Terms:

  • Kbps Kilobits per second
  • Mbps Megabits per second
  • Gbps Gigabits per second
  • OC-n Optical Carrier (Fundamental unit of SONET)
  • SONET Synchronous Optical NETwork/Synchronous Digital Hierarchy)
  • STM-1 Synchronous Transport Module, level 1 (starts at 155.52Mbps)
  • STS-1 Synchronous Transport Signal, level 1 (starts at 51.84Mbps)

  • Conversion chart:

  • T1 = 1.544Mbps
  • E1 = 2.048Mbps (European)
  • T3 = 45Mbps
  • OC-1 = STS-1 = 51.84Mbps
  • STM-1 = OC-3 = 155.52Mbps (approx)
  • STM-1 = STS-3 = 3 x STS-1 = 3 x 51.84 = 155.52Mbps
  • STM-16 = OC-48 = 48 x STS-1 = 48 x 51.84 = 2488.32Mbps

  • Network Interface Reference Table

    (borrowed from Motorola)

    Interface Medium Data Rate Capacity VT/VC Designation
    DS0 Twisted Pair 64 kbps 1 DS0
    ISDN BR Twisted Pair 144 kbps 2B+D (2DS0)
    DS1/ISDN PR Twisted Pair 1.544 Mbps 24 DS0 VT 1.5/VC-11
    E1 Twisted Pair 2.048 Mbps 32 DS0 VT 2.0/VC-12
    ADSL Twisted Pair 6.384 Mbps 96 DS0
    Ethernet Coax 10 Mbps N/A
    E3 Coax 34.368 Mbps 16 E1=512 DS0 VC-31
    FDDI Coax/Fiber 100 Mbps N/A
    STS-1 Coax 51.84 Mbps 672 DS0 28 VT 1.5 or 1 DS 3
    STS-3 Coax 155.520 Mbps 2,016 DS0 3 STS-1
    E4 Fiber 139.264 Mbps 4 E3=2,048 DS0 VC-4
    OC-1 Fiber 51.84 Mbps 672 DS0 Optical STS-1
    OC-3/STM-1 Fiber 155.520 Mbps 2,016 DS0 3 STS-1 / 1 STM-1
    OC-12/STM-4 Fiber 622.080 Mbps 8,064 DS0 12 STS-1 / 4 STM-1
    OC-48/STM-16 Fiber 2488.32 Mbps 32,256 DS0 48 STS-1 / 16 STM-1
    OC-192/STM-64 Fiber 9953.28 Mbps 129,024 DS0 192 STS-1 / 64 STM-1

    Reference Links

  • (From ZeitNet) Good overview of ATM
  • (From SunWorld) Review of Sun's new OC-12 (622Mbps) ATM Adapter for Sun workstations

  • Copyright © 1993-2001 by Robert Barnes

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