| 摘要 |
Functional definitions and data transmission protocols are provided for both downstream and upstream OAM data flows in an ATM-based point-to-multipoint broadband access network ("BAN"), such as a passive optical network ("PON"). In particular, B-ISDN OAM functions are defined from an "OAM flow" perspective, wherein some of the PON physical layer related functions are performed at the F1 level flow, including all functions relating to the sign-on, ranging, power tuning, synchronization and timing status of the ONUs. F3 flow level functions are defined to include further performance and fault management functions, as well as MAC related functions, concerning mainly upstream and for upstream bandwidth management transactions between the headend facility and the respective ONUs. The F1 and F3 OAM data flows are transported in respective downstream frames and upstream packets in preferred protocols suitable for a point-to-multipoint network configuration. In particular, downstream F1 OAM flows are carried in specifically allocated overhead of each downstream frame header, with a downstream F1 "flow unit" defined as the entire frame. Downstream F3 OAM flows may be alternately carried in either the framing overhead, or in overhead associated with specific downstream ATM slots, with a downstream F3 flow unit defined as the respective ATM slots. Upstream F1 and F3 data flows are carried in specifically allocated overhead associated with each upstream packet.
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