Comparison Zyxel NBG6615 vs Zyxel NBG6515

Methods for connecting to the Internet (or other external network, such as in bridge mode) supported by the device.

The classic, most common version of such a connection nowadays is LAN (Ethernet), but this is not limited to this. A wired connection can also be made via ADSL or SFP fiber, and wirelessly via mobile networks (using a SIM card, SIM card 5G or an external modem for 3G or 4G), as well as via Wi-Fi. Here is a more detailed description of each option:

— Ethernet (RJ45). Classic wired connection via a network cable via an RJ-45 connector. Also known as "LAN", although this designation is not entirely correct. Nowadays, it is one of the most common methods of wired Internet connection, and is also widely used in local networks. This is due to the fact that the speed of Ethernet is actually limited only by the capabilities of network controllers; at the same time, even the simplest modules support up to 100 Mbps, and in advanced equipment this value can reach 10 Gbps.

— ADSL. A technology primarily used for wired Internet connections over existing landline telephone lines. This is its main advantage — you can use ready-made lines without fiddling with laying numerous addi...tional wires; at the same time, ADSL works independently of telephone calls and does not interfere with them. At the same time, the speed of such a connection is noticeably lower than via Ethernet — even in advanced equipment it does not exceed 24 Mbps. In addition, ADSL traffic is distributed asymmetrically: full speed is achieved only when working for reception, data transmission speed is much lower, which creates problems for video communication and some other tasks. So nowadays, ADSL is gradually being replaced by more advanced standards, although the complete disappearance of this technology is still far away.

— Wi-Fi. Connect to an external data source via Wi-Fi. By definition, this format of operation is used by Wi-Fi adapters (see "Device type"), as well as by most MESH equipment. (However, if the MESH system package includes both nodes and the main control device for them, then the WAN input can be specified for the control device, and often this is not Wi-Fi). Also, this type of data input can be provided in other types of equipment — in particular, routers and access points (for example, to work in bridge or repeater mode).

— 3G modem (USB). Internet connection via 3G mobile network using a separate external modem connected to the USB port. Most often, we are talking about UMTS networks (the development of GSM mobile communications), the most common in Europe and the post-Soviet space; however, it may also be possible to use modems for CDMA networks (EV-DO technology). These nuances, as well as compatibility with specific modem models, need to be clarified separately. However, anyway, 3G may be a good option for situations where a wired Internet connection is difficult or impossible, such as in the private sector. In addition, some Wi-Fi devices with this feature are equipped with autonomous power supplies and can even be used on the go. The data transfer speed of 3G is close to broadband wired connection (from 2 to 70 Mbps with a normal signal, depending on the specific technology); however, it is less than in 4G networks (see below), but 3G coverage is more extensive, and equipment for this standard is cheaper.

— 4G (LTE) modem (USB). Internet connection via 4G mobile network (LTE) using a separate external modem connected to the USB port. The main features are similar to the 3G connection described above, adjusted for the fact that in this case more advanced fourth-generation networks are used. The data transfer rate in such networks reaches about 150 Mbps; they are not as widespread as 3G-connection, but soon we can expect a change in the situation. In addition, it should be noted that in Europe and the post-Soviet space, LTE networks are usually deployed on the basis of 3G UMTS and GSM networks; so in the absence of full-fledged 4G coverage, modems for such networks can work according to the 3G and even GSM standard.

— SIM card. Connecting to the Internet via a mobile network using a mobile operator's SIM card installed directly in the device. The specific type of supported networks depends both on the capabilities of the router and on the conditions of a particular mobile operator; however, all such equipment is compatible with at least 3G networks, and often 4G as well. The features of these networks are described in detail above (you can also read about the advantages of a mobile Internet connection there). This option is convenient because it allows you to do without a separate USB modem — you just need to purchase a SIM card, the cost of which is negligible. In addition, the use of "sim cards" has a positive effect on compactness and ease of carrying. On the other hand, the built-in mobile communication module significantly affects the overall cost — and you will have to pay for it anyway (whereas a model with support for external modems does not have to be bought immediately with a modem, such devices usually allow wired connection). Therefore, you should pay attention to this option if you initially plan to connect to the Internet through mobile networks.

- SIM card (5G). The ability to operate Wi-Fi equipment in high-speed 5G mobile networks with a peak bandwidth of up to 20 Gbps for reception and up to 10 Gbps for data transmission. Implemented via a SIM card with appropriate 5G support. This standard reduces power consumption compared to previous versions, and it also uses a number of complex solutions aimed at improving the reliability and overall quality of communication - in particular, multi-element antenna arrays (Massive MIMO) and beamforming technologies (Beamforming).

— SFP (optics). Connection via fiber optic cable of the SFP standard. Such a connection can be carried out at high speeds (measured in gigabytes per second), and the fiber, unlike the Ethernet cable, is practically insensitive to external interference. On the other hand, the support of this standard is not cheap, and its capabilities are unnecessary for domestic use. Therefore, SFP is found mainly in professional-level Wi-Fi devices.

The maximum speed supported by the device when communicating wirelessly in the 5 GHz band.

This range is used in Wi-Fi 4, Wi-Fi 6 and Wi-Fi 6E as one of the available bands, in Wi-Fi 5 as the only one (see "Wi-Fi Standards"). The maximum speed is specified in the specifications in order to indicate the real capabilities of specific equipment - they can be noticeably more modest than the general capabilities of the standard. Also, in fact, it all depends on the generation of Wi-Fi. For example, devices with Wi-Fi 5 support can theoretically deliver up to 6928 Mbit (using eight antennas), with Wi-Fi 6 support up to 9607 Mbit (using the same eight spatial streams). The maximum possible communication speed is achieved under certain conditions, and not every model of Wi-Fi equipment fully satisfies them. Specific figures are conditionally divided into several groups: the value up to 500 Mbit is rather modest, many devices support speeds in the range of 500 - 1000 Mbit, indicators of 1 - 2 Gbps can be attributed to the average, and the most advanced models in class provide a data exchange rate of over 2 Gbps.

The WAN port characterizes the ability of the device to receive a wired signal. There may be models with both one port and two WAN ports, and in rare cases, more connected providers. Such an expanded number of WAN connectors affects the cost and, accordingly, is found in more part among professional-level routers.

In terms of speed, when choosing a device, the priority is the speed of the output LAN port or Wi-Fi. However, faster WAN ports ( 1 Gbps, 2.5 Gbps, 5 Gbps, 10 Gbps) allow you to divide the load on several outputs at once without reducing speed performance, as may be the case with WAN port 100 Mbps.

The total number of antennas (of all types — see below) provided in the design of the device.

In modern Wi-Fi equipment, this indicator can be different: in addition to the simplest devices with 1 antenna, there are models where this number is 2, 3, 4 and even more. The point of using multiple antennas is twofold. Firstly, if there are several external devices per antenna, they have to share the bandwidth among themselves, and the actual communication speed for each subscriber drops accordingly. Secondly, such a design may also be required when communicating with one external device — to work with MU-MIMO technology (see below), which allows you to fully realize the capabilities of modern Wi-Fi standards.

Anyway, more antennas, usually, means a more advanced and functional device. On the other hand, this parameter significantly affects the cost; so specifically looking for equipment with numerous antennas makes sense mainly when the speed and stability of communication are critical.

Note that antennas intended for mobile communications may also be considered in this clause. So when choosing a model with support for mobile networks, it's ok to clarify this point.

Device support for MU-MIMO technology - multi-user multi-threaded I / O.

Communication in multiple streams is implemented through the use of multiple antennas on both the transmitting and receiving device. This allows you to increase the bandwidth of the channel, as well as improve the overall quality and stability of the connection. And the term "multi-user" usually means that Wi-Fi equipment is able to simultaneously work with several external devices that support multi-streaming (MIMO). The only exceptions are Wi-Fi adapters (see "Device type") - they are more about the ability to interact with the router / access point as efficiently as possible, which also uses MU-MIMO.

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.