Guidelines on Interconnection and Interoperability

Issued by the Director General of Telecommunications

July 1999

Annex B – Example proforma for digital interface publication

This publication contains two Guidelines related to interconnection and interoperability of services.

Part A contains Oftel’s Guidelines on enforcement of conditions in the licences of Public Telecommunications Operators (PTOs) requiring interconnection and interoperability of services. The Guidelines are published following public consultation and extensive discussion with the industry.

Part B contains Guidelines for customer-network interface publication. These Guidelines explain the format which should be followed by PTOs in publishing technical specifications for customer-network interfaces as they are required to do by relevant conditions in their licences, and contain templates for these publications. The Guidelines do not cover network-network interfaces. Oftel will produce separate guidelines for network-network interfaces if there is demand for them.

1.1 These Guidelines contain explanation of how Oftel will approach enforcement of rules on interoperability of services between separate networks and between customer premises equipment (CPE) and networks. These rules cover requirements to

• make services available for interconnection,

• consult with interested parties concerning new or changed interfaces, and

• publish technical interface specifications

and are backed by the following conditions in the licences of operators (numbered as they appear in the draft template licences to become effective as part of the process of implementing the EU Licensing Directive in the UK):

• Prohibition on undue preference and undue discrimination (Condition 8 in BT’s licence, Kingston’s licence, the standard PTO, cable, and mobile licences.)

• Requirement to provide connection services including co-location and facilities sharing (Condition 9 in BT’s licence, the standard PTO, cable, and mobile licences. Condition 10 in Kingston’s licence.)

• Publication of interfaces (Condition 16 in BT’s and Kingston’s licences. Condition 15 in the standard PTO, cable, and mobile licences.)

• Essential Interfaces (Condition 17 in BT’s and Kingston’s licences. Condition 16 in the standard PTO, cable, and mobile licences.)

• Fair trading (Condition 44 in BT’s licence. Condition 33 in Kingston’s licence. Condition 31 in the standard PTO, cable, and mobile licences.)

1.2 It should be noted that provisions within the Fair Trading Condition (FTC) will be replaced by parallel provisions in the Competition Act. This is because the FTC contains a clause stating that it shall cease to apply to any behaviour prohibited by or any prohibition enforceable under new legislation which:

• contains a prohibition enforceable by the Director General of Telecommunications, or gives to the Director General of Telecommunications the power to enforce an existing prohibition, of any behaviour prohibited under the Condition;

• gives to third parties in respect of a breach of that prohibition at least the rights they have under Section 18 of the Telecommunications Act in respect of a breach of a Provisional or Final Order; and

• permits the imposition on the licensee of monetary penalties in respect of the breach of that prohibition.
  

1.3 Oftel presently considers that the Competition Act meets these criteria. Consequently the FTC would automatically cease to apply to all types of agreements and conduct which would otherwise be caught by both the FTC and the Competition Act once the provisions of the latter come into force in March 2000. Oftel will therefore seek to remove the FTC from all licences with effect from 1 March 2000 to coincide with the coming into force of the Competition Act.

1.4 These Guidelines do not affect the scope of the licence conditions listed in this section or any others. The Director General will take them into account in applying the relevant conditions in licences. He would normally expect to follow them and to give his reasons if he departed from them. The Director General cannot legally fetter his discretion and he retains the ability to depart from the Guidelines where the circumstances warrant it. The Guidelines are therefore not legally binding on the Director General.

1.5 The Guidelines will be subject to review and amendment following consultation with interested parties in the light of experience of their operation, of development in telecommunications markets, and of any changes to UK or EC competition law.

1.6 These Guidelines refer to situations in which operators may have market power. The new licenses to be granted as part of the process of implementing the EC Licensing Directive in the UK include the concept of Market Influence. Market Influence is the ability to raise prices above the competitive level in a market without losing sales to such a degree as to make this unprofitable. Market power has the same meaning as Market Influence.

1.7 Under the new licences, the Director General can determine that an operator has Market

Influence in a market. Criteria which he may take into account in making such a determination are listed in the licences, as is the process for making determinations. These Guidelines refer to markets where no such determination has been made but where Oftel nevertheless considers that BT has a level of market power consistent with the possession of Market Influence. Oftel will take steps to make a determination in the event that that is required to ensure that an operator with Market Influence does not abuse its position with regard to interconnection and interoperability of services.

2.1 The requirement to provide connection services condition in the licences of operators

requires them to negotiate with other operators which are entitled to interconnection when requested to do so. This requirement extends to the provision of telecommunication services which the Director General may determine to be "reasonably required (but no more than reasonably required) to secure that points of connection are established and maintained and to enable the Operator effectively to provide the Connection Services which it provides or proposes to provide".

2.2 This section of these Guidelines is largely about how the Director General is likely to enforce this requirement. In doing so, he may, in addition to his Order making powers, use his dispute resolution and direction powers under Regulation 6 of the Telecommunications (Interconnection) Regulations 1997 (which implemented the Interconnection Directive (ICD)) (see paragraph 6 below) . However, failure to provide an interconnection service may also constitute an abuse of a dominant position or be unduly discriminatory and therefore warrant enforcement action under the Fair Trading Condition, the Competition Act, or the prohibitions on undue discrimination in licences respectively. In the event that enforcement action is necessary, Oftel will decide the appropriate licence condition under which it should proceed on a case by case basis depending on the individual circumstances of the situation.

2.3 In exercising his powers under Regulation 6 of the Telecommunications

(Interconnection) Regulations 1997, the Director General is required to take account,

inter-alia, of

• the interests of users;

• regulatory obligations or constraints imposed on any of the parties;

• the desirability of stimulating innovative market offerings, and providing users with a wide range of telecommunications services both at national and European Community level;

• the availability of technically and commercially viable alternatives to the interconnection requested;

• the desirability of ensuring equal access arrangements;

• the need to maintain the integrity of the public telecommunications network and the interoperability of services;

• the nature of the request in relation to the resources available to meet the request;

• the relative market position of the parties;

• the public interest;

• the promotion of competition;

• the need to maintain a universal service.

2.4 Any direction made by the Director General to resolve such a dispute must represent a fair balance between the legitimate interests of both parties. The direction shall be notified to both parties and published in accordance with Regulation 8(3) of the Regulations. The parties concerned will be given a full statement of the reasons on which his direction is based.

2.5 Oftel has undertaken analysis of distortions in the operation of markets for new interconnection services which can result from the existence of market power. This work has been carried out through discussion and consultation with the telecoms industry, notably through consultation on the April 1997 Statement, Interconnection and Interoperability: A Framework for Competing Networks, at the Interconnection Policy Forum (IPF – now the Operator Policy Forum) and through a Focus Group established by the IPF to look specifically at interconnection of new services. The outcome of consultation was confirmed in the Statement, Interconnection and Interoperability of Services over Telephony Networks, published in April 1998.

2.6 The existence of market power can mean that commercial incentives for operators to interconnect services between their networks are skewed, resulting in harm to

• consumers who are denied choice, and

• competitors who cannot compete fairly with the operator with market power.

In markets where there is no market power or other market failure, customers are generally best served through the uninhibited operation of market forces. Oftel will therefore normally only seek to require interconnection where such operation is hindered by the existence of market power.

2.7 Definition of market power for the purpose of applying rules on interconnection has

involved analysis of markets for telecommunication services and the characteristics which confer market power on an operator in them, and of the classes of service which are affected by the existence of that market power.

2.8 Consistent with Oftel’s general approach to measuring market power, also employed by other competition authorities around the world, Oftel will take account of the following factors in assessing market power in markets for interconnection services;

• the number of firms competing in the market;

• the vertical integration of firms;

• barriers to entry and exit, together with the history of the entry into and exit from the market;

• the price history and profitability of firms in the market;

• the degree of excess capacity that competitors possess;

• the existence of countervailing power;

• the conduct of competition in the market: for example, whether firms compete on the basis of price, by product differentiation, after sales services or other factors;

• other issues, such as customer awareness and customer inertia.

For interconnection services, vertical integration is likely to be a particularly significant indicator. This is explained below.

2.9 In assessing whether or not an operator has market power in the market for an interconnection service, Oftel expects that it will generally be appropriate to consider the extent to which interconnection with a particular network is necessary for the commercial viability of a service. This depends on whether interconnection is a necessary input to the delivery of a downstream retail service and on the existence of competitive alternatives. Where a vertically integrated firm competes in a downstream retail market with rivals who require access to its network in order to offer a competing service, the potential for abuse of market power is exacerbated. This is because there may be incentives for the firm to discriminate unduly in favour of its own retail services in the provision of necessary network inputs.

2.10 In many cases, market power in both the provision of retail and interconnection services is conditioned by the control of access to customers. This provides an operator with the means for delivery of its own services and those of other operators. It is true that control of the means of access to any customer gives an operator a degree of market power in the delivery of calls to that customer. However, there is unlikely to be any prospect that such market power can be leveraged into markets for particular services (retail or interconnect). This is only likely where an operator controls the means of access to a large proportion of customers. To understand this, one needs to consider the respective positions of a large and small operator both launching new services which are capable of being used between competing networks.

2.11 The small operator does not have a very large number of directly connected customers and so will want to interconnect with the large operator in order to provide its own customers with access to customers of the larger operator and hence extend the market for its service. The large operator on the other hand may have no need to extend the market for a service it launches because the directly connected customers of the small operator are insignificant to it. If the large operator’s customers cannot access the comparatively few customers directly connected to the smaller network, it probably is not a significant commercial disadvantage to it. Furthermore, the large operator may actually want to weaken the position of the small operator by not making a service available to its customers. Where an operator controls an overwhelming majority of access lines to customers, it is clearly questionable whether it has sufficient incentive to provide interconnection of new services without some regulatory guidance to substitute for the commercial incentive it would feel in a competitive market.

2.12 Oftel will therefore consider a large share of exchange lines providing direct access to customers as a strong indicator that an operator has market power in the provision of interconnection services which requires use of that operator’s access network. Oftel would not normally expect an operator to be in possession of market power unless it controls at least 25% of exchange lines, but it does not rule out possession of market power by an operator controlling less than 25% of exchange lines. If requested, it would consider whether an operator has market power.

2.13 Control of access to customers is not the only indicator that an operator has market power in markets for an interconnection service. Other interconnect inputs may be necessary for the provision of retail services and, where an operator controls such an input, it is likely to have market power, eg there may be no viable alternatives to elements of national networks in some areas.

2.14 At present, having taken account of all the relevant factors, Oftel considers that BT has market power in respect of interconnection of certain services (for identification of these services, see paragraph 2.16 below). A key factor in Oftel’s consideration of this is BT’s share of exchange lines in the UK which gives it control of the means of access to customers. BT controls around 86% of exchange lines (Source: Oftel’s Market Information publication for Q1, 1998/9). This means that other operators are dependent on BT for delivery of calls to a high proportion of end-user customers. This is especially so where calls originate or terminate on BT’s copper access network. The size and ubiquity of BT’s network also means that it is the operator most likely to possess market power in interconnection of a service resulting from the control of some other network input, particularly where services are delivered over the PSTN. BT is likely to have market power in markets for interconnection services required for delivery of services to its directly connected retail customers and, because it is vertically integrated (ie provides retail services and network inputs to deliver them), there is a danger that this could distort markets for both retail and interconnection services.

2.15 Oftel will take acount of the individual circumstances of any cases brought to it about launch of new services. However, because its vertical integration, control of access to a large proportion of end-users, and network ubiquity combine to give BT market power in a wide range of markets for interconnection products, these Guidelines explain how Oftel will normally expect BT to fulfil relevant licence requirements when it launches new retail products. Oftel has identified that the interconnection markets in which BT has market power are normally those for Cooperative Network Services.

2.16 As discussed in the analysis above, market power is most likely to be significant in markets where a network input is necessary for the delivery of a retail service. In this situation the retail service is unlikely to be commercially viable without the interconnection service which provides the network input. The technical characteristics of Cooperative Network Services are as follows.

2.17 Network Services are defined in BT’s licence. Certain Network Services are reliant upon networks interconnecting in order for calls crossing interconnected networks to work. To work between networks, such services require a specific capability in both the originating and terminating networks and at the point of interconnection. This type of service is defined as a Cooperative Network Service. Cooperative Network Services can also be identified by more commercial characteristics – they are services which are not commercially viable unless interconnection is available.

2.18 For the avoidance of doubt, it should be stated that Cooperative Network Services can be voice or data services. It is not appropriate to distinguish between voice and data services in the application of licence conditions which provide for interconnection and interoperability.

2.19 Interconnection of Cooperative Network Services is desirable for customers and for the development of competition. Customers obtain the benefits of interconnection of this type of services by being able to use the services available in calls to other users who may not necessarily be connected to the same network. There are benefits to competition both at the network level - because the unavailability of such services may hinder the ability of smaller networks to compete - and also in markets served by independent service providers (ISPs) offering services over networks but not owning networks themselves – because, in the absence of interoperability, ISPs are likely to use an operator with market power to ensure that their service is as widely available as possible and so will lose the advantage of having a choice of network operator.

2.20 In competitive markets, it is likely that operators would want to offer Cooperative Network Services for interconnect so as to widen the market for them. But, where an operator has market power in terms of control of the means of access to customers or some other network input, this may not be so for the reasons explained in paragraph 2.11. Oftel is therefore likely to look very carefully at any failure by an operator with market power to provide interconnection of a Cooperative Network Service.

2.21 In doing so, it will consider whether the operator with market power is launching the service or whether another operator is launching the service and seeking to make it available on the network of the operator with market power through interconnection. In either scenario, Oftel would expect the operator with market power to provide interconnection. Where the service is launched by another operator, it is possible that the network of the operator with market power will not be capable of carrying the service without upgrade. In these circumstances, Oftel would expect the operator with market power to make the necessary upgrade if it is reasonable for it to do so. In its consideration of any complaint that an operator with market power has unreasonably failed to make an upgrade to support a Cooperative Network Service requested for interconnection by another operator, Oftel would normally take account of the following factors:

- not material to the operator making the upgrade, or

- likely to be offset by revenue earned as a result of the upgrade (see other factors listed below).

Oftel would not expect major investment to be undertaken solely for the purpose of providing interconnect unless there are compelling reasons for this to happen.

• Whether the upgrade would be made irrespective of the request for interconnection. If so, then Oftel would expect the upgrade to be made and interoperability facilitated with operators requesting interconnection. The above factors would be taken into account in considering any additional costs resulting from changes to the timing of upgrades to meet requests for interconnection.

2.22 This is not an exhaustive list and Oftel may take other factors into account or place greater or less weight on one or other factor depending on the circumstances of the case. Oftel will always consult with interested parties during its consideration of these issues and will always publish its conclusions except to the extent that this is prevented because of legitimate concern about the commercial confidentiality of data.

2.23 Oftel is likely to regard any failure by an operator with market power to provide interconnection of Cooperative Network Services, launched both by itself and by other operators - except where the inability of its network to support the service means it is unreasonable so to do - as contrary to the requirements of any, a combination of, or all of the following conditions in its licence:

• Prohibition on undue preference and undue discrimination.

• Requirement to provide connection services including co-location and facilities sharing.

• Fair trading.

Where Oftel concludes that this is the case it will take appropriate action to enforce the relevant licence requirements.

2.24 Oftel expects operators with market power launching a new Cooperative Network Service to ensure that interconnection is available at the same time as the launch of any corresponding retail service (if there is one), or when the functionality becomes available on the network of the launching operator if there is not. Failure to do so might be regarded as unreasonable under the Interconnection Condition, and/or contrary to either or both of the Fair Trading Condition and the prohibitions of undue preference and discrimination in the licences of operators.

2.25 When interconnection of the new service involves interoperability at new or changed interfaces, operators will have to comply with the requirements of the Publication of Interfaces condition in their licence (see Section 3 of these Guidelines). Where there is no new interface, Oftel would still expect operators with market power to give sufficient notice of new services ahead of launch for other operators to prepare their systems for interconnection. Oftel would expect this period of notice to be sufficient to enable an efficient operator to make the necessary arrangements, but not to delay the introduction of services as a consequence of allowing for the pace of an inefficient operator. Oftel notes that the industry has agreed its own code of practice on the launch of new services which incorporates timescales for arrangements ahead of launch (the code of practice can be viewed at BT’s interconnection Website: http//www1.btwebworld.com.interconnect). Oftel would normally expect adherence to the industry code of practice to ensure that there is always sufficient lead time ahead of launch of Cooperative Network Services such that efficient operators are able to interconnect at the same time as launch of a corresponding retail service or when new functionality is available on a network. Oftel has noted that the code of practice does not apply to data services. It is not appropriate to distinguish between voice and data services in the application of licence conditions which provide for interconnection and interoperability.

2.26 Oftel’s approach to licence obligations with regard to the interconnection of services as explained above is illustrated in the ‘Decision Tree’ at Figure 1 below.

3. Publication of interface specifications

3.1 Requirements on operators to publish technical specifications for interfaces both

between networks (network-network interfaces) and between networks and customer equipment (customer-network interfaces) are established by the Publication of Interfaces condition in the licences of operators.

3.2 The Publication of Interfaces condition provides that the Director General can determine that an operator has Interface Control. Interface Control is defined in the condition as it is drafted in BT’s licence as follows.

The existence of Interface Control can result in market distortions associated with the ability of an operator with Interface Control to impose de-facto standards on other operators and equipment manufacturers. Determination that an operator has Interface Control therefore triggers requirements to consult on proposed interface specifications to encourage a consensus approach to the adoption of standards.

3.3 In January 1999, the Director General determined that BT is in possession of Interface Control in relation to telephony services provided over the telephone and ISDN networks across new technical interfaces which do not conform to interface specifications which have been adopted as standards by

• the following European standardisation bodies: the European Telecommunications Standards Institute (ETSI) or the European Committee for Standardisation/European Committee for Electrotechnical Standardisation (CEN/Cenelec), or

• the International Telecommunications Union (ITU), the International Organisation for Standardisation (ISO) or the International Electrotechnical Commission (IEC).

3.4 The effect of the determination is that, prior to publication of interface specifications which are subject to the determination, BT must notify the Director General of proposed new interfaces as follows:

• in the case of customer-network interfaces, at least 60 days in advance of publication of the specification, and

• in the case of network-network (ie interconnection) interfaces, at least 6 months in advance of publication of the specification, or

• in the case of either customer-network or network-network interfaces, such other period as the Director General agrees.

3.5 Notification is followed by a period for consultation on proposed interfaces prior to

publication. Such consultation should be conducted through the Network Interoperability Consultative Committee (NICC). For this reason, BT has agreed that it will copy notifications of proposed new interface specifications to the Public Network Operators Interest Group (PNOIG).

3.6 Further details and a full explanation of the reasons for the determination are contained in the explanatory document which accompanies the determination (see Determination that British Telecommunications PLC has Interface Control with regard to new interface specifications relating to telephony services provided over the telephony and ISDN networks).

3.7 The condition contains the required periods for publication of interface specifications. These periods are as follows:

• Publication at least 15 months ahead of implementation of new customer-network interfaces and new commonly provided network-network interfaces and withdrawal of customer network interfaces and commonly provided network-network interfaces by all licensees.

• Publication at least 3 months ahead of modification of customer-network interfaces and commonly provided network-network interfaces by all licensees.

(For explanation of the meaning of the term ‘commonly provided’, see paragraph 3.16 below.)

3.8 The timescales for publication - 15 months for new interfaces and withdrawal of interfaces, 3 months for amended interfaces - are estimated to be the likely minimum necessary for other operators to make the necessary arrangements to ensure interoperability of new or modified interfaces with their systems. The condition contains provision for the Director to consent to a shorter period if appropriate upon written application from the licensee. For customer-network interfaces, the position will be reviewed following implementation in the UK of the RTTE.

3.9 The Director General is likely to consent to a shorter period than these in the following circumstances:

For customer-network interfaces:

• Where there is a CPE approvals route in place. And

• there is an overwhelming consensus in the industry (including manufacturers and representatives of users) in favour of launch not being delayed by formal publication; or

• where the new interface is an established international, European or UK standard or a published specification with equivalent acceptance to a formal standard; or

• where the new interface is already in use to a significant degree by one or more other network operators; or

• there is sufficient availability of terminal equipment within the European Union.

For network-network interfaces:

• where there is an overwhelming consensus in the industry (including manufacturers and representatives of users) in favour of launch not being delayed by formal publication; or

• where the new interface is an established international, European or UK standard or a published specification with equivalent acceptance to a formal standard; or

• where the new interface is already in use to a significant degree by one or more other network operators.

3.10 Discussion of publication requirements and those for notification and publication which apply to operators determined as having Interface Control has given rise to questions about how new interfaces are defined. New interfaces are those for which publication for a period of 15 months is required prior to implementation (unless the Director General agrees to a shorter period of publication) and to which the requirement for notification and publication applies for operators determined as having Interface Control.

3.11 Oftel regards new interfaces to be those which are

• instituted in the operator’s network for the first time, or

• result from significant change to an existing interface. A significant change is any change which

• relates to the introduction of a new Network Service, and

• involves modification to protocols which will affect the interoperability of Network Services.

3.12 The Publication of Interfaces condition requires that operators with interface control to notify the Director General of proposed new interfaces for a period of consultation with interested parties prior to publication. This consultation should result in consensus on interface specifications sufficient to enable operators to proceed on the basis of a published specification. Oftel would expect proper consideration and debate on proposed interfaces by interested parties. As explained in paragraph 3.5 above, the Network Interoperability Consultative Committee (NICC) is the appropriate forum for industry discussion on proposed interface specifications.

3.13 In the event that there is dispute following consultation about the specification for a network-network interface, the Director General may use his powers under the Essential Interfaces condition in licences to specify an interface specification for publication and implementation.

3.14 In reaching a decision on whether to use this power, the Director General would consider the reasons for the failure to reach consensus on the proposed interface. This consideration would include the following factors:

• Cost of implementing the proposed specification. In particular, the Director General would be concerned to establish whether implementation of the interfaces specification proposed by the launching operator would result in prohibitive new costs for other operators.

• Ease of implementation of the proposed specification for other operators and equipment manufacturers. Oftel would not expect standards to be proposed by launching operators which would be unduly difficult for other operators to adopt and would therefore constitute a barrier to interoperability.

• The customer and operator disbenefits flowing from the deployment of more than one type of interface.

• The conduct of negotiations.

3.15 This is not an exhaustive list and Oftel may take other factors into account or place greater or less weight on one or other factor depending on the circumstances of the case. Oftel will always consult with interested parties during its consideration of these issues and will always publish its conclusions except to the extent that this is prevented because of legitimate concern about the commercial confidentiality of data.

3.16 Oftel does not believe it is appropriate for operators not in possession of Interface Control to be subject to onerous obligations to publish technical specifications for network-network interfaces. The licence requirement only applies with regard to ‘commonly provided’ interfaces. In enforcing the condition, Oftel is likely to take the view that ‘commonly provided’ interfaces are those supporting services which are available throughout the industry, eg

• interfaces supporting interconnection of services provided by BT as Standard Services available to all interconnecting operators on standard and non-discriminatory terms, and

• interfaces adopted by all operators to support a common service like call termination.

‘Commonly provided’ would not include an interface specification initiated by an operator without interface control and launched bilaterally between the networks of that operator and another similar operator or limited group of operators.

3.17 Part B contains Guidelines on the format of customer-network interface declarations.

Oftel has compiled a list of locations at which the published interface specifications for each operator can be found. The list is available on the Oftel Website.

This document contains guidelines that fixed Public Telecommunications Operators (PTOs) should follow when publishing technical information about their customer interfaces as a result of the application of EC Directive 98/10/EC [1] requiring publication of commonly provided interfaces. It is also relevant to subsequent obligations placed in PTO licences for the publication of interfaces for all Network Services, which includes other non-voice services. The condition is entitled Publication of Interfaces and numbered 16 in the licences of BT and Kingston, and 15 in the standard PTO, cable, and mobile licences.

These guidelines cover the obligations placed upon fixed PTOs in publishing customer-network interfaces (e.g. what the publication must contain and any legal issues that have to be resolved in publication). They take account of the existing regulatory requirements and provide guidelines for a single publication to fulfil all of these requirements.

These guidelines also apply to mobile PTOs for the publication of fixed network interfaces. Future revisions may provide guidance for air interface declarations.

The annexes to this document provide examples of proforma templates which may be used for interface publication for different types of interface.

The guidelines do not cover publication of network-network interfaces. Oftel will publish guidelines on publication of network-network interfaces if there is a demand for them.

As part of the interface publication, the PTO publishing the interface should ensure it does not knowingly make such publication in breach of any IPR and/or copyright associated.

In so far as the publisher is aware of the same, the publisher should ensure that the publication itself contains a clear indication of

(ii) the rights granted and restrictions made to users of the specification; and,

(iii) how details of any licensing requirements associated with such IPR may be obtained.

The publisher should ensure that any licensing associated with such IPR is made available on fair and non-discriminatory terms.

The annexes to this document contain example proforma which may be used in the declaration of interface specifications. The presentation style of these Annexes is provided for illustrative purposes only.

These publications should contain information to enable terminal equipment to interwork with the public telecommunications network for the purpose of establishing, modifying, charging for, holding and clearing real or virtual connections and to prevent the misuse of network resources. They should also contain details of any supplementary services or enhanced features provided by the network that is important for the design and operation of terminal equipment. Details of value added services (services provided over network connections) are not required to be published under the present regulations. Regulation RVTD6.3 requires that PTOs inform Oftel about any network characteristics which are found to affect the correct operation of terminal equipment. Any such information should also be included in the interface publication.

The interface publication should contain at least the information described under the headings in the proforma where relevant to that interface (notes are contained in the proforma to explain the nature and level of detail of the information required). PTOs may, if they chose, provide additional information e.g. relating to the interface definition, the services provided over that interface, facilities provided to terminal designers/users for interoperability testing, helplines. In producing the interface publication, the following points should be considered:

• Reference to standards: wherever possible, the interface specification should refer out to published standards. The following priority order (where 1 is highest priority) should be used to select the standards to which the publication refers:

            1. Standards published in the Official Journal of the European Communities

            2. European standards adopted by ETSI, or CEN/CENELEC.

            3. International standards or recommendations adopted by the International Telecommunications Union (ITU), the International Standards Organisation              (ISO) or the International Electrotechnical Commission (IEC),

            4. National standards or specifications, e.g. documents produced by the Network Interoperability Consultative Committee (NICC) or its sub-committees.

• Options in standards: when a standard referred to contains options, the interface specification should indicate which option(s) have been implemented. It should be noted that for some protocols, there are standards defining the associated Protocol Implementation Conformance Statements (PICS) which may be used for this purpose.

• Supplementary services: all supplementary services provided must be published, along with the service codes used for their actuation. (Note however that Oftel is likely to allow shorter advance publication periods where only the codes are being changed.)

• Reference to other documentation: network operators may refer out to existing company documentation for all or part of their customer interface publication. Where such references are made, the network operator should ensure that the same ease of access exists for the referenced document(s) as that applied to the customer interface publication.

The PTO publishing the interface, or a 3rd party, may provide facilities for interoperability testing of apparatus designed to be compatible with and to inter-operate with the published interface.

Whether such a facility is provided by a PTO is at the discretion of that PTO. When offered by a PTO, the terms under which this testing facility is provided should be fair and non-discriminatory.

It is recognised that all companies have a "house style" for all of their documentation. Customer interface publications may be made using the company "house style" but network operators should ensure that the contents of their publication provide the same information as indicated in the proforma given in the annexes to this document.

There is no requirement to have a separate publication for each customer interface; it is recognised that where customer interfaces are very similar, it may be beneficial to have all of those interfaces in a single document. Similarly, it may be desirable to specify some characteristics which are common to a number of customer interfaces (e.g. tones and announcements) in a separate publication. The criteria for deciding how to document the technical characteristics of the customer interfaces should be based on clarity, removal of ambiguity, maintainability and ease of use for the users of these publications.

Publications should be in English (as a minimum) and be issue controlled.

As a minimum, the PTO should provide details for a single point of contact to Oftel that can provide access to all interface publications provided by that PTO. The PTO shall inform Oftel immediately of any change to the given contact details to ensure that they remain current. Additionally, it is recommended that a PTO provide within specific publications, contact details to enable users of the publication to contact the PTO for the purposes of, for example, clarification or reporting errors in the publication.

Where possible, the PTO should also provide a single "on-line" point of contact for information relating to accessibility of all their interface publications.

Oftel will maintain an up to date list with the contact information for obtaining specifications from all PTOs. Oftel will make this available on request and make it available directly on the Oftel web site. PTOs are encouraged to grant permission for Oftel to establish hyperlinks from their site to the relevant PTO publications.

In order to minimise cost and complexity associated with distribution of publications, it is recommended that, wherever possible, PTOs make interface publications available "on-line". Where this is not possible, reasonable costs for reproduction and distribution may be levied by the publisher on an organisation or individual requesting a copy of a particular interface publication.

The Director General acknowledges the assistance given by the NICC in the production of these Guidelines.

Oftel

November 1998

This Annex contains details of the proposed contents of an analogue interface specification published as a result of the application of these guidelines.

This Annex contains details of the proposed contents of a digital interface specification published as a result of the application of these Guidelines.

Where a public telecommunications network is connected to a customer s network or apparatus (at the Network Terminating Point) the network and the customer s system must each be able to understand the technical operation of the other in order for services to interoperate across the connection boundary. The customer’s system and the network must both provide an interface at the point of connection and only where these interfaces are matched will there be interoperability. The technical characteristics that allow for that understanding is the customer-network interface.

Interconnection means the physical and logical connection of two operators’ networks thereby allowing customers of one system to connect with customers of the other, or to access services provided from the other system.

Interoperability means the technical features of a group of interconnected systems (‘systems’ includes equipment owned and operated by the customer which is attached to the public telecommunication network) which ensure end-to-end provision of a given service in a consistent and predictable way. Interoperability is defined here in terms of the functional delivery of services across networks - it does not necessarily imply that component parts of the systems over which such services are delivered are interchangeable.

Integrated Services Digital Network (ISDN)

A network based on the existing digital PSTN which provides digital links to customers and end to end digital connectivity between them. ISDN2 provides a maximum bandwidth of 128kbit/s.

The ability to raise prices above the competitive level for a non-transitory period without losing sales to such a degree as to make this unprofitable.

Where two operators networks are interconnected, each must be able to understand the technical operation of the other in order for services to interoperate across the interconnection boundary. The technical characteristics that allow for that understanding is the network-network interface. Each network must provide an interface at the point of connection and only where these interfaces are compatible will there be interoperability.

A committee set up to advise the Director General and provide guidance to standards bodies on interoperability.

The telecommunications networks of the major operators, on which calls can be made to all customers of all PSTNs.