ADTRAN SHDSL NxNTU specifications Multiple Services, Operation

Multiple Services

The NTU supports the configuration of multiple services. These services are routed to either the G.703/G.704 interface or the Nx64k interface. The Nx64k interface supports a single service with

1 <= N <= 36. The G.703 interface (with G.704 framing) supports multiple services (often termed “Stacked E1”). The G.703 interface without any framing supports a single 2048 kBit/s service. (See ITU-T G991.2 Annex. E.1-TPS-TC for European 2048 kbit/s digital Unstructured Leased Line (D2048U).)

The Nx64k service and G.703 service are capable of operating simultaneously. The total number of time slots must be less than or equal to the maximum number of SHDSL time slots (excluding TS0 if structured E1 is used). The G.703 interface with framing (G.704) runs over SHDSL in aligned mode and supports simultaneous services using the Nx64k port for the second service. (See ITU-T G991-2 Annex E.7 - TPS-TC for Aligned European 2048 kbit/s digital Structured Leased Line (D2048S) and Fractional.)

The SHDSL NTU supports CRC-4 detection/ generation toward the SHDSL network (Figure 22). The CRC-4 detection/generation can operate in the following modes (configurable via the management interface):

When less than 32 time slots are configured on the G.703 port, the NTU bases the CRC-4 detection/ generation on filling the unused time slots with a fixed pattern configurable via the management interface. This CRC-4 detection/generation is also required for multirate (single or simultaneous services) where less than 31 G.704 time slots are carried over the SHDSL line.

NOTE

All framed services operate in aligned mode.

Operation

The SHDSL NTU supports multiple rate line operation as specified in ITU-T G.991.2. All services described in this document operate in multiple rate mode, with a corresponding change in maximum payload. Unstructured E1 is supported for SHDSL rates equal to 32 and with all G.703 time slot assignments equal to the same G.703 service value (1 to 31).

The G.703 interface supports operation in the following modes that are selectable via the management interface:

1.Framed

2.Framed pass through

1. CRC-4 detection/generation disabled	3. Unframed	Nx64kService(10x64k)
2. CRC-4 detection/generation enabled
Nx64k Service
SHDSL Time lots
9TS876543	TS3 2 1
15432109876543210987654320 210
E1Service(12x64)
E1 Service		ReplcewithforCRCanEOC-Nx64kcalculationsdefinedServicepattern.TSs
9TS876543	2 1
1TS309876543210987654 1320 210
CRC-4Calculation
Figure 22. CRC-4 Detection/Generation

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