Beginning: 22.01.2021 – 9.46 AM
Ending: 22.01.2021 – 2.35 PM
Impacts: Outbound mobile calls partially unreachable
Dear customer, dear partner,
Please note that today one of our upstream mobile carrier was, without any valid reason, blocking a significant part of our outbound Belgium mobile traffic. As we have in place multiple failover scenery, most of the calls blocked were mitigated toward other carriers.
Nevertheless, part of the traffic sent to the faulty upstream carrier was sending back to us an incoherent error code (403. Forbidden) which we (as all other telecom carriers) consider a user based return code (meaning a code stating that the recipient of the call does not want to accept it).
Therefore, this wrongly given code made our system consider as a normal behave and, therefore, did not trigger failover routings.
When we discovered this double fault, we temporarily adapted our routing, and raised an emergency case toward the upstream carrier for investigation.
Best regards;
SEWAN Technical Team
