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TMS conference uses wrong bandwidth with OBTP

Dennis Koenig
Level 1
Level 1

Hi all,

i´m currently facing the follwoing issue:

When booking a conference via TMS directly or via Outlook (with TMSXE) the conference bandwidth when using OBTP will be set to 1152kbps regardless of the configured 4096kbps default IP or immersive bandwidth in the global conference setting in TMS. When dialing directly into the scheduled conference the configured default bandwidth on the endpoint will be used. That brings me to the presumption that it has something to do with the maximum IP bandwidth setting on each endpoint in TMS (see screenshot). This setting cannot be edited because the endpoint is registered to CUCM.


TMS conference settings:

Endpoint settings:

I have no idea where this setting is coming from and i hope that someone here in the commuity can help me fixing this issue.


This is my current setup:

- CUCM 10.5.2

- TMS 14.6

- TMSXE 4.1

- Conductor XC3.0

- vTPS 4.1

-TC7.3.0 on all endpoints (MX300G2,MX800,SX10/80)




1 Accepted Solution

Accepted Solutions
9 Replies 9

Patrick Sparkman
VIP Alumni
VIP Alumni

The conference bandwidth that is set in TMS used when it dials out to participants using Automatic Connect connection type.  Because OBTP sends out the conference dial in information to the endpoint to initiate the call and dial into the conference itself, the endpoint's default call rate and configured min/max call rates will be used and not what is set in TMS.

Take a look at the call rate settings in the SX80 Admin Guide starting on pg 73 for more details.

I'm not familiar with CUCM, I know there is a default call rate settings, but I don't know if there are any min/max call rate settings in CUCM, so you might have to go directly to the endpoint for them.

Patrick, that makes absolutely sense to me. :) But is seems that there is a different behavior when using OBTP and doing a manual dial-in from the endpoint. When scheduling a conference using OBTP, the requested bandwidth will be 1152kbps compared to the manual dial-in which will use 6000kbps (which is the default bw for SIP on the endpoint). I don´t quite understand which setting will apply in the OBTP scenario. 

Are you sure, that TMS will not set the default bandwidth when using OBTP?

I just did a OBTP test, and I stand corrected, the configured bandwidth in TMS is used for OBTP conferences.  My endpoint is configured with a default call rate of 1152, and my OBTP conference is set to use 2560, and the endpoint connected at the conference bandwidth.

I just tested with an endpoint here, I changed the max/min call rate values on the endpoints and my TMS didn't update the max bandwidth at all to what I had set on the endpoint.  It could be that TMS is pulling the that data from somewhere on the endpoint and that is what it's reporting as it capabilities, similar to the max video and audio calls.  My endpoint is directly managed by TMS, we don't have CUCM.

Unfortunately, I don't have an answer to why your SX80 is reporting such a low maximum bandwidth to TMS, especially if it can call out at a higher rate from what you said.  If the conference is configured with a higher bandwidth than what an endpoint says it can support, the endpoint will connect at the highest bandwidth it can - 1152 in your case.

Is this the only endpoint with this issue, if so, are they configured the same?

The screenshot of the SX80 was just an example. Every endpoint in our environment has this issue (MX300G2,MX800,SX10). 

I´m thinking in the same way as you that TMS will pull the max ip bandwidth setting from "somewhere". I´ve searched all the possible settings on CUCM but didn´t find any setting that could be in context with the max ip bandwidth configuration that TMS shows up.

Any ideas?

It might be good to contact TAC and see if they might have an idea or solution if one of the endpoints in question or even your TMS has a valid active service contract.

I have an SX10 (again, not using CUCM here), but it's max bandwidth is 3000 in TMS.

Looks like you're hitting a bug - fixed in TMS 14.6.1


Great find Nick!

I looked through bug search, but couldn't find anything, sometimes you get lucky and sometimes you don't.

Thanks - I was looking for something else, saw that bug and remembered this post :)

Today i did an update to Version 14.6.1 and TMS now shows the correct bandwidth on the endpoint. :) Many thanks to you, Nick!

Issue is resolved! (Cannot set your answer as correct!?)


edit: after sending this post, i was able to set the correct answer...strange ;)