| 单词 | Table S-2: SONET/SDH Signal Hierarchy |
| 释义 | Table S-2: SONET/SDH Signal Hierarchy Optical Carrier SONET STS SDH STM Signaling Equivalent Equivalent DS-0 (OC) Level Level Level Rate DS-3 Channels Channels OC-1 STS-1 51.84 Mbps 1 672 OC-21 STS-2 103.68 Mbps 2 1,344 OC-32 STS-3 STM-1 155.52 Mbps 3 2,016 OC-4 STS-4 STM-3 207.36 Mbps 4 2,688 OC-91 STS-9 STM-3 466.56 Mbps 9 6,048 OC-12 STS-12 STM-4 622.08 Mbps 12 8,064 OC-181 STS-18 STM-6 933.12 Mbps 18 12,096 OC-24 STS-24 STM-8 1.24416 Gbps 24 16,128 OC-361 STS-36 STM-12 1.86624 Gbps 36 24,192 OC-48 STS-48 STM-16 2.48832 Gbps 48 32,256 OC-961 STS-96 STM-32 4.976 Gbps 96 64,512 OC-192 STS-192 STM-64 9.953 Gbps 192 129,024 OC-768 STS-768 STM-256 39.813 Gbps 768 516,096 OC-15363 STS-1536 STM-512 79.626 Gbps 1536 1,032,192 OC-30723 STS-3072 STM-1024 159.252 Gbps 3072 2,064,384 1 OC-2, OC-9, OC-18, OC-36, and OC-96 are considered to be orphaned rates. 2 OC-3 was defined by the CCITT as the basic transport rate for B-ISDN. 3 This level is not fully defined. The STS-1 frames are organized into 9 rows of 90 octets transmitted every 125µs, which is the requirement for voice encoded using the standard pulse code modulation (PCM) technique employed in the public switched telephone network (PSTN). The STS-1 frame, as illustrated in Figure S-5, comprises a Synchronous Payload Envelope (SPE) of 783 octets, plus 27 octets of overhead comprising Section Overhead (SOH), Line Overhead (LOH), and Path Overhead (POH).The payload in each frame comprises one or more Virtual Tributaries (VTs) organized into Virtual Tributary Groups (VTGs).A process known as concatenation allows multiple STS-1 frames to be multiplexed, switched, and transported over the network as a single entity. 74570c19.qxd 9/12/07 12:41 AM Page 451 |
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