Configuring Network Devices
Working at a Small-to-Medium Business or ISP
– Chapter 5
Version 4.1
Objectives
• Configure a router with an initial
configuration.
• Use Cisco SDM to configure a Cisco ISR
with LAN connectivity, Internet connectivity
and NAT.
• Configure a Cisco router for LAN
connectivity, Internet connectivity and NAT
using the Cisco IOS CLI.
• Configure a WAN connection from
customer premises to an ISP.
• Describe, setup and configure a standalone
LAN switch.
Initial ISR Router Configuration
• ISR (Integrated Services Router combines routing, LAN
switching, security, voice, & WAN connectivity features.
• Ideal for small to medium-sized businesses & ISP
managed customers.
Initial ISR Router Configuration
• Cisco IOS – offered in modules called images
• IP Base image: entry-level Cisco IOS
• Images are specific to models of devices
Cisco 1841 Modular router
Table 1 Memory Requirements for Cisco 1841 Modular Router
Flash
RAM
Platform
Feature Set
Image
Memory1
Memory
Cisco 1841
IP Base
c1841-ipbase-mz
64 MB
128 MB
IP Voice
c1841-ipvoice-mz
64 MB
192 MB
Enterprise Base
c1841-entbase-mz
32 MB
128 MB
Advanced Security
c1841-advsecurityk9mz
64 MB
192 MB
SP Services
c1841-spservicesk9-mz
64 MB
192 MB
Enterprise Services
c1841-entservicesk9mz
64 MB
192 MB
Advanced IP
Services
c1841-advipservicesk9- 64 MB
mz
192 MB
Advanced Enterprise
Services
c1841-adventerprisek9mz
192 MB
64 MB
CISCO IOS Image: Types of Images
• Two main types of image your router may use:
1. System image - complete Cisco IOS software. This image is
loaded when your router boots and is used most of the time.
– On most platforms, the image is located in Flash memory.
2. Boot image - A subset of the Cisco IOS software. This
image is used to perform network booting or to load
Cisco IOS images onto the router. This image is also used if
the router cannot find a valid system image. Depending on
your platform, this image may be called xboot image, rxboot
image, bootstrap image, or boot loader/helper image.
• On some platforms, the boot image is contained in ROM. In
others, the boot image can be stored in Flash memory. On
these platforms, you can specify which image should be used
as the boot image using the boot bootldr global configuration
command. Refer to your hardware documentation for
information about the boot image used on your router.
Image Naming Convention
• You can identify the platform, features and
image location by the image name.
• Naming convention is: platform – features –
type
• Example: c2600-js-l_121-3.bin
•
•
•
•
c2600 js
l
121-3 -
hardware platform
features set (enterprise)
file format (relocatable, not compressed)
version & release # (version 12.1 release 3)
Image Naming Convention - continued
• Platform – variable platform that can use image
– For example c1700, c2600, c7000
• Features –feature sets supported by image.
• Type – can contain following characters
• f—The image runs from Flash memory.
• • m—The image runs from RAM.
• • r—The image runs from ROM.
• • l—The image is relocatable.
• • z—The image is zip compressed.
• • x—The image is mzip compressed.
Initial ISR Router Configuration
• Tools and equipment required for setup:
Initial ISR Router Configuration
Three-stage bootup process:
• Power-on self test (POST)
• Locate and load Cisco IOS
• Locate startup configuration file or enter setup mode
Bootup Process - contd
• POST (Power On Self Test) – test hardware
• After POST, the bootstrap program is loaded
• Bootstrap locates IOS and loads it into RAM
– IOS can be located – flash memory, TFTP server,
or another location
– By default, IOS loads from flash
• After IOS is loaded, bootstrap locates startup
configuration file in NVRAM (non-volatile random
access memory)
• Startup configuration – when loaded into RAM
(working memory), it become the “running”
configuration.
Loading Cisco IOS
Get default IOS from FLASH
Flash empty
Get IOS from TFTP Server
TFTP Server empty
Get limited Cisco IOS from ROM
Show version command output
• Router>show version
• IOS version
• Bootstrap program stored in ROM
• Complete filename of IOS
• Type of CPU; amount of RAM
• Number & type of interfaces
• Amount of NVRAM (used to store startup config)
• Amount of Flash (used to store IOS
• Configuration register in hex
Configuration register
• Default setting – 0x2102 (remember this?)
– Loads IOS from flash
– Loads startup-config from NVRAM
• Most common settings
• 0x2142 –ignores contents of NVRAM/configuration
• 0x2120 – The router into ROMmon mode
• http://www.cisco.com/en/US/products/hw/routers/ps13
3/products_tech_note09186a008022493f.shtml
– **Go to Configuration Register Values & Their
Meaning.
Initial ISR Router Configuration
Verifying and troubleshooting bootup process:
• View output from the show version command
• Use dir flash: and boot flash: in ROMmon mode
• View boot system commands
[see miage below on next slide]
Initial ISR Router Configuration
(continued)
Initial ISR Router Configuration
(continued)
• Out-of-band management for initial configuration
• In-band management over a network connection
In-Band
Out-of-Band
Terminal emulation
HTTP or Telnet
Initial ISR Router Configuration
(continued)
• Command Line Interface (CLI): textbased program
• Can be used in both in-band or out-ofband
• Extensive help system
[see image below
on next slide]
Initial ISR Router Configuration
(continued)
SDM
• Security Device Manager (SDM): web-based
GUI
• In-Band only
• SDM Express (Basic) or Full package
(Advanced configuration)
• Comes preinstalled in flash
CLI vs. SDM
CLI
User Interface
Term Emulation software
SDM
Web-based browser
Telnet
Configuration Method
Text-based Cisco commands
GUI buttons & text boxes
Expertise in Cisco
Device Config.
Depends on the config task
Do not need knowledge of CLI
commands
Help Features
Command-prompt based
GUI based online help &
tutorials
Flash Requirements
Covered by IOS requirements
6MB of free memory
Availability
ALL Cisco devices
Cisco 830 series thru Cisco
7301
What It’s Used
When device does not support
SDM
Initial config of SDM equipped
device
Using Cisco SDM Express and
SDM
• Follow best practices for installing a new
device to ensure correct functions
Using Cisco SDM Express and
SDM
Eight SDM Express configuration screens:
•
•
•
•
•
•
•
•
Overview
Basic configuration
LAN IP address
DHCP
Internet (WAN)
Firewall
Security settings
Summary
Using Cisco SDM Express and
SDM
• Use Basic NAT Wizard to configure dynamic
NAT with PAT
Configuring a Router Using IOS
CLI
• CLI command modes: two levels of access
Configuring a Router Using IOS
CLI
• Configuration modes can alter the operation of
the device
Configuring a Router Using IOS
CLI
Help features:
• Command completion
• Error indicators
• Command history
–
–
–
–
Enabled by default
Records 10 command
Max 256 commands
history size command
• Arrow and function keys
Configuring a Router Using IOS
CLI
• Show commands
display
configuration and
operation
information
• R#show run
• R#show
interfaces
• R#show ip route
• R#show protocols
Configuring a Router Using IOS
CLI
• Use Cisco IOS CLI to perform an initial router
configuration
Configuring a Router Using IOS
CLI
• Configure serial and Ethernet interfaces on a
router
(DTE) Data Terminal Equipment
endpoint of user’s device on the WAN
link; Cisco routers
(DCE) Data Communications
Equipment; provides clock rate;
modem; converts data from router to
acceptable format to cross the WAN
If back-to-back router scenario, one of
the routers will be DCE and one DTE.
Configuring a Router Using IOS
CLI
• Configure a default route for the Cisco
router
• Default route used when router does not
know where to send a packet.
IP address of
next-hop router
Or
port number
Configuring a Router Using IOS
CLI
• Configure a Cisco router to function as a
DHCP server
Configuring a Router Using IOS
CLI
• Configure static NAT on a Cisco router to
enable Internet access for an internal server
Configuring a Router Using IOS
CLI
• Back up and restore configuration files using a
TFTP server
Configuring a Router Using IOS
CLI
• Capture and save configuration file output from
a terminal session
Connecting the CPE to the ISP
• Customer Premise Equipment (CPE) – network devices installed
at customer location.
• Configuration checklists ensure that all configuration
requirements are met
Connecting the CPE to the ISP
• Use inventory and configuration checklists and
an installation plan to ensure successful
installation
Connecting the CPE to the ISP
• Documentation includes diagrams, checklists,
and activity logs
Connecting the CPE to the ISP
Types of customer connections over a WAN:
• Point-to-point: often called leased lines;
typically most expensive; price based on
bandwidth & distance between 2 points
• Circuit-switched – similar to a phone call made
over a phone network; example is ISDN or
dialup connection; physical circuit reserved
from source to destination
• Packet-switched – each customer has a virtual
circuit; example is Frame Relay
Customer Connections over
WAN
• Bandwidth and cost influence WAN choices
Connecting the CPE to the ISP
•
•
Clock rate and serial encapsulation are needed when configuring serial
WAN connections
– Clock rate is set by DCE
– DTE accepts clock rate
Leased WAN connections use serial connection & require Channel
Service Unit/Data Service Unit (CSU/DSU
DCE
DTE
Initial Cisco 2960 Switch
Configuration
•
•
•
Fixed-configuration, standalone devices – does not use modules or flash
card slots. Physical configuration can’t be changed.
Layer 2 device that directs stream of message coming in from one port,
our of another based on destination MAC address.
Configured using GUI or CLI
Cisco 2960 switch
• Comes preconfigured
• Needs to be assigned basic security info
• Basic commands (ex: hostname,
passwords) sames as ISR switch.
• Configure management IP address
• One virtual local area network, VLAN 1 is
preconfigured to provide access to
management functions.
Initial Cisco 2960 Switch
Configuration
• Switch settings can be configured using the
Cisco IOS CLI
• Assign an IP address to the default
management virtual local area network,
VLAN1
Initial Cisco 2960 Switch
Configuration
• Check switch components
• Connect cables to the switch
• Power up the switch and observe POST
Initial Cisco 2960 Switch
Configuration
• Connect the stand-alone LAN switch to the
router and verify connectivity
• Configure port security to prevent
unauthorized use
• Shut down unused ports
Switch port security
• Port security limits the # of MAC addresses allowed per port.
• Set port to access mode using switchport mode access
command
• 3 ways to configure port security:
• Static – MAC addresses are manually assigned using
switchport port-security mac-address [mac-address] interface
config command.
–
–
–
–
–
S1# configure terminal
S1(config-if)#interface fastethernet 0/20
S1(config-if)#switchport mode access
S1(config-if)#switchport port-security mac-address 1000.2000.3000
S1(config-if)#end
–
•
Switch port - contd
• Dynamic MAC addresses are
dynamically learned & stored in address
table
• # of addresses stored can be controlled;
default is one address.
• If port is shut down or switch is restarted,
address learned are cleared from the
table
S1# configure terminal
–
–
–
–
S1(config-if)#interface fastethernet 0/20
S1(config-if)#switchport mode access
S1(config-if)#switchport port-security
S1(config-if)#end
Switch port - contd
• Sticky – similar to dynamic
• Addresses learned are saved to the
running-config
–
–
–
–
–
–
–
S1# configure terminal
S1(config-if)#interface fastethernet 0/20
S1(config-if)#switchport mode access
S1(config-if)#switchport port-security
S1(config-if)#switchport port-security maximum 50
S1(config-if)#switchport port-security mac-address sticky
S1(config-if)#end
Initial Cisco 2960 Switch
Configuration
• Cisco Discovery Protocol (CDP) gathers
information about directly-connected Cisco
network devices
• Two Cisco devices directly connected on the
same local network are called neighbors
Summary
• The Integrated Services Router (ISR) is
a good choice for small to medium
businesses and ISP-managed
customers.
• ISRs can be initially configured using
SDM or the router IOS CLI.
• When using the CLI, “show” commands
verify configuration elements.
• An installation plan can minimize
disruption to a network when new
devices are being added.