Describes how to configure the Ethernet port of a router.

There are still many things worth learning about configuring routers. Here we mainly introduce Ethernet port configuration, X.25 configuration, and so on. Routers play an important role in computer networks and serve as a bridge between computer networks. It not only connects to different networks, but also selects data transmission paths and blocks illegal access.

Configuring a router is not very easy for beginners. We will introduce general router configuration and simple debugging for your reference When configuring a router. This article uses Cisco2501 as an example. Cisco2501 has an Ethernet port AUI), a Console port RJ45), an AUX port RJ45) and two synchronous serial ports. It supports DTE and DCE devices, supports EIA/TIA-232, EIA/TIA-449, V.35, X.25, and EIA-530 interfaces.

1. Configure the Ethernet port
 
# Conf t configure the router from the terminal)
# Int e0 specified E0 port)
# Ip addr abcd xxxxabcd is the ethernet address, and XXXX is the subnet mask)
# The ip addr abcd xxxx secondaryE0 port supports two address types at the same time. If the first one is A Class address, the second one is B or C Class address)
# No shutdown to activate E0 ports)
# Exit
 
2. X.25 Configuration

# Conf t
# Int S0 specified S0 port)
# Ip addr abcd xxxxabcd is the ip address of the Ethernet S0, and XXXX is the subnet mask)
# The encap X25-ABC encapsulates the X.25 protocol. ABC specifies that X.25 is a DTE or DCE operation. The default value is DTE)
# X25 addr ABCDABCD is the X.25 port address of S0, provided by the Post Office)
# X25 map ip abcd xxxx br
# X25 htc X configures the maximum number of two-way channels of the router. The value range of X is 1-4095. It must be configured according to the number actually provided by the Post Office)
# X25 nvc X: the number of virtual circuits configured. X cannot exceed the number actually provided by the post office. Otherwise, normal data transmission will be affected)
# Exit

After the S0 port is configured, use the no shutdown command to activate the E0 port. If the ping to port S0 is normal, the ping to the mapped X.25 IP address, that is, the IP address of the Peer router port, may be caused by the following situations: 1) Local X.25 address configuration error, re-check with the post office that the length of the X.25 address is 13 characters). 2) the local ing IP address or X.25 address is incorrectly configured. 3) the peer IP address or X.25 address is incorrectly configured. 4) the local or peer route configuration is incorrect. Can communicate with the other party, but packet loss occurs. In this case, there are generally the following possibilities: 1) Poor line conditions, or poor contact between the NIC and RJ45 plug; 2) the value range of x25 htc's maximum two-way channel number X and the number of x25nvc virtual circuits X exceed the number actually provided by the post office. The larger the maximum number of two-way channels and the number of virtual circuits, the better, but it must not exceed the number actually provided by the post office. Otherwise, packet loss may occur.

3. leased line configuration

# Conf t
# IntS2 port)
# Ip addr abcd xxxxabcd is the ip address of S2, and XXXX is the subnet mask)
# Exit

4. Frame Relay Configuration

# Conf t
# Int s0
# Ip addr abcd xxxx abcd is an ip address of S0, and XXXX is a subnet mask)
# Encap frante_relay encapsulate the frante_relay Protocol)
# No nrzi_encoding NRZI = NO)
# Frame_relay lmi_type q933a
# Fram-relay intf-typ ABC
# Frame_relay interface_dlci 110 br configure the DLCI data link connection identifier)
# Frame-relay map ip abcd xxxx broadcast
# No shutdown to activate this port)
# Exit

After configuring the S0 port for Frame Relay, run the ping command to check the S0 port. If the port is not activated, use the no shutdown command to activate the S0 port. If the ping to port S0 is normal and the IP address mapped by ping is abnormal, it may be that the frame relay switch or the peer router is incorrectly configured. Comprehensive troubleshooting is required.