START is the MQSC verb that turns definitions into running infrastructure. DEFINE CHANNEL creates the blueprint; START CHANNEL asks the queue manager to open TCP, negotiate with the partner, and move messages. DEFINE LISTENER declares a port; START LISTENER binds that port and waits for inbound connections. Without START, sender channels sit idle while transmission queues fill, and remote clients cannot attach to SVRCONN definitions. START is also used for SERVICE objects, trigger monitors in some configurations, and certain queue manager maintenance modes per IBM documentation. This tutorial explains START variants, prerequisites, expected CHSTATUS transitions, coordination with partners, automation at startup, and safe production procedures paired with DISPLAY verification.
START CHANNEL('PARTNER.SDR') initiates the sender side. The queue manager reads CONNAME, opens the transmission queue, and begins the channel protocol. DISPLAY CHSTATUS shows progression from INACTIVE or STOPPED to BINDING to RUNNING. Receiver channels on the partner may start automatically when the sender connects, or may need START CHANNEL on the RCVR side depending on configuration. Cluster channels (CLUSSDR, CLUSRCVR) follow cluster rules—see cluster tutorials. If messages wait on XMITQ and channel is STOPPED, START is the deliberate action after fixing root cause—not the first step when errors persist.
1234567DEFINE LISTENER('TCP.LISTENER') TRPTYPE(TCP) PORT(1414) CONTROL(QMGR) REPLACE START LISTENER('TCP.LISTENER') DISPLAY LSSTATUS('TCP.LISTENER') START CHANNEL('PARTNER.SDR') DISPLAY CHSTATUS('PARTNER.SDR') CHSTATUS SUBSTATE * LISTENER must be RUNNING before partner SDR can connect to RCVR port * DISPLAY LSSTATUS — listener state (not LSSTATUS on all releases; verify syntax)
Listeners accept inbound TCP connections. PORT(1414) is conventional but any free port works if firewall allows. CONTROL(QMGR) starts the listener when the queue manager starts—reducing manual START after reboot. Multiple listeners can bind different ports for different security zones. After START LISTENER, verify with DISPLAY LSSTATUS or netstat on the host. Certificate and CHLAUTH configuration must be complete before partners connect, or START succeeds but BINDING fails on the channel.
| START | Starts | Verify with |
|---|---|---|
| CHANNEL | Message or MQI channel session | DISPLAY CHSTATUS |
| LISTENER | Inbound TCP listener | DISPLAY LSSTATUS |
| SERVICE | Service process | DISPLAY SVSTATUS |
| TRIGGER | Trigger monitor | Application triggered |
| QMGR | Queue manager (platform-specific) | dspmq |
INACTIVE or STOPPED means not running. START transitions toward BINDING during handshake, then RUNNING when messages can flow. RETRYING means failure with automatic retry—do not spam START without fixing TLS or network. PAUSED and STOPPING appear during controlled shutdown. Learn these values for interviews and on-call—they are the language of bridge calls.
SERVICE objects run external programs for integration or administration. START SERVICE launches the defined executable with parameters. Trigger monitors watch initiation queues and START PROCESS or application instances when trigger conditions fire—pair with TRIGGER and TRIGTYPE on queue definitions. Mis-STARTed services can duplicate processes; check runbooks for singleton services.
DEFINE installed the engine; START turns the key. The car (channel) does not move until START, even if fuel (messages on XMITQ) is ready.
START tells the mail truck to leave the garage and drive to the other town. The road (listener) must be open on the other side too.
START SDR/RCVR pair in lab; log CHSTATUS every five seconds until RUNNING.
START LISTENER on wrong port; observe partner BINDING failure; fix and retry.
Document START order for your lab hub-and-spoke diagram.
1. START CHANNEL requires:
2. Healthy active channel state is often:
3. START LISTENER opens:
4. Queues are used by: