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Question 5/15 - Compression and classification in signal processing network equipment

(Continuation of Questions 6/15 and part of Question 5/15)

Background and justification

Voice-band compression equipment is utilized worldwide to optimize transmission bandwidth capacity. SG 15 has developed the Recommendations for Circuit Multiplication Equipment such as G.763, G.764, G.765, G.766 and G.767 and related TMN aspects such as G.776.1 and G.776.3. As traffic characteristics change, there is a market need to apply the following aspects in a new generation of compression equipment reflecting the experiences gained from previous generations of equipment:

  • Enhancement of signal compression techniques to accommodate new types of signals
  • Enhancement of channel multiplexing capabilities to accommodate new types of services
  • Introduction of voice band signals compression equipment to IP Networks
  • Enhancement of system controls to maintain end-to-end signal qualities as high as possible
  • Responsibility under this question includes the G.76x series of Recommendations


  • What new or revised signal compression techniques should be used?

  • How should the Recommendations be updated to account for changes in end-user equipment technologies?
  • How can the capabilities of voice-band signal compression equipment be extended to account for new network services?
  • How can the user ensure proper end-to-end operation of voice-band signals compression equipment?

  • What new, modified, or adapted techniques are to be utilized within voice-band signals compression equipment for ATM or IP networks?
  • How should Common aspects of CME be recommended to enable versatile interface to networks and OAM facilities?

Study items

Study items to be considered include:

  • Evaluation/development of traffic signal classification schemes
  • Evaluation/development of data demodulation/remodulation mechanisms for voice band signal compression equipment
  • Evaluation/development of tandem avoidance operational mechanisms for voice band signal compression equipment
  • Evaluation/development of schemes for nx64 kbit/s unrestricted services
  • Enhancement of Rec. G.766 to handle higher bit-rate and T.30 NSF protocol signals of facsimile
  • Definition of rules for automatic activation of forward error correction on demodulated facsimile traffic
  • Definition of additional controls for built-in echo cancellation capabilities implemented in voice-band signals compression equipment
  • Addition of capability to request and provide end-to-end provisioning parameters, traffic engineering and facility performance information in voice-band signals compression equipment
  • Addition of real-time configuration access to voice-band signals compression equipment
  • Mechanism for reflecting ATM or IP congestion information to corresponding PDH access side
  • Mechanism for maintaining QoS in ATM and IP Networks
  • Identifying system parameters required for voice-band signals compression equipment
  • Specifying interfaces
  • Specifying Operations and Administration aspects of Digital Circuit Multiplication Equipment (DCME), Voice on ATM Multiplication Equipment (VAME) and Circuit Multiplication Equipment Optimised for IP based Networks (IPCME)
  • Activities to enhance reliability of its Recommendations, e.g. interoperability. The question will actively participate in pre-standardization testing activities formed to such regard

Specific tasks

  • Draft new Recommendation G.768, I.733 (2001) and G.IPCME(2002)
  • Revision of G.766 (2002)
  • Re-configuration of Structure of CME Recommendations (2002)
  • Draft new Recommendation on Channel Compression (2002)
  • Draft new Recommendation on voice band signal classification (2002)
  • Draft new Recommendation on Comfort Noise Insertion (2003)
  • Draft new Recommendation on CME Tandeming Avoidance Control (2003)
  • Draft new Recommendation on Voice Band Data Demodulation/Remodulation (2004)
  • Draft new Recommendation on Configuration Map Interchange Format for CME (G.776.2) (2002)
  • Revision of relevant sections of G.776.1(Managed Objects of SPNE) and G.776.3 (DCME Configuration Map)to include G.767, G.768 DCMEs and G.IPCME (2002)
  • Draft new Recommendation on common equipment aspects of CME (2002)


  • Other SG 15 Questions as relevant on SPN functions
  • ITU-T SG 2 on dimensioning of CME
  • ITU-T SG 4 for guidance on TMN
  • ITU-T SG 8 on modems and facsimile
  • ITU-T SG 11 on signalling interfaces and protocols
  • ITU-T SG 12 on speech performance
  • ITU-T SG 13 on network implications
  • ITU-T SG 16 on speech encoding algorithms
  • ATM Forum on ATM network transport
  • IETF on IP network transport
  • ITU-R SG 4 WP4B on voice on mixed terrestrial/satellite networks


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Updated : 2004-10-21