how to configured three routers cisco 1841 frame relay with folowing steps below
To configure three Cisco 1841 Integrated Services Router routers with Frame Relay, follow these step-by-step instructions.
Network Topology
R2
/ \
DLCI DLCI
102 203
/ \
R1----------R3
DLCI
301
IP Addressing
| Router | Interface | IP Address | DLCI |
|---|---|---|---|
| R1 | S0/0 | 10.1.1.1/24 | 102 |
| R2 | S0/0 | 10.1.1.2/24 | 201 |
| R2 | S0/1 | 10.1.2.2/24 | 203 |
| R3 | S0/0 | 10.1.2.3/24 | 301 |
Step 1: Connect Routers
Use serial DCE/DTE cables:
R1 S0/0 → Frame Relay Switch
R2 S0/0 and S0/1 → Frame Relay Switch
R3 S0/0 → Frame Relay Switch
If using Packet Tracer or GNS3:
Add a Frame Relay switch/cloud device
Connect all routers to the Frame Relay cloud
Step 2: Configure Router Hostnames
Router R1
enable
configure terminal
hostname R1
Router R2
enable
configure terminal
hostname R2
Router R3
enable
configure terminal
hostname R3
Step 3: Configure Serial Interfaces
Configure R1
interface serial0/0
ip address 10.1.1.1 255.255.255.0
encapsulation frame-relay
frame-relay interface-dlci 102
no shutdown
exit
Configure R2
interface serial0/0
ip address 10.1.1.2 255.255.255.0
encapsulation frame-relay
frame-relay interface-dlci 201
no shutdown
exit
interface serial0/1
ip address 10.1.2.2 255.255.255.0
encapsulation frame-relay
frame-relay interface-dlci 203
no shutdown
exit
Configure R3
interface serial0/0
ip address 10.1.2.3 255.255.255.0
encapsulation frame-relay
frame-relay interface-dlci 301
no shutdown
exit
Step 4: Configure Clock Rate (Only DCE Side)
If your router side is DCE:
interface serial0/0
clock rate 64000
Check DCE side:
show controllers serial0/0
Step 5: Configure Static Routing
On R1
ip route 10.1.2.0 255.255.255.0 10.1.1.2
On R2
ip route 10.1.2.0 255.255.255.0 10.1.2.3
ip route 10.1.1.0 255.255.255.0 10.1.1.1
On R3
ip route 10.1.1.0 255.255.255.0 10.1.2.2
Step 6: Save Configuration
On all routers:
copy running-config startup-config
Step 7: Verify Frame Relay
Check Interface Status
show ip interface brief
Check Frame Relay Map
show frame-relay map
Expected output example:
Serial0/0 (up): ip 10.1.1.2 dlci 102
Check PVC Status
show frame-relay pvc
Status should show:
ACTIVE
Step 8: Test Connectivity
From R1:
ping 10.1.2.3
From R3:
ping 10.1.1.1
Optional: Configure Frame Relay Subinterfaces
For better WAN design:
interface serial0/0.1 point-to-point
ip address 10.1.1.1 255.255.255.0
frame-relay interface-dlci 102
Useful Verification Commands
show running-config
show frame-relay map
show frame-relay pvc
show interfaces serial0/0
show ip route
Troubleshooting
| Problem | Solution |
|---|---|
| Serial interface down | Use no shutdown |
| PVC inactive | Check DLCI numbers |
| Ping fails | Verify routing |
| Encapsulation mismatch | Use encapsulation frame-relay on both sides |
| No clocking | Configure clock rate on DCE side |
Example Full R1 Configuration
enable
configure terminal
hostname R1
interface serial0/0
ip address 10.1.1.1 255.255.255.0
encapsulation frame-relay
frame-relay interface-dlci 102
clock rate 64000
no shutdown
exit
ip route 10.1.2.0 255.255.255.0 10.1.1.2
end
copy running-config startup-config