IP revolution: advertising slogans and practice.
Already a pain in the ass. IP cameras, IP systems, IP solutions, IP revolution…
I am telling a client about a new fire alarm system, and he asks: do you transmit all your signals via IP? No, I answer, we do not use Ethernet there at all. For the simplest reason: the existing technical regulations require the use of fire-resistant cables everywhere, with a fire resistance limit of 3 hours. At the same time, there are practically no cables in the world that are certified for category 5 and simultaneously for fire resistance. This is not surprising, because if non-fire-resistant materials are used in a cable, at least as external insulation, the electromagnetic properties of the cable change in a fire, and therefore the requirements for the propagation of Ethernet signals are violated. In fact, I know manufacturers of very fire-resistant cables suitable for Ethernet, such cables are made entirely of metal and ceramics and are made to order in the required shape and length. These are solid pieces of cable that cannot be bent after leaving the factory. Not a very convenient type of cable, and it costs a little more than if it were entirely made of solid gold.
Yes, of course, Ethernet is not only via wires. There is Wi-Fi, which is transmitted via fireproof ether (although I seriously doubt the reliability of Wi-Fi, and indeed radio systems in general, in a burning building). There is Ethernet via fiber, and cables based on glass fiber can be quite fire-resistant. But how often have you seen equipment with a fiber connector or built-in Wi-Fi among newfangled IP systems? And if you plan to use external converters, then formally you are already violating the regulations.
I understand that the current set of fire safety regulations in our country is highly contradictory and incomplete, but the fact remains that I do not recommend using any IP systems for fire protection. Following the letter of the law, the use of such equipment is practically impossible. And if we recall the simple fact that a fire alarm typically transmits several bits of information per year, the use of communication networks designed to transmit hundreds of millions of bits per second does not seem very justified.
However, as modern electronics become cheaper, Ethernet connection may well become cheaper than traditional RS485 or similar interfaces due to its mass popularity. This will allow efficient use of standard infrastructure for data transmission. It is not even so much about the fact that structured cable networks are present in most modern office and industrial buildings. Both Ethernet and RS485 can be transmitted with equal success over a structured cable network. The advantage of IP systems is that data in this format can be transmitted relatively easily using standard converters or modems almost anywhere. In the most extreme case, you can install a satellite terminal and transfer it to any point on earth. However, in real life, everything is not so cloudless. Existing IP systems use a wide variety of protocols over IP. Yes, if you install a satellite terminal for each of your IP products, then everything will probably work. However, if you intend to make do with an existing channel used in parallel by other systems, you will suddenly find that the IP infrastructure, theoretically capable of meeting the needs of your system, requires only highly qualified specialists to configure it. Even worse, it may be almost impossible to meet the requirements of your equipment simultaneously with the requirements of information security.
Or, more precisely, it will unexpectedly require replacing network equipment with prohibitively expensive, unexpectedly powerful equipment. It is not surprising that many designers do not even try to reconcile the requirements of information specialists, communications specialists, production automation specialists and many others, but immediately build a separate network for the security system with its own switches, gateways and routers. So what is the advantage of IP equipment then? That instead of a kilometer of cable for 20 rubles (for RS485), you need two kilometers of cable for 30 rubles, plus a bunch of additional central equipment (switches, routers)?
In fact, there is an advantage, of course. Various special adapters are available for Ethernet and are relatively inexpensive — for transmission via radio, fiber, and regular telephone lines. This equipment is mass-produced, reliable, guaranteed to be compatible, and allows you to solve, among other things, unexpected problems. Unlike Ethernet, similar adapters for RS485 also exist, but are much less common (usually only on request, delivery time is 3 months) and their compatibility with your equipment can only be checked after testing in real conditions. However, how often have you had to solve the problem of transferring communications over the air when it is impossible to lay a copper wire? And I also lied a little about the price of cables — this is true only for fire and security systems on RS485. If a video signal occurs, then a star-shaped cable network on a coaxial cable is, of course, noticeably more expensive than a tree-shaped «twisted pair» Ethernet, even taking into account the presence of active hubs.
Another statement is that IP equipment communication channels can be easily transferred via the Internet (fortunately, the entire Internet is built on IP protocols), and thus any system can easily become global. Unfortunately, in modern conditions, when the structure of the Internet connection turns out to be very complex, and many cannot even dream of such a concept as a real IP address (and even more so a static IP address), in fact, only the http protocol can be transmitted via the Internet and only in one direction. However, not all IP systems use only the http protocol. And sometimes it is used in such a way that it does not make life much easier for the creator of a system with remote access — the equipment installed at a remote site is a server, and therefore, it must have a static real IP address accessible from the Internet (that is, not fenced off by proxy servers and other firewalls).
Another popular advertising slogan of IP systems sellers is integration. They say that IP systems are already integrated — you plug everything into one network, and they magically start working with each other on their own, since the IP protocol is standardized by the Internet community. This statement is no more meaningful than the naive belief that all RS485-based systems can be connected and will work, since RS485 is standardized by the EIA association. Alas, the formats and methods of data transmission, and even more so the meaning that this data carries, are not standardized at all. For security systems, and even for building management systems, there are currently no widely used and stable standards. Perhaps, BACnet and LONworks, but they, however, have little in common with IP. ONVIF and PSIA are focused specifically on IP, but for a very specific area. So, creating an integrated system based on IP equipment is not much easier than using any other. Of course, it is easier to physically connect equipment with an Ethernet connector to a computer. However, to connect RS485, you will only have to additionally buy an RS485-USB adapter and connect through it. After that, in any case, you will have to adapt the «language» of one equipment for the other to understand it for a very long time. In the case of IP equipment, the situation is even worse, IP equipment usually provides a lot of information, so it is noticeably more difficult to translate it all into the «language» of other equipment. Old systems are simpler (more primitive) in this regard and therefore easier to integrate.
Well, the last negative point in all IP systems is the intensive use of general-purpose computers. Yes, yes – computerization is evil. Of course, the computer has a convenient and now familiar to many operators interface. Undoubtedly, it is a really convenient and effective monitoring and control panel. However, the reliability of the computer as a central connecting element in the system, alas, is low. I am not even talking about the fact that a computer is, as a rule, Windows, with all its shortcomings, with viruses, games and watching movies at the workplace, after which even the most powerful computer does not have the resources to service even the simplest security system. A modern computer itself is an unreasonably powerful device for managing the life support system of a building, and therefore unreasonably complex and unreliable. Numerous fans tend to get clogged with dust and fail in less than a year. Hard drives are afraid of vibration and do not like it when cleaners touch the computer with a mop. Power supplies require quite expensive external means of protection against interference and additional huge (due to the huge power consumption) uninterruptible power supplies. And all this taken together requires very hothouse conditions, with air conditioning, heating and ventilation. Yes, of course, there are completely solid-state fanless computers, including those of industrial (or even military) reliability category, including those with a standard power input from a typical 12-volt uninterruptible power supply and with very moderate consumption, but they, as a rule, either have parameters that are insufficient for the operation of the IP system software (the programmer developed this wonderful software on a 4-core 4-gigahertz computer with huge memory and simply did not think that the target system could be weaker), or have a price that negates any advantages of IP systems, even if in your particular case you have found such advantages.
In general, IP systems are slightly (insignificantly) more expensive than traditional systems, noticeably more difficult to design and configure, obviously more modern and therefore, as a rule, more powerful and functional. And sometimes IP systems allow you to solve some problems of providing communication channels more easily (flexibly). But nothing fundamentally new is actually connected with the use of IP protocols.