Регистрация телефона cisco 6921 на роутере cisco 2911?

Подскажите пожалуйста в чем проблема, есть cisco 2911 и телефон cisco 6921. Сделана вот такая конфигурация на роутере.

Building configuration...

Current configuration : 1950 bytes
!
! Last configuration change at 12:35:08 UTC Fri Sep 19 2014
! NVRAM config last updated at 08:48:27 UTC Fri Sep 19 2014 by admin
! NVRAM config last updated at 08:48:27 UTC Fri Sep 19 2014 by admin
version 15.1
service timestamps debug datetime msec
service timestamps log datetime msec
service password-encryption
!
hostname CUKS_VOIP
!
boot-start-marker
boot-end-marker
!
!
enable password 7 13061E010803
!
aaa new-model
!
!
!
!
!
!
!
aaa session-id common
!
no ipv6 cef
ip source-route
ip cef
!
!
!
!
ip dhcp pool VOIP
network 172.20.0.0 255.255.255.0
option 150 ip 172.20.0.254
default-router 172.20.0.1
lease 0 0 30
!
!
ip domain name cisco
multilink bundle-name authenticated
!
!
!
!
!
crypto pki token default removal timeout 0
!
!
voice-card 0
!
!
!
!
!
!
!
license udi pid CISCO2911/K9 sn JTV1739TAI9
hw-module pvdm 0/0
!
!
!
!
redundancy
!
!
!
!
!
!
interface Embedded-Service-Engine0/0
no ip address
shutdown
!
interface GigabitEthernet0/0
no ip address
shutdown
duplex auto
speed auto
!
interface GigabitEthernet0/1
ip address 172.20.0.254 255.255.255.0
duplex auto
speed auto
!
interface GigabitEthernet0/2
no ip address
shutdown
duplex auto
speed auto
!
ip forward-protocol nd
!
no ip http server
no ip http secure-server
!
ip route 0.0.0.0 0.0.0.0 172.20.0.1
!
!
!
!
!
!
control-plane
!
!
!
!
mgcp profile default
!
!
!
!
!
gatekeeper
shutdown
!
!
telephony-service
max-ephones 10
max-dn 10
ip source-address 172.20.0.254 port 2000
max-conferences 8 gain -6
transfer-system full-consult
!
!
!
!
ephone-dn 5 dual-line
number 301
!
!
ephone 5
type 6921
mac-address F029.295A.79C4
button 5:1
!
!
end

Телефон в свою очередь все сетевые настройки получает(IP, tftp. итд) но не регистрируется.

Может что еще надо в настройки добавить ?