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Lost CCIS IP links across multiple sites

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phadobas

Technical User
Jul 30, 2005
612
US
Between our different phone systems, we have lost the CCIS IP link, while one of our main router went through a maintenance in the middle of the night, and Internet was down for about half an hour. What was down is our Internet, so our link to all other sites went down. The link between the other sites didn't go down.

When the router was put back on line, Internet came up and all the VPN tunnels that are being used by the IP CCIS connections, also came up.

However, phone calls to us from other systems didn't work. I got reports of fast busy and one person reported just silence on call attempts to us. From what I know, everyone other sites was still able to call each other, but not us. Calls between the other sites were working just fine, only calls to us didn't go through.

The way I found out in the morning was this: the IT staff at one site called my cell to see if I could call them on the CCIS IP line. I called him and it worked. He told me that he was unable to call us all morning, and that he had undone and redone his CCIS programming to try to fix it, but didn't work. But after I called him, he was then able to call me and thereafter, there were no problems with that site calling us.

But then later during the day, I started getting more reports from other sites about them not being able to call us. We started to make test calls in order to try to reproduce the problem, and somewhere along the line, calls started working without any problems.

Of course our test calls went to us and from us to other sites. What appears to have happened is that after that router maintenance and losing VPN and CCIS links in the middle of the night, calls would not be able to be placed to us until someone from us made a call to other sites.

Does this make any sense? Is it possible that if the phone system can't detect the presence of the other system, after a while it "gives up" and doesn't retry? And somehow only placing calls kicks the link back into motion?

 
It sounds like some obscure keep alive signal was lost. I usually run some continuous ping tests after any IP link interruptions to ensure that all is well afterwards. Multiple test calls in both directions follow. You neglected to mention which systems had the issue. As there may be some keep alive or link timers that could be adjusted.
 
Thank you for the reply.
To one of my sites, for sure, there were pings going after the router upgrade, but the CCIS link didn't work initially until I called out from our system to that site. You are totally correct - test calls should have been done.

I had 2 SV9300 and one SV9500 trying to make calls to my SV8500, and they couldn't. My SV8500 had no trouble calling out to them. So yes, there may be some setting somewhere, that's set correctly on my system, and maybe incorrectly on the others...
 
The CCIS Manual say this:
---
To prevent the system frin receiving abnormal UDP packets due to packet loss of release message, etc., Health Check function can be executed. Assign System Data below:
ASYDL, System Data 1, Index 803, Bit 3=0 (CCIS over IP Health Check is used)

Health Check function can be executed at longer time intervals than the conventional one (ASYDL, System Data 1, Index 803, Bit3=0) by assigning the System Data below:

ASYDL/ASYDN, System Data 1, Index 831, Bit 6=1 (CCIS over IP Health Check Enhancement is used).
-----
This latter one is not activated on our systems, but I have no idea if this is even what I'm looking for. No other manuals mention anything about this "Health Check Enhancement".

Anybody has a clue about this?
 
We may have solved it. Apparently port 57000 was blocked on the VPN, which is something CCIS over IP needs. That's now open but we don't test this until some scheduled maintenance due to the high usage of the lines. So fingers crossed
 
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