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.

thanks again everyone.

Why woul ESI not recomend communication over a VPN?

Now a days networks are done via a VPN or Dedicated line. I would not open a port on the firewall for the phones.

Yes, a VPN has overhead, but so does a Cheap firewall that has no CPU power to properly do it's job.
Bandwidth will be determined by the ISP and hardware, If it is bad for a VPN, it would be be for just stright upload for the interent linem and VoIP traffic
(and traffic at the connecting side)

Yeah,
I Thinking about it, if something is set for DoS on the phones, it can not be set right.
a "normal" ping should not cause a DoS alert.

Steve,
If you find anything out, could you please pass it along..
Thanks!

For what it's worth we have installed remote phones in two different locations (72e system) over a VPN and had no problems as a matter of fact it was the ESI tech support who recommended setting it up that way.

I see the quote from PhoneSol and am confused as to why tech support recommended it and the documentation did not. Not sure what the answer is but i can tell it is possible for it to work at least on the 72e with the feature set 1 phones

Can anyone else offer any advice on the original poster's issue of one sided echo. We have some remote licensed phones actually sitting on the LAN that have the same echo only on outgoing. A locally licensed phone has some issues, but not near the amount. Talking to other users in the building on IP or digital is fine. The echo only appears or gets bad enough to notice on calls that go out of the system.

We have installed quite a number of the IVX, CS series and IP Phones(primarily remote). In my experience if the bandwidth, latency, jitter, and lost packets are within recommended limits, I would look next at the firewall / router. Inexpensive or consumer grade units may not have the horsepower to run several advertised features at once.

Our results with VPN's have been mixed. Some work well, other do not. I don't think the cause is the VPN, but other factors.

Echo cancellers will have trouble working when there are too many analog-to-digital conversions along the signal path. That's why it is noticed more on calls out to the PSTN.

Sometime acoustic echo will be too much for an echo canceller to deal with. For example, someone has their cell phone volume cranked while talking to you, or their talking to on a bluetooth headset. What you would have heard as more "sidetone" before you now hear as echo, because of the inherent delay.

Th firewall and switches are h same we use in other office.
Mater of fact, the same setup is at a location on a Avaya system with out problem.
Our system is running on the same hardware. We are using Asterisk with Aastra IP phones
( Don't beat me up on using Asterisk )

Our latency is much higher then the customers setup.

When i was at the location, this is what i experienced.
I made a call to another company from local IP phone (to system not over the VPN) out the POT's line.

I could hear the end caller fine, but she could not hear me for a bit..then could.
It seems this is the same for a call from the two office locations also.

We were told since the bandwidth was adjusted, he had to make more setting changes to compensate for the change.

I think the vendor is Getting ESI in the system., but i still have not received info from him.
Maybe someone can help me here.

What i am looking for:
1)Are the phones able to send QoS tags if so, is it set by default and what priority?
2)Is the Phone to phone system communication over SIP or another protocol. If so..what is the port number? TCP/UDP
3)What codec does the phone use by default.
4)Can the phone be statically assigned an IP address. (i would think so)
5)Any way to adjust the link speed of the NIC on the Phone? Maybe to hard set instead of doing a auto negotiation?

More testing shows ping test around 11ms sill across the VPN. Drop packets to the phones still.

Other devices pings are fine.

Thanks again for your posts!

1. For QOS, the ESI equipment sends the highest TOS Bit. That's about the only way to tag it.

2. Phone to KSU communication is using a proprietary protocol

3. Local IP is G.711

4. Static IP Address: I beleive it can be with ESI-Address.

5. None that I know of

The static IP address that you program with ESI-access is only used if you can't get an address from the DHCP server.

The new Ip phones allow DHCP?

My remote IP phones need static, but they are the older generation for X-class. And by looking at my switch, they negotiate at 100.

A VPN between two FIOS sites may not necessarily be any different than a VPN between two sites on different ISPs. The data does not necessarily stay on the Verizon network, and may actually hit the net before being routed back into verizon's network at the other end. This is definitely true of my connection with Optimum Online.

Some ISPs like AT&T offer managed VPN service, where both ends are on the same national network, and the VPN is guaranteed. This is common for large companies, when they offer work-from-home access or have multiple locations. It provides the security of point-to-point private connections, but at a fraction of the cost.

I remember trying to make a local ip phone work over a VPN and ESI said it should, but between us, we couldn't do it. Remote all the way!

Local IP remote phones will only work over a layer 2 VPN with phone and KSU on the same subnet. Otherwise you definitely need the remote phone. (or license in the case of the new ones)

QoS is not used on local phones, since they only work as layer 2 devices.

I would try to get ESI TS to open up 2 licenses for remote phones and change them to remotes in F31.

You can then utilize QoS and you also reduce the overhead. Local phones utilize 244K (122 each way) and remotes use 88K (44 each way).