Cisco Systems 11.0 BT SNA Session Switch-End Node Dlur, Multiple Hosts Support, LU-seed LU-name

VTAM Host Configuration Considerations for Dynamic LU Allocation

SNA Session Switch—End Node DLUR

An end node DLUR function is implemented as part of the TN3270 server. The purpose of the DLUR is to allow the routing of TN3270 LUs to multiple VTAM hosts to be performed in the CIP card rather than on the VTAM hosts. The need for this feature will increase with the introduction of the new multi-CPU CMOS mainframe which comprises up to 16 CPUs that appear as separate VTAMs.

The implementation of TN3270 server LUs under DLUR also allows the server to learn about the LU names on the ACTLU, which greatly simplifies the configuration to support specifically requested LUs such as printers.

Multiple Hosts Support

The TN3270 server supports access to multiple hosts via the configuration on a PU basis (Table 4). PUs connected to different hosts or applications can be configured with different IP address.

Table 4 Direct PU Configuration in Router

					Adapte
Comman	PU				r
d	Name	IDBLK	IP-address	Type	number	LSAP	RMAC	RMAC	LU-seed	LU-name
pu	X1	05D30001	192.195.80.40	tok	1	4	rmac	4100.cafe.0001	lu-seed	TN3X1###
pu	X2	05D30002	171.69.176.43	tok	1	8	rmac	4100.cafe.0002	lu-seed	TN3X2###

From the pu (direct) TN3270 configuration command values shown in Table 4, PU X2 establishes a link to a host at SAP 8 on MAC address 4100.cafe.0002. A client connecting to IP address 171.69.176.43 is allocated an LU from that PU and is routed to that host.

Note that by using the DLUR function, all the LUs in the server can be defined and owned by a controlling VTAM. When a client requests an application residing on a different VTAM host, the controlling VTAM will issue the request to the target host which will send a BIND directly to the client. All LU-LU data will then flow directly between the target host and the client without needing to go through the controlling VTAM.

VTAM Host Configuration Considerations for Dynamic LU Allocation

Other non-Cisco implementations of TN3270 support depend on predefined, static pools of LUs to support different terminal types requested by the TN3270 clients. The CIP TN3270 server implementation removes the static nature of these configurations by using a VTAM release 3.4 feature, dynamic definition of dependent LU (DDDLU). (Refer to the VTAM operating system manuals for your host system, under the descriptions for LUGROUP for additional information.) DDDLU dynamically requests LUs using the terminal type provided by TN3270 clients. The dynamic request eliminates the need to define any LU configuration in the server to support TN3270 clients emulating a generic TN3270 terminal.

To support DDDLU, the PUs used by the TN3270 server have to be defined in VTAM with LUSEED and LUGROUP parameters as shown in Figure 2.

8Configuring TN3270 Server on the Channel Interface Processor