CDR And Transfer, An Asterisk Scaring Bug Lasting From 1.4 Version…

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Asterisk Users 2 Comments

When you use a product which version number is 11 or even 12, you might go with the assumption all big bugs are fixed and then you find there is a huge, important, expensive bug still running in the code we are relaying upon…

The problem is simple. If you transfer a call, that dialing will be not reported in the CDR, so no billing will happen. This is a simple example:

Extension 100 calls extension 101
After 10 seconds, extension 100 transfer the call to
After 100 seconds, extension 101 hangup the call

What do you find in the CDR? Just one record for a call from extension 100
to extension 101 lasting 10 seconds. What about the 100 seconds call from
100 to 00VERYEXPENSIVEDESTINATION? It will never get billed.

How do you manage these cases?


2 thoughts on - CDR And Transfer, An Asterisk Scaring Bug Lasting From 1.4 Version…

  • First, not all versions in 11 are the same. Bugs do get fixed. What version of Asterisk 11 are you using?

    Second, CDRs are not the same in Asterisk 12. Due to extensive changes in the bridging core, CDRs were re-worked heavily. You may want to take a look at the notes on the Asterisk wiki [1] for Asterisk 12, as well as the CDR specification for Asterisk 12 [2].

    And how did you do the transfer? Via DTMF features? Via a particular channel driver technology? If so, which channel drivers were involved?

    What kind of transfer was it? Blind? Attended? Failed attended (the notorious blonde transfer)?

    I’m not sure if there is a bug report filed against CDRs for the currently maintained branches for lost records during a blind or attended transfer that matches your issue. There is ASTERISK-17826, which may or may not be your issue: the noted lack of information makes it a bit hard to tell. The last issue that I’m aware of that we fixed regarding lost CDRs during a transfer was ASTERISK-21394, which was fixed in 11.4.0.

    So, if you’re using a version prior to 11.4.0, you may want to consider upgrading. Again, due to the lack of information, it’s hard to tell whether or not that would help you.

    Finally, CDRs in versions of Asterisk prior to 12 are subject to the whims of channel masquerades. This has historically made it difficult, if not impossible, to guarantee correctness during all transfer operations. Additionally, even if we could guarantee a particular set of behaviour in all circumstances, the lack of any clear agreement as to what a CDR should look like after an attended transfer (or in any situation that involved multiple parties) made the problem impossible to solve to the satisfaction of everyone. This particular reason is why CEL was created. If you continue to have problems with the billing records, you may want to consider moving your billing logic to CEL.

    Note that since (a) Asterisk 12 re-architected using a consistent bridging framework, which killed visible channel masquerades; and (b)
    we decided to not try and please everyone and just defined CDRs for how we thought they should work; the behaviour of CDRs in Asterisk 12
    and in future versions should be substantially more predictable.



  • 2014/1/23 Matthew Jordan

    I am using asterisk 11.6 and searching for “CDR transfer” in the issue tracker return unfixed bugs

    That seems great! Asterisk 12 really solved the CDR problem when transferring!

    Transfer was made using the “transfer” button of the phone and the result was the same with blind or attended transfer

    Thank you a lot! I am going to move ahead with asterisk 12!