Cisco describes 1% blockage (P.01) as a typical grade of service for PSTN trunks, noting that other applications may need different grades of service.
Checked 2026-09-25
- Vendor
- Cisco
- Product
- Unified Contact Center Enterprise
- Subsystem
- trunk and port sizing
- Deployment
- on-premises
- Region
- not restricted
- Release range
- 15.0(1)
- Checked
- 2026-09-25
Sources
- Solution Design Guide for Cisco Unified Contact Center Enterprise, Release 15.0(1) - Sizing and Operating Conditions for Reference Designs — Cisco Systems · tier 2 current vendor documentation · Contact Center Traffic Terminology > Grade of Service (Percent Blockage)
Cite this note
APA
WarmTransfer. (2026, September 25). Erlang B and Erlang C for voice and contact center sizing: source note erlang-traffic-engineering-gos-1pct-pstn-typical. WarmTransfer. https://warmtransfer.net/knowledge/claims/erlang-traffic-engineering-gos-1pct-pstn-typical
BibTeX
@misc{warmtransfer-claim-erlang-traffic-engineering-gos-1pct-pstn-typical,
title = {Erlang B and Erlang C for voice and contact center sizing: source note erlang-traffic-engineering-gos-1pct-pstn-typical},
author = {{WarmTransfer}},
year = {2026},
url = {https://warmtransfer.net/knowledge/claims/erlang-traffic-engineering-gos-1pct-pstn-typical},
note = {Source note erlang-traffic-engineering-gos-1pct-pstn-typical, checked 2026-09-25}
}