Lower Layer Q and X Protocol

INTERNATIONAL TELECOMMUNICATION UNION
ITU-T
TELECOMMUNICATION
STANDARDIZATION SECTOR
OF ITU
Q.811
(02/2004)
SERIES Q: SWITCHING AND SIGNALLING

Q3 interface
Lower layer protocol profiles for the Q and X

interfaces
ITU-T Recommendation Q.811
ITU-T Q-SERIES RECOMMENDATIONS

SWITCHING AND SIGNALLING
SIGNALLING IN THE INTERNATIONAL MANUAL SERVICE
INTERNATIONAL AUTOMATIC AND SEMI-AUTOMATIC WORKING
FUNCTIONS AND INFORMATION FLOWS FOR SERVICES IN THE ISDN
CLAUSES APPLICABLE TO ITU-T STANDARD SYSTEMS
SPECIFICATIONS OF SIGNALLING SYSTEMS No. 4, 5, 6, R1 AND R2
DIGITAL EXCHANGES
INTERWORKING OF SIGNALLING SYSTEMS
SPECIFICATIONS OF SIGNALLING SYSTEM No. 7
Q3 INTERFACE
DIGITAL SUBSCRIBER SIGNALLING SYSTEM No. 1
PUBLIC LAND MOBILE NETWORK
INTERWORKING WITH SATELLITE MOBILE SYSTEMS
INTELLIGENT NETWORK
SIGNALLING REQUIREMENTS AND PROTOCOLS FOR IMT-2000
SPECIFICATIONS OF SIGNALLING RELATED TO BEARER INDEPENDENT CALL
CONTROL (BICC)
BROADBAND ISDN
For further details, please refer to the list of ITU-T Recommendations.
Q.1Q.3
Q.4Q.59
Q.60Q.99
Q.100Q.119
Q.120Q.499
Q.500Q.599
Q.600Q.699
Q.700Q.799
Q.800Q.849
Q.850Q.999
Q.1000Q.1099
Q.1100Q.1199
Q.1200Q.1699
Q.1700Q.1799
Q.1900Q.1999
Q.2000Q.2999

Lower layer protocol profiles for the Q and X interfaces
Summary
This Recommendation provides the lower layer protocol profiles for the Q and X interfaces as
defined in ITU-T Rec. M.3010. It also provides a method for interworking.
Source
ITU-T Recommendation Q.811 was approved on 13 February 2004 by ITU-T Study Group 4
(2001-2004) under the ITU-T Recommendation A.8 procedure.
ITU-T Rec. Q.811 (02/2004)
FOREWORD
The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of
telecommunications. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of
ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations
on them with a view to standardizing telecommunications on a worldwide basis.
The World Telecommunication Standardization Assembly (WTSA), which meets every four years,
establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these
topics.
The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1.
In some areas of information technology which fall within ITU-T's purview, the necessary standards are
prepared on a collaborative basis with ISO and IEC.
NOTE
In this Recommendation, the expression "Administration" is used for conciseness to indicate both a
telecommunication administration and a recognized operating agency.
Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain
mandatory provisions (to ensure e.g. interoperability or applicability) and compliance with the
Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some
other obligatory language such as "must" and the negative equivalents are used to express requirements. The
use of such words does not suggest that compliance with the Recommendation is required of any party.
INTELLECTUAL PROPERTY RIGHTS

ITU draws attention to the possibility that the practice or implementation of this Recommendation may
involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence,
validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others
outside of the Recommendation development process.
As of the date of approval of this Recommendation, ITU had received notice of intellectual property,
protected by patents, which may be required to implement this Recommendation. However, implementors are
cautioned that this may not represent the latest information and are therefore strongly urged to consult the
TSB patent database.
ITU 2004
All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the
prior written permission of ITU.
ii
ITU-T Rec. Q.811 (02/2004)
CONTENTS
Page
1
Scope ............................................................................................................................
References ....................................................................................................................
Abbreviations ...............................................................................................................
DCN model...................................................................................................................
4.1
CONS1 ...........................................................................................................
4.2
CONS2, CONS3, CLNS3 ..............................................................................
4.3
CLNS1............................................................................................................
4.4
CLNS2............................................................................................................
4.5
CONS6 ...........................................................................................................
4.6
IP ....................................................................................................................
8
8
8
8
8
9
9
Lower layer protocol profiles: Overview .....................................................................
Requirements for network layer/transport layer interface............................................
Defined protocol profiles..............................................................................................

7.1
Connectionless-mode protocol profiles..........................................................
7.2
Connection-mode protocol profiles................................................................
7.3
CL-LAN profile (CLNS1)..............................................................................
7.4
CL-WAN profile (CLNS2) ............................................................................
7.5
ISDN protocol profile (CLNS3).....................................................................
7.6
IP protocol profiles.........................................................................................
7.7
Ethernet profile...............................................................................................
7.8
X.25/LAPB protocol profile (CONS1) ..........................................................
7.9
Packet mode bearer service on the D-channel (CONS2) ...............................
7.10
Packet mode bearer service on the B-channel (CONS3) ...............................
7.11
Signalling System No. 7 networks (CONS5).................................................
7.12
Connection oriented LAN (CONS6)..............................................................
7.13
Conformance requirements ............................................................................
9
9
10
11
16
21
22
23
23
26
27
27
27
28
Network layer service...................................................................................................

8.1
Network layer profiles....................................................................................
8.2
Internetworking ..............................................................................................
29
29
30
Annex A Protocol stack for information transfer over ISDN transparent B-channel..........
A.1
Introduction ....................................................................................................
A.2
Network profile CONS4.................................................................................
32
32
32
Annex B Examples of NSAP structures for CLNP ..............................................................
35
Appendix I Changes to ISP conformance requirements.......................................................
36
ITU-T Rec. Q.811 (02/2004)
iii

Lower layer protocol profiles for the Q and X interfaces
1
Scope
This Recommendation is a part of a series of Recommendations dealing with the transfer of

information for the management of telecommunications systems. This Recommendation defines the
requirements of lower layer protocol profiles for the Q and X interfaces1, as defined in ITU-T
Rec. M.3010 [1] and in other M.3000-series Recommendations. The companion ITU-T
Rec. Q.812 [2] defines the requirements of the upper layer protocol profiles for the Q and
X interfaces. The Q and X interfaces will support bidirectional data transfer for the management of
telecommunications systems.
The need for security functionality is recognized, but is not fully addressed in this Recommendation
and is for further study. Users may need to use mechanisms outside this Recommendation in order
to address their specific security needs. Security mechanisms chosen may depend on the network
configuration being used.
If new operational requirements are developed that imply distinctions to be made here between the
Q and X interfaces, future versions of this Recommendation, or possibly new Recommendations,
will reflect these differences.
This Recommendation defines:
the layer service profiles for the defined supported networks;
the layer protocol profiles for the defined supported networks;
the requirements at the layer 3/layer 4 service boundary for any network used to support the
Q and X interfaces of the TMN.
This Recommendation conforms to the "T" profiles in framework for International Standardized
Profiles (ISP) as specified in ISO/IEC TR 10000-1 [63] and ISO/IEC TR 10000-2 [64]. Profiles in
this Recommendation align with equivalent ISPs (as specified in conformance clause) if available.
It is the intention to align those profiles for which there are no equivalent ISPs at present to ISPs as
they are standardized by ISO SGFS.
2
References
The following ITU-T Recommendations and other references contain provisions which, through
reference in this text, constitute provisions of this Recommendation. At the time of publication, the
editions indicated were valid. All Recommendations and other references are subject to revision;
users of this Recommendation are therefore encouraged to investigate the possibility of applying the
most recent edition of the Recommendations and other references listed below. A list of the
currently valid ITU-T Recommendations is regularly published. The reference to a document within
this Recommendation does not give it, as a stand-alone document, the status of a Recommendation.
[1]
ITU-T Recommendation M.3010 (2000), Principles for a telecommunications management

network.
[2]
ITU-T Recommendation Q.812 (2004), Upper layer protocol profiles for the Q and
X interfaces.
[3]
ITU-T Recommendation X.200 (1994) | ISO/IEC 7498-1:1994, Information technology

Open Systems Interconnection Basic Reference Model: The basic model.
____________________
1
This protocol is also applicable to the Qx interface when a full seven layer stack is required.
ITU-T Rec. Q.811 (02/2004)
[4]
ISO/IEC 8802-3:2000, Information technology Telecommunications and information

exchange between systems Local and metropolitan area networks Specific requirements
Part 3: Carrier sense multiple access with collision detection (CSMA/CD) access method
and physical layer specifications.
[5]

exchange between systems Local and metropolitan area networks Specific requirements
Part 2: Logical link control.
[6]
ITU-T Recommendation X.213 (2001) | ISO/IEC 8348:2002, Information technology

Open Systems Interconnection Network service definition.
[7]

Protocol for providing the connectionless-mode network service: Protocol specification.
[8]
ISO/IEC 8473-2:1996, Information technology Protocol for providing the

connectionless-mode network service Part 2: Provision of the underlying service by an
ISO/IEC 8802 subnetwork.
[9]

Protocol for providing the connectionless-mode Network service: Provision of the
underlying service by an X.25 subnetwork.
[10]

underlying service by a subnetwork that provides the OSI data link service.
[11]

underlying service by ISDN circuit-switched B-channels.
[12]
ITU-T Recommendation X.25 (1996), Interface between Data Terminal Equipment (DTE)
and Data Circuit-terminating Equipment (DCE) for terminals operating in the packet mode
and connected to public data networks by dedicated circuit.
[13]
ISO/IEC 7776:1995, Information technology Telecommunications and information

exchange between systems High-level data link control procedures Description of the
X.25 LAPB-compatible DTE data link procedures.
[14]

exchange between systems Protocol combinations to provide and support the OSI
Network Service Part 3: Provision and support of connectionless-mode Network Service.
[15]
ISO 8648:1988, Information processing systems Open Systems Interconnection Internal

organization of the Network Layer.
[16]
ISO/IEC 8208:2000, Information technology Data communications X.25 Packet Layer

Protocol for Data Terminal Equipment.
[17]
ITU-T Recommendation X.223 (1993) | ISO/IEC 8878:1992, Use of X.25 to provide the
OSI connection-mode Network service for ITU-T applications.
[18]
ITU-T Recommendation E.164 (1997), The international public telecommunication

numbering plan.
[19]
ITU-T Recommendation X.121 (2000), International numbering plan for public data
networks.
[20]
ITU-T Recommendation X.244 (1988), Procedure for the exchange of protocol

identification during virtual call establishment on packet switched public data networks.
ITU-T Rec. Q.811 (02/2004)
[21]
ISO/IEC TR 9577:1999, Information technology Protocol identification in the network

layer.
[22]
ITU-T Recommendation I.430 (1995), Basic user-network interface Layer 1

specification.
[23]
ITU-T Recommendation I.431 (1993), Primary rate user-network interface Layer 1

specification.
[24]
ITU-T Recommendation Q.921 (1997), ISDN user-network interface Data link layer
specification.
[25]
ITU-T Recommendation X.31 (1995), Support of packet mode terminal equipment by an

ISDN.
[26]

exchange between systems Use of X.25 to provide the OSI Connection-mode Network
Service.
[27]
ITU-T Recommendation Q.702 (1988), Signalling data link.
[28]
ITU-T Recommendation Q.703 (1996), Signalling link.
[29]
ITU-T Recommendation Q.704 (1996), Signalling network functions and messages.
[30]
ITU-T Recommendation Q.711 (2001), Functional description of the signalling connection

control part.
[31]
ITU-T Recommendation Q.712 (1996), Definition and function of signalling connection

control part messages.
[32]
ITU-T Recommendation Q.713 (2001), Signalling connection control part formats and
codes.
[33]
ITU-T Recommendation Q.714 (2001), Signalling connection control part procedures.
[34]
ITU-T Recommendation Q.716 (1993), Signalling System No. 7 Signalling Connection

Control Part (SCCP) performance.
[35]
ITU-T Recommendation V.24 (2000), List of definitions for interchange circuits between
Data Terminal Equipment (DTE) and Data Circuit-terminating Equipment (DCE).
[36]
ITU-T Recommendation V.28 (1993), Electrical characteristics for unbalanced doublecurrent interchange circuits.
[37]
ITU-T Recommendation V.36 (1988), Modems for synchronous data transmission using
60-108 kHz group band circuits.
[38]
ISO 2110:1989, Information technology Data communication 25-pole DTE/DCE

interface connector and contact number assignments.
[39]

exchange between systems 34-pole DTE/DCE interface connector mateability dimensions
and contact number assignments.
[40]

Provision of the OSI connection-mode network service by packet-mode terminal equipment
connected to an Integrated Services Digital Network (ISDN).
[41]

Open Systems Interconnection Transport service definition.
ITU-T Rec. Q.811 (02/2004)
[42]

Open Systems Interconnection Protocol for providing the connection-mode transport
service.
[43]
ISO/IEC 8881:1989, Information processing systems Data communications Use of the

X.25 packet level protocol in local area networks.
[44]
ISO/IEC ISP 10608:1992, Information technology International Standardized Profile

TAnnnn Connection-mode Transport Service over Connectionless-mode Network Service.
Part 1: General overview and subnetwork-independent requirements.
Part 2: TA51 profile including subnetwork-dependent requirements for CSMA/CD Local
Area Networks (LANs).
Part 5: TA1111/TA1121 profiles including subnetwork-dependent requirements for X.25
packet-switched data networks using virtual calls.
[45]
ISO/IEC ISP 10609:1992, Information technology International Standardized Profiles

TB, TC, TD and TE Connection-mode Transport Service over connection-mode Network
Service.
Part 1: Subnetwork-type independent requirements for Group TB.
Part 5: Definition of Profiles TB1111/TB1121.
Part 9: Subnetwork-type dependent requirements for Network Layer, Data Link Layer and
Physical Layer concerning permanent access to a packet switched data network using
virtual calls.
[46]
ISO 9542:1988, Information processing systems Telecommunications and information

exchange between systems End system to Intermediate system routeing exchange protocol
for use in conjunction with the Protocol for providing the connectionless-mode network
service.
[47]

exchange between systems Intermediate system to Intermediate system intra-domain
routeing information exchange protocol for use in conjunction with the protocol for
providing the connectionless-mode network service.
[48]

exchange between systems Protocol for exchange of inter-domain routeing information
among intermediate systems to support forwarding of ISO 8473 PDUs.
[49]
ITU-T Recommendation X.75 (1996), Packet-switched signalling system between public

networks providing data transmission services.
[50]
ITU-T Recommendation I.550/X.325 (1996), General arrangements for interworking

between Packet-Switched Public Data Networks (PSPDNs) and Integrated Services Digital
Networks (ISDNs) for the provision of data transmission services.
[51]
ITU-T Recommendation X.326 (1988), General arrangements for interworking between

Packet-Switched Public Data Networks (PSPDNs) and Common Channel Signalling
Network (CCSN).
[52]
ITU-T Recommendation X.327 (1993), General arrangements for interworking between

Packet-Switched Public Data Networks (PSPDNs) and private data networks for the
provision of data transmission services.
[53]

Open Systems Interconnection Physical service definition.
ITU-T Rec. Q.811 (02/2004)
[54]

exchange between systems Open Systems Interconnection Transport protocol
identification mechanism.
[55]

exchange between systems Provision of the connection-mode Network internal layer
service by intermediate systems using ISO/IEC 8208, the X.25 Packet Layer Protocol.
[56]

exchange between systems Definition of the relaying functions of a Network layer
intermediate system.
[57]
ITU-T Recommendation Q.708 (1999), Assignment procedures for international signalling

point codes.
[58]

Open Systems Interconnection Network layer security protocol.
[59]

exchange between systems Protocol mappings for the OSI Data Link service.
[60]

Open Systems Interconnection Data link service definition.
[61]
ITU-T Recommendation Q.931 (1998), ISDN user-network interface layer 3 specification

for basic call control.
[62]
ITU-T Recommendation I.320 (1993), ISDN protocol reference model.
[63]
ISO/IEC TR 10000-1:1998, Information technology Framework and taxonomy of

International Standardized Profiles Part 1: General principles and documentation
framework.
[64]
ISO/IEC TR 10000-2:1998, Information technology Framework and taxonomy of

International Standardized Profiles Part 2: Principles and Taxonomy for OSI Profiles.
[65]

[66]

[67]
ITU-T Recommendation V.10/X.26 (1993), Electrical characteristics for unbalanced

double-current interchange circuits operating at data signalling rates nominally up to
100 kbit/s.
[68]
ITU-T Recommendation V.11/X.27 (1996), Electrical characteristics for balanced doublecurrent interchange circuits operating at data signalling rates up to 10 Mbit/s.
[69]
IETF RFC 2401 (1998), Security Architecture for the Internet Protocol.
[70]
IETF RFC 2460 (1998), Internet Protocol, Version 6 (IPv6) Specification.
[71]
IETF RFC 2402 (1998), IP Authentication Header.
[72]
IETF RFC 2406 (1998), IP Encapsulating Security Payload (ESP).
[73]
ITU-T Recommendation G.7712/Y.1703 (2003), Architecture and specification of data

communication network.
[74]
IETF RFC 1122 (1989), Requirements for Internet Hosts Communication Layers.
[75]
ITU-T Recommendation M.3030 (2002), Telecommunications Markup Language (tML)

framework.
ITU-T Rec. Q.811 (02/2004)
[76]
IETF RFC 894 (1984), A Standard for the Transmission of IP Datagrams over Ethernet
Networks.
[77]
IETF RFC 826 (1982), An Ethernet Address Resolution Protocol.
Abbreviations
This Recommendation uses the following abbreviations:

AFI
Authority and Format Identifier
AH
Authentication Header
BIS
Border Intermediate System
CD
Collision Detection
CLNP
Connectionless-mode Network layer Protocol
CLNS
Connectionless-mode Network layer Service
Conf
Confirm
CONP
Connection-mode Network layer Protocol
CONS
Connection-mode Network layer Service
COTS
Connection-mode Transport Service
CSMA
Carrier Sense Multiple Access
CUG
Closed User Group
DCE
Data Communication Equipment
DCF
Data Communication Function
DCN
Data Communication Network
DIS
Draft International Standard
DLC
Data Link Connection
DLS
Data Link Service
DSP
Domain Specific Part
DTE
Data Terminal Equipment
ES
End System
ESP
Encapsulation Security Payload
HDLC
High-level Data Link Control
IDI
Initial Domain Identifier
IDP
Initial Domain Part
IDRP
Inter Domain Routing (or Routeing) Protocol
IETF
Internet Engineering Task Force
Ind
Indication
IP
Internetworking Protocol
IPSec
Security Infrastructure for Internet Protocol
IS
Intermediate System
ITU-T Rec. Q.811 (02/2004)
ISDN
Integrated Services Digital Network
ISO
International Organization for Standardization
ISP
International Standardized Profile
IW
Interworking Unit
LLC
Logical Link Control
LME
Layer Management Entity
LSP
Link State Protocol Data Unit
MAC
Media Access Control
MD
Mediation Device
MTP
Message Transfer Part
NDM
Normal Disconnect Mode
NE
Network Element
NLR
Network Layer Relay
NPDU
Network Protocol Data Unit
NS
Network Service
NSAP
Network Service Access Point
OS
Operations System
OSI
Open Systems Interconnection
PDU
Protocol Data Unit
Ph
Physical
PhC
Physical Connection
PhS
Physical Service
PICS
Protocol Implementation Conformance Statement
PVC
Permanent Virtual Circuit
QA
Q Adapter
QoS
Quality of Service
Req
Request
Res
Result
RFC
Request For Comments
SAP
Service Advertising Protocol
SAPI
Security Application Program Interfaces
SCCP
Signalling Connection Control Part
SCF
Service Control Function
SGFS
Special Group on Functional Standards
SLP
Service Location Profile
SNDCF
Subnetwork Dependent Convergence Function
SNP
Sequence Numbers Protocol Data Unit

ITU-T Rec. Q.811 (02/2004)
SNPA
Subnetwork Point of Attachment
SVC2
Switched Virtual Circuit
TCP
Transmission Control Protocol
TMN
Telecommunications Management Network
VC
Virtual Circuit
DCN model
Table 20 identifies the lower layer protocols for interfaces requiring interworking as well as the
interworking method.
The following briefly describes the individual lower layer protocol profiles:
CONS1: A connection-mode packet interface using ITU-T Rec. X.25.
CONS2: A connection-mode packet interface using ITU-T Rec. X.31 on an ISDN

D-channel.
CONS3: A connection-mode packet interface using ITU-T Rec. X.31 on an ISDN

B-channel.
CONS6: A connection-mode packet interface X.25 over LAN.
CLNS1: A connectionless-mode interface using ISO/IEC 8802-2 type LANs using

CSMA/CD.
CLNS2: A connectionless-mode interface using ISO CLNP over a connection-mode X.25

protocol.
CLNS3: A connectionless-mode interface using ISO CLNP over ISDN B-channels

(see 7.5).
IP: Internet Protocol for use in the TMN (see 7.6).

This clause provides typical examples of the application of these profiles at the Q and X interfaces.
Other fields of application are not precluded by this Recommendation. The differences between the
following profiles will be further discussed in ITU-T Rec. Q.812.
4.1
CONS1
CONS1 is applied to the reference point between PSPDN and OS/MD/QA/NE which communicates
with OS accommodated in PSPDN and ISDN.
4.2
CONS2, CONS3, CLNS3
CONS2 and CONS3 are applied to the reference point between ISDN and OS/MD/QA/NE which
communicates with OS accommodated in PSPDN or ISDN.
4.3
CLNS1
CLNS1 is applied to the reference point between LAN and OS/MD/QA/NE which communicates
with OS accommodated in LAN or PSPDN.
4.4
CLNS2
CLNS2 is applied to the reference point between PSPDN and OS/MD/QA/NE which communicates
with OS accommodated in LAN.
____________________
2
Switched Virtual Circuit corresponds to "Virtual call" used in ITU-T Rec. X.25.
ITU-T Rec. Q.811 (02/2004)
4.5
CONS6
CONS6 is applied to OS/MD/QA/NE which is connected to the reference point on connectionmode oriented LAN.
4.6
IP
IP is applied to OS/MD/QA/NE and LANs which communicate with OS using IP accommodated in

the LAN.
5
Lower layer protocol profiles: Overview
The communication services and protocol referred to in this Recommendation are in accordance
with the Open Systems Interconnection (OSI) reference model [3].
The protocols for the different layers are based on ITU-T Recommendations and/or
ISO/IEC Standards.
The protocol profiles can be applied to DCN, as defined by ITU-T Rec. M.3010 [1].
Any Administration may use any existing network that meets the requirements at the layer 3/layer 4
service boundary.
For the Protocol Profiles defined in this Recommendation, interoperability mechanisms are to be
defined as a part of this Recommendation. For networks not using these profiles, it is the
responsibility of the individual Administration to solve any interoperability problems that may
exist.
6
Requirements for network layer/transport layer interface
See clause 8 and its subclauses.

7
Defined protocol profiles
7.1
Connectionless-mode protocol profiles
7.1.1
LAN (see Figure 2)
NOTE Figure 3/Q.811 (1993), Protocol profile for network management, has been deleted.
ITU-T Rec. Q.811 (02/2004)
7.1.2
WAN, LAN (see Figure 2)
7.1.3
ISDN (see Figure 2)
7.2
Connection-mode protocol profiles
7.2.1
X.25/LAPB [see Figure 1 (1), (3), (2), (5)]

ITU-T Rec. Q.812 upper layers
ITU-T Rec. X.612 | ISO/IEC 9574

C-Plane
X.25 PLC
ISO/IEC 8208
(ISO/IEC 8878)
U-Plane
Q.931
procedures used
as described in
Rec. X.31
ISO/IEC 8878
ISO/IEC 8208
DTE/DCE
operations
C-Plane
U-Plane
Q.931
procedures used
as described in
Rec. X.31
ISO/IEC 8878
ISO/IEC 8208
ISO/IEC 8208
DTE/DCE
operations
ISO/IEC 8881
ITU-T Rec. X.212
X.25 LAPB
ISO/IEC 7776
SLP
Rec. Q.921
(SAPI = 0)
Rec. Q.921
(SAPI = 16)
Rec. Q.921
(SAPI = 0)
ISO/IEC 7776
SLP-DTE/DCE
operation
ISO/IEC
8802-2 LLC
(Type 2)
ISO/IEC
8802-3 MAC
CSMA/CD
Q.921 Layer 2 multiplexer

Recs X.27, X.21
X.21 bis
V.11/X.27/V.36
V.28/V.24
(1) CONS1
D-channel
D-channel
B-channel
I.430 (BA) or I.431 (PRA)
I.430 (BA) or I.431 (PRA)
(2) CONS2
(3) CONS3
NOTE Further study is needed for the function of SCCP at the boundary of Network layer and Transport Layer.
Figure 1/Q.811 Connection (CONS) profiles
10
ITU-T Rec. Q.811 (02/2004)
Not specified
(5) CONS6
ITU-T Rec. Q.812 upper layers
ITU-T Rec. X.233 | ISO/IEC 8473-1 CLNP

(ITU-T Rec X.213 | ISO/IEC 8348 CLNS)
ITU-T Rec. X.625 | ISO/IEC 8473-5
ITU-T Rec. X.622 |

ISO/IEC 8473-3
ISO/IEC 8473-2
X.25 PLP
(ISO/IEC 8208)
ISO/IEC 8802-2 LLC

(Type 1)
ISO/IEC 8802-3 MAC
CSMA/CD
IP
ITU-T
Rec. Q.931
X.25 LAPB
ISO/IEC 7776
SLP
ITU-T Rec. X.622 |

ISO/IEC 8473-3
ITU-T Rec. X.623 |

ISO/IEC 8473-4
Ethernet
ISO/IEC 8208
ISO/IEC 11575
Rec.
Q.921
Not specified
ISO/IEC 7776
Not specified
Not specified
Recs X.27, X.21

X.21 bis
V.11/X.27/V.36
V.28/V.24
D-channel or B-channel
I.430 (BA) or I.431 (PRA)
(4) CLNS1
(7) CLNS2
(8) CLNS3
IP
Figure 2/Q.811 Connectionless (CLNS) profiles

7.3
CL-LAN profile (CLNS1)
7.3.1
Physical layer profile
7.3.1.1
Service profile
The service definition for the Physical layer shall comply with that specified in clause 6 of
ISO/IEC 8802-3 [4].
All of the primitives defined and listed in Table 1 are mandatory.
Table 1/Q.811 Primitives of the Physical layer
Primitive
PLS-DATA-request
PLS-DATA-indication
PLS-CARRIER-indication
PLS-SIGNAL-indication
7.3.1.2
Protocol profile
The possible bit rate will be 1 Mbit/s, 10 Mbit/s, or higher.

7.3.1.3
Physical interface
Administrations will select the appropriate physical medium, e.g., coaxial cable, screened pairs,
optical fibre according to technological and operational requirements.
ITU-T Rec. Q.811 (02/2004)
11
7.3.2
Data link layer profile
The Data Link layer provides the unacknowledged connectionless-mode service. The access method
employed is Carrier Sense Multiple Access with Collision Detection (CSMA/CD).
7.3.2.1
Media Access Control (MAC) profile
The services and protocol of the CSMA/CD access method shall comply with those specified in
ISO/IEC 8802-3 [4].
The address length used at the MAC sub-layer shall be 48 bits.
7.3.2.2
Logical Link Control (LLC) profile
The definition of the unacknowledged connectionless-mode LLC service shall comply with that
specified in ISO/IEC 8802-2 [5]. All of the primitives defined for "Type 1" operation shall be
supported.
The protocol used to provide the unacknowledged connectionless-mode LLC service shall be as
specified in ISO/IEC 8802-2 [5]. All of the commands and responses defined for "Type 1"
operation shall be supported.
7.3.3
Network layer profile
7.3.3.1
Services profile
The definition of the connectionless-mode Network service shall comply with that specified in
ITU-T Rec. X.213 | ISO/IEC 8348 [6]. Address formats supported shall also conform to ITU-T
Rec. X.213 | ISO/IEC 8348 [6].
The Network layer shall provide the N-UNITDATA service as specified in ITU-T Rec. X.213 |
ISO/IEC 8348 [6].
7.3.3.2
Protocol profile
The protocol shall be in accordance with the full protocol subset of category "Type 1" functions, as
specified in ITU-T Rec. X.233 | ISO/IEC 8473-1 [7].
7.3.3.3
Network layer attributes
Characteristics of the connectionless-mode Network layer service and the connectionless-mode

Network layer protocol shall be as shown in Table 2.
Table 2/Q.811 Connectionless-mode network layer service/protocol parameters
a
Destination and Source Addresses used by this Protocol shall conform to one of the Network Service
Access Points (NSAPs) address formats specified in ITU-T Rec. X.213 | ISO/IEC 8348 [6].
The Destination and Source Addresses are of variable length. The Destination and Source Address
fields shall be as Network Protocol Address Information using the preferred Binary Encoding
specified in ITU-T Rec. X.213 | ISO/IEC 8348 [6].
The setting of Error Reporting Flag (E/R) shall be a local matter (Note).
Partial Source Routing shall NOT be supported. A defect exists with this option which can cause
PDUs to loop in the network until their lifetime expires.
Inactive Subset Implementations shall not transmit PDUs encoded using the
ITU-T Rec. X.233 | ISO/IEC 8473-1 inactive subset. Received PDUs encoded with the inactive
subset shall be discarded.
Segmentation The non-segmentation subset shall NOT be used. However, implementations shall
be capable of receiving and correctly processing PDUs which do not contain the segmentation part.
12
ITU-T Rec. Q.811 (02/2004)
Table 2/Q.811 Connectionless-mode network layer service/protocol parameters

f
Segmentation Permitted Flag Implementations shall NOT generate data PDUs without a
segmentation part, i.e., the Segmentation Permitted Flag (SP) shall be set to 1 and the segmentation
part shall be included.
Lifetime Control The lifetime parameter shall be used as specified in 6.4 of

ITU-T Rec. X.233 | ISO/IEC 8473-1. This parameter shall have an initial value of at least three times
the network span (number of network entities) or three times the maximum transmission delay (in
units of 500 milliseconds), whichever is greater. The default initial PDU lifetime control shall be
10 seconds.
Quality of Service (QoS) The use of the QoS Maintenance Parameter shall be dependent upon the
QoS requirements of the subnetworks supporting an instance of OS-NE communications. When QoS
is used, it shall comply with the specifications in 6.16, 6.19, and 7.5.6 of
ITU-T Rec. X.233 | ISO/IEC 8473-1. It is recommended that Quality of Service Maintenance be
supported and that the globally unique QoS format be used which includes the Congestion
Experienced (CE) bit used by the Congestion Notification option.
Reassembly timer The reassembly timer must be less than the largest value of all the lifetime
parameters contained in all derived PDUs. The default Reassembly timer shall be 12 seconds.
Congestion Notification The use of Congestion Notification option is recommended. The default
value should be 0 when originating PDUs. For NEs and MDs that act as ISs, it is recommended that
Congestion Notification be supported so that end systems can take appropriate action to avoid and
recover from network congestion.
NOTE The use of error Reporting and setting the E/R flag to 1 may lead to excessive network traffic.
7.3.3.4
ES-IS routing
TMN entities that use the CLNP shall support the ISO 9542 [46] for ES-IS routing exchange. The
ES-IS protocol is provisioned as either an End System (ES) role, or an Intermediate System (IS)
role. The Data Communication Function (DCF) within the TMN entities must therefore be
provisioned in accordance with their role(s).
The ES-IS protocol subsets: Configuration Information (CI) and Redirection Information (RI) shall
be supported in accordance with the type of subnetwork, as shown in Table 3. Tables 4 and 5 give
the timer values and options for the ES and IS roles, respectively.
Table 3/Q.811 ES-IS subsets
Type of subnetwork
Protocol subset
Point-to-point (Note 1)
Broadcast (Note 2)
General topology (Note 3)
NS
Configuration
Information (CI)
Redirection
Information (RI)
M
Mandatory support
NS
Not supported
NS
NOTE 1 An example of a point-to-point subnetwork is the SDH DCC.

NOTE 2 An example of a broadcast subnetwork is a CSMA/CD LAN.
NOTE 3 An example of a general topology subnetwork is an X.25 packet network.
ITU-T Rec. Q.811 (02/2004)
13
Table 4/Q.811 ES-IS protocol timers and options for the end system role
Value/Range/Option
Default
Timers:
Configuration Timer
Holding Timer
1-200 s
1-500 s
(50 s)
(105 s)
Functions:
PDU Header Checksum Generation
Configuration Notification (Notes 1, 3)
Refresh Redirect (Note 2)
Address and SNPA Mask Processing (Note 2)
Optional, use, non-use

Use, non-use
(Non-use)
(Use)
(Use)
(Use)
Supplemental Functions per Annex B of ISO/IEC 9542:

Optimization (Note 4)
Rapid Configuration

(Use)
NOTE 1 Applies to Configuration Information (CI) subset.

NOTE 2 Applies to the Redirection Information (RI) subset.
NOTE 3 See recommendation in 6.7 of ISO/IEC 9542.
NOTE 4 See B.4 of ISO/IEC 9542.
Table 5/Q.811 ES-IS protocol timers and options for the intermediate system role
Value/Range/Option
Default
Timers:
Configuration Timer
Holding Timer
1-200 s
1-500 s
(10 s)
(25 s)
Functions:
PDU Header Checksum Generation
Configuration Notification (Notes 1, 3)
Address and SNPA Mask Processing (Note 2)

(Non-use)
(Use)
(Use)
Supplemental Functions per Annex B of ISO/IEC 9542:

Rapid Configuration
NOTE 1 Applies to Configuration Information (CI) subset.

NOTE 2 Applies to the Redirection Information (RI) subset.
NOTE 3 See recommendation in 6.7 of ISO/IEC 9542.
7.3.3.5
IS-IS intra-domain routing
ISO/IEC 10589 [47], the IS-IS intra-domain protocol for use with the CLNP, shall be used by TMN
entities that operate as Intermediate Systems for the purpose of routing connectionless NPDUs.
Each IS within the TMN must be capable of routing within their area and therefore must provide the
functionality of a Level 1 IS. Additionally, an IS may be provisioned as a Level 2 IS, which
provides the capability of routing from one area to another and therefore contains routing
information about ISs outside a specific area. The functionality of a Level 2 IS is not needed in each
IS within the TMN. An example of a Level 2 IS might be a gateway NE. Details for use of
ISO/IEC 10589 for TMN applications are found in Tables 6 through 11.
14
ITU-T Rec. Q.811 (02/2004)
Table 6/Q.811 IS-IS general protocol functions

Protocol function
Authentication
Delay Metric
Expense Metric
Error Metric
Value/Range/Option
Default

(Non-use)
(Non-use)
(Non-use)
(Non-use)
Table 7/Q.811 IS-IS general processes

Function
Decision Process:
Equal Cost Paths
Down Stream Paths
Value/Range/Option
Default

(Non-use)
(Non-use)
Table 8/Q.811 IS-IS Level 1 specific functions

Function
Protocol Summary:
Maximum Area Addresses (Note)
Area IS Count (Note)
Value/Range/Option
0-12
1-512
Default
(3)
(512)
NOTE These numbers are preliminary and are subject for study and possible change.
Table 9/Q.811 IS-IS Level 2 specific functions

Function
Protocol Summary:
L2 IS (Note 2)
L2 IS Count (Note 1)
IS Count (Note 3)
Reachable Address Prefix
External Metrics (Note 4)
Partition Repair
Decision Process:
L2 Attached Flag (Note 3)
L2 Partition DIS Election (Note 5)
L2 Partition Area Addresses
Computation (Note 5)
L2 DIS Partition Repair (Note 5)
Forward/Receive Process
L2 NPDU Encapsulation (Note 5)
L2 NPDU Decapsulation (Note 5)
Value/Range/Option
Default

1-512
1-512
Use, non-use
(Non-use)
(256)
(512)
(Non-use)
(Non-use)
(Non-use)

Use, non-use
Use, non-use
(Non-use)
(Non-use)
(Non-use)
Use, non-use
(Non-use)
Use, non-use
Use, non-use
(Non-use)
(Non-use)
NOTE 1 These numbers are preliminary and are subject for study and possible change.
NOTE 2 These functions only apply when the IS is a level 2 IS.
NOTE 3 This function is mandatory when the Level 2 functions are supported.
NOTE 4 This function is mandatory when Reachable Address Prefixes are supported.
NOTE 5 This function is mandatory when the Partition repair function is supported.
ITU-T Rec. Q.811 (02/2004)
15
Table 10/Q.811 Level 2 subnetwork dependent functions

Function
ISO/IEC 8208 Dynamic Assignment:
Call Establishment Metric Increment
Reverse Path Cache
Value/Range/Option
Default
(Non-use)
(Non-use)
Table 11/Q.811 IS-IS parameter values and timers

Type
Value/Range/Option
Default
Parameter Values:
Default Metric
Max Path Metric
Minimum LSP Receive Buffer Size
IS-IS Holding Multiplier
Max Path Splits
Max Virtual Adjacencies
1-63
1023
1492 octets
10
1-32
0-32
(20)
(2)
(2)
Timers:
Max Age
Zero Age Lifetime
IS-IS Hello Timer
Complete SNP Interval Timer
Max LSP Generation Interval Timer
Min LSP Generation Interval Timer
Min LSP Transmission Interval Timer
Partial SNP Interval Timer
Poll ES Hello Rate Timer
Waiting Timer
Reserve Timer
1200 s
60 s
0-3 s
0-10 s
0-15 min
0-30 s
0-5 s
0-2 s
0-50 s
0-60 s
2-6 s
(3 s)
(10 s)
(15 min)
(30 s)
(5 s)
(2 s)
(50 s)
(60 s)
(6 s)
7.3.3.6
IS-IS inter domain routing
Border Intermediate Systems (BISs), using the ISO/IEC 10747 Inter Domain Routing Protocol
(IDRP) [48], may be employed for routing ITU-T Rec. X.233 | ISO/IEC 8473-1 CLNP PDUs
between Administrative Domains as defined in ITU-T Rec. X.213 | ISO/IEC 8348.
7.4
CL-WAN profile (CLNS2)
7.4.1
7.4.1.1
Service profile
The Physical layer service shall be as defined in ITU-T Rec. X.211 | ISO/IEC 10022 [53].
7.4.1.2
Protocol profile
The protocol of the Physical layer of Protocol Profile CLNS2 shall comply with the following
specifications:
X.21 interface in accordance with 1.1/X.25 [12];
X.21 bis interface in accordance with 1.2/X.25;
V-series interface in accordance with 1.3/X.25.
16
ITU-T Rec. Q.811 (02/2004)
7.4.1.2.1 Bit rate

The supported bit rates are: 1200, 2400, 4800, 9600, 19 200, and 64 000 bit/s. The bit rates
48 000 bit/s and 56 000 bit/s may be used for an interim period (see Note 1 to Table 18).
7.4.1.3
Connector
Table 12 lists the connectors to be used in accessing the X.21 and X.21 bis interfaces. Tables 13,
14, and 15 list respectively the pin descriptions of ISO 2110 [38], ISO/IEC 2593 [39],
ISO 4902 [65] and ISO 4903 [66].
Table 12/Q.811 X.21/X.21 bis connectors
Data signalling rate
X.21 bis
X.21
2 400 bit/s
ISO 2110
ISO 4903
4 800 bit/s
ISO 2110
ISO 4903
9 600 bit/s
ISO 2110
ISO 4903
19 200 bit/s
ISO 2110
ISO 4903
48 000 bit/s
ISO/IEC 2593
ISO/IEC 4902
ISO 4903
56 000 bit/s
ISO/IEC 2593
ISO/IEC 2593
64 000 bit/s
ISO 4902
ISO 4903
Table 13/Q.811 ISO 2110 [38] pin description (see Note 6)

Pin
V.24 [35]
circuit
Description
Notes
1
7
101
102
Protective ground (Shield)

Signal Ground
1
2
2
3
103
104
Transmitted Data
Received Data
2
2
4
5
6
20
22
8
105
106
107
108.2
125
109
Request to Send
Clear to Send
Data Set Ready (DCE Ready)
Data terminal Ready (DTE Ready)
Ring Indicator
Received Line Signal Detector
2
2
2
3
3
2
24
15
113
114
Transmitter Signal Element Timing (DTE to DCE)

Transmitter Signal Element Timing (DCE to DTE)
4
5
NOTE 1 Equipment: removable strap to frame ground or other equivalent grounding arrangement.
Cable: connected to shield.
NOTE 2 Basic interchange circuits, all systems.
NOTE 3 Additional interchange circuits required for switched service.
NOTE 4 Circuit 113 is not used in OS-MD/NE interfaces.
NOTE 5 Additional interchange circuits required for synchronous channel.
NOTE 6 Duplex, interface type D.
NOTE 7 Circuits are grouped by function: ground, data, control, and timing.
NOTE 8 For further information see ITU-T Recs V.24 [35], V.28 [36] and ISO 2110 [38].
ITU-T Rec. Q.811 (02/2004)
17
Table 14/Q.811 V.36 [37], ISO/IEC 2593 [39] pin description (see Note 3)
Pin
Circuit
Description
Notes
A
B
101
102
Protective Ground
Signal Ground
P
S
R
T
103
103
104
104
Transmitted Data A-wire

Transmitted Data B-wire
Received Data A-wire
Received Data B-wire
2
2
2
2
C
D
E
F
105
106
107
109
Request to Send
Ready for Sending
Data Set Ready
Data Channel Receive Line Signal Detector
Y
AA
V
X
114
114
115
115
Transmitter Signal Element Timing A (DCE to DTE)

Transmitter Signal Element Timing B (DCE to DTE)
Receiver Signal Element Timing A (DCE to DTE)
Receiver Signal Element Timing B (DCE to DTE)
2
2
2
2
NOTE 2 The electrical characteristics of the interchange circuits 103, 104, 114, and 115 shall be
balanced double-current, conforming to ITU-T Rec. V.36 [37].
All other circuits shall conform to ITU-T Rec. V.28 [36].
NOTE 3 The mode is synchronous at 64 000 bit/s.
Some countries may use 56 000 bit/s for an interim period of time.
NOTE 4 Circuits are grouped by function: ground, data, control and timing.
NOTE 5 For further information, see ITU-T Recs V.36 [37], V.24 [35], V.28 [36] and
ISO/IEC 2593 [39].
Table 15/Q.811 ISO 4903 [66] pin description (see Note 2)

Pin
X.21 circuit
Description
1
8
Protective ground
Signal ground or common return
2
9
4
11
T
T
R
R
Transmit A-wire
Transmit B-wire
Receive A-wire
Receive B-wire
3
10
5
12
C
C
I
I
Control A-wire
Control B-wire
Indication A-wire
Indication B-wire
6
13
S
S
Signal element timing A-wire

Signal element timing B-wire
Notes
1
NOTE 2 Circuits are grouped by functions: ground, data, control and timing.
NOTE 3 For further information: see ITU-T Recs V.10/X.26 [67], V.11/X.27 [68], X.21 and ISO 4903.
18
ITU-T Rec. Q.811 (02/2004)
7.4.2
It is mandatory that the Data Link layer conforms to LAPB as defined in ITU-T Rec. X.25 [12]. In
addition, provision shall be made for connection between Data Terminal Equipment without an
intervening packet switched network. The interface shall conform to ISO/IEC 7776 [13].
7.4.2.1
Service profile
The Data Link layer service shall be as defined in ITU-T Rec. X.212 | ISO/IEC 8886 [60].
7.4.2.2
Protocol profile
7.4.2.2.1 Equipment type during link set-up and reset

When a packet switched network is used to connect systems, they are each designated "Data
Terminal Equipment" (DTE) and the network acts as a "Data Circuit-terminating Equipment"
(DCE). When a dedicated or dial-up link is provided, other means must be used to supply the DCE
role.
At the Physical layer the modems will provide the DCE interface, supplying bit synchronization.
At the link level, the procedures specified in ISO/IEC 7776 [13] shall be followed. A system must
be able to start the set-up or reset of the link (a DCE function in ITU-T Rec. X.25 [12]). In addition,
provision must be made for assignments of the A/B addresses. This mandatory option is to be fieldsettable and stored in non-volatile memory. Equipment which meets this requirement is compatible
with connection to either a DCE or remote DTE.
7.4.2.2.2 Window
Support of modulo 8 is mandatory. The window for unacknowledged frames is to be optional
between 1 and 7 frames and 1 to 127 with modulo 128. The standard default is 7. For efficient
operation over satellite links modulo 128 operation is required, with a default window size of 35.
7.4.2.2.3 User information
The user information is to be arranged in an integral number of octets.
The maximum length of the user information shall be user settable, consistent with the range of
values for the N1 parameter as shown in Table 16. Maximum information field lengths that shall be
supported are 131 and 259 octets with 515, 1027, 2051, and 4099 octets optional. These values
provide for three packet header octets and maximum length of User Data Field of 128, 256, 512,
1024, 2048, and 4096 octets, respectively.
7.4.2.2.4 Other frame parameters
Certain other frame parameters shall be set by the user to be consistent with the bit rate, frame size
and characteristics of the connecting network. A system design should be sufficiently flexible to
accommodate parameter sets for diverse networks, both as order options and later reconfigurations.
The range of parameters is shown in Table 16. These options, like those of the Physical layer, are to
be set at installation, changeable by the user, and non-volatile.
ITU-T Rec. Q.811 (02/2004)
19
Table 16/Q.811 LAPB Protocol Octet aligned Single Link

Procedure (SLP) LAPB data link layer attributes
Parameter
Function
Range
Default
1 to 7 (with Modulo 8)
1 to 127 (with optional Modulo 128)
1 to 127 (Modulo 128 with satellite
operations)
(7)
(7)
(35)
Waiting Acknowledgment
(Retry) timera)
For up to 9600 bit/s
For 56 000 bit/s
2 to 20 seconds
0.2 to 20 seconds
(3)
(3)
T2
Response delay par a)
Not greater than 0.3 seconds
T3
Disconnect Timer
T3 >> T4b)
T4
No activity Timer
4 to 120 seconds
N1
Bits per I-Frame, excluding flags

and zero bit insertion for
transparency c)
1080, 2104 (with Modulo 8)

optional: 4152, 8248, 16440, 32824
(with Modulo 8)d)
1096, 2120 (with Modulo 128)
optional: 4168, 8264, 16456, 32840
(with Modulo 128)d)
I-Frames Window
T1
N2
Retransmission Count
2 to 16
A/B
Address Assignment
Selectable by the user
(20)
(2104)
(2120)
(7)
a)
Further guidelines on the use of T1 and T2 can be found in ITU-T Rec. X.25 [12] and
ISO/IEC 7776 [13]. The Transport layer T1 timer should always be greater than the link layer T1 timer.
b)
The value of timer T3, the disconnect timer, is not critical for successful interworking of OSs and NEs.
Therefore no value is specified.
c)
In some cases, users may need to choose a maximum information field length of 259 octets (N1 = 2104
for Modulo 8 or N1 = 2120 for Modulo 128) with a 128 octets packet data unit in order to accommodate
call request packets containing 128 octets user data fields in addition to the packet header and facility
fields. These values are based on Modulo 8 or Modulo 128 operation at both link and packet layer.
d)
Optional.
The default values shall be part of a vendor's offering. That is, unless otherwise specified by the user,
the default parameters shall be the initial values supplied. They can be subsequently changed by the
user within the specified range.
7.4.3
7.4.3.1

Service profile
The connectionless-mode Network layer service shall be as specified in ITU-T Rec. X.213 |
ISO/IEC 8348.
7.4.3.2
Protocol profiles
The protocols for the Network layer shall be identical to the Network layer protocol of Protocol
Profile CONS1 (see 7.8) with the inclusion of ITU-T Rec. X.233 | ISO/IEC 8473-1 [7] as specified
in clause 4 of ISO/IEC 8880-3 [14], to provide the connectionless-mode Network service over the
connection-mode Network service.
For those instances of communication requiring interworking between a connection-mode service
(CONS) and a connectionless-mode service (CLNS), ITU-T Rec. X.200 | ISO/IEC 7498-1 [3] and
20
ITU-T Rec. Q.811 (02/2004)
ISO 8648 [15] provide an OSI compatible interworking capability. This capability is known as a
Network Layer Relay (NLR) and utilizes the ITU-T Rec. X.233 | ISO/IEC 8473-1 [7] protocol to
provide this service.
7.4.3.3
Network layer attributes
Characteristics of the connectionless-mode Network layer service, and the connectionless-mode

Network layer protocol shall be as shown in Table 2.
7.5
ISDN protocol profile (CLNS3)
7.5.1
ISDN protocol profile for connectionless-mode network service
This clause defines a Protocol Profile for operation of ITU-T Rec. X.224 | ISO/IEC 8073 [42]
Transport layer protocol over ITU-T Rec. X.233 | ISO/IEC 8473-1 [7] CLNP over ISDN circuit
switched B-channels. This profile is based on the Subnetwork Dependent Convergence Function
(SNDCF) defined in ITU-T Rec. X.625 | ISO/IEC 8473-5 [11].
7.5.2
Network layer
7.5.2.1
B-channel
Requirements for the topmost sub-layer (ITU-T Rec. X.233 | ISO/IEC 8473-1) of the Network layer
in the B-channel are identical with those defined in 7.3.3 (and its subclauses) for the CLNS1 and
CLNS2 Protocol Profile cases.
7.5.2.1.1 Subnetwork dependent convergence function
On the B-channel a connection may be provisioned to provide either an OSI Data Link service, or
an X.25 packet service.
7.5.2.1.1.1
B-channel OSI data link service
For B-channels providing the OSI Data Link service defined in ITU-T Rec. X.212 | ISO/IEC
8886 [60], the SNDCF shall be as defined in ITU Rec.X.623 | ISO/IEC 8473-4 [10] and ITU-T
Rec. X.625 | ISO/IEC 8473-5.
7.5.2.1.1.2
B-Channel X.25 packet service
For B-channels providing the X.25 packet service defined in ISO/IEC 8208 [16], the SNDCF shall
be as defined in ITU-T Rec. X.622 | ISO/IEC 8473-3 [9] and ITU-T Rec. X.625 | ISO/IEC 8473-5.
7.5.2.2
D-channel
ITU-T Rec. Q.931 [61] shall be used over the D-channel for the purpose of ISDN connection
establishment.
7.5.3
7.5.3.1
Data link layer

B-channel
ISO/IEC 7776 [13], used in accordance with ITU-T Rec. X.273 | ISO/IEC 11577 [58], shall be used
in the B-channel.
7.5.3.2
D-channel
ITU-T Rec. Q.921 [24] shall be used in the D-channel.

7.5.4
Physical layer
Either ITU-T Rec. I.430 [22] (basic rate) or ITU-T Rec. I.431 [23] (primary rate) shall be used in
the Physical layer.
ITU-T Rec. Q.811 (02/2004)
21
7.6
IP protocol profiles
This clause defines additional protocol profiles for use as TMN lower layer protocols. These
profiles are based on the use of Internet Protocols defined by the Internet Engineering Task Force
(IETF). The way these documents can be referenced in this Recommendation is for further study.
The protocol stack is shown in Figure 3 and uses the following.
The functions to be supported by the DCF within a TMN entity operating as a router shall meet the
requirements specified in 7.1.6/G.7712/Y.1703 [73] sections for Network Layer PDU forwarding
function and 7.1.10/G.7712/Y.1703 for Network Layer Routing Function.
7.6.1
IPv4 profile
For Layer 3 STD0005 "Internet Protocol", September 1981. (Includes RFC 791,
RFC 950, RFC 919, RFC 922, RFC 792, RFC 1112.)
The lower layers are defined in the Ethernet Profile.
7.6.2
Ipv4 with IPSec profile
This profile defines an additional option of this protocol profile for use as TMN lower layer
protocols. This profile is based on the use of Secure Internet Protocols [69] defined by the Internet
Engineering Task Force (IETF). IPSec uses two protocols to provide traffic security
Authentication Header (AH) [71] and Encapsulating Security Payload (ESP) [72]. Each protocol
supports two modes of use: transport mode and tunnel mode.
Support of ESP is mandatory. Support of AH is optional. Both transport mode and tunnel mode
must be supported for each protocol.
Lower layers are defined in the Ethernet Profile.
7.6.3
IPv6 profile
For Layer 3 RFC 2460 "Internet Protocol, Version 6 (IPv6) Specification" [70].
The lower layers are specified in the Ethernet Profile.
Note that it is mandatory to implement IPSec with IPv6.

Upper layers
See ITU-T Rec. Q.812
IPSec
RFC 2401
IPv4
IPv6
IPSec
Ethernet
Figure 3/Q.811 IP profiles
22
ITU-T Rec. Q.811 (02/2004)
7.7
Ethernet profile
When the DCF within the TMN entities supports Ethernet interfaces, the following functions are
required to support Ethernet Physical Layer Termination Function and [Network Layer PDU into
Ethernet Frame] Encapsulation Function.
7.7.1
Ethernet physical termination function
An Ethernet Physical Termination Function terminates the physical Ethernet interface.

One or more of the following rates shall be supported: 1 Mbit/s, 10 Mbit/s, 100 Mbit/s.
7.7.2
[Network Layer PDU into Ethernet Frame] encapsulation function
This function encapsulates and unencapsulates a Network Layer PDU into an 802.3 or Ethernet
(version 2) frame.
It shall encapsulate Network Layer PDUs into 802.3 or Ethernet (version 2) frames according to the
following rules:
It shall encapsulate and unencapsulate CLNP, ISIS, and ESIS PDUs into 802.3.
It shall encapsulate and unencapsulate IP packets into Ethernet (version 2) frames as per
RFC 894 [76].
IP addresses shall be mapped to Ethernet MAC addresses utilizing the Address Resolution
Protocol in RFC 826 [77].
It shall determine the received frame type (802.3 or Ethernet version 2) as per section 2.3.3 in
RFC 1122 [74].
7.8
X.25/LAPB protocol profile (CONS1)
7.8.1
See 7.3.1.
7.8.2
See 7.3.2.
7.8.3
It is mandatory that the packet layer conforms to ITU-T Rec. X.25 [12]. In addition, the packet
layer must provide for connection of data terminal equipments without an intervening packet
network; the required interface for this purpose conforms to ISO/IEC 8208 [16]. In addition, the
provisions of ISO/IEC 8878 [26] and ITU-T Rec. X.223 [17] shall apply.
The attributes which must be supported are summarized in Tables 17 and 18. Note in particular that
these tables show the different attributes needed to support PVCs [the X.25 Permanent Virtual
Circuit (PVC) procedures] and Switched Virtual Circuits (SVCs) (the X.25/SVC procedures).
ITU-T Rec. Q.811 (02/2004)
23
Table 17/Q.811 X.25 [12] packet layer attributes for permanent virtual circuits
Feature
Extended Packet
Sequence Numbering
Packet size (octets)
Window size
Extended Sequence
Number option
Interrupt packets
Range
Default
Modulo 128 optional

(128)
128, 256
512, 1024, 2048, 4096 optional
1-7 (with Modulo 8)
1-127 (with optional Modulo 128)
(2)
(2)
Optional
NOTE 1 The default values shall be part of a vendor's offering. That is, unless otherwise specified by the
user, the default parameters shall be the initial values supplied. They can be subsequently changed by the
NOTE 2 The attributes which are not marked optional are mandatory.
NOTE 3 The ranges specified for negotiated parameters in no way affect the normal negotiation rules
specified in the International Standards.
Table 18/Q.811 X.25 [12] packet layer attributes for switched virtual circuits
Feature
Flow Control Parameter
Packet size (octets)
Range
Default
128, 256
512 optional
128
Window size
1-7 (with Modulo 8)
Extended Sequence
Number Option
1-127 (with optional Modulo 128)
2 (Note 5)
Throughput Class (Note 1)

Bit rate (bit/s)
1200, 2400, 4800, 9600, 19 200 and

64 000
2400
Expedited Data Negotiation

Closed User Group
Closed User Group Selection
Basic Format
2 decimal digits
Bilateral Closed User Group Selection
Optional
Fast Select
Fast Select Acceptance
128 octets
Hunt Group
Optional
Transit Delay Selection and Indication

Calling Address Extension
Called Address Extension
Minimum Throughput Class Negotiation
End-to-End Transit Delay Negotiation
24
ITU-T Rec. Q.811 (02/2004)
Table 18/Q.811 X.25 [12] packet layer attributes for switched virtual circuits
NOTE 1 Some countries may use 56 000 bit/s for an interim period of time. In addition to the codes
specified in the table in 7.3.2.2/X.25, 56 000 bit/s shall be encoded as binary 1 100. 48 000 bit/s is encoded
as binary 1 100 in that table, but when 56 000 bit/s is supported, the code shall stand for 56 000 bit/s.
NOTE 2 The default values shall be part of a vendor's offering. That is, unless otherwise specified by the
user, the default parameters shall be the initial values supplied. They can be subsequently changed by the
NOTE 3 The attributes which are not marked optional are mandatory.
NOTE 4 The ranges specified for negotiated parameters in no way affect the normal negotiation rules
specified in the International Standards.
NOTE 5 The default window size for satellite operations is 35.
7.8.3.1
Numbering plans
To support communications over public networks, public numbering plans may be used on the
packet-switched network between OSs and MDs/QAs/NEs. The 1988 versions of ITU-T
Recs E.164 [18] and X.121 [19] specify public numbering plans. Equipment may be assigned
numbers in accordance with either of these international Recommendations. The escape code values
of "0" and "9" shall be supported as specified in Table 2/X.121. Where a public numbering plan is
not necessary, a private numbering plan may be used.
Network layer addressing as specified in ITU-T Rec. X.213 | ISO/IEC 8348 [6] shall be supported.
Additional numbering plans, such as ITU-T Rec. Q.708 for SS7 [57], may be supported in the
future as the evolution of new subnetwork technologies require.
7.8.3.1.1 CLNP (ITU-T Rec. X.233 | ISO/IEC 8473-1) communication
When an instance of data communications involves use of the ITU-T Rec. X.233 | ISO/IEC 8473-1
CLNP, a Network Service Access Point (NSAP) address scheme shall be used. For examples of
possible NSAP structures, refer to Annex B.
7.8.3.2
Services profile
7.8.3.2.1 Expedited data negotiation

The initiator shall be capable of proposing the non-use of the expedited data service. Responders
shall be capable of receiving requests for the expedited data service, but shall be capable of
responding with non-use of the service. The expedited data service is neither required nor precluded
by this Recommendation.
7.8.3.2.2 Receipt confirmation negotiation
The initiator shall be capable of setting bit 7 of the General Format Identifier to 0. Responders shall
be capable of receiving bit 7 set to 1, but shall be capable of responding with bit 7 set to 0. The
Receipt Confirmation Service is neither required nor precluded by this Recommendation.
7.8.3.2.3 Throughput class
When the end system requires only one Network layer connection on a physical access port, support
of throughput classes up to the access line transmission rate is required. When multiple Network
layer connections are required, support of the throughput class equal to the access line transmission
rate is optional. Further study of Throughput Class range and default values at various access line
rates is needed.
ITU-T Rec. Q.811 (02/2004)
25
7.8.3.2.4 Packet size negotiation

Interoperability is achieved by having the initiator propose a packet size from the set specified in
Tables 17 and 18 and by the responder selecting the most appropriate packet size between 128 and
the proposed packet size. The rules for negotiation of the size of the packet to be used in a given
instance of communication are specified in ISO/IEC 8208 [16].
The choice of packet size is a local issue which can depend on, for example, the overall Quality of
Service requested or needed by the user or Application Layer, and the subnetwork characteristics.
7.8.3.3
Protocol profile
7.8.3.3.1 Equipment type during restart

When the packet level X.25 interface is used, automatic selection of the DCE/DTE role during
restart is required, as specified in ISO/IEC 8208 [16].
7.8.3.3.2 Other features and parameters
The packet layer attributes are summarized in Tables 17 and 18.
7.8.3.3.3 User data field
When layers above X.25 are used, the initial octets of (N)-DATA primitive and the corresponding
user data field are used for peer-to-peer protocol data for those layers.
In following the procedures of ITU-T Rec. X.244 [20], ISO/IEC TR 9577 [21], and Annex B of
ITU-T Rec. X.224 | ISO/IEC 8073 [42], the initial octets of the user data field of the call request
packet may only be used for protocol identification. For those cases in which the fast select feature
is used, the call request packet may contain a call user data field of up to 128 octets.
7.9
Packet mode bearer service on the D-channel (CONS2)
7.9.1
The Physical layer conforms to ITU-T Recs I.430 [22] for basic rate access and I.431 [23] for
primary rate access.
7.9.2
Link layer C-plane profile
The link layer C-plane conforms to ITU-T Rec. Q.921 [24] with the default parameters specified for
links within the SAP identified by SAPI = 0.
7.9.3
Network layer C-plane profile
The Network layer C-plane conforms to ITU-T Rec. Q.931 [61]. Q.931 procedures are used as
described in ITU-T Rec. X.31 [25] with encodings for information elements according to ITU-T
Rec. X.31.
7.9.4
Link layer U-plane profile
The link layer U-plane profile conforms to ITU-T Rec. Q.921 [24] with the default parameters
specified for links within the SAP identified by SAPI = 16.
7.9.5
Network layer U-plane profile
The Network layer U-plane conforms to International Standard ISO/IEC 8208 for DTE-DCE
operation. The throughput class corresponds to the access-line bit rate of the D-channel which is
16 kbit/s. The Network layer attributes are specified in Table 18.
26
ITU-T Rec. Q.811 (02/2004)
7.9.6
Provision of OSI-CONS
ITU-T Rec. X.612 | ISO/IEC 9574 [40] provides the connection-mode Network service to packet
mode terminal equipment connected to ISDN.
7.10
Packet mode bearer service on the B-channel (CONS3)
7.10.1 Physical layer profile

The Physical layer conforms to ITU-T Recs I.430 [22] for basic rate access and I.431 [23] for
primary rate access.
7.10.2 Link layer C-plane profile
The link layer C-plane conforms to ITU-T Rec. Q.921 with the default parameters specified for
7.10.3 Network layer C-plane profile
The Network layer C-plane conforms to ITU-T Rec. Q.931. Q.931 procedures are used as described
in ITU-T Rec. X.31 with encodings for information elements according to ITU-T Rec. X.31.
7.10.4 Link layer U-plane profile
The link layer U-plane conforms to International Standard ISO/IEC 7776 for Single Link
Procedures (SLPs) in DTE-DCE operation. The link layer attributes are specified in Table 16.
7.10.5 Network layer U-plane profile
The Network layer U-plane conforms to International Standard ISO/IEC 8208 for DTE-DCE
operation. The throughput class corresponds to the access-line bit rate of the B-channel which is
64 kbit/s. The Network layer attributes are specified in Table 18.
7.10.6 Provision of OSI-CONS
ITU-T Rec. X.612 | ISO/IEC 9574 [40] provides the connection-mode Network service to packet
mode terminal equipment connected to ISDN.
7.11
Signalling System No. 7 networks (CONS5)

Layer 1 conforms to MTP (Level 1) [27].
Layer 2 conforms to MTP (Level 2) [28].
Layer 3 conforms to MTP (Level 3) [29] and SCCP [30] to [34].
NOTE Further study is needed for the function of SCCP at the boundary of Network layer and
Transport layer.
Layer 4 OSI Transport layer per ITU-T Rec. X.214 | ISO/IEC 8072 [41] and ITU-T Rec.
X.224 | ISO/IEC 8073 [42].
7.12
Connection oriented LAN (CONS6)
7.12.1 Physical layer profile

See 7.3.1.
7.12.2 Data link layer profile
See 7.3.2, and replace "Type 1" by "Type 2".
7.12.3 Network layer profile
For further study.
ITU-T Rec. Q.811 (02/2004)
27
7.13
Conformance requirements
This clause specifies the conformance requirements for each profile by reference to its equivalent
ISP (when it exists).
The default values shall be part of a vendor's offering. That is, unless otherwise specified by the
user, the default parameters shall be the initial values supplied. They can be subsequently changed
by the user within the specified range.
The attributes that are not marked optional are mandatory. See Table 19.
Table 19/Q.811 Summary of ISP-based protocol profile conformance requirements
Protocol
profile
Protocol
layer
Requirements
CONS1
CONS1
Table
4.1, Figure 1, 7.8,

7.13.3
Table 20
ISO/IEC ISP 10609-9 [45]

Subnetwork Dependent
Requirements (TB1111/TB1121)
as modified by Table I.1.
7.8.3 and subclauses
Tables 17, 18 and

I.1
Data Link
ISO/IEC ISP 10609-9 Subnetwork

Dependent Requirements
(TB1111/TB1121) as modified by
Table I.2.
7.8.2 (7.4.2)
Tables 16 and I.2
Physical

Dependent Requirements
(TB1111/TB1121).
7.8.1 (7.4.1 and

subclauses)
Tables 12, 13, 14

and 15
4.3, Figure 2, 7.3

7.13.1
Table 20
Table 2, Tables 3
to 11 (where
applicable),
Table I.4
Network
ISO/IEC
8473 CLNP

Independent Requirements as
modified by Table I.4.
7.3.3
Data Link
ISO/IEC ISP 10608-2 (TA51) [44].
7.3.2
Physical
ISO/IEC ISP 10608-2 (TA51).
7.3.1
Table 1
4.4, Figure 2, 7.4,

7.13.2
Table 20
CLNS2
28
Clause/Figure
Network
ISO/IEC
8208
X.25 PLP
CLNS1
CLNS1/
Q.811 references
Network
ISO/IEC
8473 CLNP

Independent Requirements as
modified by Table I.4.
7.4.3, 7.4.3.2,
7.4.3.3
Table 2, Tables 3
to 11 (where
applicable)
Network
ISO/IEC
8208 X.25
PLP
ISO/IEC ISP 10608-5

(TA1111/TA1121)
as modified by Tables I.1 and I.3.
7.4.3.2 (7.8.3 and

subclauses)
Tables I.1 and I.3
Data Link
ISO/IEC ISP 10608-5

(TA1111/TA1121)
as modified by Table I.2.
7.4.2
Tables 16 and I.2
Physical
ISO/IEC ISP 10608-5

(TA1111/TA1121).
7.4.1
Tables 12, 13, 14

and 15
Network
ISO/IEC ISP 10613-7, 10613-8,
ITU-T Rec. Q.811 (02/2004)
Table 19/Q.811 Summary of ISP-based protocol profile conformance requirements

Protocol
profile
Protocol
layer
CLNS2
Int'work
Requirements
Q.811 references
Clause/Figure
Table
10613-9 (RA51.11x1).
IPv4
Network
STD0005 "Internet Protocol", J.

September 1981. (Includes
RFC 791, RFC 950, RFC 919,
RFC 922, RFC 792, RFC 1112.)
7.6.1
IPv4 with
IPSec
Network
RFC 2401 (1998) "Security

Architecture for the Internet
Protocol" with additional required
specified in section 7.6.2
7.6.2
IPv6
Network
RFC 2460 "Internet Protocol,

Version 6 (IPv6)
Specification" [70]
7.6.3
Ethernet
Data Link
RFC 1122
7.13.1 CL-LAN profile (CLNS1)

Network layers shall conform to ISO/IEC ISP 10608, Part 1, as modified by Table I.4. Physical and
Data link layers shall conform to ISO/IEC ISP 10608, Part 2 (TA51).
7.13.2 CL-WAN profile (CLNS2)
Network (CLNP) layers shall conform to ISO/IEC ISP 10608, Part 1, as modified by Table I.4.
Packet layer shall conform to ISO/IEC ISP 10608-5 as modified by Tables I.1 and I.3. Physical and
Data link layers shall conform to ISO/IEC ISP 10608, Part 5 (TA1111/TA1121).
7.13.3 X.25/LAPB profile (CONS1)
Packet layer shall conform to ISO/IEC ISP 10609-9, as modified by Table I.1. Data link and
Physical layer profiles shall conform to ISO/IEC ISP 10609-9 (TB1111/TB1121), as modified by
Table I.2.
7.13.4 Connection oriented LAN (CONS6)
Network shall conform to ISO/IEC ISP 10609-9.
Data link (LLC and MAC) and Physical layers shall conform to ISO/IEC ISP 10609-10.
8
Network layer service
8.1
Network layer profiles
The following subclauses will describe three ways in which the lower three layers of the Protocol
Profiles may be viewed as transparent to the Transport (layer 4) and the upper layers (5, 6 and 7).
NOTE Table 10/Q.811 (1993), Homogeneous lower layer protocol profiles, has been deleted.
8.1.1
Existing lower layer profiles
The group of subnetworks described in clause 7 have been chosen so that the services provided by
the respective Network layer protocols will ensure operation of the OSI Transport protocol. The
services of the Transport layer, in turn, are those required for operation of the higher OSI layers
(i.e., layers five to seven).
ITU-T Rec. Q.811 (02/2004)
29
8.1.2
Network layer service description for new subnetworks
On a forward going basis, any subnetwork developed must meet the criteria provided for the
Network layer service as viewed by the Transport layer. There are two services provided by the
Network layer, the Connection-mode Network layer Service (CONS), and the Connectionless-mode
Network layer Service (CLNS).
These services are described in ITU-T Rec. X.213 | ISO/IEC 8348.
8.1.3
Non-conforming Network layer profile
For a subnetwork which does not, by itself, provide the CLNS, the addition of ITU-T
Rec. X.233 | ISO/IEC 8473-1 with the proper choice of SNDCP will provide a combination that
will meet the Network layer service description.
Subnetwork Dependent Convergence Protocols (SNDCPs) are described for the use of ITU-T
Rec. X.233 | ISO/IEC 8473-1 over ISO/IEC 8208/X.25 networks, ISO/IEC 8802-2 subnetworks [5],
subnetworks that provide the OSI Data Link service [10], and ISDN circuit-switched
B-channels [11].
8.1.4
Security
ITU-T Rec. X.273 | ISO/IEC 11577 [58] specifies security features for the OSI Network layer, and
some security capabilities are available in the Network layer protocols [e.g., mandatory Closed User
Groups (CUGs) and optional bilateral CUGs in the X.25 packet protocol].
8.2
Internetworking
This clause describes the technical principles for interworking between DCNs within a TMN, and
between TMNs using different protocol stacks. In some cases interworking units have to be
supplied between the different DCNs. It is the responsibility of the two TMN Administrations to
determine which Administration shall provide the IWU. This interworking procedure is known as
Network Layer Relay (NLR).
When networks of different types, such as connection-mode and connectionless-mode, wish to
transfer information across the boundary, internetworking principles are stated in
ITU-T Rec. X.200 | ISO/IEC 7498-1 [3] and ISO 8648 [15]. These standards state that
internetworking should occur within the Network layer. The Transport layer and higher layers
operate on a peer-to-peer basis between the communicating end systems. A family of subnetwork
dependent convergence protocols has been developed [8] to [11] that provide for the operation of
ITU-T Rec. X.233 | ISO/IEC 8473-1 over different subnetworks. Thus, in the example above,
ITU-T Rec. X.233 | ISO/IEC 8473-1 would operate over both the connection-mode subnetworks
and over the connectionless-mode subnetworks. The Transport layer, ITU-T Rec. X.224 | ISO/IEC
8073 [42], would provide for operation over both the connection-mode subnetworks and the
connectionless-mode subnetworks. In this example, the Transport layer would operate in the Class 4
mode. Thus, the internetworking between dissimilar subnetworks would be achieved and the
Transport layer and higher layers of the end systems would operate on a peer-to-peer basis.
There are three basic principles to be followed in adopting interworking solutions between
Q/X protocol stacks.
The three principles are:
1)
interworking should be done in the Network layer;
2)
existing standards should be applied for interworking functions; e.g., X.300-series
Recommendations should be applied for interworking between certain types of
CONS-based networks; and NLR using ITU-T Rec. X.233 | ISO/IEC 8473-1 and associated
SNDCFs should be used for interworking between CLNS-based networks;
30
ITU-T Rec. Q.811 (02/2004)
3)
new interworking functions should be specified only if existing standards for interworking
cannot meet requirements of new network capabilities.
Definition of the relaying functions of a CONS-CONS Network layer intermediate system is given
in ISO/IEC 10028 [56]. How the Network internal layer service is provided for relaying between
X.25 packet systems is given in ISO/IEC 10177 [55].
A general guide to interworking between the various Transport profile groups is given in
ISO/IEC TR 10000-2 [64].
How relaying is performed between CLNS-based subnetworks is defined in ITU-T Rec.
X.233 | ISO/IEC 8473-1 [7].
Table 20 shows Protocol Profiles which are to be applied to a reference point which has
interworking, and defines internetworking methods.
NOTE Table 11/Q.811 (1993), Internetworking functions for Q lower layers, has been deleted.
Table 20/Q.811 Interworking between protocol profiles

Protocol
profile
CONS1
X.25
LAPB
Rec.
X.75 [49]
CONS1
CONS2
ISDN
X.25 (D)
CONS3
CONS5
CONS6
CONS5
SS7
CONS6
CO-LAN
CLNS1
LAN
CLNS3
ISDN
ISO
TP0/TCP/
IP
OSI
(CONS)
OSI
(CONS)
OSI
(CONS)
Non-OSI Non-OSI Non-OSI Non-OSI
OSI
(CONS)
OSI
(CONS)
OSI
(CONS)
OSI
(CONS)
OSI
(CONS)
OSI
(CONS)

OSI
(CLNS)
CLNS1
CLNS2
WAN
Rec. I.550/ Rec. I.550/ Rec.

Rec.
X.325 [50] X.325 [50] X.326 [51] X.327 [52]
OSI
(CONS)
CONS2
CONS3
ISDN
X.25 (B)
CLNS2
OSI
(CLNS)
OSI
(CLNS)
Non-OSI
OSI
(CLNS)
OSI
(CLNS)
Non-OSI
OSI
(CLNS)
Non-OSI
CLNS3
See 8.2.1
IP
Non-OSI
Interworking above the Network layer may be required.
OSI
Interworking is either connectionless-mode (CLNS) or connection-mode (CONS) within the

Network layer.
NLR
Interworking is within the Internet Network layer (i.e., the IP layer).
8.2.1
Interworking between TMN entities supporting OSI only with entities supporting IP
Two functions as defined by ITU-T Rec. G.7712/Y.1703 shall be supported by TMN entity when IP
is connected to an entity with OSI only for interworking. These are Network Layer PDU
interworking and IP Routing Interworking. The PDU interworking is supported using Network
Layer PDU Encapsulation function (see 7.1.8/G.7712/Y.1703) and Network Layer PDU tunnelling
function (see 7.1.9/G.7712/Y.1703). The IP Routing Interworking function is supported using
Integrated IS-IS routing as defined in 7.1.10/G.7712/Y.1703.
ITU-T Rec. Q.811 (02/2004)
31
Annex A
Protocol stack for information transfer over
ISDN transparent B-channel
A.1
Introduction
This annex describes a protocol stack for connection between data terminal equipment without an
intervening packet switched network. End systems are making use of the 64 kbit/s unrestricted
circuit-mode bearer service offered by an ISDN. The OSI connection-mode service (OSI-CONS)
over ISDN transparent B-channel defined in this annex is identified as CONS4 at the Q and X
interfaces.
The CONS4 lower layer protocol profile provides for a connection-mode interface using ISDN
transparent B-channel.
A.2
Network profile CONS4
A.2.1
The Physical layer conforms to ITU-T Recs I.430 for basic rate access and I.431 for primary rate
access.
A.2.2
Link layer C-plane profile
The link layer C-plane conforms to ITU-T Rec. Q.921 with the default parameters specified for
A.2.3
Network layer C-plane profile
The Network layer C-plane conforms to ITU-T Rec. Q.931 for circuit-switched call control
procedures using codings of information element as in Table A.1.
32
ITU-T Rec. Q.811 (02/2004)
Table A.1/Q.811 Q.931 Information element encodings in support of CONS4

Bearer Capability (BC) information element codings
Coding standard (octet 3)
Information transfer capability (octet 3)
Transfer mode (octet 4)
Information transfer rate (octet 4)
ITU-T
Unrestricted digital information
Circuit mode
64 kbit/s
Called party number information element codings

Type of number (octet 3)
Numbering plan identification (octet 3)
International/national/subscriber
ISDN/telephony numbering plan
(ITU-T Rec. E.164)
Called/calling party subaddress information element codings

Type of number (octet 3)
NSAP
Low Layer Compatibility (LLC) information element codings

Coding standard (octet 3)
Information transfer capability (octet 3)
Transfer mode (octet 4)
Information transfer rate (octet 4)
User information Layer 1 protocol
User information Layer 2 protocol (octet 6)
Mode of operation (octet 6a)
Window size (k) (octet 6b)
User information layer 3 protocol (octet 7)

Mode of operation (octet 7a)
Default packet size (octet 7b)
Packet window size (k) (octet 7c)
A.2.4
ITU-T
Unrestricted digital information
Circuit mode
64 kbit/s
Not applicable (omit octet 5)
ISO/IEC 7776 DTE-DTE operation
Normal/extended (selectable by user whereby
normal is a mandatory mode while extended is an
optional mode)
1-7 (for modulo 8) (default 7)
1-127 (for modulo 128) (default 7)
1-127 (for modulo 128) (default 35 for satellite
operations)
ISO/IEC 8208 DTE-DTE operation
Normal (modulo 8)/extended (modulo 128)
128, 256, 512 octets (default 128)
1-7 (for modulo 8)(default 2)
1-127 (for modulo 128)(default 2)
Supplementary services
The supplementary service Sub-addressing (SUB) is required in order to convey the called and
calling NSAP address in the called and calling party subaddress information element, respectively.
In addition, the supplementary service Closed User Group (CUG) may be used to restrict, in a
public Data Communication Network (DCN), access of end systems which are the members of a
TMN.
A.2.5
Link layer U-plane profile
The link layer U-plane conforms to ISO/IEC 7776 for Single Link Procedures (SLPs) in DTE-DTE
operation. The link layer attributes are specified in Table 16.
A.2.6
Network layer U-plane profile
The Network layer U-plane conforms to ISO/IEC 8208 for DTE-DTE operation over circuitswitched connections.
ITU-T Rec. Q.811 (02/2004)
33
Determining "DTE" or "DCE" characteristics is based on restart procedure:

a)
acts as "DCE" when receiving RESTART INDICATION packet with the restarting cause
field "DTE originated" and no restart collision occurred;
b)
acts as "DTE" when a RESTART REQUEST packet is subsequently confirmed with a
RESTART CONFIRMATION packet (no restart collision occurred);
c)
re-initiates a restart procedure when a randomly-chosen time has elapsed following the
detection of a restart collision.
The Network layer attributes specified in Table 18 apply with the additions contained in Table A.2.
Table A.2/Q.811 Additional U-plane network layer attributes and
parameters in support of CONS4
The throughput class corresponds to the access-line bit rate of the B-channel which is
64 kbit/s.
The Network layer parameters which apply are:
T20
Restart requires response timer
180 seconds
T21
Call request response timer
200 seconds
T22
Reset request response timer
180 seconds
T23
Clear request response timer
180 seconds
T24
Window status transmission timer
Not applicable
T25
Window rotation timer
Not applicable
T26
Interrupt response timer
180 seconds
T27
Reject response timer
Not applicable
T28
Registration request response timer
Not applicable
R20
Restart request retransmission count
R22
Reset request retransmission count
R23
Clear request retransmission count
R25
Data packet retransmission count
Not applicable
R27
Reject retransmission count
Not applicable
R28
Registration request retransmission count
Not applicable
A.2.7
Provision of OSI-CONS
The Synchronization and Coordination Function (SCF) (see ITU-T Rec. I.320 [62]) provides the
connection-mode Network service to the Network service user.
34
ITU-T Rec. Q.811 (02/2004)
Annex B
Examples of NSAP structures for CLNP
This annex summarizes four examples of NSAP structure. Figures B.1, B.2, and B.3 show NSAP
structures based on ISO-DCC. Figure B.4 shows an NSAP structure based on ISO-ICD.
IDP
AFI
39
1
Number of octets
DSP
IDI
a)
JDI#
3
AREA
n
SYSTEM
6
SEL
1
a)
ISO DCC (value of 392 as Japan).

# JDI (value of 100009 as NTT)
n Range of value = 1-7
Figure B.1/Q.811 DCC type NSAP address format in Japan Standard

IDP
AFI
39
1
Number of octets
DSP
IDI
a)
ORG
3
AREA
2
a)
SYSTEM
0-6
SEL
1
ISO DCC.
Organization Identifier
Subnetwork Identifier
Subnetwork address
ORG
AREA
SYSTEM
Figure B.2/Q.811 ECMA 117 NSAP format

IDP
Number of octets
AFI
39
1
DSP
IDI
a)
DFI
128
1
a)
DFI
org
res
rd
org
3
res
2
rd
2
AREA
2
SYSTEM
6
SEL
1
ISO DCC.
The DSP Format Identifier
Organization Identifier
Reserved
Routing domain prefix
Figure B.3/Q.811 ANSI NSAP address format
ITU-T Rec. Q.811 (02/2004)
35
IDP
Number of octets
AFI
47
1
DSP
IDI
a)
DI
3
2
a)
DI
FI
TI
SEL
FI
1
TI
12
SEL
1
ISO ICD.
Domain Identifier
Format Identifier
Terminal Identifier
NSAP selector
Figure B.4/Q.811 ICD type NSAP address format for AOTC-Australia
Appendix I
Changes to ISP conformance requirements
The "Identifier", "Feature", and "Status" fields under "Base Reference Standard" refer to the PICS
for the particular base standard protocol; whereas the "Clause" field refers to the base protocol
specification.
Notation:
a)
Base standard status notation
1) Base standard type or range:
M
Mandatory.
O
Optional.
Not applicable.
O.<n>
Optional, but support of at least one of the group of options labelled by
the same numeral <n> is required.
<index>:
This predicate symbol means that the status following applies only when
the PICS states that one or more of the items identified by the index is
supported. In the simplest case, <index> is the identifying tag of a single
PICS item. <index> may also be a Boolean expression composed of
several indices.
<index>::
When this group predicate is true the associated clause should be
completed.
b)
Q.811 status notation
The status column in Tables I.1 to I.4 uses either a one-or two-character notation. The onecharacter notation indicates the static requirements only. For the two-character notation, the
first character is the static requirements and the second character is the dynamic
requirements.
1) Static:
m
Mandatory, mandatory to be implemented.
i
Out of scope. Not relevant to this profile.
o
Optional, optional to be implemented.
&
Same as Base Standard.
36
ITU-T Rec. Q.811 (02/2004)
2) Dynamic:
m
x
Mandatory (use is mandatory).

Excluded (use is prohibited within the context of this profile).
Not applicable.
Table I.1/Q.811 Network layer
Base standard
Ident.
Feature
ISP
Clause
Status
Status
ITU-T Rec. Q.811

Clause
Status
Et/d
DTE/DTE with
dynamic role selection
4.5
Vs: O.2
oi
7.8.3.3.1
mm
M128
Modulo 128
(extended)
13.2,
12.1.1,
Table 3
O.3
ox
Table 18
oo
V2s
Default window sizes

supported, sending
16.2.2.6
M8: 1-7
M128: 1-127
M8: 1-7
M128: o-
Table 18
Table 18
M8: 2
M128: 2
V2r
Default window sizes

supported, receiving
16.2.2.6
M8: 1-7
M128: 1-127
M8: 1-7
M128: o-
Table 18
Table 18
M8: 2
M128: 2
V10s
Window sizes
supported, sending
15.2.2.1.2
M128: 1-127
M128: o-
Table 18
M128:
1-127
V10r
Window sizes
supported, receiving
15.2.2.1.2
M128: 1-127
M128: o-
Table 18
M128: 1-1
T24
Window Status
Transmission Timer
ox
Table 18
oo
T25
Window Rotation
Timer
ox
Table 18
oo
FS5
FR5
Bilateral Closed User

Group Selection
Table 18
oo
13.15
15.2.2.5
ITU-T Rec. Q.811 (02/2004)
37
Table I.2/Q.811 Data link layer

Base standard
Ident.
Feature
ISP
Clause
Status
DTE/DTE
Interworking
T2
Parameter T2
procedure
5.7.1.2,
5.7.1.1
T3
Parameter T3
procedure
T4
Status
oi
ITU-T Rec. Q.811

Clause
Status
7.4.2.2.1
Table 16
5.7.1.3
Table 16
Parameter T4
procedure
5.7.1.4,
5.3.2
Table 16
SP8
If Modulo 8 was
checked with SLP
(N1 1080)
5.7.3
Table 16
SP128
If Modulo 128 was

checked with SLP
(N1 1088)
Table 16
NOTE for Tables I.1 and I.2 The referenced ISP is ISO/IEC ISP 10609, Parts 1 and 9
(TB1111/TB1121) [45].
Table I.3/Q.811 CLNS2 protocol case Packet layer

Base standard
Ident.
Feature
ISP
Clause
Status
Status
ITU-T Rec. Q.811

Clause
Status
Vp
PVC
O.1
&
Vs
VC
O.1
mm
&
Et/d
DTE/DTE with
dynamic role selection
Vs: O.2
Vs: i
4.5
7.5.3
mm
Table I.4/Q.811 CLNS2 and CLNS1 protocol cases

ITU-T Rec. X.233 | ISO/IEC 8473-1 CLNP
Base standard
Ident.
Feature
QoS Maintenance
ISP
Clause
7.5.6
Status
O
Status
i
ITU-T Rec. Q.811

Clause
Table 2
Status
mm
NOTE for Tables I.3 and I.4 Reference is to ISO/IEC ISP 10608, Parts 1, 2 (TA51), and Part 5
(TA1111/TA1121) [44].
38
ITU-T Rec. Q.811 (02/2004)
SERIES OF ITU-T RECOMMENDATIONS

Series A
Organization of the work of ITU-T
Series B
Means of expression: definitions, symbols, classification
Series C
General telecommunication statistics
Series D
General tariff principles
Series E
Overall network operation, telephone service, service operation and human factors
Series F
Non-telephone telecommunication services
Series G
Transmission systems and media, digital systems and networks
Series H
Audiovisual and multimedia systems
Series I
Integrated services digital network
Series J
Cable networks and transmission of television, sound programme and other multimedia signals
Series K
Protection against interference
Series L
Construction, installation and protection of cables and other elements of outside plant
Series M
TMN and network maintenance: international transmission systems, telephone circuits,

telegraphy, facsimile and leased circuits
Series N
Maintenance: international sound programme and television transmission circuits
Series O
Specifications of measuring equipment
Series P
Telephone transmission quality, telephone installations, local line networks
Series Q
Switching and signalling
Series R
Telegraph transmission
Series S
Telegraph services terminal equipment
Series T
Terminals for telematic services
Series U
Telegraph switching
Series V
Data communication over the telephone network
Series X
Data networks and open system communications
Series Y
Global information infrastructure, Internet protocol aspects and Next Generation Networks
Series Z
Languages and general software aspects for telecommunication systems
Printed in Switzerland
Geneva, 2004

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INTERNATIONAL TELECOMMUNICATION UNION

SERIES Q: SWITCHING AND SIGNALLING

Lower layer protocol profiles for the Q and X

ITU-T Recommendation Q.811

ITU-T Q-SERIES RECOMMENDATIONS

ITU-T Recommendation Q.811

ITU-T Rec. Q.811 (02/2004)

INTELLECTUAL PROPERTY RIGHTS

ITU-T Rec. Q.811 (02/2004)

Lower layer protocol profiles: Overview .....................................................................

Requirements for network layer/transport layer interface............................................

Defined protocol profiles..............................................................................................

Network layer service...................................................................................................

Annex B Examples of NSAP structures for CLNP ..............................................................

Appendix I Changes to ISP conformance requirements.......................................................

ITU-T Rec. Q.811 (02/2004)

ITU-T Recommendation Q.811

This Recommendation is a part of a series of Recommendations dealing with the transfer of

the layer service profiles for the defined supported networks;

the layer protocol profiles for the defined supported networks;

ITU-T Recommendation M.3010 (2000), Principles for a telecommunications management

ITU-T Recommendation X.200 (1994) | ISO/IEC 7498-1:1994, Information technology

ISO/IEC 8802-3:2000, Information technology Telecommunications and information

ISO/IEC 8802-2:1998, Information technology Telecommunications and information

ITU-T Recommendation X.213 (2001) | ISO/IEC 8348:2002, Information technology

ITU-T Recommendation X.233 (1997) | ISO/IEC 8473-1:1998, Information technology

ISO/IEC 8473-2:1996, Information technology Protocol for providing the

ITU-T Recommendation X.622 (1994) | ISO/IEC 8473-3:1995, Information technology

ITU-T Recommendation X.623 (1994) | ISO/IEC 8473-4:1995, Information technology

ITU-T Recommendation X.625 (1996) | ISO/IEC 8473-5:1997, Information technology

ISO/IEC 7776:1995, Information technology Telecommunications and information

ISO/IEC 8880-3:1990, Information technology Telecommunications and information

ISO 8648:1988, Information processing systems Open Systems Interconnection Internal

ISO/IEC 8208:2000, Information technology Data communications X.25 Packet Layer

ITU-T Recommendation E.164 (1997), The international public telecommunication

ITU-T Recommendation X.244 (1988), Procedure for the exchange of protocol

ITU-T Rec. Q.811 (02/2004)

ISO/IEC TR 9577:1999, Information technology Protocol identification in the network

ITU-T Recommendation I.430 (1995), Basic user-network interface Layer 1

ITU-T Recommendation I.431 (1993), Primary rate user-network interface Layer 1

ITU-T Recommendation X.31 (1995), Support of packet mode terminal equipment by an

ISO/IEC 8878:1992, Information technology Telecommunications and information

ITU-T Recommendation Q.702 (1988), Signalling data link.

ITU-T Recommendation Q.703 (1996), Signalling link.

ITU-T Recommendation Q.704 (1996), Signalling network functions and messages.

ITU-T Recommendation Q.711 (2001), Functional description of the signalling connection

ITU-T Recommendation Q.712 (1996), Definition and function of signalling connection

ITU-T Recommendation Q.714 (2001), Signalling connection control part procedures.

ITU-T Recommendation Q.716 (1993), Signalling System No. 7 Signalling Connection

ISO 2110:1989, Information technology Data communication 25-pole DTE/DCE

ISO/IEC 2593:2000, Information technology Telecommunications and information

ITU-T Recommendation X.612 (1992) | ISO/IEC 9574:1992, Information technology

ITU-T Recommendation X.214 (1995) | ISO/IEC 8072:1996, Information technology

ITU-T Rec. Q.811 (02/2004)

ITU-T Recommendation X.224 (1995) | ISO/IEC 8073:1997, Information technology

ISO/IEC 8881:1989, Information processing systems Data communications Use of the

ISO/IEC ISP 10608:1992, Information technology International Standardized Profile

ISO/IEC ISP 10609:1992, Information technology International Standardized Profiles