The following choices are provided in the Work with MQM channels panel and the Work with Channel Status panel.
Use the Create option, or enter the CRTMQMCHL command from the command line, to obtain the Create Channel panel. There are examples of Create Channel panels, starting at Figure 98.
With this panel, you create a new channel definition from a screen of fields filled with default values supplied by WebSphere MQ for iSeries. Type the name of the channel, select the type of channel you are creating, and the communication method to be used.
When you press Enter, the panel is displayed. Type information in all the required fields in this panel, and the three pages making up the complete panel, and then save the definition by pressing Enter.
The channel name must be the same at both ends of the channel, and unique within the network. However, you should restrict the characters used to those that are valid for WebSphere MQ for iSeries object names; see Chapter 6, Channel attributes.
All panels have default values supplied by WebSphere MQ for iSeries for some fields. You can customize these values, or you can change them when you are creating or copying channels. To customize the values, see the WebSphere MQ for iSeries System Administration.
You can create your own set of channel default values by setting up dummy channels with the required defaults for each channel type, and copying them each time you want to create new channel definitions.
Table 44 shows the channel attributes for each type of
channel. See Chapter 6, Channel attributes for details about the fields.
Table 44. Channel attribute fields per message channel type
| Attribute field | Sender | Server | Receiver | Requester |
|---|---|---|---|---|
| Batch size | Yes | Yes | Yes | Yes |
| Channel name | Yes | Yes | Yes | Yes |
| Channel type | Yes | Yes | Yes | Yes |
| Connection name | Yes | Yes |
| Yes |
| Context |
|
| Yes | Yes |
| Disconnect interval | Yes | Yes |
|
|
| Heartbeat interval | Yes | Yes | Yes | Yes |
| Long retry wait interval | Yes | Yes |
|
|
| Long retry count | Yes | Yes |
|
|
| Maximum message length | Yes | Yes | Yes | Yes |
| Message channel agent name |
|
|
| Yes |
| Message exit user data | Yes | Yes | Yes | Yes |
| Message retry exit count |
|
| Yes | Yes |
| Message retry exit data |
|
| Yes | Yes |
| Message retry exit interval |
|
| Yes | Yes |
| Message retry exit name |
|
| Yes | Yes |
| Nonpersistent message speed | Yes | Yes | Yes | Yes |
| Receive exit | Yes | Yes | Yes | Yes |
| Receive exit user data | Yes | Yes | Yes | Yes |
| Security exit | Yes | Yes | Yes | Yes |
| Security exit user data | Yes | Yes | Yes | Yes |
| Send exit | Yes | Yes | Yes | Yes |
| Send exit user data | Yes | Yes | Yes | Yes |
| Sequence number wrap | Yes | Yes | Yes | Yes |
| Short retry wait interval | Yes | Yes |
|
|
| Short retry count | Yes | Yes |
|
|
| Transport type | Yes | Yes | Yes | Yes |
| Transmission queue | Yes | Yes |
|
|
| Message exit | Yes | Yes | Yes | Yes |
Use the Change option, or the CHGMQMCHL command, to change an existing channel definition, except for the channel name. Simply type over the fields to be changed in the channel definition panel, and then save the updated definition by pressing Enter.
Use the Copy option, or the CPYMQMCHL command, to copy an existing channel. The Copy panel enables you to define the new channel name. However, you should restrict the characters used to those that are valid for WebSphere MQ for iSeries object names; see the WebSphere MQ for iSeries System Administration.
Press Enter on the Copy panel to display the details of current settings. You can change any of the new channel settings. Save the new channel definition by pressing Enter.
Use the Delete option to delete the selected channel. A panel is displayed to confirm or cancel your request.
Use the Display option to display the current definitions for the channel. This choice displays the panel with the fields showing the current values of the parameters, and protected against user input.
The status column tells you whether the channel is active or inactive, and is displayed continuously in the Work with MQM Channels panel. Use option 8 (Work with Status) to see more status information displayed. Alternatively, this can be displayed from the command line with the WRKMQMCHST command. See Work with channel status.
Use the Ping option to exchange a fixed data message with the remote end. This gives some confidence to the system supervisor that the link is available and functioning.
Ping does not involve the use of transmission queues and target queues. It uses channel definitions, the related communication link, and the network setup.
It is available from sender and server channels, only. The corresponding channel is started at the far side of the link, and performs the start up parameter negotiation. Errors are notified normally.
The result of the message exchange is presented in the Ping panel for you, and is the returned message text, together with the time the message was sent, and the time the reply was received.
When Ping is invoked in WebSphere MQ for iSeries, it is run with the USERID of the user requesting the function, whereas the normal way that a channel program is run is for the QMQM USERID to be taken for channel programs. The USERID flows to the receiving side and it must be valid on the receiving end for the LU 6.2 conversation to be allocated.
The Start option is available for sender, server, and requester channels. It should not be necessary where a channel has been set up with queue manager triggering.
The Start option is also used for receiver channels that have a DISABLED or STOPPED status. Starting a receiver channel that is in DISABLED or STOPPED state resets the channel and allows it to be started from the remote channel.
When started, the sending MCA reads the channel definition file and opens the transmission queue. A channel start-up sequence is executed, which remotely starts the corresponding MCA of the receiver or server channel. When they have been started, the sender and server processes await messages arriving on the transmission queue and transmit them as they arrive.
When you use triggering, you will need to start the continuously running trigger process to monitor the initiation queue. The STRMQMCHLI command can be used for this.
At the far end of a channel, the receiving process may be started in response to a channel startup from the sending end. The method of doing this is different for LU 6.2 and TCP/IP connected channels:
When the remote machine is an iSeries, you can use the STRMQMLSR command for this.
Use of the Start option always causes the channel to re-synchronize, where necessary.
For the start to succeed:
To transfer messages, remote queues and remote queue definitions must exist.
A message is returned to the panel confirming that the request to start a channel has been accepted. For confirmation that the Start process has succeeded, check the system log, or press F5 (refresh the screen).
Use the End option to request the channel to stop activity. The channel will not send any more messages until the operator starts the channel again. (For information about restarting stopped channels, see Restarting stopped channels.)
You can select the type of stop you require if you press F4 before Enter. You can choose IMMEDIATE, or CONTROLLED.
Normally, this option should not be used. It terminates the channel process. The channel does not complete processing the current batch of messages, and cannot, therefore, leave the channel in doubt. In general, it is recommended that the operators use the controlled stop option.
This choice requests the channel to close down in an orderly way; the current batch of messages is completed, and the syncpoint procedure is carried out with the other end of the channel.
The Reset option changes the message sequence number. Use it with care, and only after you have used the Resolve option to resolve any in-doubt situations. This option is available only at the sender or server channel. The first message starts the new sequence the next time the channel is started.
Use the Resolve option when messages are held in-doubt by a sender or server, for example because one end of the link has terminated, and there is no prospect of it recovering. The Resolve option accepts one of two parameters: BACKOUT or COMMIT. Backout restores messages to the transmission queue, while Commit discards them.
The channel program does not try to establish a session with a partner. Instead, it determines the logical unit of work identifier (LUWID) which represents the in-doubt messages. It then issues, as requested, either:
For the resolution to succeed: