• ITU-T rec. Q.541(1988)
  • 1 General
  • 2 General design objectives
    • 2.1 Exchange modifications and growth
    • 2.2 Service provisioning and records
    • 2.3 Translations and routing information
    • 2.4 Resource utilization
    • 2.5 Physical design objectives
  • 3 Integrated Digital Network design objectives
    • 3.1 Exchange timing distribution
    • 3.2 Network synchronization
    • 3.3 Slip
    • 3.4 Relative Time Interval Error (TIE) at the exchange output
    • 3.5 Synchronization requirements when interworking with a digital satellite system
  • 4 Availability design objectives
    • 4.1 General
    • 4.2 Causes of unavailability
    • 4.3 Intrinsic and operational unavailability
    • 4.4 Planned outages
    • 4.5 Total and partial unavailability
    • 4.6 Statistical basis
    • 4.7 Relevant failure events
    • 4.8 Availability independence
    • 4.9 Intrinsic downtime and unavailability objectives
    • 4.10 Operational unavailability objectives
    • 4.11 Initial exchange availability performance
  • 5 Hardware reliability design objectives