Passive, extension side call recording

The passive recording method is achieved by connecting the recorder server to a monitor port of a switch (SPAN/RSPAN port). The monitor port receives all of the traffic for each phones that need to be recorded. The recorder captures all the traffic, including the RTP media streams and the SCCP, SIP or H.323 signaling messages.

Using Verba Recording System, multiple recording servers can be deployed in order to support multi-site configurations or branch office networks and/or high volume systems with or without redundancy.

Supported platforms

The following list contains all supported platforms for passive, network monitoring based recording:

Supported Platform

Supported Signaling Protocls

Supported Media Types





Voice, Video, TelePresence
AvayaSIPVoice, Video
BroadSoftSIP, SCCPVoice
LifeSizeH.323***, SIPVoice, Video
Polycom**H.323***, SIPVoice, Video
TandbergH.323***, SIPVoice, Video
RadvisionH.323***, SIPVoice, Video
AsteriskSIPVoice, Video
Any SCCP, SIP, H.323 complient endpoint or phone-Voice, Video

* In Microsoft OCS and Lync environments, the signaling information is received from a filter application installed on the Front End servers. Recording of encrypted calls is also supported.

** For Polycom we do not support the followings: Siren22 audio codec, Polycom telepresence endpoints and all non-standard proprietary extensions.

*** H.245 tunneling and fast start are not supported.


  • Due to the nature of the passive recording method, there is no extra bandwidth or resource requirement from the network or call control servers.
  • There is no connection to the call control server(s) or usage of TAPI/JTAPI. In case of call control server failure, the recording system is not affected, the recording can work continuously if survivable telephony functionality is available on the site (e.g. Cisco SRST - Survivable Remote Site Telephony). In this case, a recording server is deployed at the site.
  • Because of the passive approach, the flow of the call is not affected at all.
  • Can be easily deployed and maintained.
  • Using Verba Recording System multi-site deployment architecture, the system can be adapted very well to a wide array of use cases.
  • If high-volume traffic is recorded, the system can be scaled easily by adding new recording servers.
  • All types of SCCP/SIP/H.323 phones can be recorded.
  • Monitor port technology is widely used approach.
  • In most cases it can be easily configured and used.
  • Silent monitoring can be supported natively by the recorder.
  • Video and TelePresence calls can also be recorded on certain platforms.


  • In complex switching infrastructure, the monitor port configuration can be a headache.
  • In a multi-site network, branches where a few calls have to be recorded, requires dedicated recording server.
  • Automatic announcement of the recording cannot be done by the recorder. An external IVR or TCL script on the gateway should be involved.
  • Encrypted calls cannot be recorded (except Microsoft OCS/Lync).

Possible deployment of passive, extension side call recording: