Transcript Slide 1

TETRA Inter System Interface
(ISI)
An update and review of specific issues
John Cox
CEO TETRA MoU Association
Inter System Interface (ISI)
• An important part of the TETRA standards
suite
• Defines interoperability between radio
networks
• Published by ETSI (European
Telecommunications Standards Institute)
• Korean National version published by TTA
(Korean Standardisation Organisation)
ISI usage
International cross-border cooperation
ISI
Country A
Country B
ISI Usage
National Multivendor Cooperation
ISI
Subnetwk B
Subnetwk A
ISI Usage
Local In Country Cooperation
ISI
User B Network
User A Network
Interoperability Certification Process
• Managed by TETRA MoU Association
• Ensures genuine multi-vendor market for
operators, users and suppliers of TETRA
• TETRA Interoperability Profile (TIP)
specifications are produced to…
– Guide the implementation and
– Give detailed instructions for conducting
Interoperability test sessions
• Test sessions are carried out under the
supervision of an independent Italian
Government Organisation, ISCTI
Status of ISI TIP’s – June 2005
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Comprehensive set of TETRA ISI TIP’s have been published for
the implementation of operational network solutions:
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Individual Call
Mobility Management
Short Data Service
Group Call
Voice Transmission Format
Lower Layer Protocols
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Original Plan – reviewed by Member’s Enquiry (ME)
Revised Plan – about to re-enter the ME stage
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Air Interface Migration tested April 2005 (required for terminals to roam across
an ISI)
ISI test
• Planned for later in 2005
• Awaiting manufacturers to inform TETRA MoU Association that they are ready
Test Plan Documents
ISI and related Test Sessions
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3-Country Pilot Interworking Verification Project
• Tested interworking between national networks
• Security agencies from Belgium, Germany & the
Netherlands participated
• Equipment
– Networks from Motorola & Nokia
– Terminals from Motorola, Nokia and other manufacturers
• Phase 1 report concluded “… that the European
TETRA standard provides the communication
requirements for the future emergence of a new
dimension of co-operation of security agencies in
Europe.”
• Full report available at www.3countrypilot.com
Developments after the 3-Country Pilot
• Functional Requirements Specification developed
• Produced by combined group working from:
– Belgian and Dutch Security Agencies
– Motorola and Nokia
• Scope – detail the communicating technology
needs based on the development scenarios (the
practical tests carried out by multi-agency teams
during the pilot)
• Specification now an ETSI Technical Report – TR
101 448
ETSI Project TETRA –
additional ISI specifications
• TR 101 448 analysed by ETSI Project TETRA and
TETRA ISI TIP Working Group
• New work item established, supported by
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Astrid (Belgian Public Safety)
ISC (The Netherlands Public Safety)
Motorola
Nokia
• New requirements for TETRA ISI TIP specification
identified
• Additional functionality for group attachment through
the ISI to the TETRA ISI Mobility Management
standard
• ETSI Project TETRA has been replaced by TETRA
Technical Committee
Update on specific functions supported
by current ISI TIP specification
• Priority call & Emergency call
– Can be delivered through ISI allowing emergency call to
continue on other side of ISI
• Individual call
– Test plan currently at ME stage – anticipated to be
completed by the end of June 2005
– No restoration during migration – not identified as
necessary by 3-Country Pilot teams
• Group call
– Not covered in ISI TIP as calls can be re-established by
Late Entry or by pushing PTT once
Encrypted functionality and the ISI
• Current ISI TIP’s are ready for air
interface encryption with Dynamic
Cipher Key (DCK)
• Over The Air Rekeying (OTAR) and
Group Cipher Key (GCK) functions
could all be included if they become
user organisation requirements
Group attachments across the ISI
• Current situation
– ISI TIP’s assume that group attachments are done in the
network where the radio is registered using a local
‘agent’
• New ETSI work item identified
– Work in progress to allow the network identifier part of
the group number to be delivered across the ISI to
enable direct attachment from the other side of the ISI
• TIP and test case will be updated when the
content of the new standard is finalised
Dynamic Group Number
Assignment across the ISI
• DGNA handling logic is same as for
Group Attachments:
– DGNA is performed in the network where the
radio is located
– DGNA message sent by the dispatcher located
in the same network as the radio
• Current ISI TIP’s do not support
DGNA between networks
Radio Enable/ Disable across the ISI
• Amendment to current ISI TIP was
identified in 3-Country Pilot
• ISI TIP Working Group suggestion:
– Enabling/disabling should be linked with
authentication
– Home network of a stolen radio would not
grant other networks a permission to
authenticate that radio
• Modification to the ISI standards
NOT needed if this proposal is
accepted by users
Packet Mode Data Call across the ISI
• IPI (Internetwork Packet Interface) is
Packet Data Gateway standard for TETRA
• ETSI reference is ETSI TS 101 747 ‘IP
Interworking (IPI)’
• Same interface as ALREADY used to
connect TETRA packet core networks to
the Internet
• Additional specification to cover packet
data NOT required
End to end encryption across the ISI
• Current ISI TIP's support end-to-end
encryption
• ISI delivers TETRA voice frames
transparently through the interface
• SwMI’s should be expected to
transport end-to-end encrypted
communication as long as they are:
– Compliant with SFPG recommendations, and
– Can support ISI connectivity
Future revisions of documents
• Drafting work for TIP’s and Test Plans is done by
voluntary resources from the manufacturers
• Manufacturer priorities typically depend on demand
from the operators and users
• In general, ISI work has high priority
• Required amendments are quite minor
• Time required to make the identified revisions is
shorter than the time required to produce the ISI
Test Plans
• Conclusion
– ‘revision’ work would NOT be the limiting factor in the time-to
market for interoperable TETRA ISI
Sources of further
information
www.tetramou.com
www.3countrypilot.com
www.etsi.org
Thank you
John Cox
Chief Executive Officer
TETRA MoU Association
[email protected]