Cisco Systems 11.0 BT manual Specific LU Allocation, Examples of Model String Mapping

Configuring TN3270 on a Channel Interface Processor

•IBM-DYNAMIC: This will result in “DYNAMIC” being put in the model type and number field. The VTAM configuration will need to have “DYNAMIC” defined as a template in the LU group. In fact “IBM-ZZ..Z,” where “ZZ..Z” does not match the preceding syntax, will be forwarded as “ZZ..Z.”

Note The “E” in the model string refers to 3270 extended datastream. It has no connection with the “E” in “TN3270E”.

•Any other string is forwarded as is.

•In all cases, the string forwarded is translated from ASCII to EBCDIC and truncated at seven characters.

A complication arises with TN3270E clients that request a copy of the BIND-IMAGE. Such clients require system control services (SCS) datastream on the system services control point (SSCP)-LU flow. All other clients require 3270 datastream on that flow. Therefore, these two kinds of client must be directed to different LUGROUP entries at the host. To make this as easy as possible, the SCS requirement is also encoded into the model string sent to the host. Following the previously described terminal type string formats accepted by the server, this additional condition is applied:

•If the client has negotiated to receive BIND-IMAGE, the character “S” is overlaid on the fifth character of the string, or appended if the string is less than five characters. (See Table 3.)

Table 3 Examples of Model String Mapping

	BIND-IMAGE
String from client (ASCII)	requested?	String to Host (EBCDIC)
IBM-3278-4	No	327804
IBM-3279-5E	No	327905E
IBM-3279-3-E	Yes	3279S5E
IBM-DYNAMIC	Yes	DYNASIC
ABC	Yes	ABCS
ABCDEFGH	Yes	ABCDSFG

Specific LU Allocation

A TN3270E client can request a specific LU name by using the TN3270E command CONNECT as documented in RFC 1647. The name requested must match the name by which the TN3270 server knows the LU (see the section “LU Names in the TN3270 Server”), and the host must have activated the LU (with ACTLU).

LU Names in the TN3270 Server

Where SNA session switching is configured (that is, on DLUR PUs) the TN3270 server learns the

LU names from the ACTLUs.

For direct PUs, a “seed” name can be configured on the PU. The TN3270 server uses this name in conjunction with the LOCADDRS to generate names for the LUs. It is best to use the same naming convention as the host, if possible.

Configuring TN3270 Server on the Channel Interface Processor 7