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Channel selection order under ISDN E1 PRI

We have the following VoIP setup:

Site1_PBX---VoIPgw--**network**--VoIPgw--Site2_PBX

ISDN type: E1 PRI

Both gateways have 03 E1 PRI setup, so total, we have 90 B channels. It seems the router select the B channel randomly.

We need to have a logical sequence of B selection for each gateway:

First E1 will be selected and B channel will be selected from 1 to 30 sequencially

the second E1 will be selected once the first e1 is fully used (all 30 B channels are used) and B channel will be selected from 1 to 30 sequencially

the third E1 will be selected once the first and the second e1 is fully used (all 30 B channels are used) and B channel will be selected from 1 to 30 sequencially

Thanks for your quick feedback as this is urgent for users

Mohamed

3 REPLIES
Hall of Fame Super Gold

Re: Channel selection order under ISDN E1 PRI

Hi,

No the router does not select B-channel at random. It always uses ascending or descending order. To have an order whitin the different interfaces, configure them in a sequential trunk-group.

Hope this helps, please rate post if it does!

Re: Channel selection order under ISDN E1 PRI

hello,

Thanks for your response.

Do you have any related documentation about trunk-group?

Which Cisco IOS command should i use?

Appreciate your help

Hall of Fame Super Gold

Re: Channel selection order under ISDN E1 PRI

Hi,

Under serial x/y interface, specify a trunk-group with a name of your liking, and a priority if necessary.

Under DP pots, specify the same trunkgroup instead of port.

Optionally, under "trunk group ", you can configure additional options.

That's it.

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