atcomsystems.ca/forum Forums VOIP Phones & IP PBX VoIP & Cloud Phones, Hosted PBX, General IP Phones VoIP Phone System Questions

ShoreTel IP-PBX has a couple of solutions for remote workers.

1)Remote worker VPNs to the main office and tells the system the telephone number that they are located at (could be home phone #, hotel room #, cell phone). (Incoming Call)Call comes to the main office...system recognizes the telephone number that they are at located at and the call will ring to their home phone number. Caller at home can see on their PC that this is a business call and answer the call appropriately. (Outgoing Call) Home worker dials number on PC...phone system at main office calls the home worker....phone at home rings...remote worker picks up the phone....phone system initiates call to the dialed number. Pro's & Con's...Pro's....Toll Quality Voice.....No VoIP what so ever....Con's...Need enough phone lines at main office....perfect solution for small business with PRI.

2) Softphone....Software VPN needed for remote worker....If customer has T1 for Internet only this should work. Need router at main office...Kentrox good solution

3) Hardphone...Hardware VPN needed for remote worker...Expensive solution depending number of remote workers. Need router at main office

"Which system would be the best? Are VPN routers needed? How much of a security threat is VoIP?"

OK. The reason VOIP connections could need VPN is because many manufacturers don't support NAT traversal on both ends of a VOIP connection, which is exactly NEC's issue. VPN's DO NOT improve VOIP performance at all, they are a way for the data packets to traverse the public network w/o NAT. That is all there is on that issue.

QOS only helps you if there is a 'Queue' of data packets waiting to be transmitted anywhere on a network. If you use compressed voice on yer VOIP T1, you will have no bottleneck there, so QOS will do you no good. QOS on the client side adheres to the same rules.

To get around NAT and the need for VPN, many vendors place the VOIP interface on a 'DMZ' or public network. The downside of this is security. Do you want yer PC on the public network? Probably not. Are alot of PBX's getting hacked right now? No. Will they in the future? Who knows, but I would play that pretty conservative if I were you.

"What happens if we implement this in and the voice quality is horrible, what will you guys do to try to fix it?

Fix what? The internet? Please... Anytime you put voice packets on the internet, you get what you get.

"Do you see a problem with DSL or Cable connection on their end?"

Of course. Cable is the worst service you can use. Most cable providers use an on/off method of limiting bandwidth, so when a users upload b/w goes too high they cease transmittimg packets until the b/w average comes back down. Not good.

Correct me if I'm wrong superfoneguy, but I would think that a VPN would actually make the voice calls worse given the extra overhead of the VPN encryption. I have no experience in this, so I'm curious if anyone who has seen this could tell me.

It does seem to me that putting a phone switch on the public side of the network is a bad idea.

You are correct. VPN cuts into bandwidth.

Bandwidth is going to be alot of the issues with quality on this one. We install Samsung, 3Com and Tadiran IP and it works behind the firewall as long as you open up the correct TCP/UDP ports. And there is a sufficient amount of bandwidth. Some IT managers do not want to open up ports on the firewall so the only way around that is to go outside the firewall. Keep in mind though that a VPN connection creates alot of extra overhead, in some situations it could be as much as 100kb per phone conversation.

That's what's cool about Allworx--no VPN and no port forwarding to get through fire walls. They have a true plug-n-play teleworker solution.

^ I was just going to post that, until I saw you did. Thanks Antony.