1. OVERVIEW - Router Config Tasks :
To configure your router or access server, you
must perform several tasks. Initially, you must
determine the following:-
Which network protocols you are supporting
The addressing plan for each network protocol
Which WAN protocols you will run on each
interface

2. External Configuration Sources
VIRTUAL
TERMINAL
CONSOLE
PORT
TFTP
SERVER
INTERFACES
ROUTER
AUXILARY
PORT
NETWORK
MANAGEMENT
STATION
Configuration Information can from many Sources

3. Internal Configuration Components
DRAM
NVRAM
FLASH
ROM
Console
Auxiliary
INTERFACE

4. Cisco routers can initialize the system (boot) in four
ways:
Netboot :Routers can boot from a server using the
TFTP.
Flash memory: Routers can boot from Flash
memory, a nonvolatile storage medium that can be
electrically erased and reprogrammed.
ROM : Routers can boot a system from built-in ROM.
PC Flash memory card: Routers can boot from a
removable Flash memory card.

5. FLASH MEMORY :
Depending on the platform, Flash memory is available
in the following forms:
1. Internal Flash memory : often contains the system
image. Some platforms have two or more banks of
Flash memory on one single in-line memory modules
(SIMM). If the SIMM has two banks, it is sometimes
referred to as dual-bank Flash memory. The banks
can be partitioned into separate logical devices.

6. FLASH MEMORY (Cont..)
2. Bootflash
Bootflash often contains the boot image.
Bootflash sometimes contains the ROM Monitor.
3. Flash memory PC cards or PCMCIA cards
A Flash memory card that is inserted in to a
PCMCIA slot. This card is used to store system
images, boot images, and configuration files.
The following platforms contains PCMCIA slots:
one PCMCIA slot
two PCMCIA slots
NPE contains 2 slots

7. FLASH MEMORY (Cont..)
Write Protection
Flash memory provides write protection against
accidental erasing or reprogramming.
Some platforms have a write-protect jumper which
can be removed to prevent reprogramming of Flash
memory. You must install the jumper when
programming is required. Some platforms have write
protect switched on Flash memory cards that you
can use to protect data. You must set the switch to
unprotected to write data to the Flash memory card.

8. NVRAM Nonvolatile random-access memory (NVRAM) stores
the following information:
1. Startup configuration file for every platform.
2. The software configuration register, which is used
to determine which image to use when booting
the router.

9. EPROM / ROM
It sometimes contains the following :
ROM Monitor, which provides a user interface when
the router cannot find a valid image.
The boot loader/helper software (also called the
boot image), which helps the router boot when it
cannot find a valid Cisco IOS image in Flash
memory.

10. DRAM : Dynamic random-access memory contains two types of memory:
1. Primary, main, or processor memory, which is
reserved for the CPU to execute Cisco IOS
software and to hold the running configuration
and routing tables.
2. Shared, packet, or I/O memory, which buffers
data transmitted or received by the router's
network interfaces.

11. Router Modes User EXEC Mode
Limited Examination of router and remote access
Router>
Privileged EXEC Mode
Detailed examination of Router, Debugging and testing.
File manipulation, Remote access.
Router#
ROM Monitor Mode
Used if the operating system dos not exist in Flash or
the boot sequence was interrupted during startup
> or romon>

12. Router Modes (Cont..) Setup Mode
prompted dialog used to establish an initial configuration
RXBoot mode
Boot helper Software which helps the router boot when
it cannot find a valid cisco IOS image in flash memory.
Router <boot>
Global Configuration Mode
Router(config)#
Other Configuration Mode
Router(config - mode) #

13. Initialising a Router Run RXBoot Load IOS POST image subset Enter ROM
Check
conf reg
Enter ROM
Monitor Mode
Load from
TFTP Server
Load From
ROM
Read
NVRAM
Load IOS
Subset
Load from
flash
Load IOS

14. ROUTER STATUS COMMANDS :
IOS version in DRAM Router# show version
Programs loaded in DRAM Router# sh processes CPU
sh protocols
Dynamic Configuration
information Router# sh running-config
Routing table in DRAM Router# sh ip route
Processor and I/O
memory usage Router# sh mem
back-up configuration
file in NVRAM Router# sh startup-config

15. ROUTER STATUS COMMANDS (Cont..)
Operating Systems Router# sh flash
interfaces Router# sh interfaces
Stack usage of
processes Router# sh stacks

16. Password recovery procedure :
Attach a terminal or PC with terminal emulation to the console port of the router. Use the following terminal settings:
9600 baud rate No parity 8 data bits 1 stop bit No flow control
Type show version and record the setting of the configuration register; it is usually 0x2102 or 0x102.
Using the power switch, turn off the router and then turn it back on.

17. Password recovery (cont..)
Press Break sequence on the terminal keyboard within 60
seconds of the power-up to put the router into ROMMON.
Type confreg 0x2142 at the rommon 1> prompt to boot from
Flash without loading the configuration. Type reset at the
rommon 2> prompt. The router reboots but ignores its saved
configuration. Type no after each setup question or press
Ctrl-C to skip the initial setup procedure
Type enable at the Router> prompt.
You'll be in enable mode and see the Router# prompt.
Type enable secret <password> to change the enable
secret password.

18. Hyperterm Win 2000 Ctrl-Break Hyperterm Win98/95 Ctrl-F6-Break
Type config-register 0x2102, or the value you recorded in
show version .
Press Ctrl-z or end to leave the configuration mode.
Type write memory or copy running-config startup-config
to commit the changes.
Break Sequence
Hyperterm Win 2000 Ctrl-Break
Hyperterm Win98/95 Ctrl-F6-Break
Hyperterm Win NT Break-F5
Shift-F5

19. Break Sequence(Cont..)
VT100 Emulation F16
Minicom Linux Ctrl-a f
PCPLUS DOS Alt-b

20. Enabling TFTP server on Linux:
Step 1 Log in as root.
Step 2 If are running Linux with " inetd," add or
uncomment the following line in your /etc/inetd.conf file:
tftp dgram udp wait root /usr/sbin/tcpd in.tftpd
If you are running Linux with "xinetd," Edit the /etc/xinetd.d/tftp
file as follows:
a. Change the line "disable = yes" to "disable = no."
b. Change the line "user = nobody" to "user = root.”
c. If you want to specify a different TFTP directory, replace
"/tftpboot" in the line "server_args = -s /tftpboot" with the name
of your directory.

21. Installing TFTP Server for Windows
Step 3 Enter the following command:
/etc/init.d/xinetd restart
Installing TFTP Server for Windows
Download the TFTP server for any version of Windows from
or search ‘tftp’ at
The file TFTPServer exe is a self-extracting
archive. Once the file is stored on your Windows system,
double-click it to start the setup program. Then follow the
prompts that appear to install the server on your system.

22. FLASH File System: The Flash file system consists of two Flash devices
on which you can store files:
bootflash: onboard Flash memory
slot0: Flash PC card in the PCMCIA slot
(or flash: Flash memory)
1. Router#show flash
System flash directory: File Length Name/status
c2600-io3s56i-mz.121-6
[ bytes used, available, total]
16384K bytes of processor board System flash (Read/Write)

23. 2. Display a list of deleted files on a Flash device.
Console> (enable) dir deleted
-#- ED --type-- --crc--- -seek-- nlen -length- ---date/time- name
1 .D ffffffff 81a027ca 41bdc Apr :27:45
5002.config cfg
3. Deleting file in flash
Console>(enable) del C7200-js-mz bin
4. Formatting flash
Console>(enable) format flash
format slot0

24. IOS Installation and Upgrade procedure :
Install a TFTP Server
Download the Cisco IOS Software image into your
workstation or PC where TFTP server is running.Store the
IOS image in appropriate directory. C:\tftp incase windows
and /tftpboot in case of Linux.
(You need to satisfy both the DRAM and the Flash
requirements to be able to use the software you choose.
If you do not meet the requirements, you can either add more
Flash or more DRAM in the router, or choose another Cisco
IOS Software release).

25. Back up the existing IOS image stored in Flash.
Router#copy flash tftp
Source filename []? C7200-js-mz bin
Address or name of remote host []?
Destination filename [C7200-js-mz bin]?
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!
bytes copied in secs ( bytes/sec)

26. Copy the new software image from the TFTP server to the
router server using the procedure below:
Router# copy tftp flash
When prompted, enter the IP address of the TFTP server as
Address or name of remote
host [ ]?
Source file name? c2600-io3s56i-mz.121-6
Destination file name? c2600-io3s56i-mz.121-6
Erase flash device before writing? [confirm] yes/no
Router#reload
*Mar 1 00:30:49.972: %SYS-5-CONFIG_I:
Configured from console by console
System configuration has been modified. Save?
[yes/no]: no Proceed with reload? [confirm] yes

27. Common Interface types supported on CISCO routers
Asynchronous serial
Dialer
Ethernet
High-Speed Serial Interface (HSSI)
ISDN Basic Rate Interface (BRI)
ISDN Primary Rate Interface (PRI)
Serial interface (Low Speed)
Synchronous serial

28. ETHERNET INTERFACE CONFIGURATION :
For example, to configure Ethernet interface 1 with the IP
address using a subnet mask of
, enter the following commands:
C400# conf t
C4000(config)#interface e1
description "MGMT LAN via Cat5k" C4000(config-if)#ip address
C4000(config-if)# no shutdown
C4000(config-if)# cntl Z
C400# wr memory / wr ter
wr memory - changes both startup and running config
wr ter - changes only running config

29. SERIAL INTERFACE CONFIGURATION :
The wan link will be connected to the serial interface.
Configure the serial interface as below
Router#conf t
Enter configuration commands, one per line. End with CNTL/Z.
Router(config)#interface serial 0
Router(config-if)#ip address
description “VSAT WAN LINK”
Router(config-if)#no shutdown
Router(config-if)#cntl Z
Eouter# wr m

30. Serial interface configuration (cont..) encapsulation Router# conf t
Router(Config)# int serial0
Router(Config-if)# encapsulation ppp / hdlc /sdlc
hdlc - serial hdlc synchronous(cisco)
ppp - point-to-point protocol
sdlc - SDLC
Router(Config-if)# bandwidth <in kilobits> S

31. Other Vital configurations :
hostname NICnet> !
no logging console (logging console 3)
no logging monitor (logging monitor 3)
enable secret rgb123
enable password cisco98
no ip finger
no ip http server
no ip bootp server
ip domain-name nic.in
ip name-server
ip name-server

32. line vty 0 4
password zigma2k
login !
banner login ^C
*******************************************
This is NIC - HQ New Delhi ^C
banner motd ^C
==========================================
Un-authorised access is prohibited

33. Static IP Routing :
If dynamic default information is not being passed to the
router, candidates for the default route may be specified with
the ip default-network subcommand. In this usage, ip
default-network takes a nonconnected network as an
argument. If this network appears in the routing table from any
source (dynamic or static), then it is flagged as a candidate
default route and is subject to being chosen as the default
route for the router. Multiple ip default-network commands
may be given. All candidate default routes, both static
(that is, flagged by ip default-network) and dynamic,
appear in the routing table preceded by an asterisk.

34. In the following example, a static route to network 10.0.0.0 is
defined as the static default route.
ip route
ip default-network
If the following global configuration command was issued on a
router not connected to network , then the router
might choose the path to that network as a default route when
the network appeared in the routing table.
ip default-network

35. Ip default-gateway
This specifies default gateway if not routing IP
ip route
ip route
This implies that packets for network will
be routed to the router at if dynamic
information about network is not available.
If you specify an administrative distance, you are
flagging a static route that may be overridden by
dynamic information