COMSPHERE 3600 Series Data Service Units4-58 July 1999 3610-A2-GB41-70Digital SharingFigures 4-46 and 4-47 show how digital sharing is usedwith LPDA-2 monitoring. When a digital-sharing group isconfigured on a tributary DSU, the DSU recognizesmultiple LPDA-2 addresses instead of one. The number ofaddresses is equal to the number of ports comprising thedigital-sharing group.The tributary DSU answers to any LPDA-2 commandcontaining one of the addresses. The DTE connected tothe digital-sharing group must use consecutive PUaddresses. The group must start with Port 1 for the DSUto support LPDA-2 monitoring on each port of the sharinggroup. (A digital-sharing group can be started on anyother port, but it will be ignored by the LPDA-2 protocol.)From the NetView operator’s perspective, thedigital-sharing feature appears as a unique DSU connectedto each DTE. The LPDA-2 address is set to the lowest PUaddress. The DTE with the lowest PU address is thenconnected to Port 1. The DTE with the next consecutivePU address is connected to Port 2 and so on, as shown inFigures 4-46 through 4-49.In Figures 4-46 and 4-48, directing a DSU/CSU andLine Status command to LPDA-2 Address 4 will reportthe DTE status of Port 3. In Figures 4-47 and 4-49,directing a DSU/CSU and Line Status command toLPDA-2 Address 4 will report the DTE status of Port 2 ofthe second tributary DSU.NOTEFor MCMP, a digital-sharinggroup is created by assigningthe same channel to each portin the group. However, for theSNA Diagnostic Interface optionto recognize the digital-sharinggroup, the group must bespecified by the Sharing DeviceA (Share DevA) configurationoption.Figure 4-46. Digital Sharing in a Point-to-Point Circuit
