In this article, we will examine the configuration of the basic interfaces on Routers using the Graphical Network Simulator software.
How to Setup a Cisco Router’s Ethernet and Serial Interfaces
The most basic process of configuring an interface is to open the port and assign an IP address.
After assigning an IP address to the Router, you can also add a description for the network on which you will use that interface. Adding comments on interfaces can prevent complexity in a growing network environment.
You can connect and use different interfaces to a router.
The most common interfaces are Serial, Ethernet, FastEthernet, and GigabitEthernet.
It is used the Ethernet, FastEthernet and GigabitEthernet interfaces for the local network.
It is used the serial Interfaces for WAN connections. The Clock Rate is configured to ensure the timing of the data communication with this interface. And also, unlike Ethernet interfaces, it requires a CSU/DSU data communication device.
CSU/DSU devices determine the clock speed through Serial Interfaces. CSU/DSU devices that regulate the clock rate timing support digital data transmission over the WAN. For analog connections, it usually requires a Modem.
These devices receive the signal from the router and then convert the packets into a suitable format for the WAN environment. Similarly, the signal outgoing from the device to the router is converted to the appropriate format.
Cisco Routers are also DTE devices.
The Clock Rate timing set by DCE devices is automatically accepted by DTE devices.
Two routers can be connected to each other via Serial Interfaces.
In network simulation programs such as GNS3 and Packet Tracer, Serial Interfaces are used to connect two devices when designing a network topology.
CSU/DSU devices are;
CSU/DSU Device 1
CSU/DSU Device 2
If the two routers are connected to each other via the Serial Interface, the clock rate must be configured for one of the routers to act as Clock Rate.
How to Configure FastEthernet and Serial Interface
If you haven’t installed GNS3 on your computer before, you can check out our article here.
After installing GNS3, run it, and create a new project.
Then, follow the steps below to add an Ethernet and Serial Interface (WIC-1T).
After creating a new project, add and wire the relevant devices to the workspace as shown in the image below.
Additionally, configure the connection of the PC that you added to the project to VMnet.
Open the Network and Sharing Center on your host and check the IP address of VMnet3.
Also, check the VMnet3 type and IP address block in the virtual network editor.
After running the virtual machine that you added to your project, be sure to configure the adapter setting to Custom: VMnet3.
Now open the Properties window to add a new interface to the router. Click the Slots tab here.
In the WICs section, you can add Serial interfaces to Routers. In this step, click on WIC0 and view the available interfaces that you can add.
From the options listed, select WIC-1T and click OK to save the settings.
WIC-1T: Adds only one Serial Interface.
To configure the router’s FastEthernet0/0 and Serial0/0 ports, run the following commands at the CLI prompt.
ip address: Adds an address and subnet mask to the interface. description: Adds a comment to the interface. no shutdown: Switches the interface from off to on. exit: Switches to the previous mode. wr: Saves the running configuration.
Enter configuration commands, one per line. End with CNTL/Z.
R1(config-if)#description Connection to LAN
R1(config-if)#ip address 192.168.8.1 255.255.255.0
R1(config-if)#description Connection to WAN
R1(config-if)#ip address 192.168.200.1 255.255.255.252
R1(config-if)#clock rate 64000
Run your VMware virtual machine and verify the TCP/IP settings by comparing the IP block you assigned to the Router.
Run the CMD and Ping the Router’s FastEthernet0/0 to test the connection.
Similarly, test the connection by pinging the Router’s Serial0/0 from the virtual computer.
Router’s Show Command Output
Execute the show running-config command and check the output.
Current configuration : 1064 bytes
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
no aaa new-model
memory-size iomem 5
no ip icmp rate-limit unreachable
no ip domain lookup
ip auth-proxy max-nodata-conns 3
ip admission max-nodata-conns 3
ip tcp synwait-time 5
description Connection to LAN
ip address 192.168.8.1 255.255.255.0
description Connection to WAN
ip address 192.168.200.1 255.255.255.252
clock rate 64000
no ip address
ip forward-protocol nd
no ip http server
no ip http secure-server
no cdp log mismatch duplex
line con 0
exec-timeout 0 0
privilege level 15
line aux 0
exec-timeout 0 0
privilege level 15
line vty 0 4