PLATFORM COMPARISON — fictional teaching example
Read platform-sessions-fictional.csv. Treat every session as [login, logout): the login instant is included and the logout instant is excluded. Count distinct active agents, not sessions or events. All three session rows are invented and complete.
Distinct agents during 09:00–10:00 UTC: 3 (A, B, C).
Peak simultaneous logged-in agents: 2 (A+B, 09:15–09:30).
At 09:45, B ends exactly when C starts. Count 1, not 2.
The same hourly DISTINCT user count would be 3. It does not establish peak concurrency. Neither metric establishes simultaneous carrier calls or purchased-license count; billing definition must come from the contract. Actual call logs alone may omit idle logged-in agents.

For real intervals: include sessions spanning the start, clip to the same window, merge overlapping sessions for the same person, document missing logout handling, distinguish observed from assumed end times and account for collection gaps. Unknown endpoints prevent a claim of exact peak. For capacity collect simultaneous calls/channels separately. Define connected/billable minute sources and exclude duplicate legs only under a verified mapping.

Fictional cost example (pre-tax USD, 12 months): Hosted scenario: 3 named licenses at a made-up 100/month + 40 add-on + 20 voice + 2 internal hours at 40 = 440/month. Self-hosted: 170 infrastructure/backup/monitoring + 20 voice + 8 hours at 40 = 510/month. Add one-time 100 versus 300: 5380 versus 6420. These are NOT Talkdesk quotes or VICIdial capacity estimates. The example does not choose a winner because equivalent workflow and recovery evidence are unknown.

Your decision record:
Named license definition and quoted quantity: Unknown
Peak logged-in agents / measurement window and method: Unknown
Peak simultaneous calls/channels / method: Unknown
Voice minutes / billing units / destinations / rounding: Unknown
Mandatory workflow tests and result: Unknown
Monthly equivalent total / currency / tax / term: Unknown
One-time and exit costs: Unknown
Named internal responsibilities and support exclusions: Unknown
Selected option or unresolved question: Unknown
Next evidence request or bounded test / owner / date: Unknown