1. Routers A router is a computer Computers have four basic components:
a CPU,
memory,
interfaces, and
a bus
The router is a computer that selects the best paths, and manages the switching of packets between two different networks

2. Cisco Routers

3. Router - internal components
RAM/DRAM
Stores routing tables, ARP cache, fast-switching cache, packet buffering (shared RAM), and packet hold queues.
also provides temporary and/or running memory for the router’s configuration file while the router is powered on.
RAM content is lost when you power down or restart.

4. Router - internal components
NVRAM
non-volatile RAM
stores a router’s backup/start-up configuration file;
content remains when you power down or restart

5. Router - internal components
Flash
erasable, reprogrammable ROM
holds the operating system image and microcode
allows you to update software without removing and replacing chips on the processor
content remains when you power down or restart
multiple versions of IOS software can be stored in Flash memory

6. Router - internal components
ROM
contains power-on diagnostics,
a bootstrap program, and
operating system software
software upgrades in ROM require replacing pluggable chips on the CPU

7. Router - internal components
Interface
network connection through which packets enter and exit a router
it can be on the motherboard or on a separate interface module

8. Routing

9. Router Configuration A router is made up of configurable components.
A router has modes
examining,
maintaining, and
changing the components.

10. Router Configuration show commands are used for examination.
You use cdp to show entries about neighbours.
You access other routers by using telnet.
You test network connectivity layer by layer.
Testing commands include ping, trace, telnet, and debug

11. Router Configuration A router can be configured from many locations:
Upon initial installation, it is configured from the console terminal. The console terminal is a computer connected to the router through the console port.
It can be connected via modem by using the auxiliary port.
After it is installed on the network, it can be configured from Virtual Terminals 0 through 4.
Files can also be downloaded from a TFTP server on the network

12. Router Modes
Whether accessed from the console or by a Telnet session through a TTY port, the router can be placed in several modes.
Each mode provides different functions:
User EXEC mode
Privileged EXEC mode
Set-up mode
Global configuration mode
Other configuration modes
RXBOOT mode

13. Router Modes User EXEC mode Privileged EXEC mode
A “look-only” mode in which the user can view some information about the router, but cannot change anything.
Privileged EXEC mode
Supports the debugging and testing commands, detailed examination of the router, manipulation of configuration files, and access to configuration modes.

14. Router Modes Set-up mode Global configuration mode
Presents an interactive prompted dialog at the console that helps the new user create a first-time basic configuration.
Global configuration mode
Implements powerful one-line commands that perform simple configuration tasks.

15. Router Modes Other configuration modes RXBOOT mode
Provide more detailed multiple-line configurations.
RXBOOT mode
A maintenance mode that can be used, among other things, to recover lost passwords.

16. Router Status Commands
show version
Displays the configuration of the system hardware,
the software version,
the names and sources of configuration files, and
the boot image.
show processes
Displays information about the active processes.

17. Router Status Commands
show protocols
Displays the configured protocols.
This command shows the status of all configured Layer 3 protocols.
show mem
Shows statistics about the router’s memory, including memory free pool statistics.

18. Router Status Commands
show stacks
Monitors the stack use of processes and interrupt routines and displays the reason for the last system reboot.
show buffers
Provides statistics for the buffer pools on the router.
show flash
Shows information about the Flash memory device.

19. Router Status Commands
show running-config
Displays the active configuration file.
show startup-config
Displays the backup configuration file.
show interfaces
Displays statistics for all interfaces configured on the router.

20. Cisco Discovery Protocol (CDP)
CDP provides a single proprietary command that enables network administrators to access a summary of what the configurations look like on other directly connected routers.
CDP runs over a data link layer connecting lower physical media and upper-network-layer protocols.

21. CDP
Because CDP operates at this level, CDP devices that support different network-layer protocols can learn about each other.
CDP starts up automatically at boot up. CDP can then automatically discover neighbouring Cisco devices running CDP.

22. CDP Discovered devices extend beyond those having TCP/IP.
CDP discovers directly connected Cisco devices regardless of which Layer 3 and 4 protocol suite they run.

23. CDP
CDP provides information about each CDP neighbour device. Values include the following:
Device identifiers—For example, the router’s configured host name and domain name (if any)
Address list—At least one address for SNMP, up to one address for each protocol supported
Port identifier—Such as Ethernet 0, Ethernet 1, and Serial 0
Capabilities list—If, for example, the device acts as a source route bridge as well as a router
Version—Information such as that provided by the local command show version
Platform—The device’s hardware platform; for example, Cisco 7000

24. Cisco Router Configuration
We have seen
show and
cdp commands
show startup-config - display the backup configuration file
show running-config—display active configuration file.

25. Cisco Router Configuration
erase startup-config - deletes the backup configuration file in NVRAM.
reload - reloads the router, causing it to run through the entire configuration process.
Setup - to enter setup mode from the privileged EXEC prompt.

26. Cisco Router Configuration
configure terminal—Configures manually from the console terminal.
copy tftp running-config—Loads configuration information from a network TFTP server.
copy running-config startup-config— Stores the current configuration from RAM into NVRAM.

27. Cisco Router Configuration
copy running-config tftp — Stores the current configuration from RAM on a network TFTP server.

28. Cisco Router Configuration
Router> enable
password:
Router# configure terminal
Router(config)# [configure mode command]
e.g. interface, subinterface, controller, line, router etc.

29. Cisco Router Configuration
Specific configuration modes:
interface mode - for configuring interfaces
subinterface mode - for configuring multiple virtual interfaces on a single physical interface
line mode - for configuring the operation of a terminal line
router mode - for configuring an IP routing protocol
etc.

30. Cisco Router Configuration
Configuring router identification
Router# config term
Router(config)# hostname LABA
LABA#
ctrl-z : back to privileged exec mode
exit : back out one level

31. Cisco Router Configuration
Message of the day banner
LABA(config)#banner motd # message #
Interface description
LABA(config)#interface ethernet 0
LABA(config-if)#description my LAN, BG

32. Password configuration
Console password
Virtual terminal password
Privileged exec password

33. Console password LABA(config)#line console 0 LABA(config-line)#login
LABA(config-line)#password cisco

34. Virtual Terminal password
LABA(config)#line vty 0 4
LABA(config-line)#login
LABA(config-line)#password cisco
Enable Password
LABA(config)#enable password class
or prefer
LABA(config)#enable secret class

35. Configuring interfaces
LABA(config)#int s 0
LABA(config-if)#clock rate 56000
clk rate is set for DCEs
LABA(config-if)#bandwidth 56
no clock rate removes clock rate
shut down/no shut down

36. Configuring routing protocols
LABA(config)#router rip
LABA(config-router)#network
LABA(config-router)# network
LABA(config-router)#ctrl-z
LABA(config)#ctrl-z
LABA#show ip protocol
LABA#show ip route [routing table]

37. Configuring routing protocols
LABA>show ip interfaces
LABA#debug ip rip

38. Exercise - Configuring LABA
Hostname:
Router>ena
password:
Router#config term
Router(config)#hostname lab-a

39. Exercise - Configuring LABA
Enable secret password - class
lab-a(config)#enable secret class

40. Exercise - Configuring LABA
All appropriate interfaces with IP addresses and subnet masks
lab-a(config)#int s 0
lab-a(config-if)#ip address
lab-a(config-if)#clockrate 56000
lab-a(config-if)#bandwidth 56

41. Exercise - Configuring LABA
lab-a(config)#int e 0
lab-a(config-if)#ip address
lab-a(config-if)#bandwidth 56
lab-a(config)#int e 1
lab-a(config-if)#ip address

42. Exercise - Configuring LABA
Configure rip
lab-a(config)#router rip
lab-a(config)#network
lab-a(config)# network
lab-a(config)# network

43. Exercise - Configuring LABA
Console login password - cisco
lab-a(config)#line console 0
lab-a(config-line)#login
lab-a(config-line)#password cisco

44. Exercise - Configuring LABA
Vty login password - cisco
lab-a(config)#line vty 0 4
lab-a(config-line)#login
lab-a(config-line)#password cisco