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The definitive engineering tool for dimensioning loss systems (M/M/c/c). Calculate the Grade of Service (GoS) or required circuit count for a given offered traffic load in Erlangs.
Erlang B sizes loss systems: given traffic in Erlangs and a blocking target, it returns how many trunks or channels you need when overflow calls are cleared rather than queued.
The Erlang B formula assumes that blocked calls are cleared (not queued). It uses the provided traffic load (Arrival Rate × Mean Holding Time) divided by the circuit count to solve for the recursive loss probability.
Built on 3GPP Technical Specifications, ensuring accuracy for production deployments and security audits.
Calculations specifically designed to identify protocol vulnerabilities and signaling misconfigurations.
Based on ITU-T E.500 recommendations. Ideal for dimensioning non-hierarchical circuit-switched networks and SIP trunking gateways.
Edge-V8 Isolate
Technical Audit
< 50ms (Global)
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Offered load A = 25 Erlangs, target B = 0.01. Erlang B yields N ≈ 34 trunks. If you only provision 30 trunks, blocking rises above 3%, which is usually unacceptable for business voice.
Assumes infinite sources, Poisson arrivals, and exponential holding times. Does not include retrials, day/night profiles, or multi-rate traffic (e.g., video + voice on one pool).
Erlang B (blocked-calls-cleared) returns the probability that an arriving call finds all servers busy, given offered traffic in Erlangs and a fixed number of trunks. Equivalently, it solves for the trunks needed to meet a target blocking probability.
Use Erlang B for circuit groups, SIP trunks, and PRI spans where blocked calls receive busy tone and leave. Use Erlang C when callers wait in queue (ACD/contact center staffing).
Erlangs = (number of calls in the busy hour × average call duration in seconds) / 3600. Example: 300 calls × 120 s / 3600 = 10 Erlangs.
Enterprise voice often targets 0.01 (1%) or 0.005 (0.5%) blocking. Emergency and interconnect trunks may use tighter targets. Lower GoS always increases required circuits.
Convert between ITU, ANSI, and other SS7 point code formats.
Interactive signaling flow generator for GTPv1/GTPv2 control plane procedures.
Optimize roaming costs and steering efficacy using Signaling and OTA methods.
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