This circuit emulation configuration could be used in a DR situation. rtr1 is at the HQ site, rtr2 is at the remote site. rtr3 is at the disaster/failover site for HQ. It utilizes EEM with object tracking as an event source, so it requires IOS 12.4(2)T or above. Given a fault-tolerant, routable IP connection, this provides a fault tolerant analog circuit, especially useful in legacy telephony and utility applications. Click “read more” for configuration details.
HQ Router: rtr1 Cisco 3845. NM-CEM-4TE1 installed in slot 3
Remote Router: rtr2 Cisco 3845. NM-CEM-4TE1 installed in slot 3
Disaster Recovery HQ Router: rtr3 Cisco 3845. NM-CEM-4TE1 installed in slot 3
rtr1: HQ
card type t1 3 controller T1 3/0 framing esf cem-group 0 timeslots 1-24 cablelength long 0db ! interface Loopback0 description HQ IP ip address 10.0.0.1 255.255.255.255 ! cem 3/0/0 payload-compression xconnect 10.0.0.2 0 encapsulation udp local ip addr 10.0.0.1 local udp port 16002 remote udp port 16001
rtr2: Remote
card type t1 3 controller T1 3/0 framing esf cem-group 0 timeslots 1-24 cablelength long 0db ! track 1 ip route 10.0.0.1 255.255.255.255 reachability ! interface Loopback0 description REMOTE IP ip address 10.0.0.2 255.255.255.255 ! cem 3/0/0 payload-compression xconnect 10.0.0.1 0 encapsulation udp local ip addr 10.0.0.2 local udp port 16001 remote udp port 16002 ! event manager applet CEM-HQ-DOWN event track 1 state down action 1.0 cli command "enable" action 1.1 cli command "configure term" action 1.2 cli command "cem 3/0/0" action 1.3 cli command "xconnect 10.0.0.3 0 encapsulation udp" event manager applet CEM-HQ-UP event track 1 state up action 1.0 cli command "enable" action 1.1 cli command "configure term" action 1.2 cli command "cem 3/0/0" action 1.3 cli command "xconnect 10.0.0.1 0 encapsulation udp"
rtr3: Disaster Recovery HQ Site
card type t1 3 controller T1 3/0 framing esf cem-group 0 timeslots 1-24 cablelength long 0db ! track 1 ip route 10.0.0.1 255.255.255.255 reachability ! interface Loopback0 description DR IP ip address 10.0.0.3 255.255.255.255 ! cem 3/0/0 payload-compression xconnect 10.0.0.2 0 encapsulation udp local ip addr 10.0.0.3 local udp port 16002 remote udp port 16001 shutdown ! event manager applet CEM-HQ-DOWN event track 1 state down action 1.0 cli command "enable" action 1.1 cli command "configure term" action 1.2 cli command "cem 3/0/0" action 1.3 cli command "no shutdown" event manager applet CEM-HQ-UP event track 1 state up action 1.0 cli command "enable" action 1.1 cli command "configure term" action 1.2 cli command "cem 3/0/0" action 1.3 cli command "shutdown"