[asterisk-users] Asterisk doesn't relay remote MOH during hold

[Richard Brady]

Furthermore, the following two IETF documents address the need to both
signal the hold and provide the music:

1. RFC 5359 (Session Initiation Protocol Service Examples)

2. draft-worley-service-example-03 (Session Initiation Protocol
Service Example -- Music on Hold)

Unfortunately they both address more complex scenarios and solutions,
but they do back me up on the fact that there are good reasons to both
signal hold and provide music.

R.

On Wed, Apr 1, 2009 at 6:16 PM, Richard Brady <rnbrady at gmail.com> wrote:
> Hi Tony
>
> I can see where you guys are coming from on this and have already
> enumerated your argument in my own email.
>
> But there are very real reasons for a PBX to signal the hold even when
> it wants to send its own MOH:
>
> 1. Bandwidth: under your scheme the PBX would continue to receive
> bandwidth-consuming media without using it.
> 2. Privacy: the far-end has an expectation of privacy while on hold
> and should have the option to mute automatically when held.
> 3. Feature richness: signalling the hold enables such innovative
> features such as reverse hold.
> 4. ISDN interworking: ISDN supports this and SIP should be compatible
> with that (as per standard ITU-T Q.1912.5)
>
> Also, can you explain why the PBX would use a=sendonly but not
> dispatch media. Why not a=inactive for that case?
>
>> IMHO, PBX-A would be broken if it passed this along the Hold message to downstream and then started servicing the MOH itself
>
> Remember it is not a hold message, it is a media attribute and we are
> discussing how that should be interpreted within the context of the
> hold feature in traditional telephony.
>
> I would also like to point out in my defence that there are several
> telephone systems in the field which behave as I described (Nortel
> BCM50, Aastra Intelligate, Mitel 3300 to name a few).
>
> Regards,
> Richard
>
>
>> I have to agree with Kevin on this one.
>>
>> I fail to understand how you have a PBX-A talking to Asterisk talking to PBX-B and the PBX-A placing the call on hold.  Typically you should have a Client/Phone to PBX-A to Asterisk to PBX-B to Client/Phone/VoiceMail.
>>
>> If the Client signals Hold, the PBX should NOT be passing that Hold status on but transition audio stream from Client to MOH (assuming MOH is handled).  Asterisk shouldn't notice a thing except more RTP packets (or less if it is my teenage daughter on the phone as the case may be).
>>
>> IMHO, PBX-A would be broken if it passed this along the Hold message to downstream and then started servicing the MOH itself on the RTP stream.  That just doesn't make sense.
>>
>> Now if PBX-A were not a PBX and were a SIP Router, and the SIP Router was attempting this, I can see how it would Re-Invite, but it shouldn't pass the hold status onto Asterisk.
>>
>> Need some clarity here.
>>
>> Tony Plack
>