Modern office infrastructure - 3

    I delayed something with the next series, but there were reasons for this: from a bunch of urgent matters at work to a wounded car :(
    Okay, this time, the organization of external inputs, the issues of building telephony and some aspects of building Wi-fi. As in of the previous series, I do not pretend to the depth of technology disclosure, trying only to show the main options for the development of infrastructure elements .. Previous series about infrastructure here and here (and here is a bonus track about Allied Telesis equipment ).

    Provider Inputs


    There is a whole range of possible decisions, each of which should be taken guided by the size of the organization, budget and external factors. Consider the main points:
    1. You are a small company (up to ten people), drop into the basement of a residential building or, moreover, into an apartment on the ground floor of a residential building.
      In this situation, you don’t have to pick and choose the provider and you need to rely on the presence of a local provider in the building (if there are several of them, you are very lucky, competition increases the level of service). You can try to save money by registering the Internet for an individual, however, in this case, you should be prepared for the fact that in prime time the local provider decides, for example, to "change the network equipment", which will lead to an unpleasant downtime. It is advisable in such a situation to provide a reserve at least in the form of mobile Internet (Skylink, Yota, Edge / GPRS) - a critical letter in this case, albeit slowly, but crawl. Telephony in this situation, as a rule, is performed in the form of a "copper-fiber channel" of the city provider.
    2. You are still a small company, but you are sitting in a garage (a change house, a stall, a treehouse, a building in the industrial zone).
      Everything is joyless - your only way out is a radio channel to the nearest point of presence of high-speed Internet, or, if there is no chance to finish off the radio, the Internet is through a cell phone. If you still have a chance, stock up on long-range directional antennas and step to the nearest place where the Internet can be. In my practice, there was a case when a car service worked for about a year through a stream, which was two kilometers from. The problems in this case are the same as in the previous one (instability of the local cable provider), however, if you use a long Wi-Fi link, you will also depend on the weather. In heavy rain or snowfall, outages are not uncommon ..
    3. You call in a business center.
      Everything is already better, but not without specifics: as a rule, business center owners have already agreed with one or two large providers, which limits your choice (you can only drag your provider if you are a very large company with a serious rental rate). The plus of the situation is that the channel is organized quickly, and most likely without problems. A clear minus - one - the monopolists in the building tariffs can turn up very sad.
    4. (my situation) You call in a separate building.
      Hemorrhoids are scary, but with the proper approach it will turn out very beautifully :) Details about this scenario are presented below.

    So, a separate building. Given that you are the master of the situation, the following should be considered when organizing provider entries:
    • Fault tolerance (any more or less serious router can choose a live channel). If possible, lay two independent channels from independent providers;
    • High cost (a more serious provider will ask for more serious money). At the same time, a cheaper provider will most likely sin with all childhood diseases of home networks - channel falls during the day, “scheduled preventive maintenance” in prime time and other delights
    • Connection time. If in the previous scenarios you most likely would have been connected within a day or two, then building an individual channel can become a matter of several months (here, coordination with city cable services, and the slowness of large providers, and problems with builders ..)


    If time presses, organize a temporary input using any of the available methods, and then wait for your provider to reach.

    In my case, the process of organizing fiber-optic input (the center of Moscow, the largest provider) took ten months, of which nine and a half lasted coordination at various levels. By the way, the local provider stretched his fiber through the air from a nearby residential high-rise for a week.
    I would like to give a special hello to an employee of the local telephone center, who walked with a protruding pocket all the time while the opticians were working, threatening to either “cut the cable in the hatch”, “they will write you a fine,” or sing old shepherd’s songs on the subject “we are all human we all want to eat ”

    When designing the input (s), agree in advance the passage of the trunk inside the building to your switching unit, if possible, providing all engineering means for the passage of cables (trays, ducts, easily accessible ceiling channels, etc.), otherwise a weekly delay of cable men can lead to catastrophic consequences from the point view of the interior decoration of the building. As a separate option, it is possible to check with cable men what type of cable they plan to lay and stretch a piece of the building on their own, leaving a tail in the closet for unwinding the fibers.

    Telephony


    The complexity of the telephone system directly depends on the size of the company and the budget. Again, consider a number of options:
    1. Basement / apartment and five employees. The copper of the city telephone provider and fax of the Panasonic system, which concurrently acts as a telephone, will suffice for you
    2. The same, but there is no urban copper: the organization of SIP-telephony (including with soft-phones), or the use of the same Panasonic and provider equipment, wrapping the city line in IP from the provider and performing the inverse conversion with you
    3. Own telephone exchange, receiving the city and carrying out switching within the office. This option - consider in more detail.

    City lines can be obtained in several ways:
    • Copper pairs (one number - one pair)
    • Sip
    • Stream E1 (or part of the stream)

    Copper is usually inherited. This is difficult from the point of view of switching (everyone saw a terrible picture of skirted boards wiring? I can’t find ..) and it is very unpleasant that organizing a multi-channel number is not a task for the faint of heart.

    SIP is a very beautiful solution in terms of the cost of a telephone system. On the one hand, you get all the charms of multichannel communication, on the other hand, save on streaming cards for the PBX (or server that acts as a telephone exchange). At the same time, the number of Linux open-source PBXs (Asterisk, SipX) with convenient management is growing every day. A potential minus of such a solution is the dependence on the load of the provider's trunk channels (during peak hours, there may be a delay, interruptions in communication / jitter and a very unpleasant echo). Similarly, if the switches on the internal network have low bandwidth or are not able to prioritize traffic, problems can arise inside the office (in the end, office switches also sometimes hang / reboot and at this moment you are sitting without communication).

    The most bourgeois method is the use of a specialized PBX (or server) that receives voice over the E1 stream and distributes voice inside the office to ip and / or specialized and / or analog devices. This approach is relatively expensive, but it allows you to forget about the dependence of voice quality on the quality of the external Internet. It is advisable to use hybrid stations that have the ability to connect both ip and system devices that do not use ethernet inside the office, placing such devices with business critical employees (secretariat, management, key employees) - thereby you insure against problems associated with the operation of the office network equipment. On the other hand, many ip-devices have the ability to power over ethernet (PoE), which minimizes the number of cables from subscribers.

    The procedure for installing and commissioning an analog Panasonic PBX has already been described on the hub If there is a desire, I can somehow describe the procedure for entering into battle the Avaya IPO500 automatic telephone exchange, which I have the pleasure to operate.

    Wifi


    Similar to the previous paragraph, it all depends on what you are ripe for:
    1. One or two access points at all (it also replaces the cabling in the office). Cheap and cheerful, but if someone decided to shake something from torrents, then the network ended :)
    2. Guest points in meeting / show rooms / admin room. Used only when visiting dear guests and, if necessary, pick up a personal laptop
    3. Serious duplicate wireless network throughout the office

    When organizing serious Wi-Fi, you will encounter the following:
    1. Security (encryption is a must!). You will have to (possibly) deal with the entire spectrum of attacks on your Wi-fi, from pioneers freeloaders to serious uncles who, by order of competitors, collect your critical information
    2. Communication stability (remember torrents, huh?). The number of access points must be redundant. If you can afford MiMo - definitely let
    3. Manageability (a separate setting for each point is still entertainment).

    Wikipedia: A key component of the 802.11n standard called MIMO (Multiple Input, Multiple Output - many inputs, many outputs) involves the use of spatial multiplexing for the simultaneous transmission of several information streams on one channel, as well as multipath reflection, which ensures the delivery of each bit of information to the corresponding a receiver with a low probability of interference and data loss. It is the ability to simultaneously transmit and receive data that determines the high bandwidth of 802.11n devices.

    In the case of organizing large Wi-Fi, it makes sense to think about a specialized controller that centrally manages access points and monitors security (identifying, for example, "spy" access points intended for implementation in your network). As an example, I can cite the Ruckus Wireless ZoneDirector 1000 (I happened to test this personally) or the Cisco 4400 or 2100 series .

    Phew For this, it seems, enough. Next time, office security.

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