Request unit names

The application program uses only network names in all requests. Network name fields in the Forward and Deliver requests use the format shown in Table 1. The SSCP changes these names into addresses. The destination name in a Forward RU is changed to a destination network address by the SSCP prior to sending the embedded NS RU to the destination. When an embedded NS RU is to contain a target-resource address, the SSCP resolves the target-resource name in the Forward request into an address, and places the address into the NS RU. This address is either a local address or a network address, depending upon the PU type of the destination resource. If the destination resource is a PU type 1 or 2, the target resource must be the PU itself. The SSCP does not validate the network name type field in the Forward RU.

NS RUs are delivered to the application program with their address fields unchanged by the SSCP. The application program should not use the address fields because they are subject to change. The SSCP, however, resolves each address in the embedded NS RU to a network name and inserts the network name into the Deliver RU. If the origin PU is a PU type 1 or 2 or if no SNA address list subvector is present in an NMVT RU, only local address 0 (that is the address of the PU itself) is supported.

If multiple network addresses are included in an NMVT RU, and the groups of two addresses are indicated as session partners, the PCID associated with the session is part of the network name field in the Deliver RU.

Table 1. Format of additional targets in Deliver requests
Byte Value Description
0–i   Network name/PCID of target N
0 X'B3' Procedure correlation identifier (PCID) for the session defined by preceding F3-E3 pair
  X'2D' Group name
  X'E3' Session partner name
  X'F1' Physical unit or link station name
  X'F3' Logical unit name
  X'F4' SSCP name
  X'F5' Procedure name
  X'F7' Link station name
  X'F9' Link name
  X'FC' Channel-link locally defined name
  X'FF' Error code indicating that address to name translation is not possible
1   Length, in binary, of target name
2–i   Symbolic name of target in EBCDIC characters