Configuring a Router

© 2002, Cisco Systems, Inc. All rights reserved.
© 2002, Cisco Systems, Inc. All rights reserved.
2
Configuring a Router
Objectives
Upon completing this lesson, you will be able to:
Use the CLI to interact with the Cisco IOS software, given an operational router
Verify the default configuration of the device, given a functioning router
Complete the initial device configuration, given
a functioning router
Configure IP addresses and IP subnet masks on router interfaces, given a functioning router
Overview of Router Modes
Saving Configurations
wg_ro_c#
wg_ro_c#copy running-config startup-config
Destination filename [startup-config]?
Building configuration…

wg_ro_c#
Copies the current configuration to NVRAM
Sets the local identity or message for the accessed router or interface
Configuring Router Identification
Configuring a Router Password
Other Console-Line Commands
Router(config)#line console 0
Router(config-line)#exec-timeout 0 0
Router(config)#line console 0
Router(config-line)#logging synchronous
Prevents console session timeout
Redisplays interrupted console input
Router(config)#interface type number
Router(config-if)#
type includes serial, ethernet, token ring, fddi, hssi, loopback, dialer, null, async, atm, bri, tunnel, and so on
number is used to identify individual interfaces
Quits from current interface configuration mode
Router(config)#interface type slot/port
Router(config-if)#
For modular routers, selects an interface
Configuring an Interface
Enter Global
Configuration Mode
Router(config-if)#clock rate 64000
Router(config-if)#
Router(config)#interface serial 0
Router(config-if)#
Router#configure terminal
Router(config)#
Router(config-if)#bandwidth 64
Router(config-if)#exit
Router(config)#exit
Router#

Specify Interface
Set Clock Rate
(on DCE interfaces only)
Set Bandwidth
(recommended)
Configuring a Serial Interface
Router(config)#interface ethernet 2
Router(config-if)#media-type 10baset
Selects the media-type connector for the
Ethernet interface
Ethernet media-type Command
Router#configure terminal
Router(config)#interface serial 0
Router(config-if)#no shutdown
%LINK-3-UPDOWN: Interface Seria0, changed state to up
%LINEPROTO-5-UPDOWN: Line Protocol on Interface Serial0, changed state to up
Enables an interface that is administratively shut down
Router#configure terminal
Router(config)#interface serial 0
Router(config-if)#shutdown
%LINK-5-CHANGED: Interface Serial0, changed state to administratively down
%LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0, changed state to down
Administratively turns off an interface
Disabling or Enabling an Interface
Unique addressing allows communication
between end stations.
Path choice is based on destination address.
Location is represented by an address
Introducing IP Addresses
IP Addressing
IP Address Classes
Host Addresses
Addressing Without Subnets
Addressing with Subnets
Subnet Addressing
Subnet Mask
Decimal Equivalents of Bit Patterns
Subnets not in use—the default
Subnet Mask Without Subnets
Network number extended by eight bits
Subnet Mask with Subnets
Subnet Mask with Subnets (Cont.)
Network number extended by ten bits
Configuring the Router IP Address
wg_ro_c#configure terminal
wg_ro_c(config)#interface ethernet 0
wg_ro_c(config-if)#ip address 192.168.1.1 255.255.255.0
wg_ro_c(config-if)#no shutdown
wg_ro_c(config-if)#exit
Router show interfaces Command
Router#show interfaces
Ethernet0 is up, line protocol is up
Hardware is Lance, address is 00e0.1e5d.ae2f (bia 00e0.1e5d.ae2f)
Internet address is 10.1.1.11/24
MTU 1500 bytes, BW 10000 Kbit, DLY 1000 usec, rely 255/255, load 1/255
Encapsulation ARPA, loopback not set, keepalive set (10 sec)
ARP type: ARPA, ARP Timeout 04:00:00
Last input 00:00:07, output 00:00:08, output hang never
Last clearing of "show interface" counters never
Queueing strategy: fifo
Output queue 0/40, 0 drops; input queue 0/75, 0 drops
5 minute input rate 0 bits/sec, 0 packets/sec
5 minute output rate 0 bits/sec, 0 packets/sec
81833 packets input, 27556491 bytes, 0 no buffer
Received 42308 broadcasts, 0 runts, 0 giants, 0 throttles
1 input errors, 0 CRC, 0 frame, 0 overrun, 1 ignored, 0 abort
0 input packets with dribble condition detected
55794 packets output, 3929696 bytes, 0 underruns
0 output errors, 0 collisions, 1 interface resets
0 babbles, 0 late collision, 4 deferred
0 lost carrier, 0 no carrier
0 output buffer failures, 0 output buffers swapped out
Interpreting the Interface Status
Verifying a Serial Interface Configuration
Router#show interface serial 0
Serial0 is up, line protocol is up
Hardware is HD64570
Internet address is 10.140.4.2/24
MTU 1500 bytes, BW 64 Kbit, DLY 20000 usec, rely 255/255, load 1/255
Encapsulation HDLC, loopback not set, keepalive set (10 sec)
Last input 00:00:09, output 00:00:04, output hang never
Last clearing of "show interface" counters never
Input queue: 0/75/0 (size/max/drops); Total output drops: 0
Queueing strategy: weighted fair
Output queue: 0/1000/64/0 (size/max total/threshold/drops)
Conversations 0/1/256 (active/max active/max total)
Reserved Conversations 0/0 (allocated/max allocated)
5 minute input rate 0 bits/sec, 0 packets/sec
5 minute output rate 0 bits/sec, 0 packets/sec
(output omitted)


BW 64 Kbit,
Serial Interface show controller Command
Router#show controller serial 0
HD unit 0, idb = 0x121C04, driver structure at 0x127078
buffer size 1524 HD unit 0, V.35 DTE cable
.
.
.
Shows the cable type of serial cables
V.35 DTE Cable
Summary
From the privileged EXEC mode, you can enter global configuration mode, giving you access to the specific router configuration modes.
Using the CLI, you will configure the router name, password, and other console commands.
A router’s main function is to relay packets from one network device to another. To do that, you must define the characteristics of the interfaces through which the packets are received and sent.
In a TCP/IP environment, end stations communicate seamlessly with servers or other end stations. This communication occurs because each node using the TCP/IP protocol suite has a unique 32-bit logical IP address.
Summary (Cont.)
By dividing a network into smaller segments, or subnets, you can make the network address use more efficient. There is no change in how the outside world sees the network, but within the organization there is additional structure.
A subnet address is created by borrowing bits from the host field and designating them as the subnet field. The number of borrowed bits is variable and specified by the subnet mask.
Each interface on a Cisco router must have its own IP address to uniquely identify it on the network.
When you complete the router interface configuration, you can verify it using show commands.