(Continuation of Question 18/13)

Background and justification

Network synchronization performance specifications are essential for successful operation and integration of digital transmission networks and associated switching and signalling systems. Network timing performance studies are needed to determine the feasibility and most effective means of implementing a time reference distribution service.

Items for study

1. How can the different clock types in G.812 be further harmonized, particularly with reference to jitter generation, filter bandwidths, TDEV and MTIE masks for input wander tolerance and jitter tolerance?
2. How can the different clock types in G.813 be further harmonized, particularly with reference to jitter generation, filter bandwidths, TDEV and MTIE masks for input wander tolerance and jitter tolerance?
3. Which jitter and wander requirements for STM-256 interfaces have to be added in Rec. G.825?
4. What new or revised Recommendations are required on network clock and time synchronization, jitter, and wander performance for digital networks that are based on B-ISDN?
5. What slip performance levels should be recommended?
6. What is the network functionality required to provide real-time distribution of absolute time-of-day reference services? What network capabilities are required to support the performance levels necessary to satisfy a selected set of time-of-day user applications?
7. How can network synchronization performance be enhanced through the use of synchronization status messages?
8. What network synchronization characteristics, for both normal and degraded mode, should be recommended for services carried over ATM? What is the dependence on synchronization of performance of various methods of service clock recovery with respect to service requirements (e.g. jitter, wander and slips etc)
9. Is synchronization a key issue for IP based networks and if so what network synchronization characteristics should be recommended for services carried over such networks?
10. What network synchronization characteristics and jitter requirements are needed for the OTN in case of possible TDM multiplexing? How does the OTN impact existing synchronization architectures?
11. Which jitter and wander requirements are needed for wireless network applications?
12. Define an additional reference chain for "modern" SDH networks to be added in Rec. G.803.

Tasks with deadlines

• Possible revised Recommendation G.810 by 2004 – based on new terminology from ATM, IP and OTN areas.
• Revised Recommendation G.811 by 2002 – revised to reflect changes as required
• Revised Recommendation G.812 by 2004 – revised to reflect changes as required
• Revised Recommendation G.813 by 2004 – revised to reflect changes as required
• Revised Recommendation G.825 by 2004 – revised to reflect changes as required
• Possible new Recommendation or Supplement on ATM synchronization by 2004
• Possible new Recommendation or Supplement on IP synchronization by 2004
• Possible new Recommendation or Supplement on OTN synchronization by 2004

Relationships

• ITU-T Study Groups on TMN
• ITU-T Study Groups on clock performance for switching equipment
• ITU-T Study Groups on transmission equipment
• ITU-R Study Groups on broadcasting and mobile aspects