. Figure 3-6 depicts the basic frame format. Figure 3-5 SONET Optical Line Rates SONET optical line Optical Carrier Level Electrical Equivalent Line Rate Mbps rates. STS-1 51.84 STS-3 155.52 OC-12 STS-12 622.08 OC-48 STS-48 2488.32 OC-192 STS-192 9953.28 Chapter 3 Transport 90 Columns Figure 3-6 Overhead 87 Columns Basic frame format. Time domain: Section 125 microseconds Overhead 9 Rows PAYLOAD Overhead Overhead (3 columns) STS-1 Synchronous Payload Envelope A1: Framing A1: Framing C1: STS-1 ID J1: Trace Section Overhead B1: BIP-8 E1: Orderwire F1: User Ch B3: BIP-8 Basic SONET rate = 9 rows X 90 columns X 64 kbps = 51.84 Mbps D1: Data Com D2: Data Com D3: Data Com C2: Signal L Total size = 9 rows X 90 columns = 810 bytes/125us Overhead = 9 rows X 3 columns = 27 bytes/125.S H1: Pointer H2: Pointer H3: Pointer A G1: Path St Payload capacity 9 rows X 87 columns = 783 bytes/125us B2: BIP-8 K1: APS K2: APS F2: User Ch Information capacity = 9 rows X 86 columns = 774 bytes/125 D4: Data Com D5: Data Com D6: Data Com H4: Multifrm Section overhead = 576 Kbps Overhead D7: Data Com D8: Data Com D9: Data Com Z3: Growth Line overhead = 1.152 Mbps Path overhead = 576 Mbps D10: Data Com D11: Data Com D12: Data Com Z4: Growth Information payload = 50.112 Mbps Z1: Growth Z2: Growth E2: Orderwire Z5: Growth One Octet Path Layer Overhead (can float to right) SONET provides several capabilities that are of interest to both carriers and users: An electrical and optical transmission standard A multiplexing hierarchy A strong OAM&P capability A restoration apparatus Figure 3-7 conveys the basic multiplexing structure of SONET. When using SONET, voice interfaces (DS1s and DS3s), high-speed data (private lines, IP, and 10 GbE), and video can be accepted by various types of service adapters. A service adapter maps the signal into the payload envelope of the Synchronous Transport Signal-1 (STS-1) or onto a virtual tributary (VT). VTs are constructs principally for the support of DS1s,5 and this book does not focus extensively on them. Ne