[VoiceOps] SIP return message on misdials - 487 or 500/503 or ?

Erick Bergquist erickbee at gmail.com
Mon Oct 5 12:19:51 EDT 2015

Thanks for the replies.

On the cause 41 I get a 503 which matches up.

Getting cause 63 back for the ones where I see SIP 500 Internal Server
Failure which is default behavior.

 I guess I'm good then, just wish I wouldn't see 5xx level for
mis-dials. Yes, the numbers are valid E164 formatted numbers for US
which the provider wants to see in that format.   I can't call these
numbers from other sytems either so they are indeed bad, un-allocated

Thanks, Erick

On Mon, Oct 5, 2015 at 10:51 AM, Jay Hennigan <jay at west.net> wrote:
> On 10/5/15 8:16 AM, Erick Bergquist wrote:
>> Hello,
>> Just trying to get idea of what is normal on what providers should
>> return for a misdial, bad unknown number, etc.
>> On one provider, I get a CANCEL and a 487 Request Terminated on mis-dials.
>> On another provider, I get a 503 Service Unavailable and a 500
>> Internal Service Error back.
> It depends. CANCEL and 487 Request Terminated typically comes from the
> originator and means that you hung up before the call completed. Carrier was
> in post-dial delay and hadn't returned anything (yet).
> 503 means that the carrier can't or won't process the call. Could be a
> misdial where the number can't be parsed as in not enough or too many
> digits, prefix starts with 1 or 0, etc. Could also be that you tried to dial
> a valid number that the carrier doesn't handle, such as international,
> 900/976, etc. Could also mean that you didn't pay your bill or are coming
> from an IP address that isn't a customer of that carrier.
> For a number that is in the correct format but isn't in service, you might
> see 503 or also 404 or 604.
> 500 internal service error is usually a technical problem with the carrier
> and not a misdial.
> Different carriers map ISDN/SS7 cause codes to SIP differently. See:
> https://www.google.com/search?q=isdn+cause+code+to+sip+mapping
> --
> Jay Hennigan - CCIE #7880 - Network Engineering - jay at impulse.net
> Impulse Internet Service  -  http://www.impulse.net/
> Your local telephone and internet company - 805 884-6323 - WB6RDV
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