Are Your Network ready for VoIP?

Enterprises and business across the globe are employing VoIP solutions to leverage max benefits and cost saving by utilizing their existing networking infrastructure.

However, like most modern technologies any VoIP deployment has a potential to be a real success or bad mess. In order to mitigate risks associated with a new VoIP deployment, it is very necessary that IT department must carry out a organization wide assessment of network readiness. Following are few of important questions which need to be sorted before going ahead with a VoIP investment.

Firstly, are your LAN and WAN ready to handle VoIP traffic? This need answers covering following aspects:

• Network availability, before putting critical voice communication on IP bandwagon, we must look whether our network has sufficient high availability, so that even minor hickup like power outages or a single WAN link unavailability shouldn't impede all connectivity.
• Bandwidth, is enough bandwidth available to carry additional voice traffic load. In most cases, LAN infrastructure may have enough room to accommodate VoIP traffic, but it is more importantly WAN links which need to be looked on. Any effective test tool like Fluke Networks's Optiwave may be utilized to get a wholesome picture of both your LAN and WAN links. Test results may suggest for purchase of additional WAN capacity or point to some erroronous application shadowing your network resources, which must be sorted out first.

Secondly, Is there a need to implement some QoS in your Network? As VoIP traffic utilizes UDP packets (usually with 20ms interval) instead of TCP, it is more effected by following network phenomenon:

• Delay, may be caused due to queing and buffering on various enroute switch and router ports, or transmission delay.
• Jitter, it relates to variation in inter packet delay. Voice quality is effected if jitter value for link exceeds the threshhold value (most IP Phones have default jitter buffer of 40ms).
• Packet loss, may happen due to ethernet errors on LAN or dropping of packets on exessive burst rate on WAN links. As mentioned above, as VoIP employs UDP any discarded packets are not retransmitted, thus packet loss also contribute to degraded voice quality.
• Expected max no of concurrent calls on the network.

Thirdly, a management ratification, what MoS (Mean Opinion Score) value can you expect (a technical assessment) and accept? MoS value represent voice call quality, ranging 5 for excellent to 1 for bad and very annoying. MoS value will be effected by delay, packet loss, jitter and audio codec selection.

Based upon the above decision for an acceptable voice quality, and results of previous questions, you may need to invest in upgradation of your existing network resources before going for VoIP deloyment. A VoIP readiness assessment test before an actual deployment will surely save a lot of sleepless night while operational and trouble shooting phase.