The status of an allocated NAU is maintained in the naustat variable, which contains valid information if the snastat variable indicates that the NAU is allocated. The naustat variable is returned on the alnau, gfsm, and rcvru verbs in the ufsm structure.
The values assigned to the naustat constants are organized in an increasing order that can be used by the application in testing for a specific condition. For example, data traffic on the LU-LU session is not allowed if naustat is less than P06_NAU. Even though more than one state can be valid at the same time, the state contained in the naustat variable is considered to be the most important of the valid states. The naustat is sufficient for most transaction programs to perform the actions required by SNA protocol.
The information presented in this appendix describes valid states for LU
and PU services, depending on which was selected at allocation time.
A recommended action is provided for each state.
Table F-1 lists the valid states for LU services.
Table F-1. Valid States for LU Services
State | Description |
|---|---|
P01_NAU | Pending ACTLU |
P02_NAU | SSCP-LU half-session active |
P03_NAU | Pending BIND |
P04_NAU | Pending BIND response |
P05_NAU | Data traffic reset |
P06_NAU | Pending UNBIND |
P07_NAU | Pending QC and receive flow quiesced |
P08_NAU | Pending QC |
P09_NAU | Pending SHUTC and send flow quiesced |
P10_NAU | Pending SHUTC and receive flow quiesced |
P11_NAU | Pending SHUTC |
P12_NAU | Send and receive flow quiesced |
P13_NAU | Send flow quiesced |
P14_NAU | Receive flow quiesced |
P15_NAU | Pending RTR |
P16_NAU | Data traffic allowed |
Table F-2 lists the valid states for PU services.
Table F-2. Valid States for PU Services
State | Description |
|---|---|
P01_NAU | Pending ACTPU |
P02_NAU | SSCP-PU half-session active |
| P01_NAU | ACTLU has not been received. Neither the SSCP-LU nor the LU-LU session is active. | |
Recommended Action: Wait for the notification of the ACTLU via an rcvru verb. | ||
| P02_NAU | The SSCP-LU half-session has been activated by an ACTLU request from the host. The transaction program may send data on the SSCP-LU half-session, and LU-LU session initiation may start. The transaction program may send an INITSELF request or a character-coded login to activate the LU-LU half-session, or it may wait for the host to start the session via a BIND request. | |
Recommended Action: Send an INITSELF RU or character-coded login to the SSCP via the sndru verb or wait for the BIND RU via a rcvru verb if automatic login by the host. |
 | Note: If a previous login has failed, delay the next try to avoid streaming logins to the host. |
| P03_NAU | The user has initiated the establishment of an LU-LU half-session by sending an INITSELF request and a positive response has been received from the host. A BIND request is expected from the host that would change the state to P04_NAU. | |
Recommended Action: Wait for the BIND RU via an rcvru verb. | ||
| P04_NAU | A BIND request has been received from the host. If the transaction program sends a positive BIND response, the | |
Recommended Action: Accept or reject the received BIND RU via the accru or rejru verb. If TS Profile 4 and sync points are used, the sync-point numbers should be set before responding to the BIND. This is done via the ssync verb. When finished, wait for the state to change into data traffic allowed via the rcvru verb. | ||
| P05_NAU | The LU-LU half-session has been established. This is done when a transaction program sends a positive response to the BIND request with the accru verb. This state is also entered when a CLEAR request is received from the host. | |
Recommended Action: Wait for the STSN RU (if TS Profile 4 is used) and the SDT RU notification via the rcvru verb. | ||
| P06_NAU | The user has initiated the termination of an LU-LU half-session by sending a TRMSLF or RSHUTD request. An UNBIND request is expected from the host that would transfer the LU-LU half-session into the P02_NAU state. | |
Recommended Action: Wait for the UNBIND RU via the rcvru verb. | ||
| P07_NAU | The receive flow is quiesced and a QEC request has been received from the host. The transaction program is asked to stop sending normal-flow requests at end of chain. | |
Recommended Action: If a chain is currently being sent by the transaction program, it should be completed. When the between-chain state is reached, a QC RU should be sent to the host via a sndru verb. | ||
| P08_NAU | A QEC request has been received from the host. The transaction program is asked to stop sending normal-flow requests at end of chain. | |
Recommended Action: Complete chains currently being sent by the transaction program. When the between-chain state is reached, a QC RU should be sent to the host via a sndru verb. | ||
| P09_NAU | The send flow is quiesced and a SHUTD request has been received from the host. A SHUTC request should be sent to the host as soon as possible. | |
Recommended Action: A SHUTC RU should be sent to the host via a sndru verb. | ||
| P10_NAU | The receive flow is quiesced and a SHUTD request has been received from the host as a first step in an orderly termination of the LU-LU half-session. The transaction program is asked to stop sending normal-flow requests when convenient. The send flow becomes quiesced when the transaction program sends the SHUTC request to the host. | |
Recommended Action: The transaction program should send a SHUTC RU when convenient via a sndru verb. | ||
| P11_NAU | A SHUTD request has been received from the host as a first step in an orderly termination of an LU-LU half-session. The transaction program is asked to stop sending normal-flow requests when convenient. The send flow is quiesced when the transaction program sends the SHUTC request to the host. | |
Recommended Action: The transaction program should send a SHUTC RU when convenient via a sndru verb. | ||
| P12_NAU | Both the send and receive flows are quiesced. No normal-flow data may be sent or received on the LU-LU half-session in this state. This state is changed, for example, when the RELQ request is either sent or received. | |
Recommended Action: The transaction program can send a RELQ RU to the host via a sndru verb if the receive quiesce state can be released. Otherwise, wait for a RELQ notification from the host via a rcvru verb. | ||
| P13_NAU | The send flow is quiesced. Either a QEC request has been received from the host and responded to by QC or a SHUTD request has been received from the host and responded to by SHUTC. No normal-flow data may be sent by the transaction program on the LU-LU half-session in this state. | |
Recommended Action: Wait for a RELQ notification from the host via a rcvru verb. | ||
| P14_NAU | The receive flow is quiesced. A QEC request has been sent by the transaction program and responded to by a QC request from the host. No normal-flow requests may be sent by the host in this state. | |
Recommended Action: The sending of data to the host can continue but the receive quiesce state should be released when possible in order to get normal-flow requests from the host. The quiesce is released when a RELQ RU is sent to the host via a sndru verb. | ||
| P15_NAU | A BID request has been rejected by the transaction program with the sense code 0814 (RTR forthcoming). The transaction program should send an RTR request when ready to receive data from the host. | |
Recommended Action: When the transaction program is ready to receive data from the host, an RTR RU should be sent via the sndru verb. | ||
| P16_NAU | This state indicates that data traffic is allowed. The transaction program may now send data on the LU-LU half-session. | |
Recommended Action: In this state the transaction program can exchange data with the host via the sndru and rcvru verbs. |
| P01_NAU | The SSCP-PU session is inactive and no FMD NS (MA) RUs may be exchanged with the host. This is the normal state after IPL. | |
Recommended Action: Wait for the notification of the ACTPU via a rcvru verb. | ||
| P02_NAU | The SSCP-PU session has been activated by an ACTPU request from the host. FMD NS (MA) RUs may be exchanged with the host. | |
Recommended Action: The transaction program can exchange data with the CNMA in the host via sndru and rcvru verbs. |