As described above, some big name vendors are pushing out new VoIP security services at breakneck speed to match the increasing deployment of the technology. Others are making tools IT leaders can use in-house to test VoIP security levels by launching attacks on the network, flooding VoIP phones with calls to see the impact and even reassigning devices to other users or none at all to see how security measures stand up. The only drawback at this point is that the new wave of VoIP security tools use the Session Initiation Protocol, which isn't being widely used as yet in VoIP systems. Article [1]