SIST ETS 300 403-1:1999/C1:1999

• Abstract:

  Corrigendum to tables 3-4/Q.931 and 3-15/Q.931

• Status: Published
• Publication Date: 30-Apr-1999
• ICS: 33.080 - Integrated Services Digital Network (ISDN)
• ICS: 35.100.30 - Network layer
• Technical Committee: SPS - Signalling protocols and switching
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 01-May-1999
• Due Date: 01-May-1999
• Completion Date: 01-May-1999
• Mandate: T-234B
• Ref Project: ETSI ETS 300 403-1/C1 ed.1 (1996-06) - Integrated Services Digital Network (ISDN); Digital Subscriber Signalling System No. one (DSS1) protocol; Signalling network layer for circuit-mode basic call control; Part 1: Protocol specification [ITU-T Recommendation Q.931 (1993), modified]

SIST ETS 300 403-1:1999/C1:1999 is a SIST corrigendum for the ISDN DSS1 layer 3 protocol used for circuit-mode basic call control. It corrects the underlying protocol tables for CONNECT and SETUP messages in ETS 300 403-1, which is based on ITU-T Recommendation Q.931 (1993), for people implementing, testing, or buying ISDN signalling equipment.

What does SIST ETS 300 403-1:1999/C1:1999 specify?

SIST ETS 300 403-1:1999/C1:1999 specifies corrections to the protocol specification for the signalling network layer used by DSS1 basic call control. In practice, it updates how two key call-control messages - CONNECT and SETUP - are listed and constrained in the underlying standard.

The corrigendum is limited to the table corrections named in the scope and foreword. Its text is organized into a foreword, an amendments section, and a history note.

The amendments point back to the corrected entries in:

• table 3-4/Q.931 for CONNECT
• table 3-15/Q.931 for SETUP

What are the key requirements of SIST ETS 300 403-1:1999/C1:1999?

SIST ETS 300 403-1:1999/C1:1999 mainly changes the information-element tables for CONNECT and SETUP, so the practical job is to send the right fields, in the right direction, with the right limits.

• CONNECT message structure - Table 3-4/Q.931 keeps Protocol discriminator, Call reference, and Message type as mandatory, and lists optional elements such as Bearer capability, Channel identification, Progress indicator, Display, Date/time, Signal, Low layer compatibility, and High layer compatibility. For implementers, this is the checklist for what a CONNECT message may carry.

• SETUP message structure - Table 3-15/Q.931 keeps Protocol discriminator, Call reference, Message type, and Bearer capability as mandatory, then defines when other elements can appear, including Sending complete, Repeat indicator, Channel identification, Network specific facilities, Display, Keypad facility, Signal, Calling party number, Called party subaddress, Called party number, Transit network selection, Low layer compatibility, and High layer compatibility. In practice, this table controls call establishment encoding.

• Low layer compatibility length correction - The foreword states that the maximum length of the Low layer compatibility information element is corrected to 18 octets. That matters for software and test tools that validate field length.

• Repeated bearer capability and compatibility elements - The notes allow repeated Bearer capability and Low layer compatibility or High layer compatibility elements when negotiation procedures apply. This affects how endpoints express priorities during call setup.

• Bearer capability selection and negotiation - The notes link Bearer capability and High layer compatibility to subclause 5.11 and subclause 5.12, while low layer compatibility negotiation is linked to annex J. This tells implementers when capability negotiation procedures are active.

• Routing and service-related information - Transit network selection is tied to annex C, Network specific facilities to annex E, and keypad-related supplementary-service use is noted for the Keypad facility element. In practice, these fields support routing choices and service signalling during call setup.

What terms does SIST ETS 300 403-1:1999/C1:1999 define?

• Integrated Services Digital Network (ISDN) - The digital network technology named in the title, used here as the environment for DSS1 signalling.
• Digital Subscriber Signalling System No. one (DSS1) - The signalling system used on the subscriber side for these ISDN call-control procedures.
• CONNECT - A call-control message whose information elements are listed in table 3-4/Q.931.
• SETUP - A call-control message used to start call establishment, with its information elements listed in table 3-15/Q.931.
• Bearer capability - The information element that carries the bearer-service capability associated with the call.
• Low layer compatibility - The information element used to pass low-layer compatibility information during call establishment or negotiation.
• High layer compatibility - The information element used to pass higher-layer compatibility information when those procedures apply.
• Repeat indicator - The information element that marks repeated capability-related entries and helps preserve priority order.

Who uses SIST ETS 300 403-1:1999/C1:1999?

Telecom engineers, switch and terminal designers, and protocol test labs use this corrigendum when they need the corrected DSS1 layer 3 table entries for CONNECT and SETUP. Quality teams and buyers use it when checking that ISDN equipment handles call setup fields, compatibility negotiation, and message lengths consistently. Network operators use it when verifying interworking and service-related signalling behavior.

What changed in SIST ETS 300 403-1:1999/C1:1999 from the previous edition?

SIST ETS 300 403-1:1999/C1:1999 is a corrigendum to ETS 300 403-1 (1995). It corrects an editorial mistake in the modification of tables 3-4/Q.931 and 3-15/Q.931, and it states that the maximum length of the Low layer compatibility information element is 18 octets, as given in table 4-3 and clause ZA.2, item 23.

Which standards are used with SIST ETS 300 403-1:1999/C1:1999?

• ETS 300 403-1 (1995) - This is the underlying European Telecommunication Standard that the corrigendum modifies.
• ITU-T Recommendation Q.931 (1993), modified - This is the protocol basis named in the title for the circuit-mode basic call control specification.

What does the SIST ETS 300 403-1:1999/C1:1999 document contain?

The document contains a short foreword, an amendments section, and a history note. The amendments present corrected versions of table 3-4/Q.931 and table 3-15/Q.931, showing information elements, directions, types, and lengths for CONNECT and SETUP. The notes under the tables explain when each element is used, including bearer capability selection, low and high layer compatibility, transit network selection, and network-specific facilities. The document also records the publication history of the first edition and this corrigendum.

SLOVENSKI STANDARD
01-maj-1999
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VLJQDOL]DFLMHãW'666LJQDOL]DFLMVNDRPUHåQDSODVW]DNUPLOMHQMHYRGRYQHJD
RVQRYQHJDNOLFDGHO6SHFLILNDFLMDSURWRNRODSUHREOLNRYDQRSULSRURþLOR,787
4
Integrated Services Digital Network (ISDN); Digital Subscriber Signalling System No. one
(DSS1) protocol; Signalling network layer for circuit-mode basic call control; Part 1:
Protocol specification [ITU-T Recommendation Q.931 (1993), modified]
Ta slovenski standard je istoveten z: ETS 300 403-1/C1 Edition 1
ICS:
33.080 Digitalno omrežje z Integrated Services Digital
integriranimi storitvami Network (ISDN)
(ISDN)
35.100.30 Omrežni sloj Network layer
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

CORRIGENDUM ETS 300 403-1
June 1996
Source: ETSI TC-SPS Reference: DE/SPS-05034-1-C1
ICS: 33.080, 35.100.30
ISDN, DSS1, layer 3
Key words:
This corrigendum modifies
the European Telecommunication Standard ETS 300 403-1 (1995)
Integrated Services Digital Network (ISDN);
Digital Subscriber Signalling System No. one (DSS1) protocol;
Signalling network layer for circuit-mode basic call control;
Part 1: Protocol specification
[ITU-T Recommendation Q.931 (1993), modified]
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Copyright Notification: No part may be reproduced except as authorized by written permission. The copyright and the
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© European Telecommunications Standards Institute 1996. All rights reserved.

Page 2
ETS 300 403-1: November 1995/Corrigendum: June 1996
Whilst every care has been taken in the preparation and publication of this document, errors in content,
typographical or otherwise, may occur. If you have comments concerning its accuracy, please write to
"ETSI Editing and Committee Support Dept." at the address shown on the title page.

Page 3
ETS 300 403-1: November 1995/Corrigendum: June 1996
Foreword
This corrigendum corrects an editorial mistake in the modification of tables 3-4/Q.931 and 3-15/Q.931 in
ETS 300 403-1 (1995).
The maximum length of the Low layer compatibility information element is corrected to 18 octets as stated
in table 4-3 and clause ZA.2, item 23).
Amendments
The modifications of table 3-4/Q.931 and table 3-15/Q.931 shall read as follows (the correction is
highlighted using shading):
Page 13, table 3-4/Q.931
Modify table 3-4/Q.931 as follows:
Message type: CONNECT
Significance: global
Direction: both
Information element Reference Direction Type Length
Protocol discriminator 4.2 both M 1
Call reference 4.3 both M 2 - 3
Message type 4.4 both M 1
Bearer capability 4.5 both O (note 1) 4 - 12
Channel identification 4.5 both (note 2) O (note 3) 2 - 34
u → n
Progress indicator 4.5 both O (note 4) 2 - 4
Display 4.5 n → u O (note 5) 2 - 82
(note 6)
Date/time 4.6 O (note 7) 2 - 7
n → u
Signal 4.5 O (note 8) 2 - 3
n → u
Low layer compatibility 4.5 both O (note 9) 2 - 18
High layer compatibility 4.5 both O (note 10) 2 - 5
NOTE 1: The Bearer capability information element is included when the procedures of subclause
5.11 for bearer capability selection apply.
NOTE 2:    Included in the network-to-user direction for support of the procedures in annex D.
NOTE 3: Mandatory if this message is the first message in response to SETUP, unless the user
accepts the B-channel indicated in the SETUP message.
NOTE 4: Included in the event of interworking or in connection with the provision of in-band
information/patterns.
NOTE 5: Included if the network provides information that can be presented to the user.
NOTE 6: The minimum length is 2 octets; the maximum length is network dependent and is either 34
or 82 octets.
NOTE 7: As a network option, may be included to provide date and time information to the calling user
for all calls or for calls involving specific telecommunication services.
NOTE 8:    Included if the network optionally provides information describing tones.
NOTE 9: Included in the user-to-network direction when the answering user wants to return low layer
compatibility information to the calling user. Included in the network-to-user direction if the
user awarded the call included a Low layer compatibility information element in the
CONNECT message. Optionally included for low layer compatibility negotiation, but some
networks may not transport this information element to the calling user (see annex J).
NOTE 10: The High layer compatibility information element is included when the procedures of
subclause 5.12 for high layer compatibility selection apply.

Page 4
ETS 300 403-1: November 1995/Corrigendum: June 1996
Pages 22 and 23, table 3-15/Q.931
Modify table 3-15/Q.931 as follows:
Message type: SETUP
Significance: global
Direction: both
Information element Reference Direction Type Length
Protocol discriminator 4.2 both M 1
Call reference 4.3 both M 2 - 3
Message type 4.4 both M 1
Sending complete 4.5 both O (note 1) 1
Repeat indicator 4.5 both O (note 2) 1
Bearer capability 4.5 both M (note 3) 4 - 12
(note 20)
Channel identification 4.5 both O (note 4) 2 - 34
Progress indicator 4.5 both O (note 5) 2 - 4
Network specific facilities 4.5 both O (note 6) 2 - *
Display 4.5 n → u
...