Voice over Virtual Private Network (VoIP VPN)
VPN (Virtual Private Network):
VPN is a network which uses internet instead of leased line for its communication and network traffic. It connects remote offices and multiple private users maintaining security through VPN’s tunnel connection, where data is encrypted and decrypted while sending information on the internet. VPN has same security and it is cost effective as it uses internet connection instead of private leased lines for its communication.
Voice over Virtual Private Network (VoIP VPN):
Combination of VoIP technology and VPN technology is termed as VoIP VPN. As VoIP carries voice in the form of digital data, it becomes simple for VPN to carry this digital data with same security and protocols which are used in VPN’s other data transfers. Analog voice from phone device is first converted into digital voice through VoIP gateway router, and then it is encapsulated into IP packets. Further this data is encrypted using IPSec, which is protocol for securing internet protocol. This encrypted voice data is passed securely through VPN, and then it is received by VoIP router at other end; which decodes, decrypts and converts this digital data back to analog data usable by phone device.
Implementing VoIP VPN technology is simple through open source software, which is readily available in the form of VoIP server, Operating system, IPSec, BSD or Linux. Few VoIP VPN service providers install client VPN software remotely on client’s Windows XP or Windows 2003 machine, which has two Ethernet cards; which will convert client’s machine into a soft VPN router. Cisco or Quintum gateway is bridged between VPN connection and dynamic or private IP of the client’s machine. This connection is secure, reliable and flexible which uses only one UDP port of the client machine, which also provides 1024 bits protection for encrypting VoIP calls with VPN tunnel.
New standards in VoIP encryption protocols such as SRTP and ZRTP uses features of VoIP PBX, which reduces VPN overhead from client machine. This new standard works without having to manage PBX and VPN gateways. Also latest technologies such as TURN, ICE and STUN overcome NAT issues of VoIP system. Before implementing VoIP VPN technology or choosing provider, few issues must be considered:
• Solution must be cost effective
• Security for internet and voice traffic
• Control over packet loss and packet delays
• Public internet’s volatility
Advantages of VoIP VPN technology:
• Security: encryption and decryption method is used for security which provides good security.
• SIP (Session Initiation Protocol): which uses random ports to establish connection through firewall.
• Cost: as long distance call charges and leased line are eliminated, overall cost is reduced.
• Works with WiFi: this technology also works well with WiFi local area network.
Disadvantages of VoIP VPN technology:
• Reliability on Service Provider: ISP’s network may crash at times which is not under direct control of the organization.
• Large bandwidth: since voice data is transmitted, high bandwidth is required.
• Detailed security knowledge: since information is transferred through internet, security software has to be updated regularly.
• Compatibility: there could be technical problems as we have to use mix and match up software and devices from different vendors, which could not be compatible sometimes.