VoIP over public network

wnanse · ‎10-05-2001

Does anyone have any thoughts or experience on implementing VoIP over the public IP network, or through a VPN tunnel over the public IP network.

dgoswick · ‎10-05-2001

I've been doing this for the past year and a half. It's important to stay on the same network if you can, because of SLA's. The only issue I have run into is when my central office VPN device was having to do so much that the CPU utilization caused some packet loss, which resulted in poor quality voice. Just make sure you VPN devices can handle the encryption on the fly with minimal fuss.

jrussi · ‎10-11-2001

Yes, I do. We have implemented Voice Over IP over a VPN IPSEC 3DES tunnel, that runs over our ADSL connection over Internet.

We have a good ADSL speed (256K/1,5Mbps), and our office is small (20 people), so even without any QoS work it runs well. But with lower data connections, QoS is a MUST.

At the other end of the tunnel we have a 1 Mbps dedicated access to the Internet, and a office with 120 people.

Sometimes at peek time we experimented some noise, but nothing so bad.

palves · ‎10-15-2001

Do you only have a Call Manager at the main site only(the site where there are 120 people?). The remote site that you mentioned (20 people), does it not have a call manager server locally? Also, which codec are you running between both sites? G.729a?

thanks,

Paul

dgoswick · ‎10-15-2001

We have a Callmanager cluster at our main site and routers with SRST at the other sites. Unless you have a DSP resource, you have to use G.711, otherwise you will not be able to use things like conference calling and some voice mail systems.

ltropiano · ‎10-15-2001

I do this often. We have several people (including myself) at the end of ADSL circuits (forcing G.729a for that region). We have shared extensions (ie. rings in the office, rings at home...) very cool.

Today, I'm at the VON (Voice on Network) http://www.pulver.com/von conference at a hotel right now with Broadband, and spent the evening making phone calls using my Cisco IP Softphone using the Hotel's broadband connection... even with 200-300ms icmp/ping times, I was getting very good connections. A slight delay, but very usable. Nothing like using all the tools you have in the office on the road!