Voice over Internet Protocol (VoIP) recording is a subset of telephone recording or voice logging, first used by call centers and now being used by all types of businesses. There are many reasons for recording VoIP call traffic such as: reducing company vulnerability to lawsuits by maintaining recorded evidence, complying with laws, increasing security, employee training and performance reviews, verifying data, sharing data as well as customer satisfaction and enhancing call center agent morale.

How VoIP recording works

Since VoIP calls travel digitally on computer networks rather than telecom cables, VoIP recording is done by tapping into the computer network rather than phone lines. Usually this is done by connecting to a router, switch, hub on the network, or through the PC attached to the VoIP phone. One way of doing this is by connecting to the SPAN (Switched Port ANalyzer) port which allows the VoIP recording unit to monitor all network traffic and pick out only the VoIP traffic to record. This is usually done by connecting an Ethernet cable being between the VoIP recording unit and the router, switch, or hub. Via the SPAN port, the recorder will "sniff" for signaling and RTP (Real Time Protocol) packets that have the identifying information contained in the headers of the packets is designated to record. There are two main ways to capture the RTP packets with the SPAN port. You can SPAN the VoIP Gateway port, giving you all the in/out bound traffic and offers one point of contact for recording. This is especially helpful in a campus with phones in multiple locations across the campus. However this method cannot capture internal, peer-to-peer (phone to phone) calls because their VoIP traffic is sent directly between the phones and doesn't flow through the gateway port. The other method is to set up a VLAN (Virtual LAN) and include all the phones within the VLAN. Then SPAN that VLAN. This will allow recording all in/out bound traffic and internal traffic. The disadvantage is that not all phones at times are on a VLAN or the same VLAN, so multiple SPANS are needed. Another method is to use a concept called RSPAN (remote SPAN), in which the VLAN's that are set to SPAN are trunked across switches to a receiving switch.

Challenges of VoIP recording

VoIP is usually implemented as a cost saving measure over POTS (Plain old telephone systems). The same holds true now for VoIP recording. Most recording vendors are able to record the various standards of VoIP such as G.711, G.729a/b and G.723 and software only solutions as compared to the intensive hardware and software associated with legacy PBX recording.

Today, most of the VoIP vendors are offering VoIP recording methods specific to their VoIP call and communications management servers. These vendors are offering what is referred to as active VoIP recording where the recording vendor's solution becomes an "active" participant within the call for recording purposes. This offers a great deal of advantages for deploying VoIP phones and recording. Some of the advantages are the flexibility to record anywhere within the VoIP network, the ability to record encrypted calls and various recording methods such as record on demand, stop recording and save last call to name a few.