Recording

On phones as on media-relay interfaces in gateway, a recording URL can be configured. When this URL is configured, for each call, the media of the call is sent via HTTP PUT (WebDav) to a webserver. The media data is sent as pcap file, containing unencrypted RTP streams along with a dummy SIP signaling, so that wireshark can directly decode the media stream. The coding of the media stream is as it was used for the conversiation.

File name used for the PUT

The URL used for the PUT is what is configured as recording URL. To this URL a filename is added which is used to encode some basic information about the call, so that it can be matched to information received thru RCC or the CDR records

Filename format:

<guid>-<mac>-<serial>(-<reg-name>)

guid

The confernce id of the call. This conference id is identical at all legs of the call, so recordings done on different devices of the same call, can all be associated to the call. The conference id is also sent in the CDRs of a call.

mac

MAC address of the device, which performed the recording

serial

Serial number of the recording, to build a unique file name in case a call is recorded multiple times from the same device.

reg-name

If a registration name is available it is added to the filename

File format

The file format is PCAP. A dummy SIP signaling is added, so that wireshark can find the RTP streams. For the RTP streams fixed port numbers are used, 16386 for the local side and 16388 for the remote side.

The media is provided with the same coder as it was sent on the actual conversation, but without any encryption. If the data shall be sent encrypted to the recorder, a HTTPS URL should be used.