182Appendix H: ASU background information

DMS-bus. While the rate adapter is responsible for mediating traffic flow between the F-bus and T-bus, the T-bus provides the following functionality:

T-bus for inter- and intra-LPP messaging (inter-LPP messaging is carried on DS30 links)

access to mapper hardware for logical-to-physical addressing

supports the LMS central processing unit (CPU), which is responsible for LPP diagnostics, maintenance, and maintaining configuration specific data in its memory

Single-shelf link peripheral processor

The SSLPP is a cost-competitive alternative for offices that do not need the number of slots offered by the LPP. The operating company can provision a maximum of 12 ASUs on the SSLPP.

The SSLPP allows the F-bus from a single link interface shelf (LIS) to connect directly to the DMS-bus with a fiber optic cable. The functions of the LMS are assumed by the DMS-bus. The shelf assembly is identical to that used in the LPP, with the major difference being the method used to connect it to the message switch (MS).

In the SSLPP, the F-bus interface circuit pack is replaced with an F-bus controller circuit pack, which handles the messaging to and from the ASUs and services and provides shelf control. The F-bus extender paddle board is replaced with a fiber interface paddle board, which interfaces to the fiber optic link and provides the system clock and out-of-band reset reception. Each F-bus controller connects to one of the two F-buses for the shelf and provides a connection to an MS. This arrangement provides the same minimum level of redundancy as in the LPP (where each F-bus is connected to only one of the two LMSs). In a single office, a maximum of two SSLPPs can be connected to the MS. The fiberized interface allows a selectable number of channels for future requirements (128 and 256 channels).

Figure 45 on page 183 provides an overview of the SSLPP configuration.

297-8991-910 Standard 03.01 August 1999

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Cabletron Systems DMS-100 manual Single-shelf link peripheral processor