Comparison TP-LINK TD-W8901N vs TP-LINK TD-W8951ND

Rated power of the Wi-Fi transmitter used in the device. If multiple bands are supported (see “Ranges of operation”) the power for different frequencies may be different, for such cases the maximum value is indicated here.

The total transmitting power provided by the device directly depends on this parameter. This power can be calculated by adding the transmitter power and the antenna gain (see above): for example, a 20 dBm transmitter coupled with a 5 dBi antenna results in a total power of 25 dBm (in the main antenna coverage area). For simple domestic use (for example, buying a router in a small apartment), such details are not required, but in the professional field it often becomes necessary to use wireless devices of a strictly defined power. Detailed recommendations on this matter for different situations can be found in special sources, but here we note that the total value of 26 dBm or more allows the device to be classified as equipment with a powerful transmitter. At the same time, such capabilities are not always required in fact: excessive power can create a lot of interference both for surrounding devices and for the transmitter itself (especially in urban and other similar conditions), as well as degrade the quality of the connection with low-power electronics. And for effective communication over a long distance, both the equipment itself and external devices must have the appropriate power (which is far from alway...s achievable). So, when choosing, you should not chase the maximum number of decibels, but take into account the recommendations for a particular case; in addition, a Wi-Fi amplifier or MESH system often turns out to be a good alternative to a powerful transmitter.

The main functions and capabilities implemented in the device.

This category mainly includes the most key functions — namely load balancing (Dual WAN), channel reservation, Link Aggregation, Bluetooth(various versions, including Bluetooth v 5), voice assistant, NAT, MESH modes, bridge, repeater, Beamforming function , firewall (Firewall) and CLI (Telnet). Here is a more detailed description of each of these items:

— Dual WAN. Possibility of simultaneous connection to two external networks. Most often used for simultaneous work with two Internet connections (although other options are possible); at the same time, there are two main modes of operation with such connections — redundancy (Failover / Failback) and balancing (Load Balance). So, in backup mode, the device constantly uses the main channel to connect to the Internet, and in case of failures on this channel, it automatically switches to a fallback option. In balancing mode, both channels are used simultaneously, while the load between them is distributed either automatically (depending on the traff...ic consumption of a particular device) or manually (clearly specified in the settings for specific devices). This allows, for example, to separate the channel for online games from the rest of the connection, minimizing lags and increasing efficiency.

— Link Aggregation. A function that allows you to combine several parallel physical communication channels into one logical one — to increase the speed and reliability of the connection. Simply put, with Link Aggregation, a device can be connected to another device not with one cable, but with two or even more at once. The increase in speed in this case occurs due to the summation of the throughput of all physical channels; however, the total speed may be less than the sum of the speeds — on the other hand, combining several relatively slow connectors is often cheaper than using equipment with a more advanced single interface. And the increase in reliability is carried out, firstly, by distributing the total load over individual physical channels, and secondly, by means of "hot" redundancy: the failure of one port or cable can reduce the speed, but does not lead to a complete disconnection, and when the channel is restored, the channel is switched on automatically.

— Bluetooth. The device supports Bluetooth wireless technology. The meaning of this function will depend on the format of the equipment operation (see "Device type"). For example, adapters with this capability allow you to supplement your PC not only with Wi-Fi, but also with Bluetooth support — thanks to this, you can get by with one adapter instead of two. And in routers and access points, this feature allows external devices to access the Internet (or local area network) over a Bluetooth connection instead of Wi-Fi. This format of work allows you to unload the Wi-Fi channel and reduce the power consumption of connected devices; this is especially important for smart home components and other IoT devices, some routers/access points expressly state that Bluetooth is intended mainly for such electronics. Other ways of using this technology, more specific, may be envisaged; however, this is rare.

— Voice assistant. Device support for a particular voice assistant. The most common options are (individually or together):

• Amazon Alexa
• Google Assistant

The specific functionality of these assistants can be clarified from special sources (especially since it is constantly being optimized and expanded). Here we note that in the case of Wi-Fi equipment, we are usually not talking about an assistant built into the device itself, but about improved compatibility with smartphones and other gadgets that have the corresponding assistant installed. Such functionality can be especially useful given that modern voice assistants are also used to control smart home components. Communication with such control is often carried out just through a home router or other similar equipment, and the support of such equipment for voice assistants greatly simplifies setup and expands the capabilities of the entire system.

— NAT (Network Address Translation). A function that allows Wi-Fi equipment, when working with an external network (for example, the Internet), to replace the IP addresses of all computers and other devices connected to this equipment with one common IP address. In other words, a network with such a router is seen "from the outside" as one device, with one common IP. The most popular use of NAT is to connect several subscribers to the Internet (for example, all computers and gadgets within a home or office) through one provider account. At the same time, the number of such subscribers within the network is limited only by the capabilities of the router and can be freely changed; this will not affect access to the World Wide Web (whereas without using NAT, one would have to organize a separate account for each device). NAT support is a mandatory feature for routers (see "Device type").

— Bridge mode. Possibility of operation of the equipment in the bridge mode. This mode allows you to wirelessly connect individual network segments to each other — for example, to combine two floors if it is difficult to lay a cable between them. However, communication over longer distances is also possible — in some directional access points (see "Device type"), created mainly for just such an application, the range can exceed 20 km. Actually, this mode supports most access points (both directional and conventional), but it is also popular in other types of equipment, in particular, routers.
Note that to work in bridge mode, it is best to use the same type of device — this guarantees high-quality communication in both directions. It is also worth mentioning that in addition to the two-way point-to-point mode, there is also equipment with support for multi-way bridges (“point-to-multipoint”); the availability of such a possibility should be clarified separately.

— Repeater mode. An operating mode in which the equipment only repeats the Wi-Fi signal from another device, playing the role of a repeater. The main function of this function is to expand Wi-Fi networks, providing access where the main device (for example, a router) does not reach. A classic example of repeaters is Wi-Fi amplifiers (see "Device type"), they have this mode by definition; however, it is also found in other types of Wi-Fi equipment. The exception is MESH systems that have similar specifics, but differ in the format of work. See below for more information about this format, but here we note that networks with repeaters are in many ways inferior to MESH in terms of practical capabilities. Firstly, the signals from the main equipment and from the repeater are seen as separate Wi-Fi networks, and when moving between them, subscriber devices must reconnect; this can happen automatically, but disconnections and network changes still cause inconvenience. Secondly, working through a repeater significantly reduces the speed of Wi-Fi. Thirdly, the repeater operates according to a strictly fixed, pre-established routing scheme. On the other hand, access points with a repeater function are much cheaper than MESH nodes, and the mentioned drawbacks are far from always critical.

— MESH mode. Ability to operate the device as a MESH network node. By definition, all MESH systems have this feature, but it can be provided in other types of equipment. A detailed description of networks of this type is given in the paragraph “Device type — MESH system”. Here we will briefly describe their features and the difference between this mode and the repeater mode (see above), which has a largely similar purpose.
MESH technology allows you to create a single wireless network using many separate nodes (access points) connected to each other via Wi-Fi. In this case, the so-called seamless mode of operation is implemented: the entire network is seen as a single whole, switching between access points, if necessary, occurs automatically, in such cases the connection is not broken and the user does not notice the transition to another network node at all. This is one of the key differences from using repeaters. Another difference is dynamic routing: MESH network nodes automatically determine the optimal signal traversal mode. Due to this, as well as due to some other features of this technology, the presence of "intermediaries" on the signal path practically does not affect the communication speed (unlike the same repeaters). The main disadvantage of equipment with this function can be called a relatively high cost.

— Beamforming. A technology that allows you to amplify the Wi-Fi signal in the direction where the receiving device is located (instead of broadcasting this signal in all directions or in a wide sector, as is the case in normal mode). Narrowing the radiation pattern allows you to send more power towards the receiver, thus increasing the range and communication efficiency; while the position of the receiving device is determined automatically, the user does not need to deal with additional settings. And many models of Wi-Fi equipment are capable of amplifying the signal in several directions at once (usually, several antennas are provided for this). At the same time, subscriber devices do not have to support Beamforming — communication improvement is noticeable even with the one-way use of this technology (although not as obvious as with the two-way one).
Also note that the unified Beamforming standards were officially implemented as part of the Wi-Fi 5 specification. However “beamforming” was also used in earlier versions of Wi-Fi, however, different manufacturers used different methods for implementing Beamforming, incompatible with each other. So these days, this feature is almost never found outside of Wi-Fi 5 compatible equipment.

— Firewall. A feature that allows a Wi-Fi device to control traffic passing through it. In fact, the Firewall is a set of software filters: these filters compare data packets with the specified parameters and decide whether or not to pass traffic. In this case, the processing can be carried out according to two rules: “everything that is not expressly prohibited is allowed”, or vice versa, “everything that is not expressly permitted is prohibited”. The main function of a firewall is to protect the network (or individual network segments) from unauthorized access and various attacks. In addition, this function can be used to control user activity — for example, prohibitions on access to certain Internet sites. Note that a firewall can also be implemented at the level of individual devices, but using it on a router allows you to secure the entire network at once.

CLI (Telnet). Ability to control the device via Telnet protocol. This is one of the protocols used today to remotely control network equipment; while Telnet, unlike another popular HTTP standard, does not have a graphical interface and uses only the command line. Such access is used mainly for service purposes — for debugging and changing settings in other text-based protocols (HTTP on web pages, SMTP and POP3 on mail servers, etc.); Telnet requires specialized knowledge.

Additional features (mostly software) supported by the device. These may include DHCP server, FTP server, Web server, file server, media server (DLNA), print server, torrent client, VPN support, DDNS support, and DMZ support, among others. Here is a more detailed description of these functions:

— DHCP server. A function that simplifies the distribution of IP addresses connected to the router (or other network equipment) to subscriber devices. Assigning an IP address is necessary for correct operation in TCP / IP networks (and this is the entire Internet and the vast majority of modern “locals”). In the presence of DHCP, this process can be carried out completely automatically, which greatly simplifies the life of both users and administrators. However, the administrator can also set additional DHCP options — for example, specify a range of available IP addresses (to prevent errors) or limit the time of using one address. If necessary, you can even manually enter a specific address for each device on the network, without automatically adding new devices — DHCP also simplifies this procedure, as it allows you to carry out all operations o...n the router without delving into the settings of each subscriber device.

— FTP server. A feature that allows you to use a Wi-Fi device to store files and access them via FTP. This protocol is widely used to transfer individual files both in local networks and over the Internet. Actually, one of the main differences between this function and the file server (see below) is, first of all, the ability to work via the Internet without much difficulty. In addition, FTP is a common standard protocol and is supported by almost any PC, while a file server can use specialized standards. So if you plan to organize file storage with the simplest and most convenient access, you should choose a device with this function. At the same time, we note that “simple” does not mean “uncontrolled”: FTP allows you to set a login and password for accessing files, as well as encrypt transmitted data. The files themselves can be stored both on the built-in storage of a network device, and on a drive connected to it, such as a USB flash drive or external HDD.

— Web server. The ability to use the router as a web server — storage that hosts ("hosts") a website. Note that this can be both an Internet site and an internal resource of the local network, strictly for personal or official use. Placing the site on your own equipment allows you to do without the services of hosting providers and maintain maximum control over the data on the site and its technical base. On the other hand, this feature significantly affects the cost of equipment, and in terms of memory and processing power, Wi-Fi devices are often inferior to dedicated servers, even based on conventional PCs and laptops (although in some models the memory can be expanded with an external drive). So in this case, the web server mode should be considered mainly as an additional option for relatively simple tasks that are not associated with high loads.

— File server. The ability to use a Wi-Fi device as a server for storing files. This function differs from the FTP server described above in the data transfer protocols used; in other words, a "file server" in this case is a network file storage based on any protocols other than FTP. A specific set of such protocols and, accordingly, the functionality of a Wi-Fi device should be specified separately; we only note that most often we are talking about accessing files over a local network (FTP is traditionally used for Internet access), and the files themselves can be stored both in the router’s own memory, and on a flash drive or external hard drive.

— Media server (DLNA). The ability to create a media library using an external USB drive and transfer content from it to other devices on your home network via cable or Wi-Fi. The function is most in demand for broadcasting video, audio files and images to smart TVs and set-top boxes. In general, the technology was conceived in order to be able to combine different devices into a single network and easily share content within this network, regardless of the model and manufacturer of individual devices. Many modern smartphones and tablets, smart home ecosystem devices, etc. have DLNA support.

— Print server. The ability of the device to work as a print server — a computer that controls the printer. This feature allows you to turn a regular printer into a network printer: all network users will be able to send print jobs through a print server, while such a server will also provide a number of additional features. So, sent jobs will be stored on it until they are executed or canceled, regardless of whether the computer from which they were sent is turned on; remote control of the print queue, etc. may be provided. And the use of a router (or other similar device) in this role is convenient because the router is usually turned on and available all the time.

— Torrent client. The presence in the device of its own torrent client or other data exchange protocol (HTTP, FTP, etc.). This feature allows you to work with file-sharing networks, which are built on the principle of "everyone's own server": the downloaded information is not on a separate computer on the network, but on the computers of the same users. At the same time, the same file can be opened for download in several places and the torrent client simultaneously downloads different parts of it from different sources - this significantly increases the speed. Using a torrent client on a device is convenient in two ways. Firstly, it allows you to offload the main computers of users - an important advantage, given that the torrent client can consume a lot of resources, especially with an abundance of simultaneous downloads / distributions. Secondly, network equipment tends to stay on at all times, allowing downloads and uploads to continue even when users' PCs and laptops are turned off. However, it should be taken into account that despite the presence of such functionality in devices, the open placement of content in torrent networks can violate copyrights. Therefore, use torrent clients in compliance with legal regulations.

— VPN (Virtual Private Network) support. Initially, VPN is a function that allows you to combine devices that are physically located in different networks into a single virtual network. The connection is via the Internet, but the data is encrypted to prevent unauthorized access to it. However, routers, access points and MESH equipment (see "Device Type") more often use a slightly different format of work: connecting to the Internet through a separate VPN server, so that all external traffic from the network served by the router goes through this server. Such a connection has a number of advantages. Firstly, additional traffic encryption increases the security of work. Secondly, “outside” in such cases, it is not the real IP address of the user that is visible, but the address of the VPN server, and in the settings you can set the address related to almost any country in the world. This also has a positive effect on security, and also makes it possible to bypass regional restrictions on visiting individual sites and accessing services.
Note that the VPN can also be “raised” on individual devices on the network (for example, through tools in some Internet browsers); however, a VPN router allows all network devices to work in this format, regardless of whether they support VPN or not. This is particularly useful on smart TVs (to access certain video services like Netflix) and on PS and Xbox (to bypass region restrictions on certain games). On the other hand, note that setting up such a connection on a router can be quite difficult, the connection speed can noticeably drop when working through a VPN, and enabling and disabling this feature on a router is usually more difficult than on user devices.

— DDNS. The device supports the DDNS function — assigning a permanent domain name to a device with a changing (dynamic) IP address. For network electronics, the IP address is of key importance, it is he who allows the equipment to send data packets to the right device. However, such addresses are sequences of numbers that are poorly remembered by a person. Therefore, domain names appeared — on the Internet these are web addresses (for example, ek.ua or e-katalog.ru), on the local network — the names of individual devices (for example, "Work laptop" or "Sergey's Computer"). Both on the Internet and in local networks, the connection between a domain name and an IP address is responsible for the so-called DNS servers: for each domain in the database of such a server, its own IP is registered. However, for technical reasons, situations often arise when the router has to use a dynamic (changeable) IP; accordingly, in order for information to be constantly available on the same domain name, it is necessary to update the data on the DNS server with each IP change. It is this update that the DDNS function provides.

— DMZ. Initially, DMZ is a function that allows you to create a segment on the local network with free access from the outside. From the rest of the network, this segment (it is called the DMZ — “demilitarized zone”) is separated by a firewall that allows only specially permitted external traffic to pass through. This provides additional protection against external attacks: in such cases, the DMZ suffers first of all, and access to other network resources is much more difficult for an attacker. One of the most popular ways to use this feature is to provide access to Internet services, the servers of which are physically located in the company's public local area network. However, it is worth noting that in some inexpensive routers, DMZ may mean the DMZ-host mode, which does not provide any additional protection and is used for completely different purposes (mainly to translate all ports to another network device). So the specific format of DMZ operation needs to be specified separately, especially if you are purchasing a low-cost category device.