National ISDN Council: SPID Simplification

Format and Definition of a National ISDN SPID

For National ISDN-2 (NI-2) and beyond, a SPID is a free-formatted numeric string between 3 to 20 characters in length. The SPID is assigned by the Local Exchange Carrier or LEC (ISDN service provider) when the customer places a service order for a BRI. Currently, the customer must enter the SPID into the terminal before the terminal can initialize at layer 3.

The Service Profile IDentifier (SPID) is a number assigned to a fully initializing ISDN terminal that enables the Stored Program Control Switching System (SPCS) to uniquely identify the ISDN terminal at layer 3 of the D-channel signaling protocol.

Each fully initializing terminal needs to be uniquely identified at layer 3 in order for the SPCS to provide terminal-dependent features. When the terminal sends its SPID during layer 3 initialization, the SPCS uses the SPID to associate the terminal with a specific set of terminal services (that have been previously provisioned in the SPCS for that terminal). The directory number of the terminal is not sufficient for this purpose because directory numbers may not uniquely identify a terminal on an interface; that is, a directory number can appear on multiple terminals on a single BRI.

SPIDs also simplify switch-based troubleshooting when multiple terminals are assigned to a BRI. Abnormality logs in the SPCS indicate the SPID of a terminal experiencing a problem. This information helps maintenance personnel isolate and resolve ISDN troubles.

One example of a configuration where different terminal-dependent features need to be assigned follows: Two voice terminals are served by a single BRI. The terminals share the same directory number, but only one terminal is provided with access to call hold and flexible calling (conference calling) features. A separate set of characteristics--or profile--is provisioned in the SPCS for each terminal. One profile includes call hold and conference calling; the other profile does not. When each terminal initializes, the SPCS uses the terminal's SPID to provide the correct features and button assignment to the terminal. There are many other examples of features that are assigned in a similar manner.

New Capabilities

As part of our National ISDN Enhancements process, new procedures and capabilities have been deployed that will simplify or eliminate terminal initialization from the user's perspective:

SPID Simplification Press Release
Generic SPID Format
Non-Initializing Terminals
Automated SPID Selection

National ISDN Council (NIC) Reports Results Of Service Profile Identifier (SPID) Simplification Survey

Detroit July 29, 1997 -- The National ISDN (Integrated Services Digital Network) Council (NIC) announced today the results of its recent industry survey on Service Profile Identifier (SPID) Simplification capabilities.

The survey, which was introduced at the June North American ISDN Users’ Forum (NIUF), solicits information from the ISDN customer premises equipment (CPE) manufacturers regarding their plans to support non-initializing terminal (NIT) and AutoSPID capabilities during 1998 and 1999. The NIC also intended the survey to identify any applications that are unique to NITs, or that could be supported more effectively by NITs than by the AutoSPID capabilities. To ensure the broadest industry coverage possible, the survey was also made available on the NIC Home Page and was mailed to the 90 attendees of the 1997 Telcordia Basic Rate Interface CPE Guidelines Seminar held in March.

Responses were received from nine ISDN CPE manufacturers. All nine suppliers indicated that they planned to support the AutoSPID feature in the 1998/99 timeframe, and five of the nine indicated that they would also support the NIT capability on the same product as AutoSPID. Six respondents indicated that they believe that any application that could be supported by the NIT capability could be equally or better handled by AutoSPID. One respondent identified the simple voice terminal as a potentially good NIT application. No respondents identified any applications that they felt could only be handled by the NIT capability.

The input from this survey helps the NIC determine the best approach for SPID Simplification and helping the NIC develop deployment plans for NITs and AutoSPID. Garrett Jenkins, chair of the NIC and BellSouth’s ISDN Industry Liaison, indicated that the NIC initially planned for the NIT capability (which allows a terminal to operate without initialization) to be an interim step in SPID Simplification deployment; AutoSPID (which automates terminal initialization by downloading the SPID from the network in lieu of manual entry) was intended to be the long-term solution which would be deployed later by the service providers.

“However, with the results of this survey available, and with the latest input from ongoing internal NIC studies on implementation and deployment complexities of the two capabilities, the NIC is planning to move forward rapidly with AutoSPID”, said Jenkins. At the June NIUF, Nortel and Siemens Stromberg Carlson provided planning information which indicated that they could have AutoSPID available by 2Q98. Lucent has already implementeded AutoSPID. Jenkins added that the NIC will continue to study the issue of NIT deployment and will provide a NIC update on SPID Simplification at the October 1997 NIUF.

Pat Donovan, Bell Atlantic’s ISDN Industry Liaison, indicated that the first step in deployment of the NITs capability is the introduction of new ISDN Ordering Codes (IOCs). “However, the industry response to date hasn’t helped identify the application that we could use to propose an IOC for NITs,” Donovan said. “We invite industry members to share any applications with the NIC or bring them to the NIUF directly,” he added.

The NIC is a forum of telecommunications service providers who participate in National ISDN platform evolution and deployment support projects with Telcordia, the communications software, engineering and consulting company. More information about the NIC is available at this site, or from Jonna Puryear, the Telcordia NIC Administrator, at (732)-758-2991. Information can also be obtained from Garrett Jenkins via email at garrett_jenkins@bbs.bellsouth.com.

Generic SPID Format

The generic Service Profile IDentifier (SPID) format defines how the SPID value will be assigned for new National ISDN lines. This format has no impact on existing ISDN installations. The generic SPID format is comprised of 14 digits which can be divided into the following three components: a 10 digit telephone number, a 2 digit Sharing Terminal Identifier, and a 2 digit Terminal Identifier (TID).

The 10 digit telephone number is the main Directory Number (DN) associated with the terminal, and includes the 3 digit Numbering Plan Area (NPA) or area code. When an ISDN user is assigned a new NPA during an area code split, the SPID may be changed to include the new NPA or the SPID may remain unchanged and continue to include the original NPA. Whether the SPID is changed depends on the capabilities of the serving switch and the policies of the ISDN service provider. If the SPID is changed, the user must enter the new SPID into the terminal.

The 2 digit TID differentiates terminals that have the same main DN and the same Sharing Terminal ID. These terminals share the same TSP, which means they have access to identical services, button configurations, and DN(s) and use the same set of switch translations. The TID values range from "01" to "08," where the values are assigned in sequential order beginning with "01." Terminals not sharing a TSP always use the "01" value.

Although the generic SPID format allows for many combinations of Sharing Terminal IDentifier and TID values, configurations that use values other than "0101" may not be available from or tariffed by all ISDN service providers.

The most frequently used SPID value will be NPANXXXXXX0101 based on the configurations being installed today.

This value is applicable to terminals having their own main DNs

This value is not applicable for the following configurations:

Multiple terminals using the same main DN
Multi-Line hunt group terminals with no DNs assigned

The generic SPID format is compatible with existing National ISDN CPE. In the future, CPE may make use of the format to assist the user. The generic SPID format or the NPANXXXXXX0101 SPID value may be presented in CPE instruction manuals. This presentation must also warn users that their particular SPID values may differ based on their configurations. Additional information on the Generic SPID Format including guidelines for instruction manual text can be found in Sections 2.3.3.2, 8.5.1.1, and Appendix B of SR-3888, 1997 Version of National ISDN Basic Rate Interface Terminal Equipment Generic Guidelines, November, 1996.

CPE suppliers may also use the NPANXXXXXX0101 SPID value as an overrideable default. The user would enter the 10 digit telephone number and the CPE would automatically append a "0101" to form a SPID. However, the generic SPID format must not be "hard-coded" into CPE; users must be able to enter any 9 to 20 digit SPID value. Any CPE which automatically generates a SPID must make it simple for the user to inspect and modify the SPID because other SPID values may be needed for particular configurations and other ISDN service providers may not implement the generic SPID format.

Table Summarizing SPID Format Technical Details

Main DN¹ Sharing Terminal ID Terminal Identifier (TID) Configurations

NPA NXX XXXX 01 01
Single non-EKTS terminal on a BRI.
Non-EKTS terminal with a unique Main DN; multiple terminals on a BRI.
EKTS terminal with a unique Main DN.

yy
where yy² =
"01" to "32" zz
where zz² =
"01" to "08"

Multiple non-EKTS terminals with same Main DN on a BRI; each terminal uses a unique TSP.
Multiple non-EKTS terminals with same Main DN on a BRI; these terminals use the same TSP³.
Multiple EKTS terminals with the same Main DN.

If a terminal has access to only one Directory Number (DN), that DN is the Main DN.
If a terminal has access to multiple DNs, then the Main DN is, in general, the DN that the terminal uses by default for outgoing calls when the user does not select a different DN.
Other terminals may access this DN, but these terminals do not use it as their Main DN.

Not all values are applicable to all configurations. Some configurations may not be available from all ISDN service providers.

A Terminal Service Profile (TSP) is a set of switch translations that defines the capabilities of one or more terminals. In order for multiple terminals to use the same TSP, the terminals must be on the same BRI, have access to identical services, button configurations and DN(s), and use the same Main DN. The Main DN used by these terminals may be the Main DN for only the terminals using this TSP, or it may also be the Main DN for terminals using different TSPs.

Benefits of the Generic SPID Format to ISDN Users

A Generic SPID Format will enable individuals and small businesses to obtain more complete SPID information from their CPE instruction manuals.

Large business customers, independent installers, and CPE suppliers with a presence in multiple territories will no longer require different SPID procedures for each location.

Implementation

The Generic SPID Format has been independently implemented for new National ISDN lines by:

Ameritech
Bell Atlantic
BellSouth
Cincinnati Bell Telephone Company
GTE
Pacific Bell
Southern New England Telecommunications Corporation
Southwestern Bell
U S WEST

The change to the Generic SPID Format is generally a "flash cut."

Non-Initializing Terminals (NIT)

Assignment of Feature Keys to Default Terminal Service Profile (TSP) (Non-Initializing Terminals)

A non-initializing terminal is a terminal that has not initialized at layer 3.

It is expected that a NIT will be the only terminal that will be provisioned on an interface. The NIT will not share the ISDN interface with another NIT or another initializing terminal. It is believed that a NIT operating on an interface will ease the ability of the user to access ISDN capabilities, since the user will not need to enter a SPID or a DN. A NIT can access DNs, features, and capabilities that are provisioned to the interface, to DN/CT pairs on the interface, and to the default TSP. A default TSP is provisioned for an interface so that a NIT will be able to access features and capabilities that are assigned on a per-TSP basis (e.g., Hold, Flexible Calling, fixed feature keys).

NITs will be able to originate and terminate calls using basic call control procedures. NITs will also be able to send and receive called party subaddress, calling party subaddress, low-layer compatibility, and high-layer compatibility information if these capabilities are provisioned. NITs are not required to support any additional call control procedures to identify themselves to the switch (e.g., NITs will not be required to include calling party number).

Non-initializing terminals will be able to be supported on a basic access interface after the interface is provisioned. At a minimum, for an interface to be considered provisioned to support non-initializing terminals the applicable bearer capabilities and the Directory Numbers must be specified for the interface. Non-initializing terminals will be able to access all NI-1 bearer capabilities (i.e., speech, 3.1-kHz audio, circuit-mode unrestricted digital information at 64 kbps, circuit-mode unrestricted digital information rate adapted from 56 kbps to 64 kbps, and packet-mode on the B channel or on the D channel).

Non-initializing terminals have access to a subset of features available to initializing terminals (e.g., Calling Name and Number Delivery, Call Forwarding, Additional Call Offering, and Hold). National ISDN Enhancement #91 allows fixed feature keys to be assigned to the default TSP, thus allowing non-initializing terminals to use the Feature Key procedures. This will allow non-initializing terminals to access additional mass market features that are available to analog users such as Conference, Transfer, and Message Service.

Non-initializing terminals may be used for the following mass market applications:

Internet Access
Remote LAN Access
File Transfer
LAN to LAN connectivity
Desktop Video
Work-at-Home (when fixed feature keys are supported for NITs)

Additional information on Non-initializing terminals can be found in Sections 2.2.10 and 8.6 of SR-3888, 1997 Version of National ISDN Basic Rate Interface Terminal Equipment Generic Guidelines, November, 1996.