Cisco Router IOS

1
Cisco Router IOS

• M Clements

2
This week

• Cisco IOS versions
• IOS Features
• Choosing an IOS
• IOS upgrade
• Practical work

3
Internetworking Operating System

• Multifunction operating system on most Cisco
  routers and switches
• Generally meant for CLI usage
• Different versions have different features
• Need correct feature set for proposed usage
• Not easy to work out necessary features

4
Why might I need an upgrade?

• Your router may have a corrupt IOS
• Your router may not be able to perform the
  actions that you want it to carry out
• You may be planning an network upgrade and the
  current IOS does not contain the features that
  you desire for the future
• Perhaps your router does not support VLANS

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Find an IOS to support VLANs

• Cisco IOS Software Selector
• http//tools.cisco.com/ITDIT/ISTMAIN/servlet/index
  
• Allows search of IOS by feature and platform
• Can see DRAM and FLASH requirements
• These are important why?

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Try it out

• Go to
• http//tools.cisco.com/ITDIT/ISTMAIN/servlet/index
  
• Click Search by Feature
• Use Search by full or partial feature name
• Type VLAN then click Search
• Narrowed results appear below

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Narrowed results
Add IEEE 802.1Q ISL VLAN Mapping and click Add
then Continue
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Results of search
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Next Step .

• What platform are you using?
• This will be necessary to ensure that the IOS you
  need is available for your particular router (or
  switch)
• Assume you are working with a 2610 router
• What choices do you see in the Quick Pick?
• What is the difference between GD and LD release?

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Release Designations Defined

• Early Deployment (ED) Software releases that
  provide new features and new platform support in
  addition to bug fixes. Cisco IOS CTED, STED,
  SMED, and XED are variations of ED software
  releases.
• General Deployment (GD) Date at which this
  software release reached the "General Deployment"
  milestone in its lifecycle. A Major Release of
  Cisco IOS software reaches the "General
  Deployment" milestone when Cisco feels it is
  suitable for deployment anywhere in customer
  networks where the features and functionality of
  the release are required. Criteria for reaching
  the "General Deployment" milestone are based on,
  but not limited to, customer feedback surveys
  from production and test networks using the
  releases, CE bug reports, and reported field
  experience. Only Major Releases are candidates to
  reach the General Deployment milestone.
• Limited Deployment (LD) A Major Release of Cisco
  IOS software is said to be in the "Limited
  Deployment" phase of its lifecycle during the
  period between initial FCS and the General
  Deployment (GD) milestones.

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Download the IOS

• For this you will need a Cisco account
• Your company will have one if it is using Cisco
  devices
• University of Greenwich has an account we
  cannot use it for student work
• We will assume we have downloaded a new IOS
  version

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IOS upgrade method

• Put IOS onto a TFTP server
• Upload from TFTP server
• Trivial File Transfer Protocol not good for
  public usage no passwords etc
• See http//en.wikipedia.org/wiki/Tftp
• It uses UDP port 69 as its transport protocol It
  cannot list directory contents.
• It has no authentication or encryption
  mechanisms.
• It is used to read files from, or write files to,
  a remote server.

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Open Packet Tracer

• You will need as a minimum
• Server PT
• Router choose 1841
• Switch any
• PC with any Ethernet interface

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Connections
15
Connection Details

• Use copper straight through between server and
  switch and also between switch and router
• Use lowest numbered interfaces on all devices for
  Cat 5 cabling
• Use console cable between PC and router
• Connects to console ports on router and RS232
  port on the PC

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Connecting to router from the PC

• Go to PC Desktop then Terminal
• Make sure settings are as shown below
• Click OK

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Setup of Router

• Give the router a /24 IP address on an Ethernet
  interface
• Work this address out before you continue
• Change the routers name to my_new_router
• You can do this yourself or follow the
  instructions on the following slides

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Router Initial Setup

• At Continue with configuration dialog? yes/no
  type n, Return
• Now type the following commands
• Routergtenable
• Routerconfigure terminal
• Router(config)interface ?
• This displays the available interfaces
• Router(config)interface fastEthernet 0/0

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Router Setup Continued

• Router(config-if)ip address 192.168.1.1
  255.255.255.0
• Router(config-if)no shutdown
• LINK-5-CHANGED Interface FastEthernet0/0,
  changed state to up
• Router(config-if)exit
• Router(config)hostname my_new_router

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Router Setup Continued

• my_new_router(config)exit
• SYS-5-CONFIG_I Configured from console by
  console
• my_new_routerwrite
• Destination filename startup-config?
• Building configuration...
• OK
• my_new_router

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Configuring the Router

• Visit the CLI and ascertain the IOS version that
  is currently running
• Use the show version command to do this
• IOS is not the same as System Bootstrap!
• Note the values for NVRAM, DRAM and FLASH
• Where are these values written?

22
Noting the IOS currently in use

• The IOS is displayed prefixed by its location on
  the router
• Make a note of the location and the FULL name of
  the IOS
• Note the value of the Configuration Register
• This tells the router where to look at boot for
  its IOS

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Configuring Server

• Open server properties by clicking on it
• Under Config, Services turn off all services
  except TFTP
• Notice the IOS versions already downloaded to
  the TFTP server
• Set a /24 address and subnet mask from the
  routers FastEthernet network range

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Check Connectivity

• Make sure that your network has connectivity
  between the server and router before continuing
• Use a ping from either the router or the server
  to make sure of this
• Copy the results of the ping
• Carry out diagnostics if the ping fails

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Boot Router to ROMMON

• The ROM monitor (also called the bootstrap
  program) is the firmware that runs when you power
  on Cisco routers
• During normal operation, the ROM monitor helps to
  initialize the processor hardware and boot the
  operating system software
• Accomplished by changing the configuration
  register to either 0x2100 or 0x0

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From the PC .

• my_new_routerconfigure terminal
• Enter configuration commands, one per line. End
  with CNTL/Z.
• my_new_router(config)config-register 0x2100
• my_new_router(config)exit
• SYS-5-CONFIG_I Configured from console by
  console
• my_new_routerreload
• Proceed with reload? confirm

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Router boots into ROMMON

• Press Enter
• Type ?
• Note the response
• Now look at files in FLASH memory
• rommon 8 gt dir flash
• File size Checksum File name
• 13832032 bytes (0xd30f60) 0x1033
  c1841-ipbase-mz.123-14.T7.bin
• Now reboot the router (reset)

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Choosing the new IOS from the TFTP server

• Choose the IOS image on the TFTP server that you
  do not currently have in the routers FLASH
  note the COMPLETE name
• Enter Priv Exec mode on your router

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Enter the relevant details

• my_new_routercopy tftp flash
• Address or name of remote host ? 192.168.1.2
• Source filename ? c1841-ipbasek9-mz.124-12.bin
• Destination filename c1841-ipbasek9-mz.124-12.bin
  ?
• Accessing tftp//192.168.1.2/c1841-ipbasek9-mz.124
  -12.bin....
• Loading c1841-ipbasek9-mz.124-12.bin from
  192.168.1.2 !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
  !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
  !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
  !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
  !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
  !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
  !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
• OK - 16599160 bytes
• 16599160 bytes copied in 30.097 secs (123409
  bytes/sec)

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Check file is in FLASH then boot it

• my_new_routerdir flash
• Directory of flash/ (read the output)
• Now re-enter ROMMON
• rommon 1 gt boot flashc1841-ipbasek9-mz.124-12.bin
  
• Observe the boot process and verify that the
  router has booted the new IOS using the show
  version command

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Delete the old IOS

• my_new_routerdelete flash c1841-advipservicesk9-
  mz.124-15.T1.bin
• Delete filename c1841-advipservicesk9-mz.124-15.T
  1.bin?
• Delete flash/ c1841-advipservicesk9-mz.124-15.T1.
  bin? confirm
• my_new_routerdir flash
• Directory of flash/
• 2 -rw- 16599160 ltno dategt
  c1841-ipbasek9-mz.124-12.bin
• 32514048 bytes total (15914888 bytes free)

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Reboot and reset config register

• Reload the IOS
• Router boots to rommon again
• rommon 2 gt confreg 0x2102
• rommon 3 gt reset
• Once router reboots, verify that the IOS is now
  the new version use show version

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Saving config file to TFTP

• my_new_routercopy running-config tftp
• Address or name of remote host ? 192.168.1.2
• Destination filename my_new_router-confg?
• .!!
• OK - 352 bytes
• 352 bytes copied in 3.184 secs (0 bytes/sec)

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Check TFTP server

• Look in the TFTP server for the config file that
  you copied
• This can be useful as a backup in case of router
  failure

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Summary

• IOS contains commands for routers and switches
• Can be upgraded over network using TFTP
• ROMMON can be used as basic boot option
• TFTP server accessed by router to copy the IOS
• TFTP server can also be used to save or upload a
  config file

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Extra Resources

• Free TFTP server see engweb.info/apps

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References

• http//en.wikipedia.org/wiki/Cisco_IOS
• http//tools.cisco.com/ITDIT/ISTMAIN/servlet/index
  
• http//www.roadkillnetworks.com/cisco/tftp_rom_mon
  itor_appendc.htm