DOWNLOAD PDF INFRASTRUCTURE AND AD HOC MODES

Transcription

1 Chapter 1 : Ansible Ad hoc Commands Infrastructure and Ad-Hoc Modes Explained. Most Wi-Fi networks function in infrastructure mode. Devices on the network all communicate through a single access point, which is generally the wireless router. Differences between adhoc networks and wireless networks? Generally a adhoc network is a wireless network but instead of been managed by a hub or switch a computer runs the network. A adhoc network is typically a wireless connection â between two or more computers without the use of a hub or switch, where as a wireless network generally has some piece network hardware running the network that is only meant to facilitate connections and not make them its self. Difference between adhoc network and cellular network? A cellular architecture would then present a challenge to the frequent handover procedure to the smaller cell size would usually induce a higher hand-off frequency. The adhoc network is non infrastructure network in which nodes can access services from one another regardless where they are. The main difference is the severe resource contraints in sensor networks in terms of power, memory capacity What is the difference between infrastructure and capital goods? Infrastructure typically refers to core components of something - most commonly associated with streets, water systems, etc Technically, there is no difference as they are both Fixed Assets of an entity. The type of entity will tell you the degree to which the terms "Infrastructure" and "Capital Goods" or correctly or incorrectly being used. What are Differences between mean and mode? Mean is the average of a set of numbers, mode is the number that occurs the most. Here is an example of â finding a mean:. Say these were your numbers Then you have to divide by how many numbers there are. In this case there are 5 numbers so divide 10 by 5 and you get your answer, 2. And here is how to find the mode Mode is Wich number there is the most of. Median is when you put the numbers in order and you find the middle number Share to: Page 1

2 Chapter 2 : [UPDATED] WLAN Road24h Ad-Hoc mode Connector for C4 MUX va An Ad-hoc Wireless Network is comprised of a group of computers that communicate directly with each other on a peer-to-peer basis without the use of a Wireless Access Point. These early packet radio systems predated the Internet, and indeed were part of the motivation of the original Internet Protocol suite. Another third wave of academic and research activity started in the mids with the advent of inexpensive Current wireless ad-hoc networks are designed primarily for military utility. The project did not proceed much further until the early s when wireless ad hoc networks are born. Perkins was working on the dynamic addressing issues. Toh worked on a new routing protocol, which was known as ABR â associativity-based routing. Another routing protocol known as AODV was subsequently introduced and later proven and implemented in Minimal configuration and quick deployment make ad hoc networks suitable for emergency situations like natural disasters or military conflicts. The presence of dynamic and adaptive routing protocols enables ad hoc networks to be formed quickly. Wireless ad-hoc networks can be further classified by their applications: It is sometimes known as "on-the-fly" networks or "spontaneous networks". Intelligent vehicular ad hoc networks InVANETs are a kind of artificial intelligence that helps vehicles to behave in intelligent manners during vehicle-to-vehicle collisions, accidents. Vehicles are using radio waves to communicate with each other, creating communication networks instantly on-the-fly while vehicles are moving on the roads. Smart phone ad hoc networks SPANs [ edit ] A SPAN leverages existing hardware primarily Wi-Fi and Bluetooth and software protocols in commercially available smartphones to create peer-to-peer networks without relying on cellular carrier networks, wireless access points, or traditional network infrastructure. It has been claimed that this is going to "change the world". In a fully connected mesh, each node is connected to every other node, forming a "mesh". A partial mesh, by contrast, has a topology in which some nodes are not connected to others, although this term is seldom in use. Wireless ad hoc networks can take the form of a mesh networks or others. A wireless ad hoc network does not have fixed topology, and its connectivity among nodes is totally dependent on the behavior of the devices, their mobility patterns, distance with each other, etc. Hence, wireless mesh networks are a particular type of wireless ad hoc networks, with special emphasis on the resultant network topology. While some wireless mesh networks particularly those within a home have relatively infrequent mobility and thus infrequent link breaks, other more mobile mesh networks require frequent routing adjustments to account for lost links. Ad hoc mobile communications [23] come in well to fulfill this need, especially its infrastructureless nature, fast deployment and operation. Military MANETs are used by military units with emphasis on rapid deployment, infrastructureless, all-wireless networks no fixed radio towers, robustness link breaks are no problem, security, range, and instant operation. MANETs can be used in army "hopping" mines, [24] in platoons where soldiers communicate in foreign terrains, giving them superiority in the battlefield. Tactical MANETs can be formed automatically during the mission and the network "disappears" when the mission is over or decommissioned. It is sometimes called "on-the-fly" wireless tactical network. UAVs can be remotely controlled i. With wireless ad hoc network technology embedded into the UAVs, multiple UAVs can communicate with each other and work as a team, collaboratively to complete a task and mission. Navy ad hoc networks[ edit ] Navy ships traditionally use satellite communications and other maritime radios to communicate with each other or with ground station back on land. However, such communications are restricted by delays and limited bandwidth. Wireless ad hoc networks enable ship-area-networks to be formed while at sea, enabling high speed wireless communications among ships, enhancing their sharing of imaging and multimedia data, and better co-ordination in battlefield operations. Sensors are increasingly connected via wireless to allow large scale collection of sensor data. With a large sample of sensor data, analytics processing can be used to make sense out of these data. The connectivity of wireless sensor networks rely on the principles behind wireless ad hoc networks, since sensors can now be deploy without any fixed radio towers, and they can now form networks on-the-fly. Ad hoc home smart lighting[ edit ] ZigBee is a low power form of wireless ad hoc networks that is now finding their way in home automation. Its low power consumption, robustness and Page 2

3 extended range inherent in mesh networking can deliver several advantages for smart lighting in homes and in offices. The control includes adjusting dimmable lights, color lights, and color or scene. The networks allow a set or subset of lights to be controlled over a smart phone or via a computer. Ad hoc street light networks[ edit ] Wireless ad hoc smart street light networks are beginning to evolve. The concept is to use wireless control of city street lights for better energy efficiency, as part of a smart city architectural feature. A single gateway device can control up to street lights. Using the gateway device, one can turn individual lights ON, OFF or dim them, as well as find out which individual light is faulty and in need of maintenance. Efforts have been made to co-ordinate and control a group of robots to undertake collaborative work to complete a task. Centralized control is often based on a "star" approach, where robots take turns to talk to the controller station. However, with wireless ad hoc networks, robots can form a communication network on-the-fly, i. At times of disasters floods, storms, earthquakes, fires, etc. Especially at times of earthquakes when radio towers had collapsed or were destroyed, wireless ad hoc networks can be formed independently. Firemen and rescue workers can use ad hoc networks to communicate and rescue those injured. Commercial radios with such capability are available on the market. The advantages and challenges cons can be briefly summarized below: Page 3

4 Chapter 3 : What is Ad-Hoc Mode? - Definition from Techopedia This page on WLAN adhoc mode vs infrastructure mode describes difference between adhoc mode and infrastructure mode in WLAN networks. WLAN Adhoc Mode In adhoc mode, WLAN wireless network is composed of only stations ( compliant NICs). Wi-Fi networks in infrastructure mode are generally created by Wi-Fi routers, while ad-hoc networks are usually short-lived networks created by a laptop or other device. Devices on the network all communicate through a single access point, which is generally the wireless router. They send packets to the access point â probably a wireless router â and it sends the packets back to the other laptop. Infrastructure mode requires a central access point that all devices connect to. Instead, devices on the wireless network connect directly to each other. Advantages and Disadvantages Ad-hoc mode can be easier to set up if you just want to connect two devices to each other without requiring a centralized access point. You can connect them directly with ad-hoc mode to form a temporary Wi-Fi network without needing a router. The new Wi-Fi Direct standard also builds on ad-hoc mode, allowing devices to communicate directly over Wi-Fi signals. Wireless routers that function as access points generally have higher-power wireless radios and antennas so they can cover a wider area. Ad-hoc mode also has other disadvantages. It requires more system resources as the physical network layout will change as devices move around, while an access point in infrastructure mode generally remains stationary. If many devices are connected to the ad-hoc network, there will be more wireless interference â each computer has to establish a direct connection to each other computer rather than going through a single access point. If a device is out of range of another device it wants to connect to, it will pass the data through other devices on the way. Passing the data through several computers is just slower than passing it through a single access point. When to Use Each Deciding when to use each type of network is actually pretty simple. Unfortunately, most operating systems will create an ad-hoc network by default. For example, you can create an ad-hoc network from the Control Panel in Windows or create an ad-hoc network on your Ubuntu Linux machine. If you need to create an infrastructure-mode access point on Linux, look into the AP-Hotspot tool. On a Mac, enabling the Internet Sharing feature will create a network in infrastructure mode, not ad-hoc mode. Routers come configured to use infrastructure mode by default, and ad-hoc mode will work for quickly connecting two laptops. Page 4

5 Chapter 4 : Difference between WLAN adhoc mode and infrastructure mode The ad hoc and infrastructure modes are used by wireless local area networks to connect devices to the networks. Although both modes allow computers and devices to connect to each other on a wireless network, infrastructure mode requires the use of an access point for this communication to take place. Infrastructure Wireless networks typically work in one of two configurations sometimes called topologies: The topology or mode you choose depends on whether you want your PCs to communicate directly or with an access point. In ad-hoc mode Figure 3. An ad-hoc network is also called a peer-to-peer network. Here are some of the benefits of an ad-hoc network: Ad-hoc networks are simple to set up. Ad-hoc networks are inexpensive. You save the cost of purchasing an access point. Ad-hoc networks are fast. Throughput rates between two wireless network adapters are twice as fast as when you use an access point. An ad-hoc network with two computers communicating directly. You can increase the range of your wireless network by adding an access point. Wireless networks that use an access point are in infrastructure mode Figure 3. More common than an ad-hoc network, an infrastructure network includes an access point. An infrastructure network enables you to: Connect to a wired network. An access point Figure 3. Your wired and wirelessly networked computers can communicate with each other. This is the most obvious strength of an infrastructure setup. This access point from D-Link can be used to connect a cable or DSL modem to provide Internet access to the wirelessly connected computers on your network. Placing an access point in between two wireless network adapters doubles their range. If you add multiple access points to your network, as you might in an office or large home, users can roam between interlocking access point cells, without ever losing a connection to the network. Probably the most useful device in a simple wireless LAN is an access point with a built-in router and firewall. The router allows you to share Internet access between all your computers, and the firewall hides your network, helping to keep network-savvy hoodlums at bay. Some of these multifunction access points include a wired hub as well, for plugging in several computers connected to your network by Ethernet. An infrastructure network takes a bit more work than setting up an ad-hoc network. Infrastructure networks cut the data transfer rate about in half, because of the time it takes to send the signal to and from the access point rather than directly to its destination, as in an ad-hoc network. The other drawback is expense: Infrastructure networks are more expensive than ad-hoc networks because you have to purchase an access point. As we already mentioned, however, that expense is well worth it for all the benefits an access point provides. Page 5

6 Chapter 5 : Ansible - Using File & Copy Modules in Ad-hoc Mode? - UnixArena An Ad-hoc network allows devices to communicate directly without a central access point, e.g. a router. Only devices set up on the Ad-hoc network can communicate. An Infrastructure network allows devices to be connected via a central access point. There are two most common modes by which we connect to Wi-Fi for connectivity for accessing internet or other computer for file sharing etc. The most common modes for Wi-Fi connectivity are as follow: These devices are connected to wireless network with the help of Access point AP. Wireless Access Points are usually routers or switches which are connected to internet by Ethernet port. Wireless Access points are always required for infrastructure mode of wireless networking. The Access point is then connected to wire network Internet to provide wireless internet connectivity to clients. Multiple access points can be added in the WLAN, this increases the reach of infrastructure for supporting many number of wireless clients. Setting Up Infrastructure Mode: Setting up infrastructure mode for wireless connectivity is not that hard, all we are require to follow number of steps which will do the job. We need to make sure that Internet cable is plugged in Ethernet port, second step is to configure AP Access point. Write this URL at your Internet browser, username and password window will appear, default settings are usually, admin username and admin password. Ad hoc Mode There is another mode of connectivity available for Wi-Fi connectivity. This mode is known to be ad hoc mode. By using ad hoc mode, devices are capable for communicating directly with each other. Setting up Ad hoc Mode For setting up ad hoc mode, wireless adaptors of all devices are required to be configured manually at ad hoc mode instead of infrastructure mode. It is also important to use same channel name and configuring all wireless adaptors using same SSID for making connection live. Setting up ad hoc network Limitation of Ad hoc mode Ad hoc mode is best used for small number of devices which are physically present in close proximity with each other and as the number of devices grows performance of network suffers. Disconnections of random device may occur time to time and managing the network can be difficult task for administrator. There is another limitation associated with ad hoc mode that is, ad hoc mode networks cannot bridge to wire LANs and cannot access internet without installing special gateways. Advantages of Ad hoc network mode Ad hoc mode networks works fine in small environment, like building, homes etc. No extra hardware Access point is required to use ad hoc mode, therefore it reduces the cost. If devices have wireless network adapters in them already then that will do the job as far as building ad hoc networks is concern. Ad hoc can be useful as back up option for time being if network based on infrastructure mode and access points are malfunctioning. Advantages of Infrastructure mode comparison between Ad hoc and infrastructure If we are to compare ad hoc with infrastructure mode then infrastructure mode provide much more stability, scalability, ease of management and improved security. Ad hoc on the other hand does not provide security to that level and managing can be difficult incase of network growth. Performance suffers as we increase devices as well. The only disadvantage associated with infrastructure mode is extra cost to for Access points routers and switches. Compared to the alternative, ad-hoc wireless networks, infrastructure mode networks offer the advantage of scalability, centralized security management and improved reach. The disadvantage of infrastructure wireless networks is simply the additional cost to purchase AP hardware. Page 6

7 Chapter 6 : Ad-Hoc Mode Into Wireless Network â Why And How? - SysTools Blog Ad-Hoc and Infrastructure Modes When architecting an network, there are two modes in which you can operate: Ad-Hoc and Infrastructure. In Ad-Hoc mode (see Figure ), sometimes called "IBSS" or "Independent Basic Services Set", all devices operate in a peer-to-peer blog.quintoapp.com are no access points used in this topology, as all. Ad Hoc Mode Infrastructure mode In infrastructure mode, each station computer STA for short connects to an access point via a wireless link. The set-up formed by the access point and the stations located within its coverage area are called the basic service set, or BSS for short. They form one cell. The distribution system can also be a wired network, a cable between two access points, or even a wireless network: Access points communicate with one another using a distribution system in order to trade information about the stations and, if necessary, to transmit data from mobile stations. This feature which lets stations move "transparently" from one access point to another is called roaming. Communicating with the Access Point When a station joins a cell, the cell sends a probe request on each channel. This request contains the ESSID that the cell is configured to use, as well as the traffic volume that its wireless adapter can support. Each access point broadcasts at regular intervals about ten times a second a signal called a beacon, which gives information on its BSSID, its characteristics, and, if applicable, its ESSID. The ESSID is automatically broadcast by default, but it is possible and recommended to disable this option. Whenever a probe request is received, the access point checks the ESSID and the traffic volume request found in the beacon. If the given ESSID matches that of the access point, the access point sends a response containing synchronization data and information on its traffic load. This way, the station that receives the response can check the quality of the signal being sent by the access point in order to determine how far away it is. Generally, the closer an access point is, the higher its data transfer capacity is. So, a station within range of multiple access points which have the same SSID may choose the access point offering the best balance of capacity and current traffic load. When a station is within range of several access points, the station chooses which one to connect to. Ad Hoc Mode In ad hoc mode, wireless client machines connect to one another in order to form a peer-to-peer network, i. The set-up formed by the stations is called the independent basic service set, or IBSS for short. An IBSS is a wireless network that has at least two stations and uses no access point. The IBSS, therefore, forms a temporary network that lets people in the same room exchange data. Unlike infrastructure mode, ad hoc mode has no distribution system that can send data frames from one station to another. An IBSS, then, is by definition a restricted wireless network. Chapter 7 : What are the differences between an 'Ad hoc mode' and 'Infrastructure mode' network? Brothe To set up a wireless ad-hoc network, each wireless adapter must be configured for ad-hoc mode instead of infrastructure mode, which is the mode used in networks where there is a central device like a router or server that manages the traffic. Chapter 8 : Whatâ s the Difference Between Ad-Hoc and Infrastructure Mode Wi-Fi? Ad-hoc networks are only able to communicate with other Ad-hoc devices, they are not able to communicate with any Infrastructure devices or any other devices connected to a wired network. In addition, Ad-hoc mode security is less sophisticated compared to an Infrastructure mode network. Chapter 9 : infrastructure vs. ad-hoc modes? - D-Link DSLReports Forums In addition, Ad-hoc mode security is less sophisticated compared to an Infrastructure mode network. Infrastructure mode: An Infrastructure mode network requires the use of an Access Point. Page 7