> For the complete documentation index, see [llms.txt](https://prosbcdocs.telcobridges.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://prosbcdocs.telcobridges.com/telecom-references/voice-and-media/custom-sip-bye-headers-format.md).

# Custom SIP BYE headers format

The custom SIP BYE headers field is formatted similarly to [Text CDR records](https://github.com/telcobridges-main/tmedia-wiki/tree/main/reference/concepts/text-call-detail-records/README.md). For example, the following content:

```
X-Test: This is a test.
P-RTP-Stat: PL=@{Stat:Rtp:Rx:Error:LostPackets}, DU=@{CallDuration}
```

Would put the following SIP headers in the BYE packet:

```
X-Test: This is a test.
P-RTP-Stat: PL=0, DU=12
```

For a call which lasted 12 seconds and had no packet loss.

For **P-RTP-Stat** SIP BYE headers, it is recommended to use the following content in release 2.8:

```
P-RTP-Stat: PS=@{Stat:Rtp:Tx:VoicePackets}, PR=@{Stat:Rtp:Rx:VoicePackets}, OR=@{Stat:Rtp:Rx:VoiceBytes}, PL=@{Stat:Rtp:Rx:Error:LostPackets}, JI=@{Stat:Rtcp:Jitter}, DU=@{CallDuration}
```

The following link provides the statistics format: [Call statistics format](https://github.com/telcobridges-main/tmedia-wiki/tree/main/reference/voice-media/call-statistics-format/README.md).

Here is the list of fields specific to SIP BYE headers:

| Field name        | Description                    |
| ----------------- | ------------------------------ |
| @{CallDuration}   | Call duration, in seconds      |
| @{CallDurationMs} | Call duration, in milliseconds |


---

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