SIST-TS ETSI/TS 101 482-1 V1.1.1:2005

Integrated Services Digital Network (ISDN); DSS1 based protocol for call control & resource management over a TCP/IP network; Part 1: Protocol specification

This document describes the DSS1 based protocol for call control & resource management over a TCP/IP network to a Network Access Server (NAS). This protocol applies at the N reference point in the ETSI EP Tiphon architecture between the Media Gateway Controller (MGC) and the Media Gateway (MG). The NAS is the MG in the Tiphon architecture. The Network Access Server terminates the SCN connections and packetizes data for forwarding to IP networks.

Digitalno omrežje z integriranimi storitvami (ISDN) – Protokol za krmiljenje klica in upravljanje virov prek omrežja TCP/IP, ki temelji na DSS1 – 1. del: Specifikacija protokola

General Information

• Status: Published
• Publication Date: 31-Dec-2004
• ICS: 33.080 - Integrated Services Digital Network (ISDN)
• Technical Committee: SPN - Services and Protocols for Networks
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 01-Jan-2005
• Due Date: 01-Jan-2005
• Completion Date: 01-Jan-2005
• Ref Project: ETSI TS 101 482-1 V1.1.1 (1999-12) - Integrated Services Digital Network (ISDN); DSS1 based protocol for call control & resource management over a TCP/IP network; Part 1: Protocol specification

Standards Content (Sample)

SLOVENSKI STANDARD
SIST-TS ETSI/TS 101 482-1 V1.1.1:2005
01-januar-2005
Digitalno omrežje z integriranimi storitvami (ISDN) – Protokol za krmiljenje klica in
upravljanje virov prek omrežja TCP/IP, ki temelji na DSS1 – 1. del: Specifikacija
protokola
Integrated Services Digital Network (ISDN); DSS1 based protocol for call control &
resource management over a TCP/IP network; Part 1: Protocol specification
Ta slovenski standard je istoveten z: TS 101 482-1 Version 1.1.1
ICS:
33.080 Digitalno omrežje z Integrated Services Digital
integriranimi storitvami Network (ISDN)
(ISDN)
SIST-TS ETSI/TS 101 482-1 V1.1.1:2005 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST-TS ETSI/TS 101 482-1 V1.1.1:2005

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SIST-TS ETSI/TS 101 482-1 V1.1.1:2005
ETSI TS 101 482-1 V1.1.1 (1999-12)
Technical Specification
Integrated Services Digital Network (ISDN);
DSS1 based protocol for call control & resource
management over a TCP/IP network;
Part 1: Protocol specification

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SIST-TS ETSI/TS 101 482-1 V1.1.1:2005
2 ETSI TS 101 482-1 V1.1.1 (1999-12)
Reference
DTS/SPAN-05208-1
Keywords
IP, ISDN, DSS1, protocol
ETSI
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Copyright Notification
No part may be reproduced except as authorized by written permission.
The copyright and the foregoing restriction extend to reproduction in all media.
© European Telecommunications Standards Institute 1999.
All rights reserved.
ETSI

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SIST-TS ETSI/TS 101 482-1 V1.1.1:2005
3 ETSI TS 101 482-1 V1.1.1 (1999-12)
Contents
Intellectual Property Rights.5
Foreword .5
1 Scope.6
2 References.6
3 Definitions.7
4 Abbreviations .7
5 Description .7
6 Operational Requirements.8
7 Coding requirements .8
7.1 Messages .8
7.1.1 LOGON .8
7.1.2 LOGON ACKNOWLEDGE.9
7.1.3 RESOURCE REGISTRATION.9
7.1.4 RESOURCE REGISTRATION ACKNOWLEDGE.10
7.1.5 SERVICE.10
7.1.6 SERVICE ACKNOWLEDGE.10
7.2 Information elements.11
7.2.1 Channel status.11
7.2.2 Continuity Indicator.12
7.2.3 Resource .12
8 State Definitions.13
8.1. States at the NAS side of the interface .13
8.2. States at the MGC side of the interface .13
9 Call related signalling procedures.14
10 Resource related signalling procedures.14
10.1 Logon procedure .14
10.1.1 Normal procedure .14
10.1.2 Exceptional procedure .14
10.2 Resource registration.14
10.2.1 Normal procedure .14
10.2.2 Exceptional procedure .15
10.3 Service procedure.15
10.3.1 Normal procedure .15
10.3.2 Exceptional procedure .15
11 Parameter values (timers).16
12 Dynamic description (SDL diagrams).16
Annex A (normative): Media Gateway (MGC) interworking with SS7 network.21
A.1 Interworking from ISUP to DSS1 based protocol for call control and resource management over a
TCP/IP network.21
A.1.1 IAM message received with continuity check required .21
A.1.2 Continuity Check Request received.22
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4 ETSI TS 101 482-1 V1.1.1 (1999-12)
A.2 Interworking from DSS1 based protocol for call control and resource management over a TCP/IP
network to ISUP.22
Annex B (informative): Message sequence charts, typical examples .23
B.1 Continuity test successful (initiated with IAM).23
B.2 Unsuccessful continuity test (initiated with IAM).24
B.3 Continuity test successful (initiated with CCR).24
B.4 Unsuccessful continuity test (initiated with CCR).25
History.26
ETSI

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SIST-TS ETSI/TS 101 482-1 V1.1.1:2005
5 ETSI TS 101 482-1 V1.1.1 (1999-12)
Intellectual Property Rights
IPRs essential or potentially essential to the present document may have been declared to ETSI. The information
pertaining to these essential IPRs, if any, is publicly available for ETSI members and non-members, and can be found
in SR 000 314: "Intellectual Property Rights (IPRs); Essential, or potentially Essential, IPRs notified to ETSI in respect
of ETSI standards", which is available from the ETSI Secretariat. Latest updates are available on the ETSI Web server
(http://www.etsi.org/ipr).
Pursuant to the ETSI IPR Policy, no investigation, including IPR searches, has been carried out by ETSI. No guarantee
can be given as to the existence of other IPRs not referenced in SR 000 314 (or the updates on the ETSI Web server)
which are, or may be, or may become, essential to the present document.
Foreword
This Technical Specification (TS) has been produced by ETSI Technical Committee Services and Protocols for
Advanced Networks (SPAN).
The present document is part 1 of a multi-part TS covering Integrated Services Digital Network (ISDN); DSS1 based
protocol for call control & resource management over a TCP/IP network, as identified below:
Part 1: "Protocol specification";
Part 2: "PICS proforma";
Part 3: "Test Suite Structure and test Purposes (TSS&TP) specification for the user";
Part 4: "Abstract Test Suite (ATS) and partial Protocol Implementation eXtra Information for Testing (PIXIT)
proforma specification for the user";
Part 5: "Test Suite Structure and test Purposes (TSS&TP) specification for the network";
Part 6: "Abstract test Suite (ATS) and partial Protocol Implementation eXtra Information for Testing (PIXIT)
proforma specification for the network".
ETSI

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6 ETSI TS 101 482-1 V1.1.1 (1999-12)
1 Scope
The present document describes the DSS1 based protocol for call control and resource management over an Internet
Protocol (IP) based network to a Network Access Server (NAS). The protocol runs between a NAS and a Media
Gateway Controller (MGC) as defined by the N reference point in ETSI TIPHON TS 101 313 [1]. The scope of
application of the protocol excludes Voice over IP (VoIP), Fax over IP (FoIP) or anything else which is not strictly
internet dial-up access. The protocol uses infull (DSS1) with additional messages and information elements.
The transport mechanism for the IP based messages is outside the scope of the present document.
The protocol uses all standard DSS1 procedures with the consideration that the network entity is the Media Gateway
Controller (MGC) and the user entity is the NAS. The present document only specifies those procedures that have been
added to fit the architectural requirements.
The present document applies to narrowband bearer services in the Switched Circuit Network (SCN) used for modem
and ISDN calls to NASs.
NOTE: Dial out access is for further study.
2 References
The following documents contain provisions which, through reference in this text, constitute provisions of the present
document.
• References are either specific (identified by date of publication, edition number, version number, etc.) or
non-specific.
• For a specific reference, subsequent revisions do not apply.
• For a non-specific reference, the latest version applies.
• A non-specific reference to an ETS shall also be taken to refer to later versions published as an EN with the same
number.
[1] TS 101 313: "Telecommunications and Internet Protocol Harmonization Over Networks
(TIPHON); Network architecture and reference configurations; Phase II: Scenario 1 + Scenario 2".
[2] ITU-T Recommendation I.112 (03/93): "Vocabulary of terms for ISDNs".
[3] EN 300 403-1: "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]".
[4] ITU-T Recommendation Q.699: "Interworking between ISDN access and non-ISDN access over
ISDN User Part of Signalling System No. 7".
[5] EN 300 899-1: "Integrated Services Digital Network (ISDN); Signalling System No.7;
Interworking between ISDN User Part (ISUP) version 2 and Digital Subscriber Signalling System
No. one (DSS1); Part 1: Protocol specification [ITU-T Recommendation Q.699, modified]".
[6] ITU-T Recommendation Q.931: "SDN user-network interface layer 3 specification for basic call
control".
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7 ETSI TS 101 482-1 V1.1.1 (1999-12)
3 Definitions
For the purposes of the present document, the following terms and definitions apply:
Integrated Services Digital Network (ISDN): see ITU-T Recommendation I.112 [2], subclause 2.3, definition 308.
Media Gateway Controller: see TS 101 313 [1], subclause 3.1.
Network: the DSS1 protocol entity at the network side of the user-network interface.
Network Access Server: the device that acts as a Media Gateway (see TS 101 313 [1], subclause 3.1).
4 Abbreviations
For the purpose of the present document, the following abbreviations apply:
DSS1 Digital Subscribe Signalling System Number 1
ISDN Integrated Services Digital Network
IP Internet Protocol
MGC Media Gateway Controller
NAS Network Access Server
SCN Switched Circuit Network
SGW Signalling Gateway
SS7 Signalling System No. 7
5 Description
This protocol is used at the N reference point defered in TS 101 313 [1] as shown in figure 1. The TIPHON architecture
is functional rather than physical. However the NAS is a physical media gateway. The MGC could be a function of a
combined Signalling Gateway (SGW)/MGC Controller or it could be a standalone device.
E.b
J
Media GW Signalling
Controller GW
N
Media GW
E.a
NOTE 1: The E.a reference point is between the gateway (Media Gateway) and the SCN. The E.b reference point
is between the gateway (Signalling Gateway) and the SCN. The J reference point is between the SGW
and the MGC.
NOTE 2: The transport mechanism for the IP based messages is outside the scope of the present document. This
transport mechanism shall be reliable and shall support redundant paths.
NOTE 3: Dial out access is for further study.
Figure 1: TS 101 313 [1] functional architecture
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8 ETSI TS 101 482-1 V1.1.1 (1999-12)
6 Operational Requirements
The primary requirement is call control as per EN 300 403-1 [3] over an IP based network. Additionally, the MGC
needs to be made aware of the state of the resources in the NAS. The continuity test procedure for incoming calls shall
be supported.
7 Coding requirements
7.1 Messages
This subclause defines the messages the MGC and NAS use for call processing, maintenance and management. These
messages are based on the "DSS1" message set, and in most cases are simply specific codings of standard DSS1
messages. However, because the requirements of the MGC based systems differ from those of ISDN access for which
the DSS1 message set was developed, some messages described in this subclause are extensions of standard DSS1
messages. Table 1 lists the extended Control Protocol message set. The Protocol Discriminator used for new all
messagesis0 x4A.
Table 1: Control Protocol message set
Message Value
LOGON 0x10
LOGON ACKNOWLEDGE 0x11
RESOURCE REGISTRATION 0x38
RESOURCE REGISTRATION 0x39
ACKNOWLEDGE
SERVICE 0x3A
SERVICE ACKNOWLEDGE 0x3B
The LOGON and LOGON ACKNOWLEDGE messages use a global call reference. The RESOURCE
REGISTRATION, RESOURCE REGISTRATION ACKNOWLEDGE, SERVICE and SERVICE ACKNOWLEDGE
messages use a unique call reference.
NOTE: Even though some messages use a unique call reference, these messages are not call related. These
messages have to be uniquely identified and the call reference is the best mechanism in DSS1 to guarantee
the uniqueness of the message.
7.1.1 LOGON
This message is sent by the NAS to the MGC to indicate a cold restart or a link level reset. See table 2.
Table 2: LOGON message content
Message type: LOGON
Significance: local
Direction: NAS to MGC
Reference Direction Type Length
Information element
(subclause)
4.2/Q.931 [6] M1
Protocol discriminator NAS → MGC
Call reference 4.3/Q.931 [6] M (note) 2-*
NAS → MGC
Message type 4.4/Q.931 [6] NAS → MGC M1
NOTE: This message is sent with the global call reference defined in 4.3/Q.931 [6].
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7.1.2 LOGON ACKNOWLEDGE
This message is sent to acknowledge the receipt of the LOGON message and to indicate that the requested logon is
completed. See table 3.
Table 3: LOGON ACKNOWLEDGE message content
Message type: LOGON ACKNOWLEDGE
Significance: local
Direction: MGC to NAS
Reference Direction Type Length
Information element
(subclause)
4.2/Q.931 [6] M1
Protocol discriminator MGC → NAS
Call reference 4.3/Q.931 [6] M (note) 2-*
MGC → NAS
Message type 4.4/Q.931 [6] MGC → NAS M1
NOTE: This message is sent with the global call reference defined in 4.3/Q.931 [6].
7.1.3 RESOURCE REGISTRATION
This message is sent by the NAS to register associated trunk (E1 interfaces) and user port resources. See table 4.
Table 4: RESOURCE REGISTRATION message content
Message type: RESOURCE REGISTRATION
Significance: local
Direction: NAS to MGC
Information element Reference Direction Type Length
(subclause)
Protocol discriminator 4.2/Q.931 [6] NAS → MGCM1
4.3/Q.931 [6] M (note 1) 2-*
Call reference NAS → MGC
Message type 4.4/Q.931 [6] M1
NAS → MGC
Resource 7.2.1 NAS → MGC M (note 2) 3-5
4.5.13/Q.931 [6 O (note 3) 2-*
Channel identification NAS → MGC
]
4.5.7/Q.931 [6] O (note 4) 3
Call state NAS → MGC
NOTE 1: This message is sent with a unique call reference defined in 4.3/Q.931 [6].
NOTE 2: When an entire E1 trunk interface or a host resource is specified, the status (octet 3) may be coded as
available or unavailable. When one or more channels of an E1 trunk interface are specified, the status shall
be coded as available if the Call state information element is included and the status shall be coded as
unavailable if the Call state information element is not included.
NOTE 3: Included when necessary to identify a trunk resource. May be repeated to identify multiple trunk interfaces.
NOTE 4: Included when one (or more) channels of a trunk resource are identified. Omitted in other cases. Applies for
all channels identified in the Channel identification information element.
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7.1.4 RESOURCE REGISTRATION ACKNOWLEDGE
This message is sent by the MGC to acknowledge the registration of associated trunk (E1 interfaces) and user port
resources. See table 5.
Table 5: RESOURCE REGISTRATION ACKNOWLEDGE message content
Message type: RESOURCE REGISTRATION ACKNOWLEDGE
Significance: local
Direction: MGC to NAS
Reference Direction Type Length
Information element
(subclause)
4.2/Q.931 [6] M1
Protocol discriminator MGC → NAS
Call reference 4.3/Q.931 [6] M (note) 2-*
MGC → NAS
Message type 4.4/Q.931 [6] MGC → NASM1
NOTE: This message is sent with a unique call reference defined in 4.3/Q.931 [6].
7.1.5 SERVICE
This message is sent by the MGC to request a change of status for one or more channels and by the NAS to indicate a
change of status for one or more channels. See table 6.
Table 6: SERVICE message content
Message type: SERVICE
Significance: local
Direction: both
Reference Direction Type Length
Information element
(subclause)
4.2/Q.931 [6] both M 1
Protocol discriminator
Call reference 4.3/Q.931 [6] both M (note 1) 2-*
4.4/Q.931 [6] both M 1
Message type
Channel identification 4.5.13/Q.931 [6 both M (note 2) 2-*
]
Channel status 7.2.2 both M 3
NOTE 1: This message is sent with a unique call reference defined in 4.3/Q.931 [6].
NOTE 2: May be repeated to change/indicate status of channel(s) of multiple interfaces.
7.1.6 SERVICE ACKNOWLEDGE
This message is sent by the MGC or the NAS to acknowledge the change of status of one or more channels. See table 7.
Table 7: SERVICE ACKNOWLEDGE message content
Message type: SERVICE ACKNOWLEDGE
Significance: local
Direction: both
Reference Direction Type Length
Information element
(subclause)
4.2/Q.931 [6] both M 1
Protocol discriminator
Call reference 4.3/Q.931 [6] both M (note 1) 2-*
4.4/Q.931 [6] both M 1
Message type
Channel identification 4.5.13/Q.931 [6 both M (note 2) 2-*
]
Channel status 7.2.2 both M 3
Continuity indicator 7.2.3 NAS → MGC O (note 3) 3
NOTE 1: This message is sent with a unique call reference defined in 4.3/Q.931 [6].
NOTE 2: May be repeated to indicate status of channel(s) of multiple interfaces.
NOTE 3: Included when necessary to indicate the result of a loopback request.
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7.2 Information elements
This subclause describes the information elements that are the building blocks of the MGC Control Protocol messages.
These information elements are based on the EN 300 403-1 [3] and, in most cases, are simply specific codings of
standard Q.931 [6] information elements. The information elements used in the Control Protocol are specified in table 8.
All information elements which are not described in the present document are described in EN 300 403-1 [3] document.
Table 8: MGC Control Protocol information elements
Information Element IE Value
Channel Status 0x11
Continuity Indicator 0x19
Resource 0x1A
7.2.1 Channel status
The purpose of the Channel status information element is to change the operational state of a specified trunk channel or
of a related resource.
The Channel status information element is coded as shown in Figure 2 and Table 9. The maximum length of this
information element is 3 octets.
Bits
87 65 43 21 Octets
00 01 00 01 1
Length 2
1 Device Status 3
Figure 2: Channel status information element
Table 9: Channel status information element
Device (octet 3)
bits
765
0 0 0 Trunk interface resource
0 0 1 Host resource
0 1 0 DSP resource
Status (octet 3)
bits
4321
0000 In service
0001 Loopback
0010 Outofservice (immediateterminationofcall(s)on thedevice)
0011 Testing
0100 Graceful shutdown(wait forcalltermination)
0101 ReserveDSP
1000 ReservationDSPfailure
All other values are reserved.
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7.2.2 Continuity Indicator
The purpose of the Continuity indicator information element is to indicate the outcome of an outgoing continuity test.
The Continuity indicator information element is coded as shown in Figure 3 and Table 10. The maximum length of this
information element is 3 octets.
Bits
87 65 43 21 Octets
00 01 10 01 1
Length 2
10 Indicator 3
Spare
Figure 3: Continuity indicator information element
Table 10: Continuity indicator information element
Indicator (octet 3)
bit
1
0 Failed
1 Successful
7.2.3 Resource
The Resource information element is used to identify a local interface resource and its status between the NAS and the
MGC.
The Resource information element is coded as shown in Figure 4 and Table 11. The maximum length of this information
element is 5 octets.
Bits
87 65 43 21 Octets
00 01 10 10 1
Length 2
1 Category Resource type Status 3
0/1 Capacity 3a
(Note 1)
NOTE: This octet may be present only if octet 3 indicates a host resource as indicated in Table 11.
Figure 4: Resource information element
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Table 11: Resource information element
Category (octet 3)
bits
76
0 0 Trunk interface resource
1 0 Host resource
Resource type (octet 3)
bits
543
0 0 1 E1 trunk interface
1 0 0 HDLC controller port
1 0 1 Modem port
NOTE 1: When the resource type HDLC controller port or modem port is used, the coding of the category shall be
coded as host resource. When the resource type E1 trunk interface is used, the coding of the category shall
be coded as trunk interface resource.
NOTE 2: An HDLC controller port is used for ISDN calls, and a modem port for analogue calls.
Status (octet 3)
bits
21
0 0 Available
0 1 Unavailable
Capacity (octet 3a)
Shall be included if the category specifies a host resource. Octet 3a shall be either one or two octets depending on the
size of the capacity value and shall indicate the number of modem ports. If it is one octet the most significant bit (MSB)
is 1 and the remaining seven digits contain the capacity value (0-127). If it is two octets the MSB of the first octet is 0
and the MSB of the second octet is 1, the combined 14 bits of these two octets contain the capacity value (0-16383), the
7 bits from the first octet is on the higher order side and the 7 bits from the second octet is on the lower side of the 14
bits.
8 State Definitions
The standard Q.931 [6] state machine shall be used for call control. For the logon, resource registration and service
procedures, a new state machine is used, based on the new states defined below. The Q.931 [6] state machine and these
new state machine shall work in parallel.
8.1. States at the NAS side of the interface
Null (NAS-U0): no controls are performed.
Logon initiated (NAS-U1): the NAS informs the MGC it had a cold restart or a link level reset.
Resource registration (NAS-U2): the NAS had a cold restart or a link level reset and will register its resources to the
MGC.
Resource registration initiated (NAS-U3): the NAS registers resources to the MGC.
Service initiated (NAS-U4): the NAS has detected an operational status change and informs the MGC of that change.
8.2. States at the MGC side of the interface
Null (MGC-N0): no controls are performed.
Logon initiated (MGC-N1): the MGC is informed of a NAS cold restart or link level reset.
Resource registration initiated (MGC-N2): the MGC is informed of resources to register.
Service initiated (MGC-N3): the MGC requests a change of status of a channel.
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9 Call related signalling procedures
EN 300 403-1 [3] describes all call related signalling procedures, subclauses 10.2 and 10.3 describe the resource
registration and service procedures. Q.931 [6] exception procedures apply to all call-related exceptions.
10 Resource related signalling procedures
10.1 Logon procedure
10.1.1 Normal procedure
When a NAS has a cold restart or a link level reset, it shall send a LOGON message to the MGC and start timer Tlogon.
On receipt of a LOGON message, the MGC shall send a LOGON ACKNOWLEDGE message to the originating entity
and shall take the appropriate actions to take into account the restart or reset indication of the originating entity. When
the originating NAS receives the LOGON ACKNOWLEDGE message, timer Tlogon shall be stopped. On expiry of
timer Tlogon, the NAS shall resend the LOGON message to the MGC.
NOTE: When a NAS has a system (re)initialization it shall be considered has a cold restart. In that case all the
calls are lost. After a cold restart, the NAS shall register all the resources. A link level reset shall be
considered as a data link reset as defined in 5.8.8.1/Q.931 [6].
The NAS shall register all its resources after a cold restart or a link level reset. It shall use the resource registration
procedure described in subclause 10.2 to register its res
...