There are three main modes that a Wi-Fi device can use. These wireless network modes determine the role of the device in it. The configuration method depends on the types of connections that you want to use between its nodes. In addition to custom phones, tablets, and laptops, routers that control the network are used. They can connect one network to another, determine what traffic passes between them and perform other functions on the network, for example, assign an IP address.
After the initial launch of the Wi-Fi standard 802.11b, it became the most common among consumer devices due to its low cost. Three years later, it was replaced by a faster 802.11g, which retained backward compatibility to support existing equipment, while still having some of the drawbacks of older models. The next major wireless mode standard in the world, 802.11ac, was released in 2013 and has become the most sought after by many mobile device owners.
A Brief History of Standards
If the user has set himself the goal of creating a fast network in his home or office, you need to understand the technical parameters of the network and equipment, and first of all, you need to understand what this strange 802 number means.
In fact, the naming system uses a number of network standards. Ethernet networks start with 802.3, Bluetooth has the 802.15 prefix, and Wi-Fi is 802.11. All different Wi-Fi options will begin with this 802.11 number, followed by a letter or two that identify the properties of the network, such as the maximum speed and range of a particular device.
To ensure compatibility of the wireless network mode with various equipment, there is a list of Wi-Fi 802.11: a, b, g, n and ac in the specification for many smartphones. It covers all of the oldest and most common modern standards to help identify incremental improvements in the model, mainly in terms of increasing speed.
In 1970, the University of Hawaii developed the first wireless data network between the islands of the same name. However, it was not until 1991 that the Institute of Electrical and Electronics Engineers (IEEE) began discussing the standardization of WLAN technologies. In 1997, IEEE ratified the initial 802.11 standard with the term “802.11 technology,” which refers to Wi-Fi.
In 1999, communication was presented to the general public with ratifications of 802.11 a and b wireless network modes. These standards had a very low speed, up to 54 Mbps and 11 Mbps, respectively, but for that time it was normal, because there were no portable mobile phones using Wi-Fi, and very few laptops.
However, by 2003, mobile devices using Wi-Fi appeared, and portable laptops became more common in use, both in business and for personal purposes. It was then that the 802.11 g standard was approved, providing a speed of up to 54 Mbps in the 2.4 GHz space. In 2007, the first smartphone was released, and with it came the ratification of 802.11n.
The n standard provides faster processing speeds (up to 450 Mbps) for Wi-Fi and supports devices with a frequency of 2.4 GHz and 5 GHz. Today, smart devices are reliable enough to replace specialized, more expensive technologies for laptops, so wireless has begun to catch up.
In 2013, the gigabit Wi-Fi standard 802.11ac appeared. 802.11ac is a fantastic new wireless technology that has brought humanity into the era of gigabit Wi-Fi.
Three wireless network roles
The role of the network determines the goals and equipment that can fulfill them.
Wireless Clients (Station). Devices such as computers, tablets and phones are common clients on the network. When a user gains access to a wireless access point or router in a home or office, his device is a client. This operating mode of the client’s wireless network is also known as the “station mode”. Some routers can work in this capacity, which allows them to function as a wireless card in a PC, and will join various access points. Station can connect two Ethernet networks or connect to more remote access points. Wireless client - accesses information through the same channel.
Access Points (Master). Most wireless networks use access points - devices that host and control a wireless connection for laptops, tablets or smartphones. If Wi-Fi is used at home and in the office, then this happens through the access point. When the router is configured as an access point, it is in Master or Infrastructure mode. Access points can cover a range of areas with a wireless signal, it all depends on the power of the device and the type of antenna. The user needs to know this before deciding which wireless mode to choose.
Special node (Mesh). Some wireless devices such as laptops, smartphones, or wireless routers support Ad-Hoc mode. This allows these devices to connect to each other without an intermediate access point controlling the network. This standard forms a different type of network. In Ad-Hoc mode, all devices are responsible for sending and receiving messages to other devices - there is nothing more between them. On a network, each device must play these roles and use the same configuration to participate. Not all devices use this mode, and some use it as a "hidden" function.
Special devices are used to create a mesh network, so when they are in this mode, they are called "mesh nodes."
Packet devices in networks
In order to provide the functionality of the wireless networks described above (clients, access points and Ad-Hoc nodes), devices that are configured for different roles are needed:
- Home or office network. This type of wireless network is usually a combination of a router and a wireless access point (AP). In many networks, they can be combined into one device. Usually they are simply called routers and have a DSL port, cable, 3G or 4G for connecting to the Internet. In large office scenarios, there may be several AP devices distributed throughout the building to ensure uniform wireless coverage.
- Point-to-point communication - long-distance connections. Such networks can be used to connect remote buildings or areas. This usually requires very focused antennas, such as cymbals (an antenna that can send a narrow beam in a certain direction). Long-distance traffic is often referred to as point-to-point or PtP. The name describes the concept: two points are interconnected and nothing else. The standard requires two wireless devices: one must be configured as an access point, the other as a client.
- Long-distance access point and client communication. This is another example of point-to-point communications, where routers have antennas for longer range communications. Two wireless devices are connected to each other, antennas determine the range in which they can be connected. The more focused the signal, the farther the point-to-point communication can come. As the distance between the devices increases, it is more important to focus the signal using antennas (at both ends of the connection).
- Point to MultiPoint - a model of a wireless Internet provider. If you combine the two principles used in the above networks, many client devices connected to the access point, and more powerful antennas used for external devices to create longer channels, then you can create multipoint networks. These are large networks of access points, where in the "center" there is one device that controls all the clients connected to it, and connects them to the Internet. These types of networks are used by wireless Internet service providers (WISPs) to connect homes and businesses to the network. Instead of laying cables around an area or city, providers install one or more powerful access points on the tallest building or tower.
- Mesh - A mesh network uses the point-to-multipoint principle and is based on the idea that each node connects to any other node in the range. Essentially, this creates a Multipoint-to-Multipoint network. To do this, all devices must be in Ad-Hoc mode. Devices in AP mode or client mode cannot perform the same function. Wireless mesh nodes are installed on the roofs of various buildings and those nodes that are in the coverage area and do not have blocking signals will be connected. They will share all resources associated with them and connect to computers, access points or routers in buildings to provide users with resources anywhere on the network.
- Hybrid networks. When designing and building urban or public networks, it may be difficult or impossible to use one method for mass connection of subscribers. For example, a single point-to-multipoint network may not cover an entire area. Grid nodes can be used to expand client sites in adjacent buildings. Point-to-point connections can connect long distances and combine several disparate networks. In this option, there is no single example that would cover all possible options for using the network.
Privacy Wired Equivalency (WEP)
This model was developed in the late 1990s as the first 802.11 standard encryption algorithm with one main goal - to prevent hacker attacks on wireless networks with access points (APs). However, from the very beginning WEP did not have enough strength to cope with the task.
Cybersecurity experts found several serious flaws in WEP in 2001 in legacy wireless mode, which ultimately led to industry-wide recommendations for phasing out WEP on both corporate and home devices.
After a large-scale cyber attack against TJ Maxx in 2009 was traced to vulnerabilities identified by WEP, the Payment Card Industry Security Standard prohibited retailers and other organizations that processed credit card data from using WEP.
WEP uses RC4 stream cipher for authentication and encryption. The standard first defined a 40-bit provisional shared encryption key. A 104-bit key was made later. The key was entered manually and updated by the administrator.
The legacy wireless mode key combines with a 24-bit initialization (IV) vector to enhance encryption. However, the small size of IV increases the likelihood of reusing keys, which in turn makes it easier to crack them. This feature, along with a number of other vulnerabilities, including problematic authentication mechanisms, makes WEP a risky choice for securing a wireless network.
Wi-Fi Protected Access (WPA)
In 2003, the Wi-Fi Alliance launched WPA as an interim standard, and the Institute of Electrical and Electronics Engineers (IEEE) worked to create a more advanced and long-term replacement for WEP.
WPA has separate modes for corporate users and for personal use. Enterprise Mode (WPA-EAP) uses stronger 802.1x authentication with EAP. In personal mode, WPA-PSK uses shared keys to simplify the implementation and management of users and small offices. Enterprise mode requires the installation of an authentication server.
Although WPA is also based on the RC4 cipher, it introduced several encryption enhancements, namely the use of the Temporary Key Integration Protocol (TKIP). The protocol contains a set of functions to improve network security:
- Using 256-bit keys, mixing keys for each packet.
- Generate a unique key for each package.
- Automatic distribution of updated keys, message integrity check, large IV size (48 bits).
- Mechanisms to Reduce Reuse IV.
WPA was designed to provide backward compatibility with WEP to provide a quick and easy implementation. Network security experts were able to support the new standard on many WEP-based devices with a simple firmware update. This structure was not able to provide adequate security; nevertheless, it was not as reliable as required by users.
WPA2: Upgrading Legacy Standard
The WPA2 standard was approved by IEEE in 2004 as 802.11i. Like its predecessor, WPA2 also offers enterprise and personal modes and still has vulnerabilities. However, today it is considered the most secure wireless security standard.
WPA2 replaces the RC4 and TKIP ciphers with two more robust encryption and authentication mechanisms — Advanced Encryption Standard (AES) and Counter Mode with Authentication Code Protocol and Encryption Message Chain (CCMP).
Designed to be compatible, WPA2 supports TKIP as a fallback if the device cannot support CCMP. AES consists of three symmetric block ciphers. Each encrypts and decrypts data in 128-bit blocks using 128, 192 256-bit keys. While using AES requires more processing power from access points and customers, continuous improvements in computer and network equipment have reduced performance issues.
CCMP protects data privacy by only allowing authorized users to use the network, using a message authentication code in the cipher block chain to ensure message integrity. WPA2 also introduced smoother roaming, allowing clients to switch from one access point to another on the same network without re-authentication, using master key pair caching or pre-authentication.
802.11 Infrastructure Mode
The 802.11 standard defines two modes of operation:
- An infrastructure mode in which wireless clients are connected to an access point. This is usually the default mode for 802.11b cards.
- Ad hoc mode in which clients connect with friends without any access point.
In infrastructure mode, Asus with a wireless mode, known as STA, connects to the access point wirelessly. The node formed by the access point and stations located within the coverage area is called a set of basic services, in English it is designated BSS and is a microcircuit. Each BSS is identified by a BSSID, a 6-byte (48-bit) identifier. In infrastructure mode, the BSSID corresponds to the MAC address of the access point.
You can connect several access points together or, more precisely, several BSS through a connection called a distribution system, designated DS to form an extended set of services or ESS. The DS distribution system can be a lead network, a cable between two access points, or a wireless network.
An ESS is identified by an ESSID (Service Set Identifier), that is, an identifier of 32 ASCII characters as a name for the network. The ESSID often connects to the SSID, shows the network name in the first level of security. When a mobile user switches from one BSS to another, when moving the wireless network adapter of his device to ESS, he can change the access point depending on the quality of signal reception from different access points.
They communicate with each other through a distribution system to exchange information and, if necessary, transmit data from mobile stations. This feature, which allows stations to easily switch from one access point to another, is called roaming. Most routers have several connection options, including legacy or n only wireless network mode, for example for ASUS RT-N18U.
Access Point Communication
When a station enters a cell, it sends a verification request to each channel containing the ESSID for which it is configured, as well as transmitting data supported by the Asus adapter with wireless mode. If the ESSID is not configured, the station listens on the network for the SSID.
Each access point regularly transmits a frame (at a rate of approximately one send every 0.1 seconds) with information about the BSSID and characteristics. ESSID is automatically translated by default, but you can (and recommended) disable this option.
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In a dedicated network, the scope of an independent BSS is determined by the scope of each station. This means that if two of the network stations are out of reach of each other, they will not be able to communicate, even if they “see” other stations. Indeed, unlike the infrastructure mode, ad hoc mode does not offer a distribution system capable of transmitting frames from one station to another. Thus, IBSS is by definition limited to a wireless network.
Mixed Transfer Mode
The 802.11n or wireless n standard offers several advantages over the old Wi-Fi standards 802.11 a, b, and g. Although 802.11 a and b standards have now almost disappeared, there are still a number of marketplaces where you can buy 802.11 g wireless routers, and many people still use equipment that uses this old standard, such as Asus wireless legacy mode.
If the user uses the entire wireless network n, and everything connected to the network is wireless n, then he will not have problems, and everything will work at full wireless speed n. If it uses wireless network n with some old wireless devices b or g connected to it, then in order for these old devices to maintain operability, the network must slow down. This means that such a scheme loses some advantages in wireless network speed n even on other wireless devices n.
Most routers provide the ability to switch modes; the user must select the n or legacy wireless network mode.
The most common schemes are described below:
- Deprecated mode - allows a / b / g standards to communicate with the wireless router n, everything works at a low speed.
- Mixed mode - allows a / b / g devices to communicate with wireless router n at wireless network speeds G, but with some of the advantages of N.
- Full n mode - allows only wireless devices n to communicate with the router and gives all the advantages of wireless network N.
New routers automatically switch between modes, so you can be sure that the best available speed and range will always be set. For some device brands, security settings can cause the router to run at slower speeds, such as WPA1 on Netgear routers.
Thus, we can summarize which wireless network mode is better to choose. If the user has the opportunity to choose between g and n modes - you always need to choose n. Almost every router will work with the old standards, but users will not receive all the advantages of the new standard, and only when they finally get rid of the old wireless g-devices, they will feel all the advantages of the wireless network n.