GaryK

I need you guys to help solve a difference of opinion.

We are just looking at VoIP and my colleague reckons the biggest difference between voice packets and data packets is that voice packets have to be received in the order they are sent whereas data ones do not.

My argument is that *some* protocols allow you to send data packets in any order but some do not. However I am not an expert so would like an expert opinion!

Cheers

Gary

stevencotton

If you're transporting voice over an IP network then it will be using IP as normal to do its thing, with packets taking potentially different routes and being reassembled at the other end. IP isn't the best method of transporting voice, dropped packets will clip vocal sounds, and bottlenecks will introduce pauses.

GaryK

Steven,

So is secure IP any different to normal IP for routing packets? And in essence what you are saying is that IP as a protocol routes packets out of sequence anyway regardless of if its voice or data?

Cheers

Gary

stevencotton

Yep, IP will use the same packet-switching method it always uses. If you secure your packets with encryption that just adds another layer of encapsulation effectively, those encrypted packets will still route the same way, but also be subject to decryption at the other end.

Chris L

Steve is spot on (as I'd expect him to be ). More importantly, you need to look at the impact of running VoIP over your existing network. What levels of traffic do you currently have? Do you have accurate analysis of all your existing applications and their usage patterns? Also encrypting the voice data will add to processing time and will add delay - so you must take this into account aswell.

How many users are you expecting to have running VoIP?

The problem with VoIP is that end users will rightly expect the same level of quality and service that they have from their traditional voice PBX. They will not tolerate downtime, crashes, reboots etc - all those things that servers like to do When was the last time your PBX crashed?

If this is a big deployment, I would invest some time and effort to doing some research and modelling. Do you use Packeteer? Very good boxes for modelling application performance and the effect of introducing new applications into your network. If you don't use it and don't want to buy them, there are firms that will do short term consultancies to model the data for you.