Mitel Call compression and Port utilization

[JOlinski]

hello!

We recently turned on the call compression for our Mitel 3300 VOIP phone system to have it use the G729a codec instead of the G711 codec to preserve bandwidth. What we're seeing is that the phones using this codec still show 60k usage. From researching, G729 should use 8k-40k with overhead. Does anyone know if there is a reason why the devices are still using 60k of bandwidth, rather than 8-40?

Also, while checking the phone utilization, we noticied that port 3602 has huge spikes in bandwidth in 2-4 hours intervals. The traffic appears to go from the phones to the primary phone controller. Anyone have any ideas on what this is and how/if you can control it?

 

[Supernova99]

I would say 40k is correct
Not sure about 60k though
Are you using any applications like Mitai, web apps etc?
All traffic will go through the controller that is hosting the trunks therefore if you have a single controller then that is where it will go
If you are talking phone to phone (internal call) then the RTP stream is PTP and should not involve the controller very much other than for signalling.

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[JOlinski]

I did not consider the Mitai. We do have the seperate Nupoint Voicemail system that uses Mitai to communicate with the phones to signal voicemails. But would voicemail indicator lights account for an extra 20k of bandwidth? I'mnot saying they can't, I just don't know much about that piece so I find it hard to believe that the indicator light could be using 1/2 the bandwidth of a phone call.


We have 5330's and 5340's but we don't use any of the PC to phone or web apps and such, so nothing to worry about there.

In our environment, we have 5 controllers on the primary system The main controller handles the phones. Controllers 2-4 each have 4 NSU's attached to them. Controller 2 handles all of the inbound/outbound calls for the Mitel phones.

controllers 3-5 (3 & 4 w/ NSUs and controller 5 with the integrated T1 ccards) connect the phone system to our outbound dialer systems.

85% of the company employees are phone agents, who are on the dialer systems all day.

In watching the traffic to phones to gauge the bandwidth usage, an agents phone hangs out at about 55-60k the entire time. However, these bandwidth spikes using port 3602 can increase usage up to 1mb or more for a brief period of time. If it were one phone or maybe a few, it wouldn't be so bad, but we see it from all of our phones every 2-4 hours...We're talking a total of 400 phones. 160 of these phones are in a "local branch office", that connect to the same primary phone system, just with a smaller network pipe.

I do expect to see communication from all the phones to controller 1 during the day, what I can't figure out is why every few hours their usage spikes momentarily to this one port at such a high rate.

 

[Supernova99]

I am not familiar with port 3602 it is cetainly not a port the 3300 uses by default.
I will check and find out what uses this port and post back

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[JOlinski]

Thanks Supernova!

Hopefully you find out more than I have. All I have found from the great Google is that 3602 is used by InfiniSwitch Mgr Client and the InfiniSwitchCL service. I haven't been able to find any information to connect this port or this serivce to Mitel.

 

[Supernova99]

I have trawled through all my docs trying to find a reference to 3602 and there is nothing.

Are you sure it is the phone that is using this port?
You say you have an outbound dialer application is this somehow taking control of the phone using this port?

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[JOlinski]

We were just monitoring the IP of the phone, so I would assume the data traffic from the attached PC would show under the PC's IP address. I'll go back and verify with out network guy to make sure it's not seeing any traffic other than the phone traffic, since there are devices plugged in to the PC ports on these phones.

If the dialer app was run locally, I'd be more inclined to say it's possible. We have thin-clients plugged in to the PC ports on the phones and the thin-clients auto-connect to a Windows 2K8 terminal server farm. So all the apps run off the server and the dialer just calls the agents phone to establish an "audio path" to direct calls to the agents. So the agents just have this single audio path open until they log out for the day.

However, it still may not be a bad idea to make sure that the dialer app isn't querying something from the phone system every few hours. I would expect to see the traffic come from the terminal servers, rather than the phone IP, but perhaps something with the audio path triggers this contact with the controller?

 

[Supernova99]

I have just emailed a colleague of mine and he says that SAP uses port 3600 to 3608 are you using SAP?

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[JOlinski]

I don't think so? I'm feeling like a noob right now, I can't remember what SAP is.

 

[Supernova99]

SAP is a CRM program if you had it you would know what it is. So we can probably discount it.

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[JOlinski]

Yes, CRM I know and nope, none in use

 

[kwbMitel]

Call recording?
Busy Lamps?

If by Agents you are refering to ACD phones then Real Time Monitoring is a bandwidth factor.

Normally, bandwidth isn't much of a factor but in your case where all phones are on active calls all the time I can see where that might be an issue.

**********************************************
What's most important is that you realise ... There is no spoon.

 

[JOlinski]

We actually got away from ACD phones so the extensions are all hard-coded to phones. By agents, I mean phone-jockey's, phone reps, people who sit around smilin' and dialin'. this was just easier for us, to assign extensions to a department and leave them there than have people with ACD extensions moving around and mixing extensions in to different groups and such.

the dialer systems we have do all the monitoring, recording and reporting and such through the dialers themselves, so we shouldn't have any of that traffic... We may have some monitoring traffic, but it should be pretty minimal. Maybe 2 or 3 monitors through the phone at a max at any given time. The managers all prefer the monitoring through the dialer because of the ease of use and reporting and such.

I also verified with the network guy... the 60k of traffic per phone should just be the phone traffic.

Maybe our Mitel system is broke and it thinks it needs 60k instead of 40k.

 

[LoopyLou]

Back to the original question regarding compression, do you have the zones etc setup? Do you compression licenses and DSP for non VoIP calls?

One good way to see if you are really getting compression is checking wireshark traces. They will report if G729 is in use or not.

The single biggest problem with communications is the illusion that it has taken place.

 

[JOlinski]

Thanks for the response Loopy.

Our network monitoring tool does confirm that the phones are using the G729 codec.

Our branch office is where we focused most of our efforts, so the phone for that office were all placed in Zone2, our primary controller (controller 1 from the above description) can handle 128 conpressed calls. We know there are more than 128 extensions in that office, but we know that at least 128 calls will be compressed, if for whatever reason everyone in that office is on the phone at the same time.

In looking through the system, we discovered that the compression option was also turned on for the routing in Controller 1. Not really sure if that's good or bad.

When we saw the 60k usage on the phones and the seemingly random usage spikes, we also verified then that the phones we were monitoring were using G729. We've monitored in the mornings, afternoons, evenings... no matter which phone, even if it's the first phone to be used from that office at the beginning of the day, the phones showing G729 show a pretty steady stream of 60k usage, aside from the aformentioned spikes.