Traditional data transmission channels will perform their function properly for many more years, but they become affordable only in densely populated buildings. In other conditions, other solutions are needed that can provide reliable high-speed communication for reasonable money.
In this article, you will learn how to solve communication problems where traditional channels are expensive or unavailable. What classes of solutions exist, how they differ, and how to choose what is needed for a particular task.
There are several classes of technologies that claim to solve communication problems where traditional communication channels do not exist or are not economically feasible. Balancers, aggregators and adders seem to do the same thing, but fundamentally differ in the quality of solving problems. Let's figure it out.
Balancers
At one point in time, any one channel is working. This solves the issue of reliability due to redundancy, but does not give an increase in speed. At the same time, the vast majority of balancers do not check which channel is faster and simply switch to the one that works. 80% of the solutions on the market that use several SIM-cards are just such Balancers - when the connection is lost through one channel, it automatically switches the connection to another.
There is a separate transitional class between the balancer and the aggregator. The speed in several streams, for example from several users at the same time, will be higher than on any one. This approach, if implemented correctly, does not even require a traffic termination infrastructure and is widely used in the class of low-cost routers. The solution is able to give an overall high speed, but each individual user will receive the speed available only on one channel. You can download torrents on such a device very comfortably.
Problem being solved
Increasing reliability. Reservation of data transmission channels.
Key characteristic
- The speed of switching from a non-working channel to a working one. The sooner the device understands that one channel is not working and needs to switch to another, the better
- Priority work on the fastest channel
pros
- Device price. The cheapest solution on the market
- Does not require an intermediate traffic termination infrastructure
- Does not require qualified personnel for use and maintenance
Cons
- No channel quality check. The device may switch to a channel with a mediocre connection, while the adjacent channel is much faster.
Target application
Services that do not require high data transfer rates and are ready for short periods of downtime
Aggregators
This term comes from the English aggregate. In the context of data transmission systems, it has been used for a very long time and is used in solutions for combining physical wired and optical data transmission channels.
These are more advanced systems compared to balancers - they use several data transmission channels at the same time. Through each channel, a connection is created with an intermediate server, on which the traffic is combined and transmitted further to the target service. Therefore, even if several channels disappear, the data transmission is not interrupted. That is, there is no concept of switching from one channel to another. It should also be noted that on wireless data transmission channels, contrary to popular belief, most of these solutions do not increase the speed or increase it slightly. For example, 4 channels of 10 Mbps in total should give 40 Mbps, however, aggregators in the L3 tunnel will give about 12-18. These are the limits of speed increase in ideal conditions. This happens because of the large non-uniform entropy in the channels. It is a non-trivial task to combine channels with different bandwidth, and most importantly, different delays.
This is certainly better than ten, but much less than the expected forty. Unscrupulous manufacturers try to hide this shortcoming by using a bunch of proxy server + source address replacement. In this case, the speed rises many times, but this only works when the connection is initiated from the device. If you initiate a connection from the outside world, then this technique will no longer work. If you want to combine two networks, for example, a point of sale with a head office or a train with a central network, the aggregator will not cope with the task, because the speed to the device will be 10 times less than from the device. In addition, if used in the networks of a telecom operator, such manipulations are guaranteed to raise questions from regulatory authorities regarding the system of operational-search activities (SORM).
Solutions for the aggregation of wireless data transmission channels are relatively simple and do not require investments in science-intensive research. Almost all of them contain at their core only ready-made, widely described Open Source solutions. Manufacturers prefer to make a simple WEB-interface and pass it off as an innovative development. This approach is very common in Russia.
Problem being solved
Increasing reliability. Slight increase in speed.
Key characteristic
Utilization of aggregated channels. Average maximum data rate.
Cons
- Device price. Multiple times more expensive than conventional balancers
- Availability of monthly payments, since it requires an intermediate traffic termination infrastructure
- Servicing requires specially trained technicians.
- Low utilization of data transmission channels in the L3 tunnel
- The use of proxies gives unbalanced network and addressing
pros
- Very well solves the problem of redundant data channels
- When using a proxy server, gives a high data transfer rate if the connection is initiated from the device
Target application
Services that need a stable connection that do not require an L3 tunnel. Private households, simple topologies that do not require a symmetrical network. Not applicable for industrial facilities and telecom operator networks.
Adders
In the context of data transmission channels, this term appeared in Russia only a few years ago. These solutions are very similar to aggregators, but differ radically in that, while retaining all their advantages, they are devoid of all their disadvantages.
If you need encryption from the device itself to the termination server, this option, like on-the-fly compression, is present in mature technologies on the market.
For L3 tunnels, the utilization of data transmission channels at adders is about 90%. For example, where the aggregator will give 40 Mbps, the adder will confidently give 70 Mbps. That is why it is called the adder. This is a very difficult task and it requires serious science-intensive research.
Successfully increasing the speed in the L3 tunnel gives a smooth network topology without "features".
Unlike aggregators, adders have no scope restrictions. They can be used on any type of data transmission channels and on any network topology. The network created by the adder is completely standard and, unlike aggregators, in operation will not raise questions from regulatory authorities and pitfalls in operation.
Problem being solved
Increasing reliability. Multiple increase in speed.
Key characteristic
Utilization of aggregated channels. Average maximum data rate.
Cons
- The presence of monthly payments, since it requires an intermediate traffic termination infrastructure.
- Price comparable to the aggregator
pros
- A highly efficient solution to the problem of redundant data transmission channels.
- A multiple increase in the speed and throughput of channels in the L3 tunnel.
Target application
Commercial, industrial and government services requiring high speed and reliability of data transfer. There are no application restrictions.
Complete solution
Technologies for increasing reliability and throughput, in addition to their main function, should be easily manageable and scalable, be comprehensive solutions to end-user problems and not solve the problem piecemeal shifting most of the infrastructure and operational tasks to the customer's competence.
What is required for a comprehensive solution?
1. Unified network management system
It allows you to manage all network devices - centrally update the firmware and configuration, display warnings and accidents, balance the load on the network. Transparently manage all the functions of each device separately and, in some cases, see the location of the device and its key characteristics on an interactive map.
A good network management system saves on engineering staff, reduces problem solving time, and does everything the "brain" would normally do.
2. Reliability
The technology involves the use of a traffic termination server, which always stands between the device and the target service. It can become a single point of failure. If the solution cannot automatically redistribute traffic from devices to termination servers, provide automatic failover, it is not recommended to use it for commercial use.
It is very important. Without an automatic redundancy system, the fastest network will sooner or later turn into a network of "bricks".
3. Quality Monitoring
The vast majority of solutions fail to capture key performance metrics for devices when they are offline. That is, if there is a problem with the network, the system operator will not be able to conduct a retrospective analysis of the device and understand what exactly was the problem.
In a critical infrastructure, devices must register the maximum number of metrics over communication channels in the event of a βdebriefingβ, be able to store and transmit this to the central system without loading the channels. No open source monitoring system can simultaneously save traffic and deliver retrospective metrics.
4. Security
The network should be maximally protected from malicious impact on the one hand and be fully controlled by the customer on the other.
5. Support from the manufacturer in 24/7 mode
It is very difficult to communicate with a manufacturer if he is in a different time zone and speaks a different language or simply considers himself a king. It is very important that the manufacturer's reaction to the customer's problem is minimal, and the solution really solves the problem.
What to choose
1. If you are satisfied with the work of any one channel and just want to play it safe, choose a balancer. Simple, cheap and effective. It will be a plus if the manufacturer has laid the following modes there:
- The concept of the main and backup channel. When the backup channel is enabled only when the main one is unavailable. The main channel turns on as soon as it becomes available.
- Channel quality control mechanism without service traffic generation.
-It will be a big plus to increase the total speed with session-by-session traffic division between available channels. This will give a significant cumulative increase in speed, but will not give an increase within a single session.
These mechanisms work effectively only together.
2. If you lack the speed of any one channel or need maximum speed, choose adders. Aggregators cost the same, but they can do less.
Source: habr.com