Understanding SIP Channels and Concurrent Calls on Yeastar P-Series Cloud Edition
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Introduction
When you order your Yeastar Cloud Edition system, one of the key decisions is how many SIP channels (also called concurrent call paths) you need. This guide explains what SIP channels are, how to count them, and what happens when you run out.
What is a SIP channel?
A SIP channel is a single voice path — one simultaneous call in or out. Every active call uses one channel.
Example: If you have 5 SIP channels and 5 calls are active simultaneously, the 6th caller gets a busy tone (no more available channels).
How many channels do you need?
A rough guide based on business size:
| Business size | Recommended minimum channels |
|---|---|
| 1–5 staff | 3–5 channels |
| 6–15 staff | 6–10 channels |
| 16–30 staff | 10–15 channels |
| 30+ staff | 15+ channels (assess based on actual call patterns) |
Rule of thumb: Not everyone calls at once. For most businesses, you need roughly 1 channel per 3 users for typical office call patterns.
Busier environments (call centres, customer-facing, retail) need more — closer to 1 channel per 1–2 users.
Checking current channel usage
In the PBX admin portal:
1. Go to the Status Centre (Dashboard).
2. The active calls panel shows how many calls are in progress right now.
3. Reports > Statistics shows peak concurrent call counts over time — useful for planning.
What happens when all channels are used?
- New inbound callers hear a busy tone or are sent to an overflow destination (if your carrier supports it).
- New outbound calls fail with a "no available trunk" error.
If your staff regularly hit the channel limit, you need to add more channels.
Adding more SIP channels
Contact X2Comms to increase your channel allocation. Additional channels can usually be provisioned the same day.
Checking your current channel limit
Your SIP trunk is provisioned with a maximum number of concurrent calls. To check:
1. Go to Extension and Trunk > Trunk and click your SIP trunk.
2. Look for Max Concurrent Calls — this shows the limit set by your carrier/trunk provider.
Tips
- If you're regularly hitting channel limits, check your CDR for call durations — long average handle times increase concurrent call demand.
- "Abandoned calls" (hung up during IVR or hold) still use a channel until the caller disconnects.
- Consider failover routing: if a call can't get a channel on your primary trunk, route it to a backup trunk.
Summary
SIP channels determine how many calls can happen simultaneously. Order enough for your peak call volume — X2Comms recommends a minimum of 1 channel per 3 staff. Monitor via the Dashboard and upgrade when you approach the limit.
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