ETSI TS 103 269-2 V1.1.1 (2015-01)

TECHNICAL SPECIFICATION
TETRA and Critical Communications Evolution (TCCE);
Critical Communications Architecture;
Part 2: Critical Communications application
mobile to network interface architecture

2 ETSI TS 103 269-2 V1.1.1 (2015-01)

Reference
DTS/TCCE-04187
Keywords
broadband, radio, security, TETRA
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3 ETSI TS 103 269-2 V1.1.1 (2015-01)
Contents
Intellectual Property Rights . 7
Foreword . 7
Modal verbs terminology . 7
1 Scope . 8
2 References . 8
2.1 Normative references . 8
2.2 Informative references . 9
3 Definitions and abbreviations . 9
3.1 Definitions . 9
3.2 Abbreviations . 10
4 Architecture overview . 11
4.1 Architecture reference . 11
4.2 Configurations . 12
4.2.1 Single CCA system . 12
4.2.2 Multi-CCA system . 14
4.2.3 Interconnection with legacy . 14
5 Components . 14
5.1 Mobile unit . 14
5.2 Access sub-systems . 15
5.3 Critical Communication Application. 15
5.3.1 Access interfaces . 15
5.3.1.1 Application control interface . 15
5.3.1.2 Media unicast interface . 16
5.3.1.3 Media multicast interface . 16
5.3.1.4 Unicast bearer control interface . 16
5.3.1.5 Multicast bearer control interface . 16
5.4 CCA functional entities . 16
5.4.1 SIP application server . 16
5.4.2 Mobility management . 16
5.4.3 Group management . 17
5.4.4 Resource management . 17
5.4.5 Application server . 17
5.4.6 Media distribution . 17
5.4.7 Security . 17
6 Reference points and protocols . 18
6.1 Identities and protocols . 19
6.1.1 Application level identities . 19
6.1.2 Transport protocols . 19
6.1.2.1 Unicast transport . 20
6.1.2.2 Multicast transport . 20
6.1.2.3 Control of unicast/broadcast transport over LTE . 20
6.1.3 Network layer protocols . 21
6.1.4 Application layer protocols . 21
6.1.4.1 Pseudo-broadcast protocol . 21
6.2 Standardised application codecs . 21
6.2.1 Voice Codec. 21
6.2.2 Video Codec . 22
7 Overview of services . 22
7.1 CCA system access . 22
7.2 Service registration . 22
7.2.1 Home network registration . 22
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4 ETSI TS 103 269-2 V1.1.1 (2015-01)
7.2.2 Migration registration . 23
7.2.3 Registration procedure . 24
7.2.4 Periodic update . 25
7.2.5 Deregistration . 25
7.3 Individual streaming communication . 26
7.3.1 Individual unit to unit call with on/off hook signalling . 26
7.3.2 Individual unit to unit call with direct signalling . 27
7.3.3 Individual unit to telephony call (outgoing call) . 28
7.3.4 Individual unit to telephony call (incoming call) . 30
7.4 Group streaming communication . 31
7.4.1 Broadcast and system call . 32
7.4.2 Group communication coverage . 32
7.4.3 Group provisioning . 33
7.4.4 Group affiliation . 33
7.4.4.1 Relation between group affiliation and mobility . 34
7.4.5 Session join and call start . 34
7.4.6 Late entry . 35
7.4.7 Message exchanges related to group call . 35
7.4.7.1 Group subscription and affiliation . 35
7.4.7.2 Joining a session . 36
7.4.7.3 Non acknowledged group communication . 37
7.4.7.3.1 Group call combined with session join . 37
7.4.7.3.2 Group call in pre-joined session . 40
7.4.7.4 Acknowledged or ringing group communication . 41
7.4.7.5 Bearer control . 43
7.5 Push-to-talk management procedures . 43
7.5.1 Initial allocation of right to transmit . 43
7.5.2 Releasing the right to transmit . 43
7.5.3 Requesting the right to transmit . 44
7.5.4 Interrupting a granted transmission. 44
7.5.5 Suspending a transmission . 46
7.5.6 End of call . 46
7.6 Call modification . 47
7.7 Management of priority and pre-emption . 47
7.7.1 Provisioned priority . 47
7.7.2 Setup priority . 48
7.7.3 Push-to-talk priority . 48
7.7.4 Scanning priority . 48
7.7.5 Resource allocation priority and resource retention . 48
7.8 Status and messaging. 49
7.8.1 Standard defined status . 49
7.8.1.1 Emergency status . 49
7.8.1.2 Call alert . 49
7.8.1.3 Urgent call back . 49
7.8.1.4 Ambience listening call request . 49
7.8.1.5 Ambience listening urgent call request . 49
7.8.1.6 Scanning on and off . 49
7.8.1.7 Transmit inhibit on and off . 50
7.8.2 Messaging . 50
7.8.2.1 Message broadcast . 50
7.9 Presence . 50
7.10 Localisation and geographic information . 51
7.10.1 Mode of transmission. 51
7.10.2 Assisted location . 51
7.11 Supplementary services . 51
7.11.1 Ambience Listening . 51
7.11.2 Talking party and calling party identity . 51
7.11.3 Dynamic group number allocation and group merging . 52
7.11.4 Disabling and enabling . 52
7.11.5 Call forwarding . 52
7.11.5.1 Call forwarding unconditional . 52
7.11.5.2 Call forwarding on busy subscriber and on no reply . 53
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7.11.6 Call barring . 53
7.11.6.1 Barring of outgoing calls . 53
7.11.6.2 Barring of incoming calls . 53
7.11.7 Call waiting and call hold . 53
7.11.8 Discreet listening . 54
7.11.9 Call transfer . 54
7.11.10 Area restriction . 54
7.11.11 Tracing & Recording . 54
7.12 Principles for mobility management . 54
7.12.1 Roaming and Migration . 54
7.12.2 Media gateway re-allocation . 55
8 Addressing and identities . 56
8.1 Identifiers . 56
8.2 List identifiers . 56
Annex A (informative): Analysed services and requirements . 57
History . 66

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6 ETSI TS 103 269-2 V1.1.1 (2015-01)
Figures
Figure 1: CCS Reference Model .12
Figure 2: Functional architecture.13
Figure 3: Multi-CCAS system .14
Figure 4: Reference points .18
Figure 5: MU to CCAS interface, control plane part.19
Figure 6: MU to CCAS interface, media plane unicast part .19
Figure 7: MU to CCAS interface, media plane multicast part.20
Figure 8: Home registration .23
Figure 9: Migration registration .24
Figure 10: Message sequence chart for registration process .25
Figure 11: Message sequence chart for a successful individual unit-to-unit call setup .27
Figure 12: Message sequence chart for a successful individual unit-to-unit call setup with direct signalling .28
Figure 13: Message sequence chart for outgoing call to an external subscriber.29
Figure 14: Message sequence chart for incoming call from an external subscriber .31
Figure 15: Message sequence chart for subscription and affiliation .35
Figure 16: Message sequence chart for joining a session .36
Figure 17: Message sequence chart for infrastructure initiated session join .36
Figure 18: Non-acknowledged group call setup including session join, using unicast bearers .37
Figure 19: Non-acknowledged group call setup with multicast bearer for receiving parties .38
Figure 20: Non-acknowledged group call at session join time with call queuing .39
Figure 21: Non-acknowledged group call setup with pre-joined session .40
Figure 22: Non-acknowledged queued group call setup pre-joined session .41
Figure 23: Acknowledged group call setup with session join .42
Figure 24: Rejection of talking party interruption .44
Figure 25: Processing of a request to transmit without pre-emption .45
Figure 26: Stopping a granted transmission .46

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7 ETSI TS 103 269-2 V1.1.1 (2015-01)
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://ipr.etsi.org).
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 TETRA and Critical
Communications Evolution (TCCE).
The present document is part 2 of a multi-part deliverable covering TETRA and Critical Communications Evolution
(TCCE); Critical Communications Architecture, as identified below:
TR 103 269-1: "Critical Communications Architecture Reference Model";
TS 103 269-2: "Critical Communications application mobile to network interface architecture".
Modal verbs terminology
In the present document "shall", "shall not", "should", "should not", "may", "may not", "need", "need not", "will",
(Verbal forms
"will not", "can" and "cannot" are to be interpreted as described in clause 3.2 of the ETSI Drafting Rules
for the expression of provisions).
"must" and "must not" are NOT allowed in ETSI deliverables except when used in direct citation.
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8 ETSI TS 103 269-2 V1.1.1 (2015-01)
1 Scope
The present document presents an overview of the architecture for a generic mission critical service for use by a Critical
Communications Application in network and terminal over a broadband IP bearer, with specific focus for LTE. The
architecture is part of the overall Critical Communications Architecture Reference Model, described in
ETSI TR 103 269-1 [1]. The overall architecture and services are described and the implementation of services
equivalent to the existing narrowband technologies, for example those in TETRA and Tetrapol systems. Off network
services are for future study and so are outside the scope of the present document.
2 References
2.1 Normative references
References are either specific (identified by date of publication and/or edition number or version number) or
non-specific. For specific references, only the cited version applies. For non-specific references, the latest version of the
reference document (including any amendments) applies.
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.
The following referenced documents are necessary for the application of the present document.
[1] ETSI TR 103 269-1: "TETRA and Critical Communications Evolution (TCCE); Critical
Communications Architecture; Part 1: Critical Communications Architecture Reference Model".
[2] IETF RFC 3261: "SIP: Session Initiation Protocol (SIP)".
[3] IETF RFC 5389: "Session Traversal Utilities for NAT (STUN)".
[4] IETF RFC 6665: "SIP-Specific Event Notification". .
[5] IETF RFC 3428: "Session Initiation Protocol (SIP) Extension for Instant Messaging".
[6] IETF RFC 3903: "Session Initiation Protocol (SIP) Extension for Event State Publication".
[7] IETF RFC 4566: "Session Description Protocol (SDP)".
[8] IETF RFC 5359: "Session Initiation Protocol Service Examples".
[9] IETF RFC 791: "Internet Protocol (v4)".
[10] IETF RFC 2460: "Internet Protocol, version 6".
[11] IETF RFC 793: "Transmission Control Protocol (TCP)".
[12] IETF RFC 4960: "Stream Control Transmission Protocol (SCTP)".
[13] IETF RFC 5246: "Transport Layer Security protocol (TLS)".
[14] IETF RFC 6347: "Datagram Transport Layer Security (DTLS)".
[15] IETF RFC 768: "User Datagram Protocol (UDP)".
[16] IETF RFC 3550: "Real Time Protocol (RTP)".
[17] IETF RFC 3711: "Secure Real Time Protocol (SRTP)".
[18] IETF RFC 5245: "Interactive Connectivity Establishment (ICE)".
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9 ETSI TS 103 269-2 V1.1.1 (2015-01)
[19] IETF RFC 5766: "Traversal Using Relays around NAT (TURN)".
2.2 Informative references
References are either specific (identified by date of publication and/or edition number or version number) or
non-specific. For specific references, only the cited version applies. For non-specific references, the latest version of the
reference document (including any amendments) applies.
NOTE: While any hyperlinks included in this clause were valid at the time of publication, ETSI cannot guarantee
their long term validity.
The following referenced documents are not necessary for the application of the present document but they assist the
user with regard to a particular subject area.
[i.1] ETSI TR 102 022-2: "User Requirements Specification Mission Critical Broadband
Communications; Part 2: Critical Communications Application".
[i.2] TETRA and Critical Communications Association; List of TIP features.
NOTE: Available at http://www.tandcca.com/Library/Documents/ListofTIPfeaturesv3.0.pdf
[i.3] ETSI EN 300 392-12: "Terrestrial Trunked Radio (TETRA); Voice plus Data (V+D); Part 12:
Supplementary services stage 3".
[i.4] 3GPP TS 22.179: "3rd Generation Partnership Project; Technical Specification Group Services
and System Aspects; Mission Critical Push to Talk MCPTT".
[i.5] IEEE 802.11: "IEEE Standard for Information technology- Telecommunications and information
exchange between systems Local and metropolitan area networks- Specific requirements -
Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY)
Specifications".
[i.6] IEEE 802.16: "IEEE Standard for Air Interface for Broadband Wireless Access Systems".
3 Definitions and abbreviations
3.1 Definitions
For the purposes of the present document, the following terms and definitions apply:
affiliation: process of negotiating access to communications with a group
NOTE 1: The TETRA term for affiliation is 'Group Attachment'.
NOTE 2: 3GPP TS 22.179 [i.4] uses the term 'Affiliation'.
call: set of one or more transmissions of media between two or more parties
call hang time: period within a call during which no communications are sent or received, and following expiry of
which, the call will be cleared
critical communications application: infrastructure based application which provides critical communications
services to its client Mobile Units
migration: obtaining Critical Communications service from a CCA other than the home CCA
mobile unit: combination of access network client terminal and client application for critical communications which
provides critical communications services to its user
registration: process of negotiating service from a CCA
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roaming: obtaining an IP connection to the home CCA from a broadband IP network other than the home broadband IP
network
NOTE: If a 3GPP LTE PLMN provides home service to a user, obtaining service from a different PLMN is an
example of roaming.
session: period within a period of affiliation to a group within which transmissions may be sent and received to and
from that group by using media control signalling only
session hang time: the period following a call during which the CCA may maintain a session before clearing it
3.2 Abbreviations
For the purposes of the present document, the following abbreviations apply:
rd
3GPP 3 Generation Partnership Project
AL Ambience Listening
APN Access Point Name
ASSI Alias Short Subscriber Identity
AVL Automatic Vehicle Location
BIC Barring of Incoming Calls
BOC Barring of Outgoing Calls
BS Base Station
CAD Call Authorised by Dispatcher
CCA Critical Communications Application
CCAS Critical Communications Application Server
CCS Critical Communications System
CF Call Forwarding
CFB Call Forwarding on Busy
CFU Call Forwarding Unconditional
CW Call Waiting
DGNA Dynamic Group Number Assignment
DHCP Dynamic Host Control Protocol
DL Discreet Listening
DMO Direct Mode Operation
DNS Domain Name Server
DOTAM DMO Over The Air Management
DTLS Datagram Transport Layer Security
DTMF Dual Tone Multi Frequency
eMBMS evolved Multimedia Broadcast Multicast Service
EPC Evolved Packet Core
EPS Evolved Packet System
E-UTRAN Evolved Universal Terrestrial Access Network
FFS For Further Study
GBR Guaranteed Bit Rate
HPLMN Home Public Land Mobile Network
ICE Interactive Connectivity Establishment
IMS IP Multimedia Subsystem
IMSI International Mobile Subscriber Identity
IP Internet Protocol
ISDN Integrated Services for Digital Network
LIP Location Information Protocol
LTE Long Term Evolution
MCP Media Control Protocol
MU Mobile Unit
N/A Not Applicable
NAT Network Address Translation
PABX Private Automatic Branch Exchange
PDN Packet Data Network
PIN Personal Identification Number
PLMN Public Land Mobile Network
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PMR Private/Professional Mobile Radio
ProSe Proximity Services
PSTN Public Switched Telephone Netwokr
PTT Press To Talk
RFC Request For Comment
RTCP Real-time Transport Control Protocol
RTP Real-time Transport Protocol
SCTP Stream Control Transmission Protocol
SDP Session Description Protocol
SDS Short Data Service
SDS-TL Short Data Service – Transport Layer
SIM Subscriber Information Module
SIP Session Initiation Protocol
SIP/IP Session Initial Protocol/Internet Protocol
SMS Short Message Service
SRTCP Secure Real-time Transport Control Protocol
SRTP Secure Real-time Transport Protocol
SS Supplementary Service
STUN Session Traversal Utilities for NAT
TBD To Be Decided
TCP Transport Control Protocol
TIP TETRA Interoperability Process
TLS Transport Layer Security
TMGI Temporary Mobile Group Identity
TURN Traversal Using Relays around NAT
TX Transmitter
UDP User Datagram Protocol
UE User Equipment
UMTS Universal Mobile Telecommunications System
URI Universal Resource Identifier
URS User Requirements Specification
UTRAN UMTS Terrestrial Radio Access Network
VPLMN Visited Public Land Mobile Network
WAP Wireless Application Protocol
WCMP Wireless Control Message Protocol
WLAN Wireless Local Area Network
WMAN Wireless Metropolitan Area Network
XML Extensible Markup Language
4 Architecture overview
4.1 Architecture reference
The Critical Communications Architecture Reference model is detailed in ETSI TR 103 269-1 [1]. The architecture and
interfaces are shown in Figure 1.
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Figure 1: CCS Reference Model
The present document describes the architecture of interface 4 in the reference model shown in the figure.
NOTE: ETSI TR 103 269-1 [1] contains the normative version of this figure.
4.2 Configurations
The functional architecture covered in the present document is presented below.
4.2.1 Single CCA system
The functional architecture for a single CCA system according to the present document is presented in Figure 2.
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Figure 2: Functional architecture
NOTE 1: The SIP proxy function may be part of the 'application control' interface or may be separate.
The Critical Communications Application Server CCAS has a number of entities responsible for establishing the service
and for exchanging individual and group communications with Mobile Units. The various entities of the CCAS use the
transport interfaces of the underlying broadband networks to exchange signalling and media with the mobile units.
Depending on the nature of the broadband access and of its capabilities and available interfaces, the CCA uses Control
interfaces of the broadband network to manage the transport bearers, i.e. to set up and release bearers and to request for
specific Quality of Service. This is typically the case when the Broadband access is an LTE Core Network, as illustrated
by the '3GPP EPS' in Figure 2. If those Control interfaces do not exist, for instance in the case of WiFi access, or are not
available, for instance in the case of an LTE network for which the control interface (Rx) is not made available to the
CCAS (for example in a back up commercial operator network), then the CCAS uses transport on default bearers. (Note
that in this case, a fully mission critical service may not be available.) This is illustrated by the 'Broadband Access'
network in Figure 2.
NOTE 2: The term Critical Communications Application Server is used to denote the set of entities that provide the
fixed end part of the CCA, which provide service to the client, or mobile, part of the application in the
MUs. The term 'server' does not imply any physical structure or number of physical devices that provide
this service.
One CCAS may make use of more than one broadband network. The broadband networks may be of the same type, for
example in the case where multiple 3GPP LTE networks are used to provide access to one CCAS. The broadband
networks may also be of mixed network types, such as a mixture of 3GPP LTE and WiFi networks which provide
service to the same CCAS. Multiple CCASs may also share the same broadband IP access network. Therefore there can
be a many-to-many relationship of CCASs and broadband IP access networks.
The CCA provides services to additional third party applications, for example to provide group addressed services, or
prioritised access services.
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4.2.2 Multi-CCA system
A multi-CCAS system is depicted in Figure 3.

Figure 3: Multi-CCAS system
In the multi-CCAS system each CCAS may be in contact with "home" mobile units, but may also offer access to mobile
units that have migrated to that CCAS as visitors. The visited CCAS allows routing of the signalling from a migrated
mobile unit to its home CCAS. The same inter-CCAS connection may also support communications between two MUs,
each at home in different CCASs.
NOTE 1: Each CCAS may use one or more broadband IP network for access by MUs.
NOTE 2: Multiple CCASs could be using one or more broadband IP networks in common for communication with
their respective MUs, and still support the migration behaviour.
NOTE 3: The interface between CCASs is outside the scope of the present document.
4.2.3 Interconnection with legacy
Interconnection with legacy networks is outside the scope of the present document. It will be satisfied by interface 8b
(8 bis) in figure 1, and its function is described in [1]. It may be realised by an existing interface from a legacy
technology, for example an Inter System Interface from the appropriate technology.
An interconnection with a legacy network may put constraints on services within the CCA, where a call includes one or
more parties connected over a legacy interface.
5 Components
This clause describes the functional groups involved in the implementation of the mission-critical PMR services over
broadband.
5.1 Mobile unit
The Mobile Unit (MU) is the (mobile) sub-system used by the user to access the mission critical application. The MU
contains the client part of the application and one or several modems able to interface with the access sub-systems
which provide IP connectivity for the client application.
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The access device may be an LTE UE, but the MU may alternatively comprise further access devices such as a WLAN
interface based on IEEE 802.11 standard [i.5] and/or various types of IP based wire-line interfaces.
5.2 Access sub-systems
The access sub-systems provide the link between the mobile client application and the infrastructure based application.
They are generally based on wireless technologies, particularly the 3GPP Long Term Evolution (LTE) technology, but
access may also be based on other type of wireless technologies such as WLAN (IEEE 802.11) or WMAN
(IEEE 802.16 [i.6]), or wire-line technologies.
It is assumed that the access sub-systems provide an IP based transport from the mobile unit (MU) to the application
server(s). It is also assumed that the corresponding sub-systems provide any ancillary functions required for proper use
of IP, e.g. a DHCP function to give a dynamic IP address to the MU where required and a master DNS function to allow
the MU to discover the addresses, ports and protocols, etc. of the available CCA server(s) where this is needed.
NOTE: No assumption is made on the use of a specific version of IP, i.e. IPV4 and/or IPV6.
5.3 Critical Communication Application
The CCA compris
...