Implementing Phones in CUCM

Tasks behind implementing phones into CUCM

Services and Protocols to support IP Phones

• NTP – Network Time Protocol
  • Standard for providing network based time synchronization
  • Convenience and consistency of the same time on all devices
  • Timestamp for CDR and CMR
  • Some features rely on time (calendar)
  • NTP can be implemented on a core switch or router in the network – configuration examples were done in previous notes
  • During CUCM install NTP is required to be entered before moving forward.
    • Subscriber servers sync their clocks to the Publisher server and IP Phones (SCCP) get their time from the subscriber. SIP based phones need an NTP reference
• CDP – Cisco Discovery Protocol
  • Layer 2 protocol – mapping information of the network
  • Phones generate CDP messages to learn voice vlan ID
• DHCP – Dynamic Host Configuration Protocol
  • Allows phones to get IP addresses dynamically
  • IP Address, subnet mask, default gateway, DNS, TFTP (option 150)
  • Router example was done in previous notes
  • I’ll show DHCP being hosted from CUCM later
• PoE – Power Over Ethernet
  • Described in earlier notes
• TFTP – Trivial File Transfer Protocol
  • Phones user TFTP to download their configuration files, firmware and other data
  • Required for phones to function properly
• DNS – Domain Name System
  • Hostname to IP address resolution
  • DNS server must be external to CUCM cluster
  • Asked for during CUCM installation
  • Not required for phones to function, if DNS reliance is disabled (example to follow later)
  • DNS is not hosted by CUCM

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IP Phone Registration

1. Phone gets power – POE or power adapter
2. Phone loads locally stored firmware imsage
3. Phone learns voice vlan through CDP
4. Phone uses DHCP to learn ip information
5. Phone contacts TFTP server and requests configuration file
   1. Each phone has a customized config file – SEP<mac address>.cnf.xml
6. Phone registered with primary CUCM server in the config file
   1. CUCM sends softkey template to phones using SCCP

SIP Phone Registration

1. Same steps 1 – 4 as above
2. Phone contacts TFTP and request Certificate Trust List File (only if cluster is secured)
3. Phone contacts TFTP server and requests config file – SEP<mac address>.cnf.xml
4. Phone downloads SIP dial Rules
5. Phone registers with primary CUCM in the config file
6. Phone downloads localization files from TFTP
7. Phone downloads softkey configuation
8. Phone downloads custom ringtones

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Prepare CUCM to Support Phones

Service Activation

Configure and Verify Network Services

• NTP
• DHCP
• TFTP

DHCP Server Configuration on CUCM

First start with defining DHCP server parameters. The DHCP service on CUCM is only meant to host IP Phones. It is limited to 1000 phones.

Only one DHCP server is supported per cluster. Multiple scopes can be configured on the server

Now that the server is define, we need to add subnets for the hosts

Configure Enterprise Parameters

Cluster wide default settings

• Device Pool – common configurations to a group of devices. Template to apply several different settings all at once 
• Cisco Unified CM Group – Top/down ordered list of redundant call processing servers that phones can register to. The list can include a max of 3 servers plus an option SRST reference. Servers can be listed in one or more CM groups
• Region – Virtual assignment to allow for control of bit rates of calls. Influence the codec used between locations
• Location – Defines the max bandwidth to be used for concurrent number of calls. If there is not enough bandwidth to add another call, the call is either dropped or rerouted over PSTN if AAR is configured.
  • This is one mechanism of CAC – Call Access Control
• Date/Time Group – Allows to display the time and date in a desired format. Have the correct timezone show up for sites across the globe
• Phone NTP reference – SIP phones require an NTP server
• Device Defaults – Lists all supported devices, firmware, device pool and phone button template each endpoint uses by default
• Softkey Template – Controls what softkey button functions are available to users
  • Default template provides 2 lines and as many speed dials that are remaining buttons on the phone model
• Phone Button Template
• SIP Profile – Allow for one time configuration of repetitive tasks
• Phone Security Profile – Default is security disabled. Can change to configure the device as secured, encrypt TFTP and modify certificate authority proxy
• Common Phone Profile – Common phone profile settings

Configuration of these settings is shown below

Adding Phones in CUCM

Phones can be added to CUCM multiple ways

• Manual Configuration – Config shown below
• Auto Registration – Phones dynamically add self to CUCMn
• Bulk Administration Tool (BAT) – Template (CSV) that can be filled out and used to upload phone information
• Auto Registration Phone Tool (TAPS) – Uses IVR (Interactive Voice Response) to enhance auto registration and BAT
• Self Provisioning – 

Manually Adding Phone

Add New, choose the phone model type, choose the protocol to register with (SIP or SCCP)

Created an End User and associated with the phone and added to Access Groups: Standard CCM User and Standard CTI User

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End User and Application Users

Adding a end user was shown above.

End users

• Associated with an actual person
• Individual use
• Assign users features for administrative rights
• Included in the user directory
• Can be synced with LDAP

End users can be added using the following:

• Manual Entry
• Bulk Import with BAT
• LDAP Sync

Application User

• Associated with an application
• no interactive logins
• For application authorization
• Not in user directory
• Locally provisioned 

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Disable DNS Reliance

I did this task before creating the blog. Screenshots below are after changing hostname to IP address.

Disable DNS reliance means that phones will rely on using IP addresses to reach CUCM instead of trying to do DNS resolution.

Next go to System>Enterprise Parameters, scroll down and change the hostname to IP address in the URL

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CUCM Configuration

Cisco Unified CM Group

NTP Reference

Date/Time Group

Region

Location

Device Pool

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Partitions

Calling Search Space