SONET/SDH Digital Hierarchy

ANSI SONET Standards

The American National Standards Institute (ANSI) coordinates and approves SONET standards. The standards are actually developed by Committee T1 which is sponsored by the Alliance for Telecommunications Industry Solutions (ATIS) and accredited by ANSI to create network interconnection and interoperability standards for the United States. T1X1 and T1M1 are the primary T1 Technical Subcommittees responsible for SONET. T1X1 deals with "digital hierarchy and synchronization". T1M1 deals with "internetworking operations, administration, maintenance, and provisioning (OAM&P). Listed below are some of the most commonly cited SONET standards available from ANSI. Refer to the ANSI web site at http://www.ansi.org for a complete list of SONET standards along with information on purchasing the documents.

• ANSI T1.105: SONET - Basic Description including Multiplex Structure, Rates and Formats
• ANSI T1.105.01: SONET - Automatic Protection Switching
• ANSI T1.105.02: SONET - Payload Mappings
• ANSI T1.105.03: SONET - Jitter at Network Interfaces
• ANSI T1.105.03a: SONET - Jitter at Network Interfaces - DS1 Supplement
• ANSI T1.105.03b: SONET - Jitter at Network Interfaces - DS3 Wander Supplement
• ANSI T1.105.04: SONET - Data Communication Channel Protocol and Architectures
• ANSI T1.105.05: SONET - Tandem Connection Maintenance
• ANSI T1.105.06: SONET - Physical Layer Specifications
• ANSI T1.105.07: SONET - Sub-STS-1 Interface Rates and Formats Specification
• ANSI T1.105.09: SONET - Network Element Timing and Synchronization
• ANSI T1.119: SONET - Operations, Administration, Maintenance, and Provisioning (OAM&P) - Communications
• ANSI T1.119.01: SONET: OAM&P Communications Protection Switching Fragment

ITU-T SDH Standards

The International Telecommunications Union (ITU) coordinates the development of SDH standards. ITU was formerly known as the CCITT. It is sponsored by the United Nations and coordinates the development of telecommunications standards for the entire world. Listed below are some of the most commonly cited SDH standards available from ITU. Refer to the ITU web site at http://www.itu.int for a complete list of SONET standards along with information on purchasing the documents.

• ITU-T G.707: Network Node Interface for the Synchronous Digital Hierarchy (SDH)
• ITU-T G.781: Structure of Recommendations on Equipment for the Synchronous Digital Hierarchy (SDH)
• ITU-T G.782: Types and Characteristics of Synchronous Digital Hierarchy (SDH) Equipment
• ITU-T G.783: Characteristics of Synchronous Digital Hierarchy (SDH) Equipment Functional Blocks
• ITU-T G.803: Architecture of Transport Networks Based on the Synchronous Digital Hierarchy (SDH)

Bellcore Documents

Bell Communications Research (Bellcore) has issued over 50 documents that relate to SONET. The document most commonly cited is listed below. Refer to the Bellcore web site at http://www.bellcore.com for a complete list of documents along with information on purchasing the documents. Bellcore documents are very expensive with the following document listing for US $740.

• GR 253 CORE: SONET Transport Systems: Common Generic Criteria

ATM over SONET

The following standard from ITU defines the mapping of an ATM cell stream into an SDH frame structure.

• ITU-T I.432: B-ISDN User-Network Interface - Physical Layer Specification

Packet Over SONET (POS) Documents

The Internet Engineering Task Force (IETF) has released RFCs that describe the use of Point-to-Point Protocol for transferring IP traffic natively over SONET and SDH circuits. These RFCs were developed by the PPP Extensions Working Group of IETF.

• IETF RFC1619: PPP over SONET/SDH
• IETF RFC1661: The Point-to-Point Protocol (PPP)
• IETF RFC1662: PPP in HDLC-like Framing