CCIE Pursuit Blog

May 19, 2007

A Series Of Unfortunate Router Events: Part I

Filed under: Home Lab,IOS — cciepursuit @ 8:30 pm

I have a home lab of 2600’s which I have been upgrading the IOS to 12.4 from 12.3 in a piecemeal fashion.  Of the seven routers, four of them are 2651XM’s with 3 2620’s.  I upgraded the IOS from “c2600-is-mz.12.3-22.bin” to “c2600-adventerprisek9-mz.12.4-10.bin” on r2 today.  I didn’t notice that the router that I was upgrading was one of the 2620’s.  This started a chain of events that ate up more than an hour as I tried to fix my screw-up.

I downloaded the IOS from one of the 2651’s (r3).  This is actually a very easy process.  Simply configure the router to act as a tftp server:

r3(config)#tftp-server flash:c2600-is-mz.123-22.bin

Then you just need to make sure that you have connectivity between the router to be upgraded and the router serving as a tftp server.  You can then copy the IOS from one router to another (make sure that you have room in flash for the image):

r2#copy tftp flash
Address or name of remote host []? 137.1.2.1
Source filename []? c2600-adventerprisek9-mz.124-10.bin
Destination filename [c2600-adventerprisek9-mz.124-10.bin]?
Accessing tftp://137.1.2.1/c2600-adventerprisek9-mz.124-10.bin…
Erase flash: before copying? [confirm]
Erasing the flash filesystem will remove all files! Continue? [confirm]
Erasing device… eee

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
[OK – 29631128 bytes]

Check out this document for more detail:

How To Copy a System Image from One Device to Another

Since the flash is being erased, once the new image has been downloaded you’ll just need to reload the router to boot to the new IOS.  It’s that easy…unless you are a bonehead like me.  Can you spot the warning that I ignored:

Verifying checksum…  invalid (expected 0xC7EA, computed 0x47DC)29631128 bytes copied in 420.980 secs (70386 bytes/sec)
r2#sh flash

System flash directory:
File  Length   Name/status
  1   29631128  c2600-adventerprisek9-mz.124-10.bin [invalid checksum]
[29631192 bytes used, 3398948 available, 33030140 total]
32768K bytes of processor board System flash (Read/Write)

Although the above warnings were not in bold on the router, they might as well have been.  I thought that the image might have been corrupted during the tftp download, so I downloaded it again.  Same messages.  Oh well, let’s reload:

*Mar  1 00:51:11: %SYS-5-RELOAD: Reload requested by console. Reload Reason: Reload command.
System Bootstrap, Version 12.2(10r)1, RELEASE SOFTWARE (fc1)
TAC Support: http://www.cisco.com/tac
Copyright (c) 2002 by cisco Systems, Inc.
C2600 platform with 65536 Kbytes of main memory

program load complete, entry point: 0x80008000, size: 0x1c42120

Error : memory requirements exceed available memory
Memory required     : 0x045C487C

*** System received a Software forced crash ***
signal= 0x17, code= 0x4, context= 0x80080404
PC = 0x0, Vector = 0x0, SP = 0x0

System Bootstrap, Version 12.2(10r)1, RELEASE SOFTWARE (fc1)
TAC Support: http://www.cisco.com/tac
Copyright (c) 2002 by cisco Systems, Inc.
C2600 platform with 65536 Kbytes of main memory

rommon 1 >

Crap!!!  I probably should have paid heed to those invalid checksum messages.  Now I’m stuck in ROMMON due to a forced software crash!

First let’s see what I should have done before trying to throw this IOS image on a router with 64M of RAM (that “Error : memory requirements exceed available memory” message is probably a clue) 🙂

I should have spent a few minutes at this page: Cisco Feature Navigator

You can look up the specs on different IOS versions by name, features, or even router type.  You can even compare two IOS’s head-to-head.  If I had done my due diligence, I would have seen that although my 2620 had enough flash memory to host the IOS image, it did not have enough RAM to run the image:

Old IOS Version
Image Name       c2600-is-mz.12.3-22.bin 
DRAM / Min Flash      64 / 32 
Enterprise Product Number     S26CP-12322

New Version
Image Name       c2600-adventerprisek9-mz.12.4-10.bin 
DRAM / Min Flash      128 / 32 
Enterprise Product Number     S26AESK9-12410

So I’ve discoved how I managed to screw up my router, now how do I fix it?  That is the topic of my next post.

Links:

Cisco Feature Navigator

How To Copy a System Image from One Device to Another

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1 Comment »

  1. […] Series Of Unfortunate Router Events: Part II In my last post I found out the hard way about the need to verify the memory capabilities of a router before […]

    Pingback by A Series Of Unfortunate Router Events: Part II « CCIE Pursuit — May 21, 2007 @ 6:53 pm | Reply


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