Aastra multicast paging garbles active calls

Harding
Posts: 28
Member Since:
2011-02-03

Trixbox 2.8.0.4 with ~30 Aastra 6757i phones (2.6 firmware). Working well other than this small issue which I'm fairly sure is a phone issue.

For all-pages, we have setup multicast paging on the phones and it works great, very fast and clear audio. To avoid disturbing users who are in a call I setup the following settings in aastra.cfg:

#Allow intercom, Asterisk server page, or RTP group page to place active call on hold and broadcast. 1 on, 0 off.
sip intercom allow barge in: 0
#Turn off call waiting notification. CW tone will still play on extension's active call.
switch focus to ringing line: 0

This seems to work, users in calls do not hear the pages. The problem is the pages seem to interfere with calls in progress (ie: users on their phones during the page) so their conversations breakup and become very garbled during the page. This only seems to affect the conversations at our end (the called party does not hear it AFAIK). Not sure if this is supposed to be the "call-waiting" tone but all it does is garble the conversation so if there is another setting to shut it off that would be great.

Anyone seen this or have any ideas as to why this happens or what I could do to try and trace the issue?

I had a look at the latest 3.2 Aastra firmware but it doesn't list any issues like this plus I've heard it breaks the Aastra XML scripts so I'd rather not update to it (I may try it as a test on one phone).

Thanks.
--
AW



markwho
Posts: 675
Member Since:
2006-09-24
Have seen this on one of our

Have seen this on one of our installs. A multicast page would cause on going conversations to seem to cut in and out, sound garbled.

We set the port on the switch that the telephone server is connected to.... to not accept multicast. Cleared up the problem for us.



Harding
Posts: 28
Member Since:
2011-02-03
Thanks

I had a look at my switches and I don't think I can block multicast per port (they are layer 2 with some "smartswitch" enhancements). They do have IGMP snooping which I will turn on to see if I can get them to better manage the multicasts. I also noticed that my multicast paging address 224.0.0.2:10000 (from the Aastra guide) may not be the best choice as it is reserved as "224.0.0.2 All Routers on this Subnet" so I may change it to something in the adhoc range. Hopefully this will help...Thanks again.



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