Configuring TN3270 Server on the Channel Interface Processor 7
Configuring TN3270 on a Channel Interface Processor
•IBM-DYNAMIC:This will result in “DYNAMIC”being put in the model type and number field.
TheVTAM configuration will need to have “DYNAMIC”defined as a template in the LU group.
Infact “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.
Acomplication arises with TN3270E clients that request a copy of the BIND-IMAGE. Suchclients
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 Table3.)

Specific LU Allocation

ATN3270E 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
knowsthe 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
conjunctionwith the LOCADDRS to generate names for the LUs. It is best to use the same naming
convention as the host, if possible.
Table3 Examples of Model String Mapping
String from client (ASCII) BIND-IMAGE
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