4 6 FSU User Manual 61200.130L1-1Chapter 6. DTE Port ConfigurationEdit Previous Entry (PREV key on front panel)Edit the previous entry in the address table.Delete This Entry (DEL key on front panel)Delete the current entry in the address table.Add New Entry (ADD key on front panel)Add a new entry to the address table.There should be one entry for every virtual circuit on the frame relayDTE port.SDLC ProtocolSDLC is a synchronous, bit-oriented, full-duplex, Layer 2protocol used to connect SDLC devices to a frame relay network.At Layer 2, SNA networks use SDLC between FEPs (front-endprocessors) and cluster controllers. This protocol selectionprovides Logical Link Control Type 2 (LLC2). LLC2 defines thedata link frame header and supports the multiplexing of one ormore data links to/from separate service access points (SAPs).Type 2 provides acknowledged, connection-oriented service. SeeFigure 6-5.The PU (physical unit) address, LLC2 SSAP, LLC2 DSAP, andoutgoing DLCI are used to set up an end-to-end SDLC sessionfor each PU in the network. The PU address elements shouldmatch the address of each controller address attached to the port.The DLCI determines the path across the frame relay networkand is given by the service provider. The SSAP/DSAP pairs areuser-defined but should match between two FSUs for each SDLCsession.All PU addresses for a port must be unique, but it is not necessary thatthey match the PU address at the remote end. The SSAP/DSAP/DLCIis used to make the connection across the frame relay network.
