[VoiceOps] SIP return message on misdials - 487 or 500/503 or ?
jay at west.net
Mon Oct 5 11:51:41 EDT 2015
On 10/5/15 8:16 AM, Erick Bergquist wrote:
> 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
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:
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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