How to choose which BRI to dial from

[federico_tv]

Cisco 17xx or 28xx as VoIP to ISDN gateway for a generic IP pbx

Using destination pattern in dial peers I can choose which port to use for outgoing calls based on dialed number

But how if different extensions on same pbx (i.e. different companies) want to dial the same outgoing number using a different BRI port ??

If I had two ISDN gateways I could choose different trunks at pbx level , but what mechanism can I use for a single trunk/single gateway ??

Thank you very much. 

[Aaron Harrison]

Hi

Option 1:

To select a different BRI on the gateway, the gateway needs to receive the numbers with different prefixes.

This means your PBX must be able to assign different prefixes based on which user is dialling.

E.g.

CompanyA user dials a 9xxxxx number, PBX inserts a 7 and sends 79xxxxx to the gateway

CompanyA user dials a 9xxxxx number, PBX inserts a 7 and sends 89xxxxx to the gateway

The gateway then strips the leading digits and routes.

Option 2

You could do this using some clever dial-peer matching - basically match the 'calling' number and map that to an inbound dial-peer, and use dial-peer CoS to limit the available outbound peers to those that point at the BRIs belonging to that company. 

This is more complicated and relies on each company having a seperate number range or it would get too complicated. Option 1 should be much easier.

Regards

Aaron

[federico_tv]

Thanks for reply

So the easiest way is to manage the pattern matching the dialpeer

Some other gateway allow the simultaneous connection of more trunks on same ip using different tcp port 

Is this allowed by cisco routers ? Should I fight against dial pattern conflict anyway ?? 

Thanks

[Aaron Harrison]

Hi Federico

With a Cisco router you don't really have a concept of 'trunks' as such, so that same IP/different port approach may not be easy. You have more of a per-call routing approach rather than trunks as you have with CUCM etc.

Aaron

[federico_tv]

Prefix method works like a charm !!

Is there also a method to mark the incoming calls coming from one or the other bri ??

I have a single voip dial-peer serving both bri :

dial-peer voice 1 voip
 destination-pattern .
 session protocol sipv2
 session target ipv4:<pbxipaddress>
 session transport udp
 dtmf-relay rtp-nte
 codec g711alaw
 no vad

can I add a digit to mark calls from different bri ?

Thank you very much

[Aaron Harrison]

Hi

Sure - the gateway runs through a list of matching items on the dial-peers; you just need to make sure calls from each BRI match a specific inbound dial peer, and run a translation-profile on that dial-peer.

http://www.cisco.com/c/en/us/support/docs/voice/call-routing-dial-plans/14074-in-dial-peer-match.html#topic1

Regards

Aaron