The LUMAP and PRTMAP statements allow LUs to be mapped based on a Client Identifier. The LU group can be mapped Generically or Specifically. The default mapping is Generic. The keyword SPECIFIC must be coded to define a Specific mapping.
For example, use the following statements to create two LU groups. Map one group Generically to the IP group IPGPAY and map the other group Specifically to the same Client Identifier. When a Generic connection request is received, Telnet will assign the next available LU from LU group LUGRPGEN. When a Specific connection request is received, Telnet will verify the requested LU name is included in the LU group LUGRPSPC. If it is, Telnet will assign the LU name to the connection.
LUGROUP LUGRPGEN LUG101..LUG400..FFFXXX ENDLUGROUP
LUGROUP LUGRPSPC LUS001..LUS100..FFFXXX ENDLUGROUP
IPGROUP IPGPAY 255.255.0.0:9.8.0.0 ENDIPGROUP
LUMAP LUGRPGEN IPGPAY
LUMAP LUGRPSPC IPGPAY SPECIFIC Generic request connections can be assigned LUs only from Generically mapped LU groups. If no Generic mapping exists, the DEFAULTLUS group is checked. No Specific group is checked. This safeguards the Specific LU names from being used by Generic requests.
For Specific requests, Telnet first checks to see if the LU is in a Specifically mapped LU group. If the LU name is not found, the Generically mapped groups are searched. If neither LU group type contains the requested LU name, the connection request is rejected. The DEFAULTLUSSPEC group is not checked in this case because LU group mappings exist. If no LU group mappings exist, only the DEFAULTLUSSPEC group is checked. If the LU name is not found, the connection request is rejected. The Generic DEFAULTLUS group is not checked.
In addition to requesting an exact LU name, the client can request an LU group name. Telnet first searches within the mapped groups, assuming the name is an exact LU name. If that search fails, Telnet then checks the requested name against mapped Specific LU group names and then checks the name against mapped Generic LU group names. If the group name is found, the next available LU in the group is assigned using sequential LU selection unless it has been turned off.
The LU group itself is not defined as Generic or Specific. Rather, the LU group is mapped Generically or Specifically. It is possible to map the same LU group both Generically and Specifically. IBM® recommends that you do not map the same group Generically and Specifically unless you are an advanced user.