IBM BC-201 manual Other Implementation Considerations, BC-223

Overview of IBM Networking

SNA FRAS

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.

SNA FRAS

Using Frame Relay Access Support (FRAS), the Cisco IOS software allows branch SNA devices to connect directly to a central site front-end processor over a Frame Relay network. FRAS converts LAN or Synchronous Data-Link Control (SDLC) protocols to a Frame Relay format understood by the Network Control Program (NCP) that runs in an FEP. The Cisco IOS software and the NCP support two frame formats:

•RFC 1490 routed format for LLC2, specified in the FRF.3 Agreement from the Frame Relay Forum and known in NCP literature as Frame Relay Boundary Network Node (BNN) support. Support for this feature requires NCP 7.1 or higher.

•RFC 1490 802.5 source-route bridged format, known in NCP literature as Frame Relay Boundary Access Node (BAN) support. Support for this feature requires NCP 7.3 or higher.

	Cisco IOS Bridging and IBM Networking Configuration Guide
78-11737-02		BC-223