Receiver Channels

The receiver channel (CHLTYPE RCVR) is the inbound half of point-to-point distributed MQ. While the sender at the remote site connects to your CONNAME, the receiver accepts the session, validates the partner, and instructs the queue manager to put messages onto local queues. Misconfigured receivers are why transmission queues grow on the far side while your listener shows no connections—firewall blocks, wrong port, or CHLAUTH denying the sender MCAUSER. This tutorial covers DEFINE RCVR, listener dependencies, security at the inbound edge, monitoring inbound CHSTATUS, RCVR versus CLUSRCVR, and troubleshooting patterns for beginners who administer the data center that receives traffic.

Inbound Architecture

A LISTENER object binds to TCP port 1414 (example). Multiple channel types may share the port: RCVR channels for message partners, SVRCONN for clients. When a sender connects, the queue manager associates the TCP session with the RCVR definition whose name matches the protocol exchange. Messages deserialize into local puts. The sending queue manager removes messages from XMITQ only after protocol commit rules succeed—receiver disk and authority matter.

RCVR vs SDR (inbound perspective)
AspectRCVRSDR (partner)
TCP roleListenConnect out
CONNAMENot requiredRequired
XMITQNoYes
StartsWhen partner connectsXMITQ work or START

Defining a Receiver Channel

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DEFINE LISTENER('TCP.LISTENER') TRPTYPE(TCP) PORT(1414) CONTROL(QMGR) START LISTENER('TCP.LISTENER') DEFINE CHANNEL('PARIS.TO.LONDON') CHLTYPE(RCVR) TRPTYPE(TCP) + MCAUSER('mqm') HBINT(300) * Partner QM_PARIS defines same name as SDR with CONNAME to this host:1414 DISPLAY CHSTATUS('PARIS.TO.LONDON')

MCAUSER on RCVR is the user under which inbound messages are put unless overridden by protocol or message context per IBM rules for your release. Grant this user put authority to target QLOCAL objects and remove authority from overly broad IDs.

Explainer: Dock Door That Accepts Trucks

The receiver is the warehouse dock that only opens when a truck identifies itself with the right paperwork (channel name). The listener is the street address where trucks arrive. If the address is wrong on the sender van (CONNAME), trucks never reach your dock even though your dock is ready.

Security at the Inbound Edge

  • CHLAUTH — allow known partner IPs or certificates; block default wide open.
  • TLS — encrypt wire; map DN to MCAUSER or use certificate labels.
  • MCAUSER — least privilege on target queues.
  • Firewall — only partner sender IPs to listener port.

Inbound receivers are high-value targets: a rogue sender with a matching name and broken security could inject messages. Pair technical controls with change management on CHANNEL definitions.

Monitoring Receiver Instances

DISPLAY CHSTATUS shows RCVR instances in BINDING or RUNNING when senders connect. Multiple senders do not share one RCVR name from different unauthorized partners if CHLAUTH is correct—each legitimate pair uses agreed names. MSGS and BYTES counters help capacity planning. Absence of instances while partner XMITQ grows points to network or listener failure on your side.

Target Queues and Routing

Messages arrive with routing from the sending side—remote queue name, cluster headers, or reply-to context. The receiver queue manager resolves to QLOCAL puts. Authority failures send messages to DLQ or block channel with errors depending on configuration. Test with non-production senders before production cutover.

RCVR vs CLUSRCVR

CLUSRCVR accepts cluster sender connections and participates in cluster repository updates. Production clusters often have multiple CLUSRCVR definitions. Point-to-point RCVR is simpler: one partner SDR, one name, one listener port often shared. Document which listeners serve which channel sets.

Troubleshooting Inbound Failures

  1. Listener running? DISPLAY LSSTATUS.
  2. Sender CONNAME port matches listener PORT.
  3. Channel name identical on both queue managers.
  4. CHLAUTH and TLS logs on connect attempt.
  5. MCAUSER authority on target queues.
  6. Sequence number issues after DR on either side.

Explain Like I'm Five: Receiver Channels

The receiver channel is the door you open when your friend's delivery van calls your house—the van has to know your address and your name on the intercom must match what you agreed.

Practice Exercises

Exercise 1

Write MQSC for LISTENER plus RCVR for one inbound partner.

Exercise 2

Partner SDR in RETRY—list checks on receiver QM only.

Exercise 3

Why share one listener port for RCVR and SVRCONN?

Frequently Asked Questions

Frequently Asked Questions

Test Your Knowledge

Test Your Knowledge

1. Receiver channel CHLTYPE is:

  • RCVR
  • SDR
  • CLNTCONN
  • XMITQ

2. RCVR waits for connection on:

  • Listener port
  • Outbound CONNAME
  • FTP
  • JES

3. XMITQ on RCVR is:

  • Not used
  • Required
  • Same as DLQ
  • Topic name

4. Channel names for SDR/RCVR pair must:

  • Match on both QMs
  • Differ
  • Be random
  • Be DLQ
Published
Read time16 min
AuthorMainframeMaster
Verified: IBM MQ 9.3 documentation