Cisco 7941 and Preferred Codec Selection
Submitted by bendernz on Thu, 06/12/2008 - 10:47pm.
Hi all,
I'm having problems with Trixbox and Cisco 7941 phones and preferred codecs. I have set "g729" in my preferred codec section and it is the first codec in my permit list for sip.conf and on my trunk.
However, when I make/receive calls, the Cisco is still using g711u instead, and when I run debugs I see g711u ordered first in the INVITE from the Cisco.
Has anyone managed to make this work properly? What firmware do you run and how did you do it?
I can make it run g729 by forcing it on my Extension and disabling g711u but I'd rather not transcode if I don't have to. I do have g729 licenses etc installed.
Any help would be wonderful
Thanks,
-Scott
I got the same problem. I
Wed, 06/18/2008 - 5:04pm
I got the same problem. I got a few licenses to play around with and see how we like it but only the trunk side seems to use.
I tried in the config to use g729 and than tried g729a as have seen it listed both ways depending whos site you read it on, but either way no go... The default was none which uses ulaw.
Any advise? Using 2.6.0.7 w/ 1.4.19 ast.
Thanks in advance!
It definitely seems to be
Wed, 06/18/2008 - 5:10pm
It definitely seems to be related to the phones rather than Trixbox, other handsets I have such as Linksys SPA942, Polycom IP330 etc work fine with g729. The only way to make the Cisco handsets do g729 seems to be to make Trixbox force it for that extension. This has the result that most of our calls go in g729 as our SIP provider prefers g729, but for certain calls like calls to mobiles in NZ, these often get switched as g711 calls and I don't want the quality loss associated with going from AMR/GSM on the cell phone to g711 to our provider to g729 to the handset.
I'm picking it's probably a bug in the Cisco firmware, but how I would report this I don't know. Would just like to hear from anyone who does know a bit about the Cisco firmware as I'm relatively new to it.
Cant report it really. Cisco
Wed, 06/18/2008 - 6:12pm
Cant report it really. Cisco does not provide SIP support like that I dont think unless its with their endpoint system.
Its just got to be some special thing to do in the config file we havnt figured out, like for nat instead of 0 I have to have it blank...
Anyway what firmware do you have? I am running the latest one for the 7941g.
Maybe try posting this under help as it will get more eyes.
Well not sure it matters
Thu, 06/19/2008 - 9:51am
Well not sure it matters right now as it still dont work, the correct word to use seems to be g729a (for my firmware ver at least)
I found looking at the settings on the phone, under device config, than sip and general it shows the prefered codec. With g729 it said none, with g729a it shows g729a. So the only thing now is figure out why trixbox not doing it...
Nah, it's a phone problem.
Thu, 06/19/2008 - 3:47pm
Nah, it's a phone problem. If you grab some packet dumps (try debug mode or put Ethereal between a phone and your trixbox), you'll see when the Cisco sends the INVITE it puts g711u at the top of its codec list. This means that the preferred codec option is basically having no effect.
Try the same thing with the Linksys or Polycom phones with prefer g729 and you'll see that they list g729a at the top of their list.
What we need is someone from Cisco to sort it out - I might try getting hold of our account manager and see if they can pass me a contact
-Scott
But does your phone show
Fri, 06/20/2008 - 6:51am
I had just upgraded to 2.6.1
Tue, 07/01/2008 - 11:20am
I had just upgraded to 2.6.1 and had very high cpu usage, after digging I found that I had to set each ext to allow g729, before it worked with just the setting in sipdefualt.config. my trunks were all g729 but my phone were ulaw and the cpu was having to translate every call.
Where did you do this at?
Im
Thu, 07/03/2008 - 6:29am
Where did you do this at?
Im not on 2.6.1 but running 2.6.0.7 w/ 1.4.20 ast so "shoud" be the same if I have any luck :P
My Cisco 7940's are doing it correct and I did nothing special other than set the codec on the config file just these darn 7941's.
Let me know,
Thx!
I had looked at this before,
Mon, 07/07/2008 - 9:17am
I had looked at this before, it did actually work, thanks.
But just does not do it right. This is kind of forcing it, which means it cant fall back to ulaw if it needed to. My 7940's use the preferred and fallback if they start getting to many active calls or something due to overhead. The 7941 wont be able to do that due to forcing it this way.
But I guess its a start. So long as dont cause no problems I will live with it.
Thx again
Member Since:
2008-06-01