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?

CCM 6 backups

To be able to create CCM 6 backups, you need a SFTP server. The easiest way to accomplish this (assumed you have some experience with managing *NIX systems and you have linux system at your disposal) is to create an extra account like ‘ccmbackup’ on a running Linux system:

adduser ccmbackup -s /bin/bash

Next, configure the backup settings on the CCM environment and perform a backup. Expect the backup to be around 300MB in size, depending on the information stored in your environment. YMMV.

Callmanager Migration Thoughts

Here are some thoughts about migrating to a new Callmanager version. Should you have any remarks or addition to these points please post them in the comments.

Backups, backups, backups

Backups provide a really good starting point for your migration. They really do. There are different ways to accomplish this:

• You can pull a hard disk from the RAID set on any (or all :-) ) of the running machines. If you pull a disk, you might want to consider replacing the disk rather than just pulling it. Remember to check for the right disk size (you need at least the same capacity, so 72GB for a pulled disk of 36GB is fine) and preferably the same RPM count (if you replace a 15K disk with a 10K disk, the set will run at 10K: the lowest disk dictates the speed of the set).
• You can create a backup through the BARS or serviceability interface.

Oh, and about replacing that pulled disk rather than just pulling it: I’ve heard about situations where that single disk decided to fail in the little timespan it had to work on its own.

Consider yourself warned, you might find yourself in a situation where you’re empty handed and have no-one to blame except yourself.

Communicating towards your end users

Perhaps the most important bit about migrating from one CCM version to another. Talk to your end users. Let them know what’s happening.

• What is going to change?
• What remains the same?
• What is the planned outage of your environment?
• Who can be contacted (on which phone number) in case of any problems?

Software

• Collect all the PC software from you old and new CCM version. In a large environment, you might consider scripting the various pieces of software, like the Attendant Console, Assistant Console, etc.
• Collect all the phone loads you intend to use. Don’t forget ATA’s and conference phones like the 7936.
• Consider upgrading your phones beforehand, so you don’t have to wait for the phones to come back after the upgrade when you are migrating your CCM environment. If you choose to do this, make sure that your old CCM version has no issues with the new phone load(s).
• Make sure the IOS versions of your switches and routers are compliant with the CCM version you’re migrating to.

So you read through all this? Good for you. Now read that section about backups again.

Partitions and Calling Search Spaces

• Do your new calling search spaces contain the right partitions?
• Are the partitions in your calling search spaces prioritized right?

Using BAT (Bulk Administration)

• Import your phones and users (and all other data like pickupgroups if applicable), and check whether everything is imported as desired. Not really a ‘dry run’, but validating the BAT templates just isn’t cutting it.
• Specifically, pay attention to call forward destination columns and call forward calling search spaces.

Speeddials and Personal Address Book

• The Speeddials in applications like the Assistant and Attendant console can’t be export if you’re using the CCM 4.x version. The ones in the assistant Console can’t be exported or duplicated. You need to copy them by hand. The ones in the Attendant Console are automatically saved when the network connection is lost. If you have more than one location (for example, multiple branch offices), you could log in to the same (local) pc with the software installed, pull the plug on the network interface and save the local stored file. You can copy this file to the pc with the upgraded software and use it.
• The Speeddials and Personal Address Book can be exported from within the DC Directory Administrator (note: still to provide an example DN)

Licensing

• If you’re migrating to CCM6, be aware of the new licensing structure; be sure to calculate the right amount of license units needed.
• Disable any functionality which you don’t really need (like Mobility (not to be confused with Extension Mobility).

Other issues

• Consider decreasing the DHCP lease time for your voice VLAN(s). The best way to this is by gradually decreasing the lease time. Should your DHCP server fail while preparing for the CCM migration, the department responsible for the DHCP server has the maximum amount of time to fix it. For example, if the voice VLAN leasetime is 10 days, you set it to be 5 days on day 11 before the CCM migration date. On the 6th day before the CCM migration date, you set the leasetime to 2 days. On the 3th day for the migration date, you set it to one day, etc. You can also use this strategy when increasing the leasetime after the upgrade.

How to broadcast a call with CME

Here’s how to broadcast a call with Cisco Callmanager Express. You will need to use the overlay DN functionality. In this case we want to broadcast calls to DN 100 on two phones.

First, you define 2 ephone-dn’s with the number you want to broadcast calls for:

ephone-dn 98 dual-line
number 100
huntstop channel
no huntstop
!
ephone-dn 99 dual-line
number 100
preference 1
huntstop channel
!

Then, you use the overlay feature to add multiple ephone-dn’s to 1 button on the ephone’s:

ephone 101
button 1o101,98,99
!
ephone 102
button 1o102,98,99
!

This has been tested and approved on CCME 4.0(3).