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| thindk00 |
 Posted: Wed Oct 19, 2005 2:57 am Post subject: MQ client channel connectivity questions |
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Voyager
Joined: 16 May 2001
Posts: 75
Location: UK
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Hi,
We're thinking of providing a central WMQ server to our business to allow WMQ client channels to connect to it, rather than them having to need local WMQ servers that their channels need to connect to.
Questions that spring to mind:
1) The WMQ client channels will come in over a WAN link rather than over a LAN link, is this a problem? Is there something that we need to consider? E.g. is there a timeout for the client connection channel that we need to be aware of?
2) We could have hundreds/thousands of client connections to the server. Is there a limit on the number of client connections? Can this be tuned? We're running on Solaris.
TIA,
Kulbir. |
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| jefflowrey |
| Posted: Wed Oct 19, 2005 3:22 am Post subject: |
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Grand Poobah
Joined: 16 Oct 2002
Posts: 19981
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You should read the Intercommuncations manual, at least some sections of it, and the Clients manual.
I personally do not feel comfortable with MQ client connections coming in from business partners. I much prefer knowing that they have at least one QM on their side because it implies a certain amount of MQ knowledge and because it provides a larger degree of reliability and isolation.
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I am *not* the model of the modern major general. |
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| PGoodhart |
| Posted: Wed Oct 19, 2005 3:28 am Post subject: |
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Master
Joined: 17 Jun 2004
Posts: 278
Location: Harrisburg PA
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"I personally do not feel comfortable with MQ client connections coming in from business partners. I much prefer knowing that they have at least one QM on their side because it implies a certain amount of MQ knowledge and because it provides a larger degree of reliability and isolation."
- Unless I supply/configure the MQ client software I agree completely. There are too many things to go wrong that you get into a "what-does-this-button-do" duel with the other side's developers. This doesn't mean it isn't possible, just possibly ill advised. Read the manuals Jeff suggested and see if you agree....
_________________
Patrick Goodhart
MQ Admin/Web Developer/Consultant
WebSphere Application Server Admin |
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| thindk00 |
| Posted: Wed Oct 19, 2005 3:38 am Post subject: |
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Voyager
Joined: 16 May 2001
Posts: 75
Location: UK
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Thanks Guys, I'll run through the manuals.
The client connections would be from internal business applications that would be tested thoroughly prior to entering the relevant environments. I'm just trying to find technical reasons for why it may cause a problem (e.g. use of WAN link, # of connections, etc).
Cheers. |
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| jefflowrey |
| Posted: Wed Oct 19, 2005 3:44 am Post subject: |
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Grand Poobah
Joined: 16 Oct 2002
Posts: 19981
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Client connections are, by nature, less reliable than bindings connections and subject to network issues. If your network is stable, and your WAN links are reasonably reliable, you might be fine. If your WAN links are slow, you're much better off putting at least gateway QMs on each end.
Also, it is not possible to do two-phase commit with a client connection. You have to pay for the Extended Transactional Client, and that costs the same as a qmgr. This could be a complete show stopper for using clients for all applications.
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I am *not* the model of the modern major general. |
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| thindk00 |
| Posted: Wed Oct 19, 2005 3:48 am Post subject: |
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Voyager
Joined: 16 May 2001
Posts: 75
Location: UK
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Thanks.
I should have mentioned this, the applications are currently using client connections to communicate with regional WMQ servers and we're looking at replacing the regional servers with a Central server.
We're already using the WAN links to do server <--> server connections and now looking to use the same WAN links for client <--> server. |
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| jefflowrey |
| Posted: Wed Oct 19, 2005 4:07 am Post subject: |
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Grand Poobah
Joined: 16 Oct 2002
Posts: 19981
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Ah.
That's a whole other ball of wax.
You'll need to tune your QM to support the maximum number of connections you need.
And you should run tests to make sure your client connections are reliable enough over the WAN. I want to say lots of tests, but it's probably not that bad.
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I am *not* the model of the modern major general. |
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| Tim |
| Posted: Wed Jun 21, 2006 4:58 am Post subject: |
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Newbie
Joined: 14 Oct 2005
Posts: 4
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Hi,
we are exactly in the same situation since a few years. We have a central MQ server, and external clients connect to us over a WAN
Untill a few months ago this worked perfectly : even over slow iVPN connections. However we recently had serious troubles with a client connecting over ISDN, and the ISDN line was going up and down.
The client application was in a state where it did got an error message (RC 2009) when sending a messages, although the message was send to the MQ server. Client resend the message, resulting in doubles etc. etc.
conclusion : if you want a fully waterproof solution over a WAN, go for the MQ server of transactional client |
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| zpat |
| Posted: Wed Jun 21, 2006 5:09 am Post subject: |
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Jedi Council
Joined: 19 May 2001
Posts: 5866
Location: UK
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Client channels are actually very similar operationally to server channels and work fine over a WAN. However MQ applications which rely on client connections MUST be coded to deal with disconnections (MQ RC 2009).
The apps should retry after about 30 secs when RC 2009 is received - if they retry in a tight loop it will severely impact your network and QM.
As a rule of thumb I would trust a Windows based QM to work well with up to 500 concurrent clients, a Unix QM to work with up to 2000 clients and a mainframe to work with up to 10,000 clients.
These are not architectural limits, just my opinions. |
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| thindk00 |
| Posted: Wed Jun 21, 2006 5:52 am Post subject: |
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Voyager
Joined: 16 May 2001
Posts: 75
Location: UK
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Tim - Did you log your problem with IBM? What version of WMQ are you on and which platform?
Thanks. |
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