Depends. If the customer is using Direct Routing, then it's whomever is providing their SIP trunk. If the customer is using Calling Plans, then it's Bandwidth.com. ________________________________ From: NANOG <nanog-bounces+rschoneman=blumenthalarts.org@nanog.org> on behalf of Adam Thompson <athompson@merlin.mb.ca> Sent: Friday, March 26, 2021 5:42 PM To: nanog <nanog@nanog.org> Subject: MS Teams orig/term carrier? Despite having worked for an ILEC in network ops for 10yrs, I can't figure out how to answer this without an SS7 sniffer (which I obviously no longer have, nor access to an SSP or SCP). What 3rd-party carrier(s), if any, does Microsoft use to originate & terminate MS Teams-to-PSTN voice calls in Canada? Pointers to rabbit holes welcome, if you think there’s an actual answer at the end ;-). Thanks, -Adam Adam Thompson Consultant, Infrastructure Services [[MERLIN LOGO]]<https://www.merlin.mb.ca/> 100 - 135 Innovation Drive Winnipeg, MB, R3T 6A8 (204) 977-6824 or 1-800-430-6404 (MB only) athompson@merlin.mb.ca<mailto:athompson@merlin.mb.ca> www.merlin.mb.ca<http://www.merlin.mb.ca/>