The signaling bandwidth is normally considerably smaller than the corresponding media bandwidth. However, we often must estimate it, especially in SIP configurations and when separating the bearer and signaling network. Two components typically make up signaling bandwidth:
The value of the keep-alive signaling and per-call signaling associated with a particular configuration depends on the types of endpoints and gateways involved and must be determined empirically. Once we determine the per-call signaling bandwidth for the various call types involved, those values are multiplied by the corresponding call rates, and those results are then added together.
We can then apply the Erlang B formula with a P001 grade of service to determine the 99.9th percentile bandwidth. See 99.9th percentile traffic.
