atcomsystems.ca/forum Forums Other TDM Phone Systems Vertical Telephones & Systems SBX to SBX system networking through VPN.

I have a customer that wants to connect two SBX systems together with IP trunks. They insist on using their VPN. I have had problems with their Netgear VPN routers not releasing the audio stream after a call completes for 2 minutes. (SBX to SBX on same network has been tested and VOIP calls are fine. Only trouble is through VPN.) This is not a question about how to set up SBX to SBX but rather what VPN router has worked for other installs. Thank you for any suggestions. They are a small company so budget is a consideration.

Good luck. I know some will not agree with me, but voip just doesn't work well behind NAT. You have to open so many ports in the vpn as to make it almost worthless. Put both systems in front of the vpn on each end. All you need is a couple more public IPs and two small switches. You won't have to worry about port forwarding or anything else. I have a lot of systems connected this way and it works well.

Thank you. I have had plenty of XTS systems connected that way also using a static IP address from an ISP. However, the customer has made it clear that the two systems must use a VPN. The way security is these days, I also would like to get them connected through a VPN. So if anyone else can give any suggestions... Make and model and even software version for the VPN routers.

You didn't post what Netgear router your customer is using. If it has QOS than some parameter is not set correctly, but if it has no QOS than I would take a look at the Adtran Netvanta series with the 3120 having the minimum requirements that you need...voip ready with QOS and its own VCM (voice quality monitoring.) Your customer will have to spend a bit more than the typical Netgear vpn router costs.

Derrick,
Tech support says networking 2 systems together they want a VPN or MPLS in place. If you are just doing IP Phones it is ok to go over the public internet.

Keith, in the past with XTS systems that were using IP phones, I found that removing the remote stations from the all-call page group solved a similar problem.

In my case, we had a dozen+ IP phones located across the country that kept a dedicated IP channel live so that they would be able to receive paging.

This would cause the IP channels to remain engaged for inordinate amounts of time, to the extent that there weren't any available channels for other off-prem stations.

Once we removed the off-prem stations from the paging group, things began working flawlessly.

I know that your system and situation are different, but I thought that I'd toss something out that may point you in the right direction.

I know they do...same thing with the XTS...but try telling that to a customer that has sites hundreds of miles apart that they need MPLS. By the way a VPN setup adds virtually nothing to the quality of a voip call between systems. It may allow you to allocate bandwidth at each site if using managed switches and "reserve" bandwidth for the voip connection but you are still at the mercy of the public internet, so don't be surprised when the customer complains of jittery calls and says "I don't get why it sounds bad...when we have a vpn!"

We are using Juniper Firewall/Router for our VPN SBX networking. I've got all my required ports opened on both ends. Should ALG feature in the firewall be turned off?

To answer my own question; Yes, it needs to be turned off. We decided to turn it off. What harm could it do to turn it off? If it's not the problem then turn it back on. Calls on the VPN are stable with good audio.

Thanks for sharing, Hardyj, but this thread effectively died back in April. It would be so much more beneficial to everyone here if you started a new thread and told us what you needed and managed to do in order to get it resolved. You can always reference a link to this former thread to enlighten everyone. I'm glad that you managed to get over that hurdle!