Receive Bitrate
Inbound bitrate in bits per second — detect bandwidth throttling, congestion, and asymmetric network conditions.
Receive Bitrate
| Property | Value |
|---|---|
| Key | bytes_recv_rate_bps |
| Unit | Bits per second (bps) |
| Type | Gauge |
| Direction | Receive |
| RFC | RFC 3550 |
What It Measures
Receive Bitrate measures the inbound data rate of the RTP stream in bits per second. It shows how much media bandwidth is arriving at the endpoint from the remote sender at any given moment.
This is the reception counterpart to Send Bitrate. Comparing the two across endpoints reveals whether the network delivers bandwidth symmetrically or if one direction is constrained.
Why It Matters
- Throttling detection — If receive bitrate is consistently lower than the sender's send bitrate, an intermediate device is throttling traffic. This is a common issue with ISP-level rate limiters and poorly configured QoS policies.
- Congestion visibility — Receive bitrate that gradually decreases during a call indicates progressive congestion on the inbound path.
- Asymmetric path analysis — Many networks have different upload and download capacities. Receive bitrate helps identify when the inbound path is the bottleneck.
- Video quality tracking — For video, receive bitrate directly correlates with visual quality. A drop in receive bitrate usually means the video will degrade.
How CallMeter Measures It
CallMeter calculates the receive bitrate by measuring the total bytes received during each one-second window and converting to bits per second. The resulting gauge responds in real time to changes in network delivery.
Thresholds
This metric does not have fixed thresholds. Compare against the remote sender's Send Bitrate to detect delivery gaps.
What Causes Unexpected Values
- Bitrate lower than sender's rate — Packet loss is removing data from the stream. Each lost packet removes its payload bytes from the received total.
- Bitrate drops periodically — Congestion cycles on a shared link, or traffic shaping with a periodic token bucket.
- Bitrate drops to zero — Complete interruption. Either the sender stopped or the network path is blocked.
- Bitrate fluctuates without sender changes — Variable network conditions or competing traffic on the same link.
How to Fix It
- Compare with sender bitrate. The ratio of receive to send bitrate gives you the byte-level delivery rate.
- Check for throttling. If the delivery ratio is consistently below 100% but stable, a rate limiter is likely in play. Verify QoS policies and bandwidth allocations.
- Test at different times. If receive bitrate varies with time of day, shared bandwidth contention is the likely cause.
- Check for asymmetry. Test both directions independently. If one direction is fine but the other is throttled, the problem is direction-specific.
Related Metrics
- Send Bitrate — Outbound bandwidth for comparison
- Bytes Received — Cumulative data volume this rate is derived from
- Packets Received Rate — Packet-level view of the same reception
- Packet Loss Rate — Packet loss accounts for the bitrate delivery gap