| |
|
RSS Feed - WebSphere MQ Support
|
RSS Feed - Message Broker Support
|
  |
|
| MQ network traffic overhead? |
« View previous topic :: View next topic » |
| Author |
Message
|
| Cliff |
 Posted: Thu Aug 16, 2001 5:58 am Post subject: |
 |
|
Centurion
Joined: 27 Jun 2001
Posts: 145
Location: Wiltshire
|
Folks, I am engaged in some measuring/timing work for distributed queuing over a WAN between MQ 5.2 on OS/390 and MQ 5.2 on Win2K over TCP/IP. The network guy here is looking at the IP frames to see what traffic is generated, and for a message we see the expected Xmit header, then the data, but BEFORE the Xmit header is 48 bytes starting with an eyecatcher of TSH, then about halfway along (within the 48 bytes) is another of MSH.
Does anybody know what this is/these are? Are they to do with MQSeries? Could they have something to do with hearbeats (I have HBINT=5)?
Any information gratefully received.
Thanks - Cliff
|
|
| Back to top |
|
 |
| bduncan |
| Posted: Thu Aug 16, 2001 8:32 am Post subject: |
|
|
Padawan
Joined: 11 Apr 2001
Posts: 1554
Location: Silicon Valley
|
It sounds like you are looking at the additional header information provides the necessary routing information for the message (because if you think about it, the MQMD doesn't contain such fields). When I was testing the encryption exit in the software repository ( http://www.mqseries.net/pafiledb203/pafiledb.php?action=viewfile&fid=5&id=2 ) I noticed that when the receiving (decryption) exit would run, it would log the contents of the message it received, and there was additional header information and it had the same TSH eyecatcher.
Just like you I wanted to find out what this was, but looking through the manuals didn't turn up anything. Then I resorted to a good ol' google search which apparently indexed the IBM site better than IBM's own search engine because it came up with this "TSH" reference in one of the MQSeries manuals (which by the way, doesn't appear in the index):
For Channel Communication -- When a channel between two MQSeries Queue Managers is started, the two Queue Managers will negotiate which CCSID and encoding protocol they will use for channel communications. This CCSID and encoding scheme is then used for encoding the MQSeries TSH (This is the Transmission Segment Header -- an MQSeries control block that you may see passed back and forth between Queue Managers if you look at an MQSeries trace) and the Message Descriptor. The Message Descriptor is created and populated by your application when you do the MQPUT, but MQSeries needs to be able to understand what it contains, regardless of the platform that it was created on, thus it will be converted automatically by MQSeries regardless of whether the user portion of the message is converted or not.
So the TSH is appended when the message is put to a transmit queue. You can try this test. Have a remote queue pointing to some other queue manager, and then stop the channel between the two. Put a message to the remote queue, and because the channel is stopped, the message will sit on the transmit queue. To browse the message on the xmitq queue, you'll need to get enable it, and then just run amqsbcg. You should see the TSH information appended to the front of the message.
_________________
Brandon Duncan
IBM Certified MQSeries Specialist
MQSeries.net forum moderator
[ This Message was edited by: bduncan on 2001-08-16 09:33 ] |
|
| Back to top |
|
|
| Cliff |
| Posted: Thu Aug 16, 2001 8:47 am Post subject: |
|
|
Centurion
Joined: 27 Jun 2001
Posts: 145
Location: Wiltshire
|
Brandon,
many thanks! I tried Google too but all I found was a load of stuff about Thyroid Stimulation Hormone! I got bored after about 6 pages of that - maybe I should have been more patient.
Thanks again - Cliff |
|
| Back to top |
|
|
| EddieA |
| Posted: Fri Aug 17, 2001 5:04 am Post subject: |
|
|
Jedi
Joined: 28 Jun 2001
Posts: 2453
Location: Los Angeles
|
Brandon,
Just a little nit-pick.
These headers do NOT appear on the XMITQ.
You can only see them if you capture the data after the MCA has picked them off and is preparing to send. Or in the case of the original post, if you sniff the packets.
Cheers,
_________________
Eddie Atherton
IBM Certified Solution Developer - WebSphere Message Broker V6.1
IBM Certified Solution Developer - WebSphere Message Broker V7.0 |
|
| Back to top |
|
|
| bduncan |
| Posted: Fri Aug 17, 2001 8:03 am Post subject: |
|
|
Padawan
Joined: 11 Apr 2001
Posts: 1554
Location: Silicon Valley
|
Eddie,
Thanks for the correction. I guess I should have actually tried the test I recommended!  Actually I had been pretty sure that this was the case because I had thought I always remembered seeing additional data in the message when I would browse it on the transmit queue. I guess for my on piece of mind I will test that out and see exactly what I was looking at. But I do know that you don't necessarily have to watch the MCA or packet sniff to see this header information. If you run a channel exit program and have it log what passes through it, you will see this information because the channel exit is the last thing to run before the message actually goes out over TCP/IP...
_________________
Brandon Duncan
IBM Certified MQSeries Specialist
MQSeries.net forum moderator |
|
| Back to top |
|
|
|
|
|
| |
|
Page 1 of 1 |
|
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
|
|
|
|
