VoIP Quality and Security

The day and age of analog landline phones are going to the wayside and becoming a nice to have but not necessary staple of today's society. Cell phones and now VoIP appears to emerging in today's technology and becoming more popular. VoIP or Voice over Internet Protocol is a method for taking analog audio signals and turning them into digital data that can be transmitted over the internet. VoIP has been around for a while, but has recently made waves in today's market with it's enticing cost savings. However, with VoIP, quality and security can be a major task to ensure it's availability, integrity, and confidentiality in today's cyber driven world.


When dealing with the internet in general, quality of service is vital for businesses. VoIP is not immune to problems and is subject to latency, jitter and packet loss. As you can imagine getting choppy messages and/or bits and pieces of a conversation is not ideal and is not, by any means, an accepted practice at any level using VoIP. Let's discuss latency, jitter and packet loss. Latency is essentially the time it takes the data to get from the source to the destination. Latency will vary depending on the speed of the network, what components are used, and how secure you want your VoIP communication. Security is often sacrificed some for better quality to decrease latency. When packets of data have different latencies and arrive at different times, this is called jitter. Sometimes jitter can cause packet loss if the delay is so great. As you can imagine finding the right balance of network eqipment, security and network service will be key for a successful VoIP deployment.


As we mentioned above security is sometimes sacrificed to improve quality of VoIP. However, if you have less security, a business or your home could be subject to hackers and denial of service (DoS) attacks. With any internet related services protocols are utilized. There are 2 most common of protocols with VoIP. These 2 types of protocols are H.323 and Session Initiation Protocol (SIP). H.323 is a standard foundation for multimedia communications across IP-based networks and is an umbrella recommendation by the International Telecommunications Union (ITU). SIP is structurally a faster protocol than H.323. The use of the H.323 protocol presents a huge security concern as it uses random ports thus leaving ports in a firewall open and susceptible to other traffic. So a stateful firewall and/or application firewall is required to ensure consistency of the characteristics of the connections. Also, just like with any IP related information and voice conversations it is susceptible to hijacking, cyber attacks, and tampering. Just like H.323, SIP presents the same attacks and vulnerabilities with using random ports thus leaving holes in the firewall. In order to protect SIP networks, the use of TLS or Transport Layer Security which is an upgrade from the known SSL or Secure Sockets Layer. What TLS does is it provides an encrypted channel that allows SIP messages to be sent. TLS encryption relies on digital certificates by use of the public key cryptography. When using SIP, make the firewall you choose or use is SIP-aware



VoIP is an emerging market and at some point will probably replace the old analog phone system. With that in mind, VoIP will continue to evolve and security will improve as well as quality. The key to a successful deployment and implementation of VoIP especially in businesses is to find a happy medium between quality and security. As what was said earlier, to improve quality you have to sacrifice security. With this concept in mind, defense-in-depth concept of security should be utilized to ensure a company's network safe from outside threats.