Solved: Questions on MOH?

techToddler · ‎03-13-2016

Hello Friends,

Could someone help me understand my below questions. Thank you in advance.

1. I was told when a call was put on hold, only MTP can hold the RTP stream or the call till it resumes from hold. Is that true?

2. If two phones registered to the same call manager cluster talk and places on hold, will MTP be used? If not which is holding the call?

3. In Cisco SRND, It says everytime you put a call on hold the music will not start from beginning or first of the .wav sound. How does this work or how to make this work to have music played from beginning?

Please help

Regards

Sanjay

Rajan · ‎03-13-2016

Hi Sanjay,

1. I was told when a call was put on hold, only MTP can hold the RTP stream or the call till it resumes from hold. Is that true?

No. This is not true. MTP is not at all needed to put the call on hold. When you put a call on hold, the CUCM simply signals to stop media transmission and once you resume the same call, it again signals start media transmission.

2. If two phones registered to the same call manager cluster talk and places on hold, will MTP be used? If not which is holding the call?

As mentioned, CUCM itself will take care of this and no MTPs needed

3. In Cisco SRND, It says everytime you put a call on hold the music will not start from beginning or first of the .wav sound. How does this work or how to make this work to have music played from beginning?

This I suppose is for multicast MOH though I have not tried with unicast MOH. Usually multicast music has this behavior because in that case music is streamed always on that multicast IP and whenever any endpoint needed for ex. while putting on hold, will listen to the streamed music and hence it wont be from the beginning.

HTH

Rajan

View solution in original post

Rajan · ‎03-13-2016

Hi Sanjay,

1. I was told when a call was put on hold, only MTP can hold the RTP stream or the call till it resumes from hold. Is that true?

No. This is not true. MTP is not at all needed to put the call on hold. When you put a call on hold, the CUCM simply signals to stop media transmission and once you resume the same call, it again signals start media transmission.

2. If two phones registered to the same call manager cluster talk and places on hold, will MTP be used? If not which is holding the call?

As mentioned, CUCM itself will take care of this and no MTPs needed

3. In Cisco SRND, It says everytime you put a call on hold the music will not start from beginning or first of the .wav sound. How does this work or how to make this work to have music played from beginning?

This I suppose is for multicast MOH though I have not tried with unicast MOH. Usually multicast music has this behavior because in that case music is streamed always on that multicast IP and whenever any endpoint needed for ex. while putting on hold, will listen to the streamed music and hence it wont be from the beginning.

HTH

Rajan

Jaime Valencia · ‎03-13-2016

As Rajan mentioned, the MTPs are out of this picture, the process of MOH does not ask for an MTP to work, not even sure where/how you came to that idea.

The phone will simply create a one way audio connection, to either the MOH server for a unicast stream, or will subscribe to the MOH multicast stream

#3

The MOH feature causes any party that gets placed on hold to hear the same point of the audio source that is streaming, regardless of when the party is placed on hold.

If you are using the MOH to deliver a spoken announcement when a party is placed on hold, the standard MOH configuration can create a problem. Users do not hear the announcement from the beginning, except for the first party that gets placed on hold: other parties join the announcement (audio source) in progress.

Both multicast and unicast configurations present the same audio-source behavior to held parties. Each audio source gets used once, and the stream gets split internally and gets sent to the held parties. The only difference between multicast and unicast, in this case, is how the data itself gets sent over the network.

Thus, basic MOH configuration is unsuitable for playing announcements that users must hear from the beginning.

http://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/admin/8_5_1/ccmfeat/fsgd-851-cm/fsmoh.html

HTH

java

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John Gowen · ‎09-30-2016

Jaime,

I just wanted to get your opinion on something.

I understand that unicast and multicast MOH are both one file playing, the main difference (apart from the network delivery) is that if nobody is on hold Unicast will play from the beginning of the file for the first held call and Multicast is continuous and it will be heard from wherever it is in the file.

In my lab testing I have observed a behaviour in both 10.5 and 11.5.
- When the Allow Multi-casting is ticked within the Music On Hold Audio Source Configuration
and
- When I ticked Enable Multi-cast Audio Source on this MOH Server and configured Base Multi-cast IP and port within the Music on Hold Server
- But I haven't configured Multi-cast on the Media Resource group
The MOH is played continuously and its still Unicast, that is, if nobody is on hold the first person held hears the file from wherever it is in the file.

I've verified this using RTMT and they are definitely Unicast.

The reason I ask is that this behaviour is exactly the requirement of a customer of mine and I'm wondering could there be any risks or knock on impacts? I thought it was appropriate to ask this as a reply hear instead of a new thread.

Thanks in advance,
John

Manish Gogna · ‎10-03-2016

Hi John,

Please check the following enhancement

https://bst.cloudapps.cisco.com/bugsearch/bug/CSCue85258/?reffering_site=dumpcr

Play continuously needs to be removed from CM Features & Services Guide

CSCue85258

Description

Symptom:
Documentation in the "Music On Hold" section of the Cisco Unified Communications Manager Features and Services Guide, Release 9.0(1), and also Release 9.1(1), is incorrect. The "Play continuously (repeat)" field is no longer an option in versions fo Cisco Unified Communications Manager 9.0 and later.

Conditions:
The "Play continuously (repeat)" field is no longer needed because:
- Unicast audio sources will now always repeat as long as anyone is on hold. About 10 seconds after the last held device is removed from MOH, the MOH source will "stop" and the next held device will hear MOH from the beginning.
- If the source is multicast it will continuously be played and repeat.

Workaround:
None needed. The documentation for the field can safely be ignored for CUCM 9.0 and later.

Manish

John Gowen · ‎10-03-2016

Hi Manish,

I've read that bug and I think I understand it, its more about the v9 documentation really.

My query is just regarding weird behaviour I've observed in terms of the Unicast MOH been played continuously (whether anyone is on hold or not).

If you look at this paragraph from the bug:

- Unicast audio sources will now always repeat as long as anyone is on hold. About 10 seconds after the last held device is removed from MOH, the MOH source will "stop" and the next held device will hear MOH from the beginning.

In my lab, in v10.5 and v11.5 I've noticed that if I enable multi-cast on the file and on the server, but NOT on the MRG, the file will play continuously using unicast whether anyone is currently on hold or not.

Regards,

John

techToddler · ‎03-15-2016

Thank you Friends

Regards

Sanjay