All cable connection on three sites are already configured . 2- WAN Connection detail - CME1-NEST265 Fa0/0 connect to CME2-NEST265 Fa0/1 - CME1-NEST265 Fa0/1 connect to CME3-NEST265 Fa0/1 - CME2-NEST265 Fa0/0 connect to CME2-NEST265 Fa0/0 3- WAN IP and routing protocol OSPF is already configured and all three site subnets are reachable. 4- Following are the steps to configure Site by Site. Step-1 Site-A 1-1 Site basic network is configured. - Interfaces are configured except phone and PC connected interfaces. - WAN Protocol OSPF is configured Please configure following On router 1- DHCP for DATA ( 192.168.15.0/24) and VOICE ( 10.10.10.0/24) 2- VLAN 10 is VOICE VLAN 20 is DATA 3- Configure Telephony Service according to following options a. Max-ephone 10 b. Max-DN 10 c. Source ip address 10.10.10.1 port 2000. d. No auto registration 4- Configure ephone-dn 4101, 4102 , 4203 , 6666 5- Configure Ephone and assign there DN to button according to the Diagram . Make sure you use right MAC address 6- Configure PC1 interface so it get the DATA VLAN IP address. On Switch 1- VLAN 10 and 20 2- Interface fa0/1 for Phone and PC 3- Interface fa0/3 for phone and PC 4- Interface fa0/4 for Data 5- Interface fa0/5 for phone and PC Testing : Check all phone get the phone number and you can make a call to other Site A phones. Step-2 Site-B 2-0 Site is using DHCP server to provide IP addresses to the Devices. Server is already configured . you have to configure DHCP relay to forward DHCP broadcast . Trunk is also configured between Router and Switch . VLAN are configured. 2-1 You have to configure DHCP relay CME2-NEST265 interface FastEthernet1/0.10 ip helper-address 192.168.100.2 2-2 Trunk and subnet IP already configured , VLAN are already configured 2-3 you have to configure all three IP-Phone Port in Switch 2-4 You have to configure Telephony-Service Source IP for Telephony-Service is 10.100.100.1 You have you configure Ephone-dn according to the Phone numbers. Configure all Three Ephone 2-5 Please configure NTP in the switch and router so These devices get Time from Site-A NTP server 2-5 Testing Site-B Call within the Site-B Step-3 Site-C 3-0 Site-C DHCP is configured. All IP are configured . TelephoneService is configured. Switch port is configured for phone and trunk between router and switch .VLAN is configured 3-1 You have to configure Ephone-dn and Ephone according to the Site-C 3-2 Please configure NTP in the switch and router so These devices get Time from Site-A NTP server Step-4 All Site Connectivity Testing . 4-1 Before we go to the Next step . We need to test all three site. Ping between all three sites ( Site-A PC to Phone Site B and C ) 4-2 Make a call between sites. Call will not work . There is no Dial-Plan on the Gateway Routers to forward the call Step-5 5-1 Creating Dial-Peers on Gateway routers. Create Dial Peers on Site-A router to make call to Site-C for 9111. ! 5-2 Create Deal Peer on Site-A router to make call to Site-B For Phone 6111, 5111, 5011 5-3 Create Deal Peer on Site-B router to make call to Site-C for 9111 5-4 Create Deal Peer on Site-B router to make call to Site-A for Phone number 4102, 4203, 4101, 6666 5-5 Configure Deal Peer on Site-C router to make call to Site-B For Phone 6111, 5111, 5011 5-6 Configure Deal Peer on Site-C router to make call to Site-A. For Phone number 4102, 4203, 4101, 6666. Step-6 All Site Voice Calls Testing. 6-1 Make calls between all three site from each phone to make sure this voice solution is working.