scope:

This Recommendation specifies a protocol suite structure of Ethernet frame (defined by IEEE WG 802.3) over LAPS for the purpose of providing the future protocol compatibility among peer systems in the light of ITU-T X.200, and applies to Synchronous Digital Hierarchy (ITU-T G.707/Y.1322). LAPS protocol and specification introduced in ITU-T X.85/Y.1321 continue to be used to address its capabilities of providing the adaptation from Ethernet to LAPS. LAPS describes an HDLC-like framing structure to encapsulate IEEE 802.3 Ethernet MAC frame as shown in Figure 7, provide a point-to-point full-duplex simultaneous bidirectional operation. Connecting Ethernet Switches to a SDH network is a very attractive way to provide Ethernet over a Wide Area Network. It is transparent to the Ethernet switch that one or more Ethernet switch ports are connected. The relationship between LAPS and Ethernet and SDH physical layer, together with the Rate.

This Recommendation does not specify the method of mapping LAPS to SDH. No change is made for all Ethernet-based protocols (including IEEE 802.3 Ethernet) and all SDH standards.

NOTE 1 - It is intended that Ethernet over LAPS can be extended, in future amendments, to support additional new types of data service.

NOTE 2 - LAPS used in this Recommendation is not used to coexist with HDLC (ISO/IEC 3309 or RFC 1662), LAPB/ITU-T X.25, LAPD/ITU-T Q.921 and LAPF/ITU-T Q.922 within the same physical layer in future.

NOTE 3 - This Recommendation shall be applied to SDH sub-rates for IEEE 802.3 Ethernet.