployed on the 2.4 GHz band. A typical system contains base station gateways, access points and wireless bridging relays. Other configurations are mesh systems where each access point acts as a relay also. When combined with renewable energy systems such as photo-voltaic solar panels or wind systems they can be stand alone systems.

Mobile devices networks

With the development of smart phones, cellular telephone networks routinely carry data in addition to telephone conversations:
Global System for Mobile Communications (GSM): The GSM network is divided into three major systems: the switching system, the base station system, and the operation and support system. The cell phone connects to the base system station which then connects to the operation and support station; it then connects to the switching station where the call is transferred to where it needs to go. GSM is the most common standard and is used for a majority of cell phones.[5]
Personal Communications Service (PCS): PCS is a radio band that can be used by mobile phones in North America and South Asia. Sprint happened to be the first service to set up a PCS.

D-AMPS: Digital Advanced Mobile Phone Service, an upgraded version of AMPS, is being phased out due to advancement in technology. The newer GSM networks are replacing the older system.

Marlon Guerrero

17810603

C.A.F

http://en.wikipedia.org/wiki/Wireless_network#Types_of_wireless_connections

802.11 Wireless Standard

Before setting up wireless network, you need to understand 802.11 wireless standard that can be used. 802.11a, 802.11b and 802.11g are three popular wireless communication standards. Wireless networks can be built using any of the three, but each has its advantages and disadvantages. 

802.11b

In September of 1999, the IEEE 802 committee extended the 802.11 standard, created 802.11b standard. It became popular due to low setup cost and bandwidth support up to 11Mbps in the 2.4GHz S-Band Industrial, Scientific, and Medical (ISM) frequency range. For your information, the maximum bandwidth supported by original 802.11 standard is only 2Mbps.

Being an unregulated frequency, 802.11b device can suffer interference from other wireless users, cordless phones, microwave ovens and other devices using the same 2.4 GHz band. However the interference can be avoided by placing 802.11b device a reasonable distance from other devices.

802.11a

802.11a was created the same time with 802.11b with the ability to support 55Mbps in the 5GHz band. 802.11a is not popular due to the slow availability of the 5 GHz components needed to implement products by vendor, more expensive cost and not compatible with 802.11b. The higher frequency also makes 802.11a signals have more difficulty to penetrate walls and other obstructions.

However the advantage of 802.11a is that it operates at a radio frequency that's less clogged by competing signals from other wireless users, cordless phones and microwave ovens. Its maximum bandwidth is higher as well comparing to 802.11b. 802.11a is usually found on business networks whereas 802.11b better suits the home network.

802.11g

Due to 802.11b is not compatible with 802.11a and there are needs for higher bandwidth, 802.11g was ratified in June 2003 to provide high data rate and maintain backward compatibility with 802.11b products.

802.11g supports bandwidth up to 55Mbps in the 2.4GHz band. 802.11g is compatible with 802.11b products because they both use the same radio frequency (2.4GHz) to transmit data over the airwaves, it means 802.11g wireless router will be able to talk to 80.11b wireless adapter. 802.11g also provides better security features, such as WiFi Protected Access (WAP) and WPA2 authentication with pre-shared key or RADIUS server.

Again, 802.11g also suffers from the same interference as 802.11b in the already crowded 2.4 GHz range, but can be avoided by placing 802.11g device a reasonable distance from other devices

802.11n

802.11n is latest wireless communication standard that was approved by IEEE in October 2009, and it can provide bandwidth up to 600Mbps, 10 times faster than 802.11g.

Prior to the release of this final approved 802.11n, several vendors already produced the wireless products based on 802.11n draft standard and they're called 802.11pre-n or 802.11n(draft) wireless products, and it's good to know that the 802.11n wireless product is backward compatible with those draft-n products.

Furthermore, 802.11n can operate in 2.4GHz or 5GHz band, and is backward compatible with 802.11a (5GHz band), 802.11b (2.4GHz band) and 802.11g (2.4GHz band) products.

If you want to set up a wireless network, you can use wireless products that support 802.11n standard that supports much higher bandwidth, but it's more expensive if you compare to 802.11g products.

Marlon Guerrero

17810603

C.A.F

http://www.home-network-help.com/802-11.html

Setting Up Ad Hoc Wireless Network in Windows XP

Do you know that you can set up ad hoc wireless network to share Internet Connection at home without using router and switch? Of course you can also use it to share files or printer between 2 or more computers wirelessly.

Please note you can have up to 9 wireless clients in an ad-hoc wireless network, which the computers send their data directly to each other. The only drawback of this approach is its limited wireless range support. You would need to have wireless router or access point for better wireless coverage.

IP Address Allocation: 

You need to allocate the IP address to each computer that involves in this ad-hoc wireless network. If you have 3 computers, you can simply assign 192.168.0.1, 192.168.0.2 and 192.168.0.3 to each computer with netmask 255.255.255.0.

Host Computer Configuration

1) Let's start with the configuration, here I will choose one computer to start the configuration, right click wireless adapter and then click properties.

Note: Please enable this host computer's ad hoc configuration on ICS host computer if you want to use Microsoft's Internet Connection Sharing feature.

2) Wireless Network Connection Properties will appear. Click Wireless Networks tab, here I tick Use Windows to configure my wireless network settings. After that click Advanced button.

Note: You can also use the configuration tool provided by wireless adapter manufacturers to configure ad hoc wireless network.

3) Advanced window will appear. Select Computer-to-computer (ad hoc) networks only option. Click Close at last.

Note: Don't tick Automatically connect to non-preferred networks in order to ease the configuration.

4) After that, click Add to add new ad hoc wireless network.

5) Name your ad hoc network, here I use home-adhoc. Try to use open authentication without encryption first. After tested it works well, only proceed to enable WPA or WEP encryption. Click OK at last.

6) Now you will see your created ad hoc network (PC card icon) in preferred networks list. Wooo.. You have finished configuring this host computer.

Client Computer Configuration

1) On other client computers, you only need to set its wireless adapter to use Windows to configure its network settings and enable Computer-to-computer (ad-hoc) networks only. Simply follow step 2 and 3 on host computer configuration above to get it done.

2) You then right click wireless adapter to view available wireless networks, you will see your ad hoc wireless network, proceed to connect to it. At this stage, you should be able to connect to this ad hoc wireless network!!! Have fun… :o)

Note: If you have Internet Connection Sharing enabled on host computer, you can just set each client computer to obtain an IP address automatically, then these computers should be able to access Internet.

Marlon Guerrero

17810603

C.A.F

http://www.home-network-help.com/ad-hoc-wireless-network.html

Wireless Operating Mode

The IEEE 802.11 standards specify two operating modes: infrastructure mode and ad hoc mode.

Infrastructure mode is used to connect computers with wireless network adapters, also known as wireless clients, to an existing wired network with the help from wireless router or access point. The 2 examples which I specified above operate in this mode.

Ad hoc mode is used to connect wireless clients directly together, without the need for a wireless router or access point. An ad hoc network consists of up to 9 wireless clients, which send their data directly to each other.

Marlon Guerrero

17810603

C.A.F

http://www.home-network-help.com/wireless-network.html

What is wireless network?

Wireless network is a network set up by using radio signal frequency to communicate among computers and other network devices. Sometimes it's also referred to as WiFi network or WLAN. This  network is getting popular nowadays due to easy to setup feature and no cabling involved. You can connect computers anywhere in your home without the need for wires.

Here is simple explanation of how it works, let say you have 2 computers each equipped with wireless adapter and you have set up wireless router. When the computer send out the data, the binary data will be encoded to radio frequency and transmitted via wireless router. The receiving computer will then decode the signal back to binary data.

It doesn't matter you are using broadband cable/DSL modem to access internet, both ways will work with wireless network. If you heard about wireless hotspot, that means that location is equipped with wireless devices for you and others to join the network. You can check out the nearest hotspots from your home here.

The two main components are wireless router or access point and wireless clients.

Marlon Guerrero

17810603

C.A.F

http://www.home-network-help.com/wireless-network.html

Setting Up a Wireless Network For a Home and Business

What is Wireless Networking?

It is a type of networking technology that allows computers to communicate with other computers (as well as other wireless-equipped devices) without using cables. Instead, wireless networking uses radio signals to receive and transmit data between wireless access points and wireless network cards operating on the 2.4 GHz frequency band.

Each wireless device exchanges signals with an Access Point, also called a Router. Access points, in turn, communicate with other network devices. An Access Point is typically a piece of hardware, but solutions are also available that allow a computer with a wireless card to act as an Access Point.

Setting Up a Home Wireless Network:

    * First, you will need to choose an Internet Service Provider (ISP). Many ISP's offer a flat rate service while others may charge an hourly rate. In either case, choose one that makes sense for your needs. If you currently have a wired connection, you can inquire with your current ISP, they may provide wireless services as well.

    * You will need to purchase a wireless 802.11b wireless broadband router. Most routers will connect to a broadband modem, a 10/100 Ethernet backbone, or wireless network. They typically support a range of 300 feet indoors and 1,500 feet outdoors. When placing your router, keep in mind that walls, water pipes, cables or anything that could produce interference can decrease your range. Try to keep to a range of around 150 feet. This will create a greater throughput (A measure of the data transfer rate through a typically complex communications system or of the data-processing rate in a computer system).

    * Now it is time to install the PCI (Peripheral Component Interconnect) card into your desktop computer. Many of the newer laptops come equipped with mobile technology so the need for additional cards may not be necessary.

    * Next, turn off your broadband connection device and your PC. Then unplug the cable from your broadband device (Ethernet cable) and plug it into a Local Area Network (LAN) port on the back of the wireless broadband router. Keep the other end connected to your PC.

    * You are now ready to connect a second Ethernet cable between your wired broadband modem's Ethernet port and the wireless broadband router's Wide Area Network (WAN) port. Once all connections are made, turn the modem on and wait for the status lights to indicate that it's communicating with your ISP. Be patient, this may take a few moments.

    * Now you can plug in the wireless broadband router. The status lights will blink as it performs a self diagnostic check (this also may take a few moments). Once the lights stop blinking, indicating that everything is working properly, you can turn on your wired PC.

    * Next, refer to the router's printed quick-start guide, launch your Web browser, and type in the address indicated in the guide. Follow the on-screen setup wizard, which should guide you step by step through the process. It is important to note that the default SSID (Service Set Identifier) number is often set to 101, so you should change it to a different number to ensure that your wireless connection remains secure. Hackers know many of the default SSID's.

    * By default, encryption is not enabled. Encryption is important, because hackers equipped with the necessary devices can sniff the packets transmitted by the wireless network, thereby compromising your data. Wired Equivalent Privacy (WEP) is a protocol used for encrypting packets on a wireless network. It uses a 64-bit (or 256-bit, depending on the vendor) shared key algorithm. Using WEP will increase the protection on your data, but doing so will reduce the effective data rates.

Setting Up a Wireless Network for a Business:

A number of small businesses are finding success in installing wireless networks. They produce higher production rates, better flexible application mobility, easier to reconfigure your office space as your company grows and changing to a wireless infrastructure is becoming much more affordable.

Below you will find instructions on setting up a wireless network and will help you to understand the impact that a wireless infrastructure may play in your companies networking solution.

    * Educating yourself about the benefits of a wireless network may help in your decision to install a network solution. Things to consider are the fact that wired networks have definite limits on signal strength thus making your system slower and less productive. Another factor is that wired networks are more difficult to expand upon and can be much more expensive to reconfigure or upgrade. As your company grows, a wireless infrastructure is a much more flexible alternative making a reconfiguration easily workable and affordable.

    * A factor that scares many business owners is that the LAN hardware and software is more expensive than that of a cabled connection. But the costs are offset by lowered installation costs and far superior mobility creating better productivity.

    * Before jumping into a costly infrastructure change. It may not be a bad idea to bring in a contracted IT professional specializing in wireless technology to help you determine if a wireless solution is right for your company. This will also be helpful if you need help determining what equipment or other resources will be needed to suit your business needs.

Once you have a plan its time to set it up. Two basic components needed are:

   1. Wireless LAN Client Adapters:
      Wireless LAN client adapters can increase productivity by enabling mobile users to have network and Internet access anywhere within a building that is equipped with a wireless network infrastructure.

   2. Wireless Access Point:
      A wireless access point (WAP or AP) is a device that "connects" wireless communication devices together to create a wireless network. A wireless access point acts as the network's arbitrator, negotiating when each nearby client device can transmit. The WAP is also usually connected to a wired network, and can relay data between devices on each side.

Now lets build the wireless LAN:

    * Purchase your equipment such as:
          o  Wireless Notebooks
          o  Access Points
          o  Wireless LAN Adapters
          o  Wireless Cards.

    * Determine the number of users who'll need to have access to the network. This will be the determining factor on the amount of access points needed.

    * Placement of your wired LAN is critical. The obvious goal is to maximize the access point's wireless range. A usual range is a maximum of 300 feet, but many environment factors come into play, such as, walls, water pipes, cables or anything that could produce interference thus decreasing the range. Try to keep to a range of around 150 feet. This will create a greater throughput (A measure of the data transfer rate through a typically complex communications system or of the data-processing rate in a computer system).

    * Configure your wireless devices to work with your network. Before you go live with your new network, ensure that you test the installation using link test software. Test for signal strength, percentage of data sent correctly and the time it takes to receive a response from the destination device.

Make sure that you provide security for your new LAN. Wireless communications are transmitted through the air making it very easy to extract information, providing you do not have network security. There are many wireless-specific security solutions that you can implement. The three basic security tactics used are:

   1. MAC:
      Medium Access Control: In a WLAN network card, the MAC is radio controller protocol. It corresponds to the ISO Network Model's level 2 Data Link layer. The IEEE 802.11 standard specifies the MAC protocol for medium sharing, packets formats and addressing, and error detection. 

   2. WEP Encryption:
      Short for Wired Equivalent Privacy- a security protocol for wireless local area networks (WLANs) defined in the 802.11b standard. WEP is designed to provide the same level of security as that of a wired LAN. 

   3. Traditional VPN:
      Virtual Private Network - A way to communicate through a dedicated server securely to a corporate network over the internet. Windows NT, 2000 and XP offer native VPN support. Also, VPNs are recommended to secure 802.11b wireless LANs as well.

Guidelines For Securing Your Wireless Network:

Though your new wireless network allows you to have the freedom to surf the Internet anywhere in your house, it's also good news for your close neighbors, because some of them can now surf the Internet for free! Unlike a wired network, where you need to have physical access to a network point in order to gain access to the network, a wireless network extends beyond the four walls of your house.

Most wireless access points and routers provide a Web-based configuration program for configuring the wireless access point. Below are some guidelines for "securing" your wireless network:

    * Change the default SSID: To improve the security of your home wireless network, change the SSID to a different name than the default. The SSID can be accessed from within these products' Web-based or Windows-based configuration utilities. Common examples of pre-defined SSIDs are simple names like "wireless," "netgear," "linksys," or "default." An SSID can be changed at any time, as long as the change is also made on all wireless clients. 

    * Disable SSID broadcast: By default, most wireless access points will broadcast the SSID to all wireless devices. This would allow anyone with a wireless network card that can detect the SSID you use to gain access to your network. This feature of Wi-Fi network protocols is intended to allow clients to dynamically discover and roam between WLANs. In a home Wi-Fi network, roaming is largely unnecessary and the SSID broadcast feature serves no useful purpose. 

    * Use MAC address filtering: MAC filtering is the process of configuring an access point with a list of MAC addresses that will be allowed or not allowed to gain access to the rest of the network via that WAP. Only MAC addresses that have been registered with the wireless access point are able to gain access to your network. You can usually locate the MAC address of your network card on the device itself.

   * Always change the default user name and password for your wireless access point: Guessing the default user names and passwords for the wireless access points is a common practice for hackers to gain access to networks.

    * Turn off DHCP:
      Consider setting the wireless router to assign static IP addresses to the machines on your home network and turn off DHCP.

    * Refrain from using the default IP subnet:
      If you turn off DHCP, consider changing the IP subnet. Many routers use 192.168.1.0 for the network and 192.168.1.1 as the address for the router. It is easy for people to guess the IP addresses used and illegally gain access to the network.

    * Enable WEP:
      It is disabled by default. WEP is not considered totally secure, but it is free and will provide an initial barrier. Purchase network adapters and access points that support at least 128-bit WEP. Some network adapters may only require a driver upgrade to increase to 128-bit encryption.

Reduce Interference in your wireless network

It is important to consider all potential sources of interference when deploying a wireless LAN (local area network). If you don't, you will likely never see the peak performance of your wireless network.

Many wireless devices can cause interference to your wireless network if they are transmitting on the same band. Also, if you have neighbors that use a 802.11b or 802.11g wireless access point (WAP) then this also could create interference.

For example, when neighboring companies and homes have their 802.11b/g access points set to channel 6 (default), this would have a great impact on the interference created in your network.

If you are experiencing poor performance with your LAN, then you should consider changing the frequency that you are operating on. When re-configuring your WAPs channel, try channels 1, 6 or 11 as these are non-overlapping channels and should yield the best performance.

Related Terms:

    *  WEP:
      Wired Equivalent Privacy is a security protocol, specified in the IEEE Wireless Fidelity (Wi-Fi) standard, 802.11b, which is designed to provide a wireless local area network (WLAN) with a level of security and privacy comparable to what is usually expected of a wired LAN.

    * SSID:
      A service set identifier is a sequence of characters that uniquely names a wireless local area network (WLAN). MAC address– In a local area network (LAN) or other network, the MAC (Media Access Control) address is your computer's unique hardware number. (On an Ethernet LAN, it's the same as your Ethernet address.)

    * Static IP:
      A static IP address is a number that is assigned to a computer to be its permanent address on the network.

    * DHCP:
      Dynamic Host Configuration Protocol (DHCP) is a communications protocol that automates the assignment of Internet Protocol (IP) addresses in a network.

    * Subnet:
      A subnet is an identifiably separate part of a network. Typically, a subnet may represent all the machines at one geographic location, in one building, or on the same local area network (LAN).

    * LAN:
      Local Area Network - A network connecting computers in a relatively small area such as a building. 

    * WLAN:
      Wireless Local Area Network - Refers to wireless networks between computers within one building or a group of buildings. 

    * Wi-Fi:
      Wireless Fidelity - A standard that ensures equipment from different manufacturers works together with reasonable certainty. 

    * MAC:
      Media Access Control - the globally unique hardware address of an Ethernet network interface card. 

    * WAP:
      Wireless Application Protocol - standard for accessing the internet with wireless devices.

    * Sniffer:
      A program used to capture data across a computer network. Used by hackers to capture user id names and passwords. Software tool that audits and identifies network traffic packets. Is also used legitimately by network operations and maintenance personnel to troubleshoot network problems.

Bonus Tip:

How WI-FI Works:

Short for Wireless Fidelity. Wi-Fi technology, or 802.11a/b/g, works much the same as your digital cordless phone. Your voice is picked up by a microphone, then your voice is converted into a digital signal. This digital signal is then transmitted to the base unit. The base unit takes the data coming in from the phone line and converts that signal and sends it to the cordless phone.

A wireless connection of any kind works in this same fashion. There will always be a two-way communication going on. Your wireless access point or router is like your cordless phone base unit and your network interface card is like your cordless phone. The only difference between these two types of technology is that one converts a sound signal and the other converts a radio signal.

Hernández Caballero Indiana
Asignatura: CRF
Fuente:http://www.5starsupport.com/tutorial/wireless.htm#terms

Wireless Network Security

Before we talk about wireless network security, we must first understand how a wireless network operates.

For most home and small business users, a wireless network is basically a set of devices that enable all of the personal computers in your location to use a broadband internet connection simultaneously.

Wireless networks don't use cables for connections, but instead use radio waves, like cordless phones. Also known as Wi-Fi, or Wireless Fidelity, wireless networks allow you to use your networked computers or laptops anywhere in an office or home.

Wireless networking is also available in public "hotspots," like coffee shops, hotel rooms and lobbies, and airports.

You may have heard the term "Internet Cafe". This refers to a place of business (most often, a coffee shop) which offers wireless network access for anyone who wants to bring in a laptop equipped with a wireless network card. The wireless network card picks up the wireless network signal and the two communicate over that signal. Here's a web page which talks about the wireless network security risks of using Internet Cafes, if you are interested.

But, just as with a cell phone, a wireless network (and any computer you have connected to it) can be hacked, especially if it isn't secured.

CAVEAT and Disclaimer: Wireless networks are inherently unsafe and cannot be completely secured, as there are hackers who will always be one step ahead of the commercial security vendors.

So I, Ellen Davis, do not guarantee that your wireless network security will be impenetrable after completing the steps offered on this site.

However, in my opinion, the majority of hackers are going after bigger fish, and don't have much interest in your wireless home network, except maybe to use it for free internet access.

So unless you are storing hundreds of credit card numbers on your computers for some reason, or you have some kind of important information that can be sold on the black market, or you make some hacker mad, applying the steps below will help ensure your wireless network security is at least better than it would be if you did nothing.

Let's take a closer look at setting up a wireless network and the best practices for building in wireless network security.

First, here's a list of components needed to build a basic home or small office wireless network:

   1. Windows based personal computers, and/or personal laptops with Windows XP SP2 installed. (Windows XP SP2 is compatible with WPA2 Personal encryption, which is what I recommend using).

   2. WPA2 enabled wired or wireless network adapters, which should be (or may already be) installed in each of your computers.

      If you aren't sure whether Windows XP and the network cards installed on your computer are enabled for WPA2, here's an excellent page that walks you through how to upgrade Windows XP, routers and network cards to WPA2.

   3. Ethernet cables, also known as CAT 5 cables. They come in 3, 6, 10, 25, and 50 foot lengths. Desktop and laptop computers won't need a cable if a wireless network card in installed.

   4. A wireless router that supports WPA and WPA2 encryption. There are many different brands, but I use Linksys wireless routers because they are reliable and easy to set up. They cost around $60 in the big office supply or computer stores.

   5. A broadband internet connection.

   6. The wireless network security steps below.

Second, you need steps on how to secure a wireless network. I've included the details on how to implement reliable wireless network security below: (I'm assuming that we are in your home or small business office, and that you have a desktop PC wired into your broadband box and that you will be using a new Linksys router):

   1. First, you must have either a regular or wireless network card in all of the computers in your house. For most wireless networks, a desktop computer nearest to the broadband jack will be connected via a wired network card and cable. Laptops or any other computer not close to the router will be connected via wireless card (or long CAT 5 cable).

      IMPORTANT Note: If you have older network cards, they may not be compatible with the new WPA2 security protocol. Upgrade the drivers or the cards if you have to, because relying on any other security protocol like WEP is just not as good when it comes to wireless security.

      You may also need to upgrade Windows XP SP2 to be compatible with WPA2 security. Here's the Microsoft page to do this.

   2. If you haven't done so already, place an order for a broadband (aka high speed) internet service installation with your local internet service provider. (This can be a cable company, the telephone company or a wireless tower provider – shop around for the best deal).

   3. Purchase a wireless router and install it. NOTE: Be careful about buying used routers; the previous owner could install malicious software on them that could hurt your computer. New is better if you don't know how to clean them up.

   4. Following the instructions that come with the router, set it up next to the computer that is plugged into the broadband connection box.

   5. IMPORTANT!! SECURE your wireless router. Follow each of these steps to make sure your wireless network security is reliable and your network is safe from outside intrusion:

          * Change the default wireless network name or SSID to something unique but not personal (no social security numbers or house addresses). The name you choose can be up to 32 characters long and you need to be able to remember it. Linksys sets the default name to Linksys on their routers and every hacker in the world knows that, so don't leave it unchanged.

          * Change the default password. Linksys sets a default password of admin, and every hacker knows that too. Change it to a password that includes both letters and numbers. Avoid using words that can be found in a dictionary. Also, make sure you either remember it or note it somewhere secure. You will need if you want to access your router later to make changes.

          * Enable Encryption. Linksys routers offer several kinds of security protocols – WPA, WPA2 and WEP are the major types.

            The newest and most secure kind of encryption is WPA2. Both WEP and WPA have already been cracked by hackers. WPA2 is the most secure, so I would implement it over the other choices.

            When the router setup asks you to choose a wireless security encryption method, choose security mode "WPA2 Personal". Then choose algorithms "TKIP+AES". Choose a strong password for your encryption key, such as a combination of letters and numbers. It can be from 8 to 63 characters, I would use at least 14 characters. Leave the key renewal interval as it is, and save the setting. Make sure you can remember the key. I hate to tell you to write it down, but if you must, you must.

            Later, when you try to connect your wireless clients to your network, the card utility should automatically ask you for the preshared key. Enter it twice and you should get connected. If not, please check that the wireless card in the computer is actually compatible with WPA/WPA2.

            Note: If you have an older router that supports WEP only, and you don't want to upgrade it, please remember that WEP is very easy to crack, so your wireless network won't be as secure. You'll be at least safer if you use 128-bit WEP keys, but I would recommend that you check the router manufacturer's website for a firmware upgrade that will add WPA support.

          * DON'T turn off SSID Broadcasting. A wireless router can broadcast its SSID name by sending out a continuous radio ping. This is convenient for people trying to connect to it, because they don't have to remember the name of the network. It seems like it would be good to turn that off, but on Windows XP, it isn't a good idea.

            Windows XP, by default, always tries to connect to the first broadcasted wireless network. If you turn off SSID broadcasting, Windows XP won't connect to your network first if it finds a broadcasting network in close enough range. That's not good wireless network security, for sure. So it's best to continue broadcasting while implementing WPA2 encryption instead.

            Plus you won't have to choose to connect to "nonbroadcasting networks" on your computers, and then type in the name of the network to connect to it.

          * You have now successfully implemented wireless network security on your router that should keep your data relatively safe (see caveat above for more info).

      Let's keep going to finish setting up our network, and connecting to the internet.

   6. Change the network card settings in each of your PCs to match the router settings. Pay particular attention to the SSID, the type of encryption, and the key you used when you set up the router.

      You'll need to know this info when are ready to connect any wireless PCs or laptops. Wired computers will get the information they need automatically, as long as the network card is set up to use DHCP, which basically means the network card goes out and gets what it needs from the network automatically.

   7. If you have a laptop with a wireless card, check to make sure the wifi capabilities are on. NOTE: On some laptops, there is a switch or button on the laptop that turns the wireless network card on or off. If you are having trouble "seeing" the wireless network, you may have to "turn on" your wireless network card.

   8. Once your computer network cards have the network information that matches the router, they will connect and you'll be able to connect to the internet, with confidence that your wireless network security is set up correctly.

   9. Note: Look for the wireless signal strength in the system tray located in the bottom right hand corner of your Windows desktop. It will look a bunch of colored bars.

      Green means the signal is strong, yellow is weaker, and red means no signal at all.

      Walk around your house with your laptop and see how good the signal is in each room.

      Being able to work anywhere in your house depends on how big your house is, and where your wireless router is located. As you walk around, you'll see the signal strength icon in the Windows system tray changed.

      Very quickly, you'll find out the best places to be for full network speed. It's makes working on your computer kind of fun, and now you have the peace of mind that your wireless network security is keeping your computers safe.

      All done! You now know the best steps for setting up a wireless network and configuring strong wireless network security. I hope this information helps you keep your computers and your data safe.

      One more note: If setting up wireless network security seems a little overwhelming, and you live in Cheyenne, Wyoming, I can help. Send me a note via my contact form, and I'd be happy to come out and set it up for you. My rates are reasonable.

Hernández Caballero Indiana
Asignatura: CRF
Fuente:http://www.sensible-computer-help.com/wireless-network-security.html

What is the best WiFi antenna for me?

The single most important thing you can do to extend the range of your 802.11 system is to install an external antenna with some good gain and directional or omni-directional qualities. WiFi is simply a radio, which is used for computer. You can think of your antenna as the "speaker system" of your WiFi card. Get a bigger antenna; your WiFi will go a lot further. However, don't install a speaker on your wifi system or your range will be horrible!

Directional Antennas  

Directional antennas are used for Point-to-Point or sometimes for Multi-Point systems depending on the setup. If you are trying to go from one location (say for instance your router), to another location, this is the type of antenna we recommend. Directional antennas are Backfires, Yagi, Panel and dish type antennas.

Omni-Directional

This is the common "Base" antenna used for Point-to-Multi-Point or can be an omni-directional antenna for your car. An Omni-Directional antenna would serve as your main antenna to distribute the signal to other computers or devices (such as wireless printers, PDAs, etc) in your workgroup. You can use 2 Omni-Directional antennas for a point to point system, but this is usually not recommended because there is no real point to distributing your signal all over the place when you only want to going from point A to point B. Please refer to Directional antennas above. Typical Omni-Directional WiFi antennas consist of Vertical Omnis, Ceiling Domes, Rubber ducks, Small Desktops and Mobile vertical antennas.

Point-to-Point

Point-to-Point systems usually involve 2 different wireless points, or building to building wireless connections. But there are exceptions to every rule. If the access point is across a long valley and the owner of the system wishes to share the connection with multiple users on the other side of the valley. This would be a point to Multi-Point system but using directional antennas.

Point to Multi-Point

Point to Multi-Point systems is usually for sharing a WLAN (Wireless Local Area Network) or a high-speed internet connection inside of your home or with neighbors (oops, we didn't say that). They can also be for WAP (Wireless Access Points) such as you find at local coffee shops, truck stops, airports, RV parks and the ever expanding list of WAPs becoming available. Traveling with a notebook computer is extremely fun and can be a great business tool for the frequent traveler.

Range

The range of the signal will depend on several factors, including power output of your wireless card or router, receive strength of the wireless card or cards you are transmitting to, obstructions buildings or trees which may be in the way of your transmitting path, walls, etc. Since there are so many factors which can determine the overall range of your wireless system, it is impossible to cover it in this simple article. A rule of thumb however is to always choose an antenna which you think may be overkill. Why? Because the power output is extremely small it is necessary to have as much gain as possible. Most wireless cards have a power output of 32 milliwatts (+15dBm), which is roughly the same amount of power it takes to light a high power LED (Light Emitting Diode). LEDs are bright, but imaging trying to see one at a large distance or through a building or trees. This is why the antenna is critical for amplifying that signal so it is as strong as possible. Why is the power output so small? Because 802.11 works at the same frequency as a microwave oven (2.4 GHz) and if it put out a large amount of power…. well, enough said. Microwave popcorn! If you are somewhat technical, please visit our online wifi range calculator to learn more. 

One of our most frequently asked questions is how to choose the correct WiFi antenna for a particular situation. This can be either very simple or very complex depending on your particular application or what you need to do. 802.11b (11 Mbps) and 802.11g (56 Mbps) (Mbps stands for megabits per second and is a measure of bandwidth) standards provide excellent speed, but this completely depends on your signal strength and noise level of your wireless card and wireless system. This basically equates to, the larger the signal strength and the less noise your wireless card receives, the better.

There are many uses for wireless applications, either in a home, office or rural situations. Let's examine each of these applications.

Home

Home antennas are always the easiest types of antennas to purchase and take the least amount of effort in choosing and installing. In most circumstances, only one antenna is needed on the remote computer. We recommend putting any external antenna on the remote computer, simply because if you install it on your router and don't plan on setting up security, it will provide less signal strength outside of your home and your system will be less prone to hackers. If you have a multi-story home or a very large house, you may have to install antennas on every computer to get the range or bandwidth required. Every wall that you have to penetrate will decrease the signal strength of your system. For the best signal strength and signal, we recommend installing a 5dB ceiling dome antenna and either wireless desktop antennas or RL-1000 antennas on all remote computers. It is best to start with 1 antenna on a remote computer and test the signal strength and range.

Office

Office antennas are pretty straight forward. If you want to run a network system inside of your office building and don't want to run cables all over the place, first, purchase a good wireless card, install a Ceiling Dome, Desktop or Wibberduck antenna to extend and maximize the signal to your office router. It's that simple. However, this can get a little complex if the office is split between 2 different points or if the office is really large or on multiple stories of a building.

Mobile WiFi antennas

Why would anyone want WiFi in their car? Well, there are a lot of truck-stops and RV parks around the country now that offer wireless access. In fact, many public high speed wireless networks can be accessed directly from your car, truck, or RV. There is also something called WarDriving which is where bad people drive around neighborhoods and get their high-speed access for free. We don't condone this, but if you want to read more about it, please go to www.wardriving.com. It's fun and entertaining reading.

Yagi Antennas

Yagi antennas were the design of two Japanese people, Hidetsugu Yagi and Shintaro Uda, and are sometimes referred to as Yagi-Uda antennas. They were originally designed for radio, but are now also used for 802.11 systems. These antennas are typically very directional and are used for point to point, or to extend the range of a point to multi-point system. We highly recommend using the RadioLabs 14 or 16 element weatherproof Yagi antenna if you want to install your system outside. They have excellent signal strength and in the right circumstances can communicate for miles!

Backfire antennas 

The backfire is a small directional antenna with excellent gain. They look similar to a parabolic dish, but the gain isn't as high. We highly recommend Backfire antennas for point to point or point to multipoint systems because of the excellent gain and the good noise figures. We offer a backfire antenna with 15 dBi of Gain!! This is excellent considering the antenna is only 10 inches diameter.

Parabolic or dish antennas

This is where the real power is! Parabolic dish antennas put out tremendous gain but are a little hard to point and make a connection with. As the gain of an antenna increases, the antenna's radiation pattern decreases until you have a very little window to point or aim your dish correctly. Dish antennas are almost always used for a point to point system for long haul systems. The Parabolic Dish antennas work by focusing the power to a central point and beaming the radio's signal to a specific area, kind of like the adjustable reflector on a flashlight. These antennas are highly focused and are the perfect tool if you want to send your signal a very long distance. To calculate the distance of your WiFi...... WiFi Range Calculator or please call us for advise.

Gain Considerations

The gain you will require for each individual WiFi antenna system will dependant on any direct objects in your path, the distance you must cover and the individual wifi cards. These all must be taken into consideration before choosing the proper antenna system. If our calculator is too difficult to use, please feel free to contact us for information.

Interference

As with all radio systems, interference is always a problem. If you are listening to an AM radio and you hear static, this is interference. The same thing applies to WiFi systems, however not to such a large degree. Things that cause interference with WiFi systems are Microwave ovens, certain lighting systems, other 802.11 access points or systems, microwave transmitters, even high speed processors for computers can cause interference for 802.11 systems. All these problems must be isolated before you can expect any significant range out of your system. If you need help, please don't be afraid to ask us. Afterall, WiFi is our business.

Hernández Caballero Indiana
Asignatura: CRF
Fuente:http://radiolabs.com/Articles/wifi-antenna.html

Pasos para montar una red Wi-Fi

No hace mucho, tener una red inalámbrica en la casa era un privilegio de pocos. La mayoría de los usuarios solo contaba con un PC de escritorio y por eso la movilidad, una de las ventajas de poseer una red Wi-Fi, era nula. Además, solo una minoría de los usuarios disponía de banda ancha residencial, por lo que tampoco se justificaba tener una red de este tipo.

Para otros, la limitación era el costo de los equipos, ya que los computadores habilitados para Wi-Fi y los enrutadores necesarios para montar la red eran costosos. Pero quizás el principal obstáculo para muchas personas era la parte técnica: la idea de tener que lidiar con la configuración de una red intimidaba a mucha gente o le hacía pensar que inevitablemente debía conseguir a un experto para realizar el montaje.

Esto no es así. A medida que pasa el tiempo, fabricantes de enrutadores como Linksys, D-Link o Belkin han disminuido el costo de los equipos y la complejidad del proceso de configuración. Ahora, con algo de atención y especialmente paciencia (para seguir las instrucciones paso a paso), son muchos los que pueden intentar montar su propia red inalámbrica en la casa.

Hay que aclarar, sin embargo, que no todos los productos que encontrará en el mercado son fáciles de montar y usar. Nuestra recomendación es que compre equipos de buena marca, así pague más; aparte de ser confiables y de alta calidad, suelen ofrecer buena documentación, no tienen problemas de compatibilidad con el PC, ofrecen sitios web con información técnica y drivers (controladores de dispositivos), algunos traen un CD-ROM que lo guía paso a paso durante el montaje de la red, etc.

Con la asesoría de María Teresa Chaparro, ingeniera de sistemas de Cisco, ENTER 2.0 le ofrece una guía de lo que debe tener en cuenta para instalar una red inalámbrica en su hogar.

Para este tutorial se utilizó un enrutador Wireless-G modelo WRT54G, de marca Linksys-Cisco (lo escogimos porque es muy fácil de usar, incluso por no expertos).

 
Puesta a punto del hardware

Después de comprar el enrutador inalámbrico (Wi-Fi), debe conectarlo al PC principal de la casa y al módem de banda ancha. Por ello, lo mejor es ubicar el enrutador en la misma mesa o escritorio donde tiene esos equipos. Aunque un enrutador promedio no presenta problema alguno en llevar la señal a diferentes partes de su residencia (tienen un alcance de entre 30 y 100 metros, dependiendo de la versión de Wi-Fi que use), se recomienda que lo ubique en el salón donde suele trabajar con el computador o en un punto central de la red; así se asegura de que todos los equipos que están integrados a esa red obtengan un rendimiento parejo. Siga las instrucciones sobre la ubicación física del enrutador; por ejemplo, el manual del que usamos para este tutorial sugería colocar las antenas en forma paralela apuntando hacia arriba.

Si ya está familiarizado con los elementos necesarios para el montaje de su red inalámbrica (ver recuadro 'Los componentes de la red'), puede proceder a su instalación.

1. Encienda el computador e introduzca el CD o DVD que suelen entregarle junto con el enrutador (allí le indicarán los pasos a seguir y le ofrecerán varias opciones para la configuración de su red).

2. Desconecte de la toma de energía eléctrica y posteriormente de su computador el módem que le entregó su proveedor de Internet (en el caso de Cablenet, un cable módem).

3. El cable que estaba conectado del módem a su PC, ahora debe insertarlo en el puerto Internet del enrutador. Cuando se haya cerciorado de que quedó bien conectado (al halar con suavidad el cable, ninguna de las dos puntas se debe salir), enchufe de nuevo el módem a la toma eléctrica.

4. Tome el cable azul que viene con el enrutador y conecte un extremo al puerto de red de su PC, que está en la parte trasera del computador (en el que estaba conectado el módem inicialmente).

5. La otra punta de este cable insértela en uno de los puertos numerados del enrutador (en nuestro caso estaban marcados del 1 al 4). Puede hacerlo en el puerto que desee, pues los cuatro están habilitados para enlazar igual número de dispositivos a la red.

6. Conecte el adaptador de corriente al puerto de alimentación del enrutador y luego enchúfelo en el tomacorriente.

Si todo salió bien, en el panel frontal del enrutador deben encenderse varias luces: en nuestro caso, la luz Power (alimentación de energía); WLAN (que indica que está en actividad la red inalámbrica); 1, 2, 3 o 4 (eso comprueba que quedó conectado al puerto en forma adecuada) y la luz de Internet (que muestra actividad de navegación).

Configuración del software

Después de comprobar que el PC reconoce el enrutador y que tiene conexión a Internet (este proceso lo hace automáticamente el computador), puede empezar a configurar los valores que quiere asignar a su red.

En nuestro caso, por ejemplo, apareció un mensaje que dice 'Configure Cable o DHCP' (esto es para definir los parámetros de su conexión y hacer que la red funcione adecuadamente, de acuerdo con lo que tenga contratado con su proveedor de Internet). Si maneja la información técnica y tiene los datos de su cuenta de Internet (dirección IP asignada, dominio, etc.), escoja la opción que se acomode a sus parámetros; si no conoce estos datos o no sabe muy bien de qué le están hablando, no cambie nada (el PC hace un reconocimiento automático de algunos parámetros) y dé clic en 'Siguiente'.

7. Asigne una contraseña de acceso al enrutador (eso evitará que otras personas entren a su configuración y cambien los parámetros asignados al equipo o la red). Los enrutadores suelen tener una clave predeterminada, que por lo general es 'admin' (la debe usar la primera vez), pero lo recomendable es que la cambie por una que solo usted conozca.

8. En nuestro equipo luego apareció la pantalla Secure Easy Setup. Elija Secure Easy Setup (si tiene más de un equipo que maneje esta tecnología de Cisco) o dé clic en Omitir (recomendable).

9. Al elegir Omitir, aparecerá la ventana Parámetros inalámbricos, en la que deberá escribir el nombre con el que va a identificar su red inalámbrica (SSID); este nombre debe ser el mismo para todos los dispositivos que incluya en su red, puede ser entre mayúsculas y minúsculas, pero no mayor a 32 caracteres.
En la casilla siguiente deberá seleccionar el canal en el que operará su red inalámbrica. Los canales más usados son 3, 6 y 11 (como opción predeterminada, el enrutador viene en este último canal); lo recomendable es cambiarlo solo si se presume que puede estar siendo interferido por otros enrutadores cercanos.

10. Aunque la ventana siguiente se titula Configurar los parámetros de seguridad inalámbrica y tiene el aviso de 'opcional', este es uno de los pasos más importantes en la configuración de su red, pues si no pone seguridad (opción Desactivada), corre el riesgo de que cualquiera pueda acceder a ella, navegue desde su cuenta o en el peor de los casos ingresen a algunos de los archivos de su PC. Lo recomendable es usar el sistema WPA Personal y que en la casilla Clave asigne una contraseña que combine letras, números y algunos caracteres especiales (ver recuadro 'Cuidado con la seguridad').

11. Aparecerá un cuadro en el que le resumen todos los parámetros seleccionados (nombre de la red, método de seguridad empleado y clave asignada, entre otros); guarde estos datos directamente en su computador o en un dispositivo de memoria externa tipo USB. Es importante que almacene y tenga a la mano todos esos datos, ya que cada vez que vayaaintegrar un nuevo equipo a la red, intente modificar su configuración (cambiar la clave, por ejemplo) o trate de reparar o mejorar el funcionamiento de la misma tendrá que escribir o confirmar algunos de estos parámetros.

12. El paso final es registrar su enrutador en línea, si lo desea. De lo contrario, use la opción salir.

CÓMO INTEGRAR OTROS COMPUTADORES A LA RED WI-FI

Instalar un segundo computador a la red (por lo general un portátil habilitado para Wi-Fi) es una de las primeras tareas que intenta ejecutar una persona después de configurar su red inalámbrica. El siguiente es el procedimiento que debe realizar para que el nuevo equipo se conecte de forma inalámbrica a la red y a Internet:

1. Encienda el portátil. Si este incorpora Wi-Fi, después de entrar a Windows debe aparecerle un aviso que le dice qué redes inalámbricas hay disponibles; abra ese cuadro. Si no aparece automáticamente este aviso, vaya al ícono que identifica las redes inalámbricas en la barra de tareas, en la parte inferior de la pantalla, o busque por menú Inicio, 'Conectar a' y luego 'Conexiones de red inalámbricas'.

2. Aparecerá un listado con todas las redes inalámbricas disponibles (las que están al alcance de su computador); seleccione la suya y espere unos segundos.

3. Si la red a la que intenta conectarse cuenta con seguridad, aparecerá un cuadro que le pedirá que escriba y confirme la contraseña (es la clave del sistema WPA o WEP con el que encriptó la red).

4. Si después de hacer eso no se conecta (quizás solo vea un letrero en el que le indican que la red está Comprobando identidad), deberá definir los parámetros de la red manualmente en el portátil.

5. Para esto, en el menú 'Tareas de la red' (parte izquierda en la ventana Conexiones de red) abra 'Cambiar configuración avanzada' y luego la pestaña 'Redes inalámbricas'. En 'redes preferidas' aparecerá un listado con todas las redes que ha configurado en su equipo (si no aparece ninguna, puede crearla en Agregar). Seleccione la red a la que desea entrar y dé clic en Propiedades.

6. En la ventana que se abre tendrá que escribir los parámetros con los que fue configurada inicialmente la red inalámbrica (los que debió haber guardado al configurar el enrutador inalámbrico, en el paso 12). Debe escribir el nombre de la red (SSID), autenticación de red (la tecnología de encriptación), el método de cifrado de datos (TKIP y otro) y la clave. Tenga en cuenta que estos datos deben ser exactamente iguales a los introdujo en el enrutador; si alguno varía, no podrá conectarse.

7. Ahora debe aparecer conectado y por consiguiente podrá navegar en Internet. Si aún no lo logra, verifique que los datos escritos son los correctos; que la opción conexiones de red inalámbricas esté activada (Inicio, Conectar a, Mostrar todas las conexiones); o que tenga servicio a Internet (los indicadores del módem y enrutador lo muestran).

8. Por último, si necesita modificar la configuración del enrutador, use el programa de administración del mismo, al cual se accede mediante una dirección IP indicada en su manual (en el caso de las redes Linksys-Cisco es 192.168.1.1), desde un PC que esté conectado al enrutador mediante un cable de red.

LOS COMPONENTES DE LA RED

Los dispositivos que necesitará para crear su red inalámbrica casera son los siguientes:

Enrutador Wi-Fi: es el corazón de la red inalámbrica. Este equipo controla el flujo de datos en la red y comunica todos los dispositivos que hacen parte de ella. Cumple, además, otra función: gracias a él, todos los computadores del hogar que estén integrados a la red Wi-Fi podrán usar la conexión a Internet de banda ancha, de forma simultánea. El enrutador se conecta al PC principal de la casa mediante un cable.

El enrutador trae una o varias antenas que le permiten comunicarse a través de ondas de radio con los portátiles o demás equipos del hogar que estén habilitados para Wi-Fi.

En la parte frontal, el enrutador tiene varios indicadores de actividad; en la parte trasera, cuenta con varias entradas para conectar dispositivos.

PC principal: Es el equipo en el que se configuran o cambian los parámetros de su red inalámbrica. Puede ser un computador de escritorio o un portátil. Con un equipo de escritorio puede mantener el enrutador inalámbrico conectado –mediante un cable de red–, y así podrá modificar la configuración (por ejemplo, cambiar la clave de seguridad) periódicamente. Si utiliza un computador portátil, podrá utilizarlo como un equipo más de la red inalámbrica (con movilidad), pero tendrá que conectarlo al enrutador cada vez que quiera cambiar la configuración de la red.

Portátiles u otros PC: estos equipos son los que se conectan a la red de manera inalámbrica (sin cable alguno). Todos deben soportar la tecnología Wi-Fi (los portátiles modernos ya vienen habilitados; pero si tiene un computador que no soporta esa tecnología, puede comprarle un adaptador Wi-Fi para puerto USB).

Módem de banda ancha (cable o DSL): este dispositivo es el portal de entrada a Internet en su hogar (se lo suministró su proveedor de acceso a Internet). Durante el proceso de montaje de la red Wi-Fi, usted tendrá que enlazar este módem con el enrutador Wi-Fi (mediante un cable) para que así todos los computadores que hacen parte de la red puedan usar la conexión de alta velocidad a Internet.

Cable de red: enlaza el PC y el enrutador. Va desde uno de los puertos numerados del enrutador hasta el puerto de red Ethernet del PC.

Cable de red: este va conectado entre el puerto de red del módem y la entrada de Internet del enrutador.

CUIDADO CON LA SEGURIDAD

Si no cuenta con un sistema de seguridad en su red inalámbrica, cualquier otro usuario puede detectarla y conectarse a su cuenta de Internet (al compartirla, bajará la calidad de su conexión); también puede pasar que un intruso utilice esa puerta de entrada y acceda a sus archivos o información guardada en su computador.

Existen varias alternativas para garantizar la seguridad de las redes inalámbricas. La más común es la utilización de protocolos de cifrado de datos, que codifican la información transmitida de forma que nadie la pueda interceptar. Los más comunes en Wi-Fi son WEP (los expertos dicen que es casi de 'adorno'; muy poco confiable) y WPA (que es más seguro).

Según Cisco, lo ideal es usar WPA2; este es el protocolo más robusto y seguro disponible en los enrutadores recientes; sin embargo, todos los dispositivos de la red (los portátiles, el enrutador, etc.) deben soportar WPA2 para que usted lo pueda usar en la red; de lo contrario, tendrá que quedarse con WPA.

Según los voceros de Cisco, el usuario "debe tener en cuenta que para la utilización de WAP2 con Windows XP se requiere el Service Pack 2 y una actualización adicional. También es necesario tener hardware (enrutadores y portátiles) de última generación, que soporten WPA2, pues los equipos antiguos no manejan esa tecnología".

Agregan, además, que al momento de seleccionar una contraseña, lo mejor es tener una combinación de letras y números que además incluya algunos caracteres especiales (como #$%&*!). Aconsejan no usar contraseñas basadas en nombres personales, fechas, apodos o números consecutivos. Lo recomendable es cambiar la contraseña por lo menos cada tres meses. También es importante que active el firewall de Windows, de forma que un intruso no pueda penetrar a su red desde Internet.


CÓMO SELECCIONAR EL ENRUTADOR

La selección de los elementos que va a utilizar en la red es esencial, especialmente en lo que se refiere al enrutador, que es el corazón de la red. Para acertar en su decisión debe tener en cuenta aspectos como el estándar de Wi-Fi en el que se basa, las características y el precio.

Los enrutadores inalámbricos basados en el estándar 802.11n (el más reciente) son los que mayor alcance y velocidad le proporcionan: hasta 100 metros y una velocidad de unos 100 megabits por segundo (Mbps). Sin embargo, no son actualmente los más difundidos pues su precio todavía es alto (casi el doble que los 802.11g) y no son muchos los equipos (portátiles, por ejemplo) que usan esa versión de Wi-Fi. Los más usados son los enrutadores 801.11g, que ofrecen una velocidad máxima de 54 Mbps (casi cuatro veces más la proporcionada por 802.11b, la versión más antigua de Wi-Fi) y un alcance de unos 30 metros. La mayoría de los portátiles se basan en la versión 'g' de Wi-Fi.

"Es importante tener en cuenta el estándar de Wi-Fi que tienen los equipos que se van a conectar a la red; no tiene sentido adquirir un enrutador 802.11n si los equipos se basan en 802.11g. En ese caso, la velocidad máxima sería de 54 Mbps, que es la que brinda el estándar 802.11g, y se estarían desperdiciando las bondades del estándar n", explica María Teresa Chaparro, de Cisco.

Hernández Caballero Indiana
Asignatura: CRF
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