Connecting Cisco CME to Voipbuster

Here’s something I’ve been looking forward to for a long time: connecting Cisco Call Manager Express to Voipbuster for outbound calls (inbound will be covered in another article). The Internets aren’t exactly flooded with examples like that.

This example uses the FQDN name for the Voipbuster service. Let’s define the prerequisites for this quest:

• A Voipbuster account;
• DNS Resolving on our router;
• An outbound dial peer;
• A sip-ua configuration;
• A translation rule and profile (I don’t want to dial international numbers for local calls).

Step 1

Get a Voipbuster account if you don’t already have one.

Test for this step: Login with your account details on the Voipbuster website.

Step 2

We need to configure DNS servers and tell the router to perform DNS lookups just like so:

ip name-server a.b.c.d
ip name-server w.x.y.z
ip domain-lookup

With a.b.c.d and w.x.y.z being the IP addresses of the primary and secondary DNS servers used by your provider.

Test for this step: Try to ping sip1.voipbuster.com from the router prompt and see if the name is being resolved.

Step 3

Configuring a dial peer to route outbound traffic to Voipbuster:

dial-peer voice 10 voip
 description Voipbuster Outbound
 destination-pattern 00T
 progress_ind setup enable 3
 voice-class codec 1
 session protocol sipv2
 session target dns:sip1.voipbuster.com
 dtmf-relay rtp-nte
 no vad
!

In this case, all numbers prefixed with “00″ are being sent to Voipbuster.

Step 4

Define the sip-ua part:

sip-ua
 authentication username USERNAME password PASSWORD
 retry invite 3
 retry response 3
 retry bye 3
 retry cancel 3
 timers expires 300000
 registrar dns:sip1.voipbuster.com expires 3600
!

You need to substitute USERNAME and PASSWORD with your username and password, obviously.

Step 5

Create a translation rule and profile, then, apply the translation profile to the Voipbuster dial peer:

voice translation-rule 1
 rule 1 /^0/ /0031/
!
voice translation-profile Strip0Add0031
 translate calling 1
!
dial-peer voice 10 voip
 translation-profile outgoing Strip0Add0031
!

Test for this step: Test the new rule with the following command and check for the output, it should show something alike:

test voice translation-rule 1 0521234567
Matched with rule 1
Original number: 0521234567       Translated number: 0031521234567

Update 2009.09.14

I experienced call delays when dialing out. Turned out I forgot about the interdigit timeout configuration:

telephony-service
  timeouts interdigit 3
!

Todo and new questions:

• Explain the various settings
• Add troubleshooting hints & tips
• What about incoming Voipbuster calls?
• Is it possible to register to multiple SIP servers simultaneously?