atcomsystems.ca/forum Forums Other TDM Phone Systems ESI Telephones & Systems ESI VoIP problem

Hello All,

To start off, I am not a Reseller of ESI nor do I install them.
This question is being submitted by a network guy


We seem to have a problem with a client that has an ESI-100 IP system.

All phones are IP local, 2 phones are at a remote location. IP
Main system has 4 POTs lines for inbound and outbound calls.
Location is now connected by a VPN with FiOS on both sides.
FiOS lines have static IP’s VPN and is stable.
Round trip pings to remote site are about 11ms no jitter
Round trip Local network <1ms steady

We are getting complaints about the remote IP phone getting echo or one side of the phone conversation can not hear the other. NOTE: this also does happen at the main location going out to POTs sometimes also
I ran a ping plotter test for about a week and noticed many drops to the ESI Phones.

I would get a good ping for a bit, then a packet would drop. Then a good ping for a bit. Then maybe two drops.

All other ping to other remote devices do not drop.

Even Locally, I will get a drop to IP phones every so often.

We are using the same managed switches, and firewall as we do at other locations with VoIP systems with out problems

I have QoS as much as I can on the switches and Router, still drops.


My self at our office, we have remote IP phones connect across a VPN that has around 45ms round trip and we do not get any of these problems. We are not using ESI for our system.

The ESI vendor is insisting it is a network problem. But, I my eyes drops should never happen to a device. Or as many as I see to the ESI devices.

This is now the second site we followed behind this vendor. We had the same drop packet problem with another client, but I was told ESI is a proprietary system and the drop packets were fine. This was normal. We put a different switch in for that Job and router just for the phone system and remote phone. Problem was still there.

Well, as a network guy Drop packets are not fine. 

Any help would be great.
PS. I do not know any Firmware version or nothing else that is configured on the phone system. The vendor will not let me look at it with Him.

Thanks in advance for your help.

It seems to me that you are asking for trouble using local phones over vpn. ESI makes local and remote phones. Try using a remote phone with port forwarding on the pbx end.

He said he was having similar issues with local ip phones also.

Since I know almost nothing about ESI, I'll stay out of it but I do know with several VOIP phones(from other mfg's) that ping tests aren't exactly helpful since the phone will stop responding to ping requests after "x" amount of requests to help prevent DOS attacks.

That's not how I read it.

Thanks for posting back.

All phones are IP based. local and remote.

hmm. DoS setting on the phone could be the reason for the drop packs, but i have never seen that on other IP phones.

As far as port forwarding, the phones should work fine over a VPN. Forwarding ports into the network is not an option on this network.
The VPN is not Nat'd or anything...plain old routing from point A to Point B.
Nothing more different then what is setup on other networks with VoIP that we have done/seen.

Over a VPN or dedicated line should work as is.

What is the diff. in a remote phone and local phone from ESI?

Thanks again

The communications servers IP phones can be both remote and local , it's the older systems(72e,128's, etc.) that there were local and remote phones, they are feature 1 , and the new ones for the 100's,200's,etc.. are feature 2.

I am having the same problem with a 100 I just installed with 4 remote phones , ESI said it was the network routers. I am going to call there CG :bang: and hopefully he will be willing to try and help.

Local IP phones are designed to operate on the local LAN.

Remote phones are designed to operate on a remote LAN. They use the local gateway and the remote PBX's WAN as the target IP address. Remote phones have remote licensing.

I believe the IP phones are local until you purchase the remote license for them.

Not exactly... the phones are now either local or remote (on the Comm Servers) and are made such by licensing. On the IVX line, the phone itself was not license based, so it was purchased as a local OR remote phone, but could not be changed (problem).

Also, the remote and local phones use different CODECS, the local phone uses G.711, the remote G.726 and FYI ESI-Link uses G7.29. Each one is used differently based on band-width requirements, and is why in many instances the ESI phones work well with minimal setup, as long as sufficient band-width is available.

Also, as we have found, ESI suggests NOT using VPN's with it's IP products (see below, from their literature.....)

"Virtual Private Networks (VPN) use encryption techniques to provide a secure connection across the Internet. Encryption is not necessary for a Remote Phone application and, in fact, may increase latency. However, some VPNs guarantee
optimum latency levels by reducing the number of hops through the Internet."

I've never worked on a 100% IP ESI system. However on an X Class with an ESI link card I've ran a ping plot for about 3 days and not a single drop.

The only time I've ran into echo issues is when a PC is pushing out a lot of garbage (part of a BOTNET). However, by the sounds of it, you've got the network managed pretty well and could detect these problems, if not prevent them.