SMPP Disconnected

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Omar
New member
Username: Kfsmart

Post Number: 11
Registered: 01-2008
Posted on Wednesday, February 04, 2009 - 07:30 am:   

Dear Des,

I have 3 SMPP conmection with the same operator,one is working fine but the other two I'm facing now a problem.I'm unable to receive Incoming SMS from their side,I need to restart the nowsms service to receive the incomings,then again I'm not able to receive and then restart again.
I mean to restart the nowsms service all the time to receive the incomings.
I connected my operator and he told ensure the enquire link option activated,I checked keep alive and I see it is activated "58 sec",
Is there any config. in nowsms that can I do regards this?
Des - NowSMS Support
Board Administrator
Username: Desosms

Post Number: 422
Registered: 08-2008
Posted on Wednesday, February 04, 2009 - 04:14 pm:   

Hi Omar,

That is strange.

If NowSMS does get disconnected, it will automatically reconnect. No problems are logged about the disconnection unless reconnection attempts fail for several minutes.

Do you see any entries in SMSOUT-yyyymmdd.LOG which include the text "SMPP Failure"? Those would be indications of reconnect problems.

Similarly, if NowSMS is configured to send enquire link (keep alive) packets, and it does not get a response to the enquire link, it will disconnect and attempt reconnection, making an assumption that the connection is dead.

It's not clear why shutting down and restarting NowSMS would make a difference.

Unless...

Actually I do remember a situation somewhat similar to this. The SMS provider had a limited number of connections that they allowed, and the customer had multiple binds. When NowSMS first started up, the receiver bind was able to connect ok. But if it got disconnected, it wasn't allowed to reconnect.

Are you using the default configuration which uses separate binds for the sender and receiver? Or are you using the transceiver option (under the Advanced Settings for the SMPP connection)? If you're not using the transceiver bind, you might want to try this, as this is probably what your provider prefers.

If that's not it, enable the debug logs, and let's take a look at SMPPDEBUG.LOG. That file will likely be large, so you may need to either e-mail it to me or upload to an FTP site. For now, enable the SMS debug log, as we might need to take a look at it.

--
Des
NowSMS Support
Des - NowSMS Support
Board Administrator
Username: Desosms

Post Number: 443
Registered: 08-2008
Posted on Friday, February 06, 2009 - 05:26 pm:   

Hi Omar,

I've been looking over the logs that you sent ... and I wish I could see something unusual, but I don't.

The other side of the connection seems to simply stop delivering messages (I assume that there are more messages pending).

Normally, in this type of situation, sending enquire_link packets would detect if there was a problem with the connection. But the provider is continuing to respond to enquire_link packets, indicating that everything is ok.

I assume that when you are in this state, that you are still able to send messages?

In this case, it is hard to guess why the provider would stop delivering any messages to you.

Does this happen on just one of the SMSC connections, or more than one?

Will the provider allow you to use separate sender and receiver binds instead of transceiver? Perhaps that would make a difference on their end?

I'm not sure what other strategy to take in a situation like this. I think something is going wrong on the provider end ... and I don't know how we would detect this problem.

The only idea that I have would be an update with a configuration setting where NowSMS would automatically disconnect and reconnect if no messages were received within some configurable interval. This would trigger unnecessary disconnects/reconnects during idle periods ... but given the situation, I don't know what other strategy could be taken.

Thoughts?

--
Des
NowSMS Support
Omar
New member
Username: Kfsmart

Post Number: 12
Registered: 01-2008
Posted on Sunday, February 08, 2009 - 01:53 pm:   

"I assume that when you are in this state, that you are still able to send messages? "

"Does this happen on just one of the SMSC connections, or more than one?"

With this provider I have 3 connections have the problem and the other is working fine.
One notice that the 2 connections have the same IP and some time it work fine with 3 ,4 or 5 consecutive hours,then agin it didn't work.

Will the provider allow you to use separate sender and receiver binds instead of transceiver? Perhaps that would make a difference on their end? "
I tried this option ,but no difference.

"The only idea that I have would be an update with a configuration setting where NowSMS would automatically disconnect and reconnect if no messages were received within some configurable interval"
what update should I add?
Omar
New member
Username: Kfsmart

Post Number: 13
Registered: 01-2008
Posted on Monday, February 09, 2009 - 11:39 am:   

Dear Des,
Through going to the above problem,Please check my thoughts:
1-The nowsms disconnect the SMPP connection if it didn't recieve packets within 58secs(configured in keep-alive)from the provider.
2-Then My provider assuming that the connection is disconnected so it unable to send more SMS to my gateway.This is strange somewhile but I think this what happening,this clarifies why when restart the service,then I will get the pending SMS.

"Solution"
I changed keep alive to "0",so not to be the connection disconnected after timeout.


Comments?
Des - NowSMS Support
Board Administrator
Username: Desosms

Post Number: 450
Registered: 08-2008
Posted on Monday, February 09, 2009 - 03:52 pm:   

Hi Omar,

I don't think that will be a solution. Well, maybe it will be a work-around for you, but it is not pretty.

Let me explain what the "keep alive" means...

It means that if there has been no activity for x seconds, then NowSMS will send an "enquire_link" packet to the provider.

If NowSMS does not get an "enquire_link" response back from the provider, then NowSMS will disconnect, assuming there is a problem with the connection, and then reconnect.

Most SMPP providers will disconnect you if there is not an "enquire_link" packet sent at some interval. (Frequently this interval is 60 seconds, which is why we default to 58.)

In NowSMS, if you set the "keep alive" to "0", then this means that NowSMS will never send an "enquire_link".

If the SMPP provider requires an "enquire_link", then this will mean that the provider will keep disconnecting you if there is no activity. NowSMS will then reconnect.

For your particular problem, this may help you ... because when your provider stops sending you messages, a reconnect seems to fix the problem.

However, this is not an ideal solution. Your provider will not like that you are constantly disconnecting and reconnecting.

That said, I cannot think of any other alternative. If for some reason your provider stops delivering messages to you, this seems to be a system problem on their side.

--
Des
NowSMS Support