IBM BC-203 Other Implementation Considerations, QLLC Command, Analogous SDLLC Command, BC-225

Overview of IBM Networking

IBM Network Media Translation

circuits (PVCs) are available, but the favored use is SVC. While the router maintains a permanent connection to the X.25 network, a remote device can use each SVC for some bounded period of time and then relinquish it for use by another device. Using a PVC is very much like using a leased line.

Table 3 shows how the QLLC commands correspond to the SDLLC commands.

Table 3 QLLC and SDLLC Command Comparison

QLLC Command	Analogous SDLLC Command
qllc largest-packet	sdllc ring-largest-frame, sdllc
	sdlc-largest-frame
qllc partner	sdllc partner
qllc sap	sdllc sap
qllc srb, x25 map qllc, x25 pvc qllc	sdllc traddr
qllc xid	sdllc xid
source-bridge qllc-local-ack	source-bridge sdllc-local-ack

Other Implementation Considerations

Consider the following when implementing QLLC conversion:

•To use the QLLC conversion feature, a router must have a physical link to an X.25 public data network (PDN). It must also have an SRB/RSRB path to an IBM FEP. This link could be a Token Ring or Ethernet interface, or even FDDI, if RSRB is being used.

•QLLC conversion can run on any router with at least one serial interface configured for X.25 communication and at least one other interface configured for SRB or RSRB.

•QLLC conversion security depends upon access control in SRB/RSRB and X.25 and upon XID validation.

You can configure DLSw+ for QLLC connectivity, which enables the following scenarios:

•Remote LAN-attached devices (physical units) or SDLC-attached devices can access an FEP or an AS/400 over an X.25 network.

•Remote X.25-attached SNA devices can access an FEP or an AS/400 over a Token Ring or over SDLC.

For information on configuring DLSw+ for QLLC conversion, refer to the “Configuring DLSw+” chapter.

You can configure DSPUs for QLLC. For more information on this configuration, refer to the “Configuring DSPU and SNA Service Point” chapter.

Cisco IOS Bridging and IBM Networking Configuration Guide

BC-225