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(Continuation of Question 11/15)
Background and justification
During the previous Study Period, a great part of the activity
of the Question has been dedicated to the definition of the
Network Node Interface (NNI) for the Optical Transport Network (OTN).
This work led to the development of the first version of
Recommendation G.709.
Moreover, new functionalities necessary to allow for the
transport of data (ATM, IP) over previously defined technologies
(such as SDH) have also been specified.
In view of the importance of IP-type traffic in the transport
network, there is no doubt that work will have to be further
progressed in these two areas.
The area of responsibility under this Question includes:
- Transport signal structure
- Client signals adaptation into transport signal
- Interfaces characteristics for the transport and
supervision of client signals
Responsibilities under this Question include the following
draft or published Recommendations:
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- Digital hierarchy bit rates |
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- Physical/electrical characteristics of hierarchical
digital interfaces |
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- Synchronous frame structures used at 1544, 6312, 2048,
8488 and 44 736 kbit/s hierarchical levels |
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- Frame alignment and Cyclic Redundancy Check (CRC)
procedures relating to basic frame structures defined in
Recommendation G.704 |
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- Network Node Interface for the Synchronous Digital
Hierarchy (SDH) |
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- Sub STM-0 Network Node Interface for the Synchronous
Digital Hierarchy (SDH) |
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- Network Node Interface for the Optical Transport
Network (OTN) |
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- Transmission performance characteristics of Pulse Code
Modulation channels |
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- Loss of Signal (LOS), Alarm Indication Signal (AIS) and
Remote Defect Indication (RDI) detection and clearance
criteria for PDH signals |
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- Vocabulary of terms for Synchronous Digital Hierarchy (SDH)
networks and equipment |
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- Characteristics of a 64 kbit/s cross-connect equipment
with 2048 kbit/s access ports |
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- Characteristics of a flexible multiplexer in a
Plesiochronous Digital Hierarchy environment |
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- ATM cell mapping into plesiochronous digital hierarchy
(PDH) |
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- Transport of SDH elements on PDH networks: Frame and
multiplexing structures |
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- Principles and guidelines for the integration of
satellite and radio systems in Synchronous Digital Hierarchy
(SDH) transport networks |
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- Hardware aspects of digital exchanges |
Question
- What enhancements should be made to the existing
Recommendations or what new Recommendations should be developed,
to reflect additional transport network applications and
interworking scenarios?
- What should be specified for the definition of new transport
network, while insuring transverse compatibility and interworking
with previously defined ones?
- What enhancements should be made to existing Recommendations or
what new Recommendations should be developed for networks
optimized for transport of packet data?
Study items
- Complete/enhance the definition of the OTN Network Node
Interface as regards its structure, the various embedded overhead
functionalities and the client signals (SDH, ATM, IP, Ethernet …)
mappings
- Specifications of the features necessary to implement an
Automatically Switched Optical Network (ASON)
- In the context of the evolution of the OTN, take into account a
more extensive use of (all) optical technology
- Outstanding study items identified in previously developed
Recommendations
- Specify additional Section Overhead (SOH) and Path Overhead (POH)
capabilities of the SDH for new network applications or
maintenance related aspects
- If appropriate, modify existing PDH related Recommendations
- Transverse compatibility of transport equipment in a
multi-vendor, multi-operator environment
- When applicable, backwards compatibility between new and
previously specified functionalities
Specific tasks
- Revisions to Recommendation G.703 by 2002
- Revisions to Recommendation G.707 by 2003
- Approval of G.709 by 02/01 and further revisions during the
Study Period
- Revisions to other Recommendations as required.
- Development of other relevant new Recommendations
Relationships
- Other Questions of SG 15 addressing transport equipment and
optical networks aspects
- ITU-T SG 4 on TMN and network maintenance.
- ITU-T SG 5 on overvoltage protection and EMC
- ITU-T SG 7 on IP related aspects
- ITU-T SG 13 on transport network architectures and network
performance objectives
- ITU-R SG 4 on satellite systems
- ITU-R SG 9 on radio-relay systems
- IETF - pppext Working Group on IP transport
- IEEE on Ethernet transport
- ATM Forum on ATM transport
- ATIS Sub-Committee T1X1.5
- ETSI
- Other fora and standardization bodies, as appropriate
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