When a transaction program issues an ALLOCATE verb naming a transaction program to be run at the other end of the conversation, an Attach FMH-5 carries the transaction program name (TPN) to the receiving half-session.
________________________________________________________________________
| FM Header 5: Attach (LU 6.2) |
|_______ _____ __________________________________________________________|
| Byte | Bit | Content |
|_______|_____|__________________________________________________________|
|_______ _____ __________________________________________________________|
| 0 | | Length, in binary, of FMH-5, including this Length byte |
|_______|_____|__________________________________________________________|
|_______ _____ __________________________________________________________|
| 1 | 0 | Reserved |
|_______|_____|__________________________________________________________|
| | 1-7 | Type: 0000101 |
|_______|_____|__________________________________________________________|
|_______ _____ __________________________________________________________|
| 2-3 | | Command code: X'02FF' (Attach) |
|_______|_____|__________________________________________________________|
|_______ _____ __________________________________________________________|
| 4 | 0-2 | Security Indicators |
|_______|_____|__________________________________________________________|
| | 0 | Already-verified indicator: |
|_______|_____|___ ______________________________________________________|
| | | 0 | user ID is not already verified |
|_______|_____|___|______________________________________________________|
| | | 1 | user ID is already verified (Password subfield not |
| | | | included in this Attach) |
|_______|_____|___|______________________________________________________|
| | 1-2 | Persistent-verification indicator: |
|_______|_____|____ _____________________________________________________|
| | | 00 | persistent verification not supported or needed |
|_______|_____|____|_____________________________________________________|
| | | 01 | sign-on requested |
|_______|_____|____|_____________________________________________________|
| | | 10 | already signed on (Password subfield not included |
| | | | in this Attach) |
|_______|_____|____|_____________________________________________________|
| | | 11 | reserved |
|_______|_____|____|_____________________________________________________|
| | 3 | Substituted password indicator: |
|_______|_____|___ ______________________________________________________|
| | | 0 | If a Password subfield is present in this Attach, |
| | | | the password is in the clear. |
|_______|_____|___|______________________________________________________|
| | | 1 | A Password subfield is present and contains a |
| | | | substituted password. |
|_______|_____|___|______________________________________________________|
| | 4 | Program initialization parameter (PIP) presence: |
|_______|_____|___ ______________________________________________________|
| | | 0 | PIP not present following this FMH-5 |
|_______|_____|___|______________________________________________________|
| | | 1 | PIP present following this FMH-5 | |
|_______|_____|___|______________________________________________________|
| | | 5 | Extended authentication indicator: |
|_______|_____|___ ______________________________________________________|
| | | | 0 | Authentication Token Data GDS variable does not |
| | | | | follow the FMH-5. |
|_______|_____|___|______________________________________________________|
| | | | 1 | Authentication Token Data GDS variable follows the |
| | | | | FMH-5. (In this case, the other security bits in |
| | | | | byte 4, bits 0 - 3 are also set to 0.) |
|_______|_____|___|______________________________________________________|
| | | 6-7 | Reserved |
|_______|_____|__________________________________________________________|
|_______ _____ __________________________________________________________|
| 5 | | Length (j minus 5), in binary, of Fixed Length |
| | | Parameters field (currently 3--future expansion |
| | | possible) |
|_______|_____|__________________________________________________________|
|_______ _____ __________________________________________________________|
| 6-j | | Fixed Length Parameters |
|_______|_____|__________________________________________________________|
|_______ _____ __________________________________________________________|
| 6 | | Resource type: |
|_______|_____|_______ __________________________________________________|
| | | X'D0' | half-duplex basic conversation |
|_______|_____|_______|__________________________________________________|
| | | X'D1' | half-duplex mapped conversation |
|_______|_____|_______|__________________________________________________|
| | | X'D2' | full-duplex basic conversation |
|_______|_____|_______|__________________________________________________|
| | | X'D3' | full-duplex mapped conversation |
|_______|_____|_______|__________________________________________________|
|_______ _____ __________________________________________________________|
| 7 | | Reserved |
|_______|_____|__________________________________________________________|
|_______ _____ __________________________________________________________|
| 8(=j) | 0-1 | Synchronization level: |
|_______|_____|____ _____________________________________________________|
| | | 00 | none |
|_______|_____|____|_____________________________________________________|
| | | 01 | confirm |
|_______|_____|____|_____________________________________________________|
| | | 10 | confirm, sync point, and backout |
|_______|_____|____|_____________________________________________________|
| | | 11 | reserved |
|_______|_____|____|_____________________________________________________|
| | 2-7 | Reserved |
|_______|_____|__________________________________________________________|
|_______ _____ __________________________________________________________|
| j+1-q | | Variable Length Parameters |
|_______|_____|__________________________________________________________|
|_______ _____ __________________________________________________________|
| j+1-k | | Transaction Program Name Field |
|_______|_____|__________________________________________________________|
|_______ _____ __________________________________________________________|
| j+1 | | Length (values 1 to 64 are valid), in binary, of |
| | | transaction program name |
|_______|_____|__________________________________________________________|
|_______ _____ __________________________________________________________|
| j+2-k | | Transaction program name: a symbol string identifying a |
| | | transaction program name known at the receiver; |
| | | receivers may constrain such names to be type A, AE, GR, |
| | | or DB, depending on the implementation |
|_______|_____|__________________________________________________________|
|_______ _____ __________________________________________________________|
| k+1-m | | Access Security Information Field |
|_______|_____|__________________________________________________________|
|_______ _____ __________________________________________________________|
| k+1 | | Length (0 or m minus (k+1)), in binary, of Access |
| | | Security Information subfields |
|_______|_____|__________________________________________________________|
|_______ _____ __________________________________________________________|
| k+2-m | | Zero or more Access Security Information subfields | | | |
|_______|_____|__________________________________________________________|
|_______ _____ __________________________________________________________|
| m+1-n | | Logical-Unit-of-Work Identifier Field |
|_______|_____|__________________________________________________________|
|_______ _____ __________________________________________________________|
| m+1 | | Length (values 0 and 10 to 26 are valid), in binary, of |
| | | Logical-Unit-of-Work Identifier subfield |
|_______|_____|__________________________________________________________|
|_______ _____ __________________________________________________________|
| m+2-n | | Logical-Unit-of-Work Identifier Subfield |
|_______|_____|__________________________________________________________|
|_______ _____ __________________________________________________________|
| m+2 | | Length (values 1 to 17 are valid), in binary, of |
| | | network-qualified LU name o.) |
|_______|_____|__________________________________________________________|
|_______ _____ __________________________________________________________|
| m+3-w | | Network-qualified LU network name |
|_______|_____|__________________________________________________________|
|_______ _____ __________________________________________________________|
| w+1-w+| | Logical-unit-of-work instance number, in binary |
|_______|_____|__________________________________________________________|
|_______ _____ __________________________________________________________|
| w+7-w+|(=n) | Logical-unit-of-work sequence number, in binary |
|_______|_____|__________________________________________________________|
|_______ _____ __________________________________________________________|
| n+1-p | | Conversation Correlator Field |
|_______|_____|__________________________________________________________|
|_______ _____ __________________________________________________________|
| n+1 | | Length (values 0 to 8 are valid), in binary, of |
| | | conversation correlator of sender |
|_______|_____|__________________________________________________________|
|_______ _____ __________________________________________________________|
| n+2-p | | Conversation correlator of the sending transaction: a |
| | | 1- to 8-byte symbol-string type G identifier (unique |
| | | between partner LUs) of the conversation being allocated |
| | | via FMH-5 (an example construction of this field would |
| | | be the composition of a transaction program instance |
| | | identifier and a resource identifier) |
|_______|_____|__________________________________________________________|
|_______ _____ __________________________________________________________|
| p+1-q | | Attach Sequence Number Field |
|_______|_____|__________________________________________________________|
|_______ _____ __________________________________________________________|
| p+1 | | Length (values 0 and 8 are valid), in binary, of the |
| | | sequence number for this Attach (always present if byte |
| | | 4, bit 3 is set to 1; otherwise, optional) |
|_______|_____|__________________________________________________________|
|_______ _____ __________________________________________________________|
| p+2-q | | 8-byte sequence number for this Attach, in binary, if |
| | | preceding Length field = 8; otherwise, not present |
|_______|_____|__________________________________________________________|
|_______ _____ __________________________________________________________|
| Note: | | Trailing Length fields (bytes p+1, n+1, m+1, and k+1) |
| | | that have value X'00' can be omitted. |
|_______|_____|__________________________________________________________|