SIP Channels, CPS and Failover for Call Centers

Channels vs. CPS

Channels (concurrent calls) cap how many calls can be in progress at once — ringing and connected combined. CPS caps how many NEW call attempts can start each second. A 10-agent predictive campaign may need 25–40 concurrent channels at peak because the dialer places more calls than there are free agents, while CPS may only need to be a few per second. Size each separately.

A simple sizing method

• Peak channels ≈ agents × dial ratio × (average seconds a call occupies a channel ÷ average seconds between an agent's calls), then add 20–30% headroom.
• Required CPS ≈ peak call attempts per minute ÷ 60, then allow for campaign-start bursts.
• Inbound traffic needs its own channel allowance on top of outbound.
• Use the SIP channels and bandwidth calculator to check the network side.

Failover design

• Configure a second carrier or route in your dialer with a lower priority, so calls overflow when the primary returns 503 or times out.
• Keep the failover route tested — send a small share of traffic through it regularly.
• Make sure your caller ID, codec and DTMF settings work on both routes.
• Watch billing increments on both routes: a failover route with 60/60 billing can be much more expensive for short calls.

At CallCenterBoost

Concurrency and CPS are agreed per service during provisioning. CallCenterBoost can be used as a primary or secondary route; state which, and your expected peak, in the route-test request.