How many phones and directory numbers can be configured on Cisco Unified Communications Manager Express by default?
Answer: Zero!
Yes, by default, no ephones or directory numbers can register. Before doing anything else, the following configuration is required:
Router>enable
Router#configure terminal
Router(config)#telephony-service
Router(config-telephony)#max-ephones 4
Router(config-telephony)#max-dn 8
This allow up to 4 phones to register / be configured and 8 directory numbers.
If you don’t do this, the router will not allow ephones or ephone-dns to be created. Here is an example of what would happen:
R1(config)#ephone 1
ephone tag 1 exceeds max-ephones 0
R1(config)#ephone-dn 1
dn 1 exceeds max-dn 0
The maximum number of ephones and ephone-dns that can be configured is platform dependent. Here is an example of my router that can support 30 phones with up to 150 ephone-dns:
R1(config-telephony)#max-ephones ?
Maximum phones to support
R1(config-telephony)#max-dn ?
Maximum directory numbers supported
Cisco have a great document showing you how many ephones/dns are supported on specific platforms. Have a look here
As an example, using CME version 4.3:
The 2801 supports 25 phones and 120 ephone-dns
The 2811 supports 35 phones and 144 ephone-dns
The 2821 supports 50 phones and 192 ephone-dns
The 3845 supports 250 phones and 720 ephone-dns
(There are others, please refer to the link above for a full list)
Cisco also recommend that you only enable the number of ephones and ephone-dns for the number you require, not the maximum the platform can support. The reason is that when a ephone / ephone-dn is created, it uses up memory on the router. Don’t just create them because you can! Create only what is required.
To your success!
