Triple Play: How does a phone, TV and Internet coexist in a single IP environment?

    The term Triple Play (3P) itself was originally purely marketing, reflecting a kind of joint provision of services based on new generation networks. Experience has shown that all modern communication services (of any complexity) are a set of three basic services for an individual subscriber:
    • Telephone service;
    • Internet access;
    • Television

    Technologically, all three basic services “live” on different platforms, but in the same environment, so there are many difficulties with billing, working with SORM, blocking services with zero balance (while maintaining the possibility of an emergency call), technical support and anti-fraud.


    Triple Play-services and their platform IT systems

    :
    • Telephony - on telephone switches (Private branch exchange - abbreviated PBX) or VoIP-platforms (sometimes called IP Multimedia Subsystem - IMS);
    • Internet access - for example, on Broadband Remote Access Servers (BRAS or BBRAS);
    • Television . Includes a headend and a TV content distribution system. In the case of cable TV, content is distributed on a physical level (by transmitters), and in the case of IP-television, the control IP TV platform is used.


    An essential sign of the implementation of the 3P-concept is a unified operator environment, on the basis of which all three services are built. The above picture shows the most perhaps the most common implementation of these services at the moment: the operator creates a broadband access network on the basis of the fiber-optic network and subnets are created on its basis for the provision of telephony and television services.

    Actual implementation


    Historically, cable television and ADSL networks were the first to create 3P environments. Both there and there used analog frequency division for voice, Internet connections and television. Now such technologies make up the bulk of all 3P connections on the planet.

    But such solutions are being actively superseded by optics-based connections. The fiber-optic network itself, used for 3P services, in Russian realities can have either a ring or star-shaped structure. Almost all operators use one of the varieties of FTTx technology (Fiber to the X - optics to point X):
    • FTTH - Fiber To The Home (bringing fiber to the apartment);
    • FTTB - Fiber To The Building (bringing fiber to the building);
    and their varieties:
    • FTTC - Fiber To The Curb (bringing fiber to the cable cabinet);
    • FTTCab - Fiber To The Cabinet (similar to FTTC);
    • FTTR - Fiber To The Remote (bringing fiber to a remote module, hub);
    • FTTP - Fiber To The Premises (bringing fiber to the point of presence of the client);
    • FTTO - Fiber To The Office (bringing fiber to the office);
    • FTTOpt - Fiber To The Optimum (bringing fiber to the optimum point).

    The dominant way to connect to the Russian Federation is now FTTB. A typical network usually has a ring structure around the city (to ensure redundancy of highways) and transfers to quarters, which are reserved by the ring only in the case of a very large number of houses / apartments.

    Traffic balancing, of course, is applied on a city-wide basis - at the level of aggregation nodes, appropriate solutions are used to balance traffic between trunk links. Traffic balancing between blocks or even houses is also applied, but usually the scheme is simpler - i.e. balancing between half rings is used and, of course, depends on the volume of subscribers at a particular object.

    Further, almost all Russian operators have the same technical design: in the attics or in the basements are metal cabinets that contain Ethernet equipment for connecting end users. Moreover, the telephony design may differ: it is possible to install VoIP gateways in common metal cabinets (and then the subscriber receives an analog RJ-11 telephone jack), or install a VoIP adapter / VoIP phone immediately in the subscriber’s apartment. The design of IP-television is also the same - a television set-top box (STB, Set Top Box) is always placed in the subscriber’s apartment, after an Internet router.

    Among the most significant organizational and technological problems in this part, it is necessary to note the need to configure individual subnets:
    • For telephony. This is necessary for playing answering machines about various events by telephony; it is necessary for emergency calls to work;
    • For IP TV, a dedicated subnet is needed to display the mandatory federal Russian 8 channels, even in the case of a financial block of the subscriber (often associated with the cut-off of Internet services).

    Telephony: emergency calls and communication with SORM


    Let us describe separately the implementation of calls to emergency services (01, 02, 03, 04, 112 in certain regions). The IP-telephony implementation scheme with the implementation of the legislation requires the presence of some switching node in each city providing the service. It is to this node that the task of routing emergency calls to specific emergency numbers of each city is entrusted. Figure 2 shows, for comparison, the passage of a green ordinary call (telephone signaling goes through the core of the system, the call is set by the border device) and a red emergency call (control is not used, the call is immediately forwarded to the public telephone network, PSTN).

    Border devices in telephony are commonly called border session controllers (SBC, Session Border Controller). Their functions are similar to firewalls in the Internet environment, plus a number of specific functions to ensure the normal operation of VoIP connections.


    Differences between regular and emergency VoIP calls

    Here we note an interesting Russian feature of the implementation of telephone connections within the framework of 3P: the obligation of each Russian law-abiding operator to send all calls to SORM. And here a technological problem arises, because All multimedia platforms are configured to provide direct connectivity between all registered users. And we have two problems:
    • Firstly, there are two types of calls (calls with dialing, which, according to the legislation of the Russian Federation, are telephone calls, because with numbering, and calls over the broadband network, which, according to the legislation of the Russian Federation, cannot have PSTN numbers);
    • And, secondly, different cities with different units of the FSB, which control only their regional numbering.


    To solve these problems, they again use SBC, to which FSB remotes are connected (well, or SBC are connected to local telephone exchanges). All calls with SBC numbers are output to such remotes. So the problem of telephone SORM is solved. And all calls with logins, nicknames, etc. (i.e. calls over the broadband network, including video calls) are output to the telematic SORM, which is used to control Internet connections.

    Bandwidth requirements


    The bandwidth requirements for traffic for services are different. Telephony is a low-bandwidth service. The following voice coding algorithms are mainly used: G.711 A-law / G.711 u-law with a bandwidth (bitrate) of 64 kbps, G.729 variants with a bandwidth of 8 kbps and a GSM codec with a bitrate of 13 kbps from. Given the total volume of IP packet headers, we get the necessary band from 30 to 90 kbit / s.

    IP-TV requires a significantly larger bandwidth (for example, MPEG2 / MPEG4 codecs are often used): for example, ordinary SD TV channels require from 2 to 4 Mbit / s, and high-quality HD channels from 8 to 12 Mbit / s. It is clear that for such capacities smart control of multicast television traffic is required: each channel is supplied to a node and / or residential quarter only once, regardless of the number of watching subscribers. Statistics help here - if subscribers turn on all non-overlapping channels in one quarter, then the operator providing 100-120 regular channels and 5-20 HD channels will refuse the network in this area. But this does not happen in life - the distribution of “watching” usually allows you to place the requirements for IP TV in the band 1-2 Gb / s per region / quarter.

    Separation by type of traffic to ensure the quality of work of all three services is usually used in the segment of corporate customers and is not used in services for individuals. This is due to the following factors, since residential buildings are fairly predictable in terms of consumption.

    Problems with billing Triple Play services


    Depending on which service is more important for the operator, a billing master system is chosen, let’s say. For example, account management is organized in a system that serves Internet access. Accordingly, two other systems (telephony and television billing) occupy a subordinate position and should be tailored to the requirements and features of the master system. These systems are implemented in the form of various modules of one system or it is generally a system of one manufacturer, it does not matter, and historically, often (in Russian realities) these are different systems from various IT companies.

    Master billing work on Internet access charging


    Let's see schematically the tariffing of Internet access on the example of an unlimited tariff plan, because in Russia, subscribers using limit tariff plans (per megabyte) are left with no more than 5%. Two basic algorithms are used: the monthly amount is debited either immediately on day X (and the subscriber’s account decreases stepwise), or in equal shares every day (and the subscriber’s account decreases smoothly, but constantly). Below is shown how master billing stops the subscriber’s Internet access when reaching zero balance on the account or leaving in the negative.


    Monitoring the status of the account of the Internet subscriber

    Telephone billing


    The basis of telephone billing is tariff tables in which all directions of the possible sending of voice traffic and their cost are crammed. When a subscriber makes a call in any direction, the system analyzes the telephone prefix (country code, city code) and writes off the funds according to the tariff tables. At the same time, the call authorization algorithm, even in the 3P pre-paid version, can be pre-paid and post-paid (this is due to the implementation features of various billing systems and telephone platforms).


    Postpaid phone call authorization

    The scenario of call authorization is shown below in the case of the post-pace option for setting up telephony. In this case, the subscriber makes a call, the IMS platform checks that the subscriber is not blocked and passes the call to the public switched telephone network (PSTN) or to the VoIP network. During a call (and after its end), the IMS platform generates CDR files (Call Detail Recording) containing all the information about the subscriber’s call. Telephone billing processes these CDR files, displaying this information first on their internal accounts (minus the customer’s account based on the results of incoming CDRs), and then on the subscriber’s account in the master billing. It’s possible to reduce the subscriber’s account in master billing at the same time as decreasing in telephone billing, but there are already questions of performance when systems interact,


    Pre-call authorization of a phone call

    Here you can see a diagram of a call authorization scenario in the case of a pre-mail option for setting up telephony. In this case, the subscriber wants to make a call, the IMS platform contacts the authorization server (RADIUS or DIAMETER protocol), and the authorization server addresses the telephone billing. Telephone billing informs the authorization server that the subscriber is not blocked and reports the limit of possible minutes in the direction chosen by the subscriber. He allows the IMS platform to miss a call to the public switched telephone network (PSTN) or to the VoIP network.

    At the same time, telephone billing blocks on the client’s account a certain amount for paying for the call, which is adjusted (increases or decreases) based on the results of the end of the call. Further, similarly to post-paid billing, an adjustment is made to the subscriber’s account in the master billing. It is important to note here that in both scenarios, the subscriber can go negative, only with the pre-paid scheme it will be less.

    Television billing work


    Ideologically, television billing is no different from billing other television services. In the case of cable TV billing, it’s very simple - it’s just writing off fixed amounts for certain packages of TV programs, and in the case of IP TV, the “Video On Demand” (VoD) service can be added when the subscriber pays extra for some then a single film or broadcast.

    To implement these functions, a billing intermediary is used that solves the following tasks:
    • It blocks subscribers on the TV platform when they are blocked in the master billing;
    • Sends tasks to the master billing for debiting funds when using the VoD service.


    Based on the above algorithms, one of the main problems when launching Triple Play packages is immediately visible - the correct management of subscribers' balances. So, the operator needs to decide if all services will be blocked when money is exhausted, or only those for which there is not enough money? Blocking all services at the same time requires an appropriate agreement with the subscriber, since according to Russian legislation, telephony, television and Internet access services are considered as independent services with different rules for their provision (310th, 785th and 575th rules, respectively). Will the billing cycle be monthly or daily? If it is monthly, then the operator can correctly process all the charges within the subscriber's account, but the risk of going negative is increased; and with daily debiting, all subscribers will ultimately “scatter” according to their start dates for the billing month, which increases the requirements for the power and complexity of the operator billing system by an order of magnitude. It is also necessary to provide conditions - in what order funds are debited from the subscriber’s balance for services (or are not debited at all, while they are not enough to pay all three services at once).

    New Services


    The 3P concept assumes that within the framework of a single environment, new services will become available to subscribers. This is true, however, many of them are either not needed or not familiar to users - for example, it makes little sense to receive a phone call on the TV screen when watching IP TV. The vast majority of users will not tire at all to pick up the phone separately from the TV.

    At the same time, there are services that are beginning to enter the user’s turnover - video calls, instant messaging (sending messages) and chat. In a normal 3P environment, it is already highly desirable for the operator to support these services. And here a new problem arises - services are needed, but no one will pay money for them, because There are a huge number of free alternatives. Therefore, it is important for the operator to consider such non-refundable costs when calculating a business case for 3P services.

    Creating 3P offers, even without taking into account technical problems (and there are also plenty of them) is a non-trivial task for the operator. And statistics help here: the frequency of calls and their duration are analyzed, the amount charged for television and the frequency of VoD usage are analyzed, the typical balances of users when using the Internet access service and the rates for cancellation are analyzed. The ideal cannot be achieved here, but it is possible to select the parameters of the 3P offer in such a way as to maximize user satisfaction and reduce the number of critical states that users may end up in the complex process of interaction of all 3P systems.

    Fraud


    Another significant problem is the implementation of a password protection system for services when providing 3P offers. The fact is that hacking an Internet account currently does not give a cracker anything - with unlimited Internet, a subscriber does not lose anything when an unauthorized user uses his account by an attacker - it’s just that more traffic will be displayed on his account and that’s it. Maximum - the forder will be able to order some additional services provided by the operator, for example, an antivirus license.

    In case of integration with the password of the IPTV password system, an attacker will be able to download films for the balance amount, which is a medium risk. The fact is that he will not be able to capitalize this money of the subscriber himself - such IP TV films cannot be sold. But it will cause damage to the operator, since if the hacking is proved, the operator returns the money to the client (although this is not the duty of the operator, but only his work to increase loyalty), but the operator himself will be required to pay these films.

    But unification with the common password of the telephony service will already lead to a real capitalization of account hacking - an attacker can sell this traffic, i.e. due to the balance of the subscriber, the connections of VoIP-operators working under this scheme will be paid.

    To prevent such situations, operators can first enter different passwords for all three services (which, however, reduces the usability of the 3P service package), and secondly, increase the overall quality of password protection for all three services, especially Internet access services.

    User support


    Triple Play also creates another difficulty in organizing customer support services (in terms of services for the mass market). The implementation of the concept involves the allocation of a single number to receive all incoming calls from subscribers, but at the same time, the presence of three different technical and billing subsystems requires the creation of different groups of qualified engineers to resolve issues separately on the Internet, separately on television and telephony.

    A possible solution to this problem is to create various groups of the 2nd support line, which is located behind the general 1st support line, as in the picture:


    Multi-level support service for serving Triple Play subscribers

    In this case, the 1st support line solves the most popular issues of subscribers: financial blocking when a zero balance is reached, informs subscribers about the write-offs, consults on general issues of connecting / disconnecting services. In the case of a specialized question, for example, IP TV inoperability, the 1st line operator sends a call to the 2nd support line (opens Trouble Ticket), where the IP TV technician can answer the call in a qualified manner. If he cannot solve the problem, the technician opens an incident where engineers from the general pool of the operator’s technical unit are already attracted, where engineers own specific systems and technologies for services.

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