Single LAN cable for data and voice for 200 users is OK?

We are planning to move to new office and plan to use Asterisk to replace the old PABX system. Our office has more or less 200 users, and we will have 2xT1 from telco. My biggest concern is now the LAN cabling. Our vendor said it is recommended to separate the data line and VOIP line to get better performance issue, but my understanding is that one of the reason to move to VOIP telephony is that we can share the data and voice line over a single ethernet connection.

So should I follow the supplier recommendation to use separate cabling for data and voice or we will be fine using single ethernet cabling? Thanks a lot to enlighten this noob question…

Most telecom vedors and data vendors will tell you to seperate the two networks. If you are moving into a site, I would suggest it as well. I would make sure they are seperate because, if they are on the same which works well too, but you better be sure your data network is up to par! The vendor is correct in saying that it will save you headache by splitting them. Think about it this way, what if a data switch has an issue and you have 24 phones on that data switch as well, now 24 people cannot use their computer or phone. Or what if people decide to start doing a backup over the network or downloading big files, if your data network doesnt have QoS on then people start to hear stutter and gitter and calls degrade. See how it all depends on how well your network is…Its really up to you, but I dont know many people that wouldnt recomend two networks(we dont always get our way though).


In an ideal world yes, or at least separate vlans. If neither are possible then make sure QOS is set up.
With 200 users I would expect you are going to segment the lan into separate vlans anyway

Its upto you really , Best to do it well to start with than suffer the slings and arrows of 200 irate users telling you that VoIP is rubbish and they should not have listened to you and stuck with what they had.