Look at SBC status in the Teams admin center and at the SBC’s OPTIONS log.If TLS failed, stop.Certificate name, expiry, and chain come before regex.If OPTIONS succeed and one number fails, then you have earned the right to open the dial plan.
SIP Tester language shows up in operations chatter.Use the health view and a real test call.Do not invent a hidden tester result you did not run.
Trunk health first: certificate, OPTIONS, admin-center status.Then the dial plan.
A site map for Trunk health. LBR is toll-bypass control, not emergency location by itself.Do not start at the dial plan. Counts in this drawing are teaching order, not customers.
The client waits a little so late packets can still be played. Too small and you hear gaps. Too large and you talk over each other. CQD jitter and the buffer are related and not the same number. Source: https://learn.microsoft.com/en-us/microsoftteams/cqd-what-is-call-quality-dashboard accessed 2026-10-14.
A colleague reports: A WAN with 40 ms jitter is ‘fixed’ by a slide that says buffer. Where do you start?
A WAN with 40 ms jitter is ‘fixed’ by a slide that says buffer. Fix the network before you hunt a hidden buffer setting. Source: https://learn.microsoft.com/en-us/microsoftteams/cqd-what-is-call-quality-dashboard accessed 2026-10-14.
Which description of Round-trip time is accurate?
How long a packet takes to go and come back. Long RTT with low loss means distance or hairpin, not a dirty cable. People add bandwidth and the delay stays. Source: https://learn.microsoft.com/en-us/microsoftteams/cqd-what-is-call-quality-dashboard accessed 2026-10-14.
Call Analytics The per-user, per-call quality view in the Teams admin center. Use it when one person had one bad call. Config: Open the user’s call and read jitter, loss, and RTT on each stream. Fault: A site problem is hunted one user at a time.
Call Quality Dashboard The aggregate quality report. Use it for subnets, buildings, and trends. Config: Confirm the subnet-to-building map before you trust a building chart. Fault: HQ looks terrible because the VPN pool was labeled HQ.
Poor stream clues Teach yourself to look at jitter, packet loss, and round-trip time separately. A mark of DSCP 0 plus high jitter is a different fault from 12% loss with EF still set. Config: Capture at the egress and compare with CQD. Fault: The ticket says ‘Teams is down’ and loss is 0.2% with a 600 ms RTT.
SIP ladder A time-ordered picture of requests and responses between client, proxy, SBC, and carrier, joined by Call-ID. Config: Capture on the SBC, filter the Call-ID, and read the first non-success code. Fault: Two captures are compared and they are different calls.
Sister technologies
Around the call: compliance recording, workforce management, emergency location, analytics, CRM screen pop, and an agent with a human escape. Each one has its own failure.
Config and troubleshooting
The dial plan is rewritten while the certificate is expired.
Cross-platform bridges
CUCM
Cisco CUBE is one of the SBC families named in this lab’s certification lesson. A certified release can be the Direct Routing SBC between Unified CM and Teams.
The tenant still needs a verified domain on the SBC FQDN, and the user still needs Teams Phone. The studio translator does not open a live AXL session. Confirm the current certified release before you build.
Webex
Teams Phone and Webex Calling are separate clouds. This lab does not describe a feature that registers a Webex Calling user into a Teams tenant.
A number move is usually a carrier port, a certified SBC, or a meetings interop product. Confirm before relying.
UCCE
Unified CCE stays the ACD until you migrate it. Microsoft’s contact-center articles name Connect, Extend, and Unify. They do not name a UCCE connector in the notes this lab cites.
Session Initiation Protocol — Wikipedia — last checked 2026-10. Wikipedia fallback for background. Confirm the vendor page before you change a tenant
Microsoft Teams blog index — Community — last checked 2026-10. Community index for the Microsoft Teams blog. This is the index, not a claim that a post discusses this room
