ETSI TS 183 059-1 V2.1.1 (2009-08)

Telecommunications and Internet converged Services and Protocols for Advanced Networks (TISPAN); Network Attachment Sub-System (NASS); a2 interface based on the DIAMETER protocol

DTS/TISPAN-03117-1-NGN-R2

General Information

• Status: Published
• Publication Date: 06-Aug-2009
• Technical Committee: TISPAN 3 - TISPAN Protocols
• Current Stage: 12 - Completion
• Due Date: 07-Aug-2009
• Completion Date: 07-Aug-2009

Standards Content (Sample)

ETSI TS 183 059-1 V2.1.1 (2009-08)
Technical Specification


Telecommunications and Internet converged Services and
Protocols for Advanced Networks (TISPAN);
Network Attachment Sub-System (NASS);
a2 interface based on the DIAMETER protocol

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2 ETSI TS 183 059-1 V2.1.1 (2009-08)



Reference
DTS/TISPAN-03117-1-NGN-R2
Keywords
interface, stage 3
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3 ETSI TS 183 059-1 V2.1.1 (2009-08)
Contents
Intellectual Property Rights.5
Foreword.5
1 Scope.6
2 References.6
2.1 Normative references.6
2.2 Informative references.7
3 Definitions and abbreviations.7
3.1 Definitions.7
3.2 Abbreviations.7
4 Overview.8
5 Procedure Descriptions.8
5.1 General.8
5.1.1 Information elements.8
5.2 Procedures on the CLF - NACF interface .9
5.2.1 Bind indication/Acknowledgement .9
5.2.1.1 Overview.9
5.2.1.2 Procedure at the NACF side.10
5.2.1.3 Procedure at the CLF side .10
5.2.2 Unbind indication.11
5.2.2.1 Overview.11
5.2.2.2 Procedure at the NACF side.11
5.2.2.3 Procedure at the CLF side .12
5.2.3 Bind information query/acknowledgment .12
5.2.3.1 Overview.12
5.2.3.2 Procedure at the CLF side .13
5.2.3.3 Procedure at the NACF side.13
6 Use of the Diameter base protocol .13
6.1 Securing Diameter Messages .13
6.2 Accounting functionality.13
6.3 Use of sessions .14
6.4 Transport protocol.14
6.5 Routing considerations.14
6.6 Advertising application support .14
7 DIAMETER application.14
7.1 Commands.15
7.1.1 Push-Notification-Request command.15
7.1.2 Push-Notification-Answer command.15
7.1.3 User-Data-Request command.16
7.1.4 User-Data-Answer command.16
7.2 Result-Code AVP values.17
7.2.1 Success.17
7.2.2 Permanent Failures.17
7.2.3 Transient Failures .17
7.3 AVPs.17
7.3.1 Logical-Access-ID AVP.18
7.3.2 Physical-Access-ID.19
7.3.3 Terminal-Type AVP.19
7.3.4 IP-Connectivity-Status.19
7.3.5 CNGCF-Address.19
7.3.6 SIP-Outbound-Proxy .19
7.3.7 Access-Network-Type AVP.19
7.3.8 Location-Data AVP.19
ETSI

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4 ETSI TS 183 059-1 V2.1.1 (2009-08)
Annex A (informative): Mapping of a2 operations and terminology to Diameter .20
Annex B (informative): Bibliography.21
History .22

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5 ETSI TS 183 059-1 V2.1.1 (2009-08)
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 ETSI 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://webapp.etsi.org/IPR/home.asp).
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 ETSI 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 Telecommunications and Internet
converged Services and Protocols for Advanced Networking (TISPAN).
ETSI

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6 ETSI TS 183 059-1 V2.1.1 (2009-08)
1 Scope
The present document is applicable to the a2 interface between the Connectivity Session Location and Repository
Function (CLF) and the Network Access Configuration Function (NACF).
Whenever it is possible the present document specifies the requirements for this protocol by reference to specifications
produced by the IETF within the scope of Diameter. Where this is not possible, extensions to Diameter are defined
within the present document.
2 References
References are either specific (identified by date of publication and/or edition number or version number) or
non-specific.
• For a specific reference, subsequent revisions do not apply.
• Non-specific reference may be made only to a complete document or a part thereof and only in the following
cases:
- if it is accepted that it will be possible to use all future changes of the referenced document for the
purposes of the referring document;
- for informative references.
Referenced documents which are not found to be publicly available in the expected location might be found at
http://docbox.etsi.org/Reference.
NOTE: While any hyperlinks included in this clause were valid at the time of publication ETSI cannot guarantee
their long term validity.
2.1 Normative references
The following referenced documents are indispensable for the application of the present document. For dated
references, only the edition cited applies. For non-specific references, the latest edition of the referenced document
(including any amendments) applies.
[1] ETSI ES 282 004 (V2.y.z): "Telecommunications and Internet converged Services and Protocols
for Advanced Networking (TISPAN); NGN Functional Architecture; Network Attachment Sub-
System (NASS)".
NOTE: The latest version in the V2.y.z series applies.
[2] ETSI ES 282 003 (V2.y.z): "Telecommunications and Internet converged Services and Protocols
for Advanced Networking (TISPAN); Resource and Admission Control Sub-System (RACS):
Functional Architecture".
NOTE: The latest version in the V2.y.z series applies.
[3] ETSI TS 129 229: "Digital cellular telecommunications system (Phase 2+); Universal Mobile
Telecommunications System (UMTS); LTE; Cx and Dx interfaces based on the Diameter
protocol; Protocol details (3GPP TS 29.229)".
[4] ETSI TS 129 329: "Digital cellular telecommunications system (Phase 2+); Universal Mobile
Telecommunications System (UMTS); LTE; Sh interface based on the Diameter protocol; Protocol
details (3GPP TS 29.329)".
[5] IETF RFC 2960: "Stream Control Transmission Protocol".
[6] IETF RFC 3588: "Diameter Base Protocol".
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7 ETSI TS 183 059-1 V2.1.1 (2009-08)
[7] IETF RFC 3309: "Stream Control Transmission Protocol (SCTP) Checksum Change".
[8] draft-ietf-geopriv-radius-lo-24 (January 2008): "Carrying Location Objects in RADIUS and
Diameter".
[9] ETSI ES 283 034 (V2.y.z): "Telecommunications and Internet converged Services and Protocols
for Advanced Networking (TISPAN); Network Attachment Sub-System (NASS); e4 interface
based on the DIAMETER protocol".
NOTE: The latest version in the V2.y.z series applies.
[10] ETSI ES 283 035 (V2.y.z): Telecommunications and Internet Converged Services and Protocols
for Advanced Networks (TISPAN); Network Attachment Sub-System (NASS); e2 interface based
on the DIAMETER protocol".
NOTE: The latest version in the V2.y.z series applies.
[11] DSL Forum TR-069 (May 2004): "CPE WAN Management Protocol".
[12] IETF RFC 3986: "Uniform Resource Identifier (URI): Generic Syntax".
2.2 Informative references
The following referenced documents are not essential to the use of the present document but they assist the user with
regard to a particular subject area. For non-specific references, the latest version of the referenced document (including
any amendments) applies.
[i.1] IETF RFC 3554: "On the use of Stream Control Transmission Protocol (SCTP) with IPSec".
3 Definitions and abbreviations
3.1 Definitions
For the purposes of the present document, the following terms and definitions apply:
access record: set of information stored in the CLF in relation to an IP address
Application Function (AF): element of the network architecture offering - or providing access to - applications that
require information about the characteristics of the IP-connectivity session used to access such applications
attribute-value pair: corresponds to an Information Element in a Diameter message
NOTE: See RFC 3588 [13].
nASS user: See definition in [1].
3.2 Abbreviations
For the purposes of the present document, the following abbreviations apply:
ABNF Augmented Backus-Naur Form
AF Application Function
A-RACF Access RACF
AVP Attribute-Value Pair
CLF Connectivity session Location and repository Function
CSCF Call Session Control Function
FQDN Fully Qualified Domain Name
IANA Internet Assigned Numbers Authority
IETF Internet Engineering Task Force
IPSec IP Security
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8 ETSI TS 183 059-1 V2.1.1 (2009-08)
NACF Network Access Configuration Function
NASS Network Attachment SubSystem
PNA Push-Notification-Answer
PNR Push-Notification-Request
RACF Resource and Admission Control Function
RACS Resource and Admission Control Subsystem
RFC Request For Comments
SCTP Stream Control Transport Protocol
UCS Universal Character Set
UDA User-Data-Answer
UDR User-Data-Request
4 Overview
The Network Attachment SubSystem (NASS), defined in ES 282 004 [1], maintains information about IP-connectivity
associated with NASS User connected to TISPAN networks.
The a2 reference point allows the NACF to register in the CLF the association between the IP address allocated to a
NASS User and information identifying the network access to which this equipment is connected.
The following information flows are used on the a2 interface:
• Bind Indication.
• Bind Acknowledgment.
• Unbind Indication.
• Bind information query.
• Bind information query acknowledgement.
The present document specifies the protocol for the a2 Diameter interface.
Service control
subsystems and
applications
Scope of the present
document
e2
e2 Resource
e4
Admission
CLF
Control
e2
Subsystem
e5
a2 a4
CNGCF NACF UAAF PDBF
e3
a1 a3
e1 e1
TE CNG
ARF AMF
UE

Figure 4.1: a2 interface
ETSI

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9 ETSI TS 183 059-1 V2.1.1 (2009-08)
5 Procedure Descriptions
5.1 General
5.1.1 Information elements
The following clauses describe the realization of the functional procedures defined in the NASS [1] and RACS
specifications [2] using Diameter commands described in clause 7. This involves describing a mapping between the
information elements defined in the NASS specification [1] and Diameter AVPs.
In the tables that describe this mapping, each Information Element is marked as (M) Mandatory, (C) Conditional or (O)
Optional:
- A mandatory Information Element (marked as (M) in the table) shall always be present in the command. If this
Information Element is absent, an application error occurs at the receiver and an answer message shall be sent
back to the originator of the request with the Result-Code set to DIAMETER_MISSING_AVP. This message
shall also include a Failed-AVP AVP containing the missing Information Element i.e. the corresponding
Diameter AVP defined by the AVP Code and the other fields set as expected for this Information Element.
- A conditional Information Element (marked as (C) in the table) shall be present in the command if certain
conditions are fulfilled:
- If the receiver detects that those conditions are fulfilled and the Information Element is absent, an
application error occurs and an answer message shall be sent back to the originator of the request with
the Result-Code set to DIAMETER_MISSING_AVP. This message shall also include a Failed-AVP
AVP containing the missing Information Element i.e. the corresponding Diameter AVP defined by the
AVP Code and the other fields set as expected for this Information Element. If multiple Information
Elements are missing, all corresponding AVP codes shall be included in the Failed-AVP AVP. If those
conditions are not fulfilled, the Information Element shall be absent. If however this Information
Element appears in the message, it shall not cause an application error and it may be ignored by the
receiver if this is not explicitly defined as an error case. Otherwise, an application error occurs at the
receiver and an answer message with the Result-Code set to DIAMETER_AVP_NOT_ALLOWED shall
be sent back to the originator of the request. A Failed-AVP AVP containing a copy of the corresponding
Diameter AVP shall be included in this message.
- An optional Information Element (marked as (O) in the table) may be present or absent in the command, at the
discretion of the application at the sending entity. Absence or presence of this Information Element shall not
cause an application error and may be ignored by the receiver.
5.2 Procedures on the CLF - NACF interface
5.2.1 Bind indication/Acknowledgement
5.2.1.1 Overview
This procedure is used to report the binding between the IP address allocated to a user equipment and identity of the
access to which this equipment is connected from the NACF to the CLF. This information flow occurs when an IP
address has been allocated to a user equipment.
The NACF should trigger this procedure as soon as an IP address has been allocated.
This procedure is mapped to the commands Push-Notification-Request/Answer in the Diameter application specified in
clause 7. Tables 5.1 and 5.2 detail the involved information elements as defined in the NASS specification
ES 282 004 [1] and their mapping to Diameter AVPs.
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10 ETSI TS 183 059-1 V2.1.1 (2009-08)
Table 5.1: Bind indication (NACF -> CLF)
Information Mapping to Diameter Cat. Description
element name AVP
Globally Unique Globally-Unique-Address M This information element contains:
IP Address - The IP address of the NASS User.
- The addressing domain in which the IP address is significant.
Logical Access Logical-Access-Id M The identity of the logical access to which the user equipment is
ID connected.
Physical Physical-Access-Id O The identity of the physical access to which the user equipment is
Access ID connected.
Access Access-Network-Type O The type of access network providing IP connectivity to the NASS
Network Type user.
Terminal Type Terminal-Type O The type of user equipment.

Table 5.2: Bind Acknowledgment (CLF -> NACF)
Information Mapping to Diameter Cat. Description
element name AVP
CNGCF CNGCF-Address O The address of the CNGCF entity from which configuration data
address may be retrieved by the user equipment.
Geographic Location-Data O Geographic location information.
Location
Information
P-CSCF SIP-Outbound-Proxy O The Identity of the P-CSCF for accessing IMS services.
Identity
(optional)

5.2.1.2 Procedure at the NACF side
After allocating the IP address to a user equipment, or when a Renew is received from a different access line, the NACF
shall send a Bind Indication with the following information to CLF:
• The Globally-Unique-Address AVP shall contain a Frame-IP-Address or Frame-IPv6-Prefix AVP value, and
an Address-Realm AVP.
• The Logical-Access-ID AVP shall be present.
• Physical Access ID and Terminal Type may be present if available.
If the NACF is implemented as a DHCP v4 server, the Logical-Access-Id AVP shall be derived from the value of the
DHCP option 82, sub-option 1 and 2 received from the ARF. The Physical-Access-ID may also be derived from the
value of these sub-options.
If the NACF is implemented as a DHCP v4 server, the Terminal-Type AVP shall be set from the value of the DHCP
option 77 received from the user equipment.
On receipt of a Bind Acknowledgement with a Result-Code AVP indicating DIAMETER_SUCCESS, the NACF shall
process the received AVPs as follows:
• If the NACF is implemented as a DHCP v4 server, the CNGCF-Address AVP shall be used to set the value of
DHCP Option 43 (DSL Forum Autoconfiguration Server) or DHCP Option 66 (TFTP server).
• If the NACF is implemented as a DHCP v4 server, the Location-Information AVP shall be mapped to the
DHCP option 123 or 99.
• If the NACF is implemented as a DHCP v4 server, the SIP-Outbound-Proxy AVP shall be mapped to the
DHCP option 120.
The behaviour when the NACF does not receive a Bind Acknowledgement, or when it arrives after the internal timer
waiting for it has expires, or when it arrives with an indication that is different to DIAMETER_SUCCESS, is outside
the scope of the present document.
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11 ETSI TS 183 059-1 V2.1.1 (2009-08)
5.2.1.3 Procedure at the CLF side
If at least one of the specified AVP(s) is invalid, the CLF shall return a Binding Acknowledgement with a Result-Code
AVP value set to DIAMETER_INVALID_AVP_VALUE and a Failed-AVP AVP containing a copy of the invalid
AVP(s).
If the globally unique identifier contained in the Globally-Unique-Address AVP is not known, the CLF shall:
• Create an internal record to store the received information for future use.
If the globally unique identifier contained in the Globally-Unique-Address AVP is already known and the received
Logical Access ID is different than the one stored in the internal record, the CLF shall:
• interact with RACS entities (i.e. A-RACF) to remove transport policies associated with the existing record and
clear associated resources;
• replace the entire content of the internal record with the received information for future use.
If the CLF cannot fulfil the received request for reasons not stated in the above steps, e.g. due to database error, it shall
stop processing the request and return a Bind Acknowledgement with a Result-Code AVP value set to
DIAMETER_UNABLE_TO_COMPLY or an Experimental-Result-Code AVP set to
DIAMETER_SYSTEM_UNAVAILABLE.
Otherwise, the requested operation shall take place and the CLF shall return a Bind Acknowledgement with the
Result-Code AVP set to DIAMETER_SUCCESS and one or more of the AVPs identified in table 5.2.
5.2.2 Unbind indication
5.2.2.1 Overview
This procedure is used by the NACF to report the case the allocated IP address is released (e.g. DHCP leased timer
expiry) or due to a release of the underlying layer 2 resources. This enables the CLF to remove the corresponding record
from its internal database.
This procedure is mapped to the commands Push-Notification-Request/Answer in the Diameter application specified in
clause 7. Tables 5.3 and 5.4 detail the involved information elements as defined in the NASS specification ES 282 004
[1] and their mapping to Diameter AVPs.
Table 5.3: Unbind indication (NACF -> CLF)
Information Mapping to Diameter Cat. Description
element name AVP
Globally Unique Globally-Unique-Address M This information element contains:
IP Address - The IP address of the NASS User.
- The addressing domain in which the IP address is significant.

Table 5.4: Unbind indication acknowledgement (CLF -> NACF)
Information Mapping to Diameter Cat. Description
element name AVP
Result Result Code / M Result of the request.
Experimental_
Result Result Code AVP shall be used for errors defined in the Diameter
Base Protocol.

Experimental Result AVP shall be used for other errors. This is a
grouped AVP which contains a Vendor Id AVP, and the error code
in the Experimental Result Code AVP.

ETSI

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12 ETSI TS 183 059-1 V2.1.1 (2009-08)
5.2.2.2 Procedure at the NACF side
On receipt of release request for the allocated IP address from the user equipment or in case of expiry of the lease
period or on receipt of an indication that the underlying layer 2 connection has been lost, the NACF shall clear all
information stored against the IP address and issue a Push-Notification-Request representing a
Globally-Unique-Address.
The IP-Connectivity-Status AVP shall be set to IP CONNECTIVITY LOST.
5.2.2.3 Procedure at the CLF side
If the globally unique identifier contained in the Globally-Unique-Address AVP is not known, the CLF shall stop
processing the request and set the Experimental-Result-Code to DIAMETER_ERROR_USER_UNKNOWN in the
Unbind Indication acknowledgement.
If the globally unique identifier contained in the Globally-Unique-Address AVP is already known, the CLF shall:
• remove the existing session record;
• interact with RACS entities (i.e. A-RACF) to remove transport policies associated with the session and clear
associated resources.
If the CLF cannot fulfil the received request for reasons not stated in the above steps, e.g. due to database error, it shall
stop processing the request and set Result-Code to DIAMETER_UNABLE_TO_COMPLY or an
Experimental-Result-Code set to DIAMETER_SYSTEM_UNAVAILABLE.
Otherwise, the requested operation shall take place and the CLF shall return an Unbind Indication response with the
Result-Code AVP set to DIAMETER_SUCCESS.
5.2.3 Bind information query/acknowledgment
5.2.3.1 Overview
This procedure is used by the CLF to request binding information from the NACF, in the context of recovery
procedures.
This procedure is mapped to the commands User-Data-Request/Answer in the Diameter application specifi
...