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Regions / dial peer codecs

canowlin
Level 1
Level 1

Can anyone tell me which takes precedence? The codec configured with CCM Regions or the codec configured under the voip dial-peer?

4 Replies 4

Aaron Harrison
VIP Alumni
VIP Alumni

Both and neither...

If you set a dial-peer to use a particular codec and set a CCM controlled device to use a particular codec then the devices will:

1) be directed to use a transcoder by CallManager if one is available to the device

2) Drop the call as no common codec is found

Default for dial-peers is normally to use G729.

You can set up a list of codecs to be used by the dial-peer that points at CallManager by using the following:

voice-class codec 1

codec preference 1 g729r8

codec preference 2 g711ulaw

exit

dial-peer voice

voice-class codec 1

This gives an ordered list of codecs to be matched on that peer - now whatever you set in CallManager (provided it's in the class you set on the dial-peer) should go through OK.

Aaron

Aaron Please remember to rate helpful posts to identify useful responses, and mark 'Answered' if appropriate!

thanks Aaron,

so if I have gateways in the default region, phones in their respective regions. do I get this ?

local ip phone >> remote ipphone ==== g729

local ip phone >> remote gateway ==== g711

my phones are using the remote PSTN as the backup gateway set through the RL's.I have 1760's all around so I'm thinking dsp's aon these cannot be used as transcoders?

thanks,

Claude

If you put the commands I suggested onto your 1760s, then you can use the regions in CallManager to set the codec you want between those regions and the 1760 will be able to accept them. So depending on your region setup you may have any of these combinations and it will work:

local ip phone >> remote ipphone ==== g729

local ip phone >> remote ipphone ==== g711

local ip phone >> remote gateway ==== g729

local ip phone >> remote gateway ==== g711

If you have two sites(for example), you could have all gateways and phones from one site in region A, all from the other site in Region B, then have g729 configured between the regions and G711 within each region. You shouldn't need to use G711 accross the WAN unless you have something on the other site that won't terminate G729.

This method doesn't require a transcoder - that's only required if the two ends of the call don't support a common codec.

In more recent versions of IOS 12.3 the DSPs on the motherboard of the 1760s can be set up as a farm and used by callmanager as a transcoder - but you'll probably be using your DSPs for the voice ports and I think you can't share them...

Aaron

Aaron Please remember to rate helpful posts to identify useful responses, and mark 'Answered' if appropriate!

canowlin
Level 1
Level 1

I'll be trying out this method soon thanks for your input