IPSEC and VoIP

[cagboh]

Has anyone had bad experiences with tunneled IPSec from CPE to CPE? We are about to start our VoIP trials so any help, tips and tricks will be VERY usefull.

Charles Agboh

IP Telephony Systems Engineer - Ebone/GTS

Belgium

[8dgoswick]

It actually works quite well. We have not had any issues with it whatsoever. What equipment and encryption level are you using for ipsec?

[cagboh]

we sure using cosine equipment in our network. What equirpment do you use. Where does the IPsec Tunnel terminate in your architecture? At the CPE or in your network?

[8dgoswick]

We use Cisco 2600 series routers with a 3des IOS on them. We are about to implement the new hardware encryption cards in these routers. Our ISP provides us the link and we take care of the tunnel. It is very important that all of your sites are on the same ISP, so that you are on one network. We chose an ISP that had a good service level agreement so that we could better trust our voice traffic over their network. Besides that, the Cisco Callmanager is smart enough to route calls through the PSTN if the WAN/VPN link is down.

[memorylane]

So, would you recomend the cisco call manager for a small ip telephony network, we are installing a frame relay network in wehich we will be using only IP telephones on it, 3 locations with about 5 phone throughout these 3 sites. which phone is best for this also,

[mtashiro]

We have been using IPSec tunnels back to our CallManager for some time now. We are also running IP Telephony to remote users over the internet via a IPSec tunnel. Our engineers have Softphone on their laptops so when they are on-site they can tunnel back to the office and they have their extention. Remember however, using IP Telephony over the Internet is not recommended or supported but it works assuming you have enough bandwidth.

Some hints:

1. Use compression (codec and rtp compression)

2. Prioritize you voice traffic

3. A gatekeeper might need to be used as well

Hope this helps, good luck and have fun. -Mark