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ITU-T Study Group 15 List of Questions Under Study (Study Period 2005-2008) |
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ITU-T SG 15 Question 3/15 |
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General characteristics of optical transport networks (Continuation of Question 19/15)
- Motivation
Due to the widespread introduction of high bit-rate, Internet, and Ethernet
services, the transport network is continuing to evolve worldwide based
on optical networking technologies. The optical network able to dynamically
provide multiplexing, routing and transporting of optical channels carrying
a variety of client signals is becoming reality. These new optical
networking characteristics are being developed to improve management
capabilities, expand service opportunities, and optimize transport of IP
and other data traffic.
Recognizing that without a strong coordination effort there is the
danger of duplication of work as well as the development of incompatible
and non-interoperable standards, the WTSA-2000 designated Study Group 15
as Lead Study Group on Optical Technologies within ITU-T.
SG 15 is continuing studies under various Questions on the following
aspects of optical transport networks, leading to several series of
published and planned Recommendations. These Recommendations include
aspects such as:
- architecture;
- functional characteristics;
- structure and mapping aspects;
- management aspects; and
- physical layer characteristics.
The most established series of Recommendations describes SDH networks.
Another series of Recommendations describes the OTN . A third series of
recommendations addresses ASON (Automatically Switched Optical Network).
ASON, based on requirements in Recommendation G.807, includes:
(a) distributed connection management; (b) automatic discovery;
(c) optical route selection; (d) connection access control.
In addition to these three series, metropolitan optical networks,
Ethernet frames over transport and studies on individual aspects of
optical networks continue to be pursued.
A coordination and communication activity among the involved Questions
is fundamental in order to facilitate the most efficient completion of
the work. This activity includes the identification of missing work
areas and those that are overlapping, or potentially so, between multiple
Questions or other standards groups. It also includes encouraging the
relevant work items in the most appropriate Questions, helping to
define a suitable time schedule, and monitoring its development in
a consistent way. For example, with regards to the introduction of
optical transport of Internet packets (“IP over Optical”), coordination
with IP-related groups inside and outside of ITU-T shall be pursued.
This should allow a proper integration of the indications coming from
Internet experts and those related to optical networking, and eventually
should ensure the mutual consistency of the standards prepared by the
various bodies, on this subject.
In addition, some general aspects of the optical transport network
including OTN, ASON, and Ethernet frames over transport, such as
general terminology or reliability/availability, need to be captured.
A communications, publicity, and promotion activity is also important
to support the adoption of ITU-T Recommendations throughout the industry.
External communications activities should aid in the consistency of
Recommendations and other standards related to optical technologies
across the industry.
The following major Recommendations, in force at the time of approval
of this Question, fall under its responsibility: G.871, G.911, G.780/Y.1351,
G.870/Y.1352, G.8081/Y.1353.
- Question
- What characteristics of optical transport networks still need to
be fully developed in the various network environments
(e.g. metropolitan, backbone, etc.), in what Study Question
and within what time schedule?
- What aspects of optical transport networks, related to
optical transport of IP, Ethernet, or Storage Area Network traffic,
need to be assigned to what Study Question for timely development?
- What enhancements to Rec. G.871 or what new Recommendation(s)
or mechanisms are necessary to capture, within this framework,
new or evolving aspects of optical transport networks, their
general terminology, and reliability/availability characteristics?
- What form of communication or publicity is prudent to
enhance the use of and alignment with ITU-T standards in the
area of optical transport networks and technologies?
Study items to be considered include, but are not limited to:
- Coordination of work in the following areas
- Automatically Switched Transport Network requirements aspects (Q12/15)
- Optical access networks (Q2/15)
- OTN & ASON functional characteristics (Q9/15)
- OTN & ASON structures and mapping (Q11/15)
- OTN & ASON architectural aspects (Q12/15)
- OTN synchronization characteristics (Q13/15)
- OTN & ASON management aspects (Q14/15; SG 4)
- OTN physical layer characteristics (Q5, 6, & 7/15)
- IP, NGN, and Ethernet aspects (Q5/13, 7/13, 16/12, and 17/12)
- Tasks
Tasks include, but are not limited to:
- Develop, maintain, and regularly distribute a baseline
overview/work plan that documents the work and time schedules
of all major new optical transport network activities
- Prepare possible new Recommendation(s) to address the
tasks above, and other items that may be identified
(e.g. a terminology Recommendation), as required
- Harmonize and align related terminology definitions
across Recommendations, striving for a single normative
definition for each term
- Maintain terminology Recommendations G.780/Y.1351,
G.870/Y.1352, & G.8081/Y.1353, creating amendments and
corrigenda to correct and add new terms as necessary
- Revise Recommendation G.871; as appropriate
- Facilitate the update of Recommendation G.911 in the
most appropriate technical Question as necessary
- Publicize results of ITU-T related to optical transport
networks and technologies in the form of press releases,
brochures, etc. when appropriate.
Note: An up-to-date status of work under this Question is contained in
the SG 15 Work Programme.
- Relationships
- Recommendations:
- All SDH, OTN, ASON, and Ethernet frames over transport related Recommendations
- Questions:
- Q2/15, Q6/15, Q7/15, Q9/15, Q11/15, Q12/15, Q13/15, Q14/15, Q5/13, Q7/13, Q16/12 and Q17/12
- Study Groups:
- ITU-T SG13 on IP, Ethernet, and NGN requirements
- ITU-T SG 4 on management and testing aspects
- Standardization bodies, forums and consortia:
- IETF on IP-related networks and protocols
- IEEE on Ethernet
- MEF on Ethernet
- OIF on optical networking
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