12 Feb

Bits or bytes – Cisco, you should know that!

Lets look at output of booting process of Cisco 3925 router

System Bootstrap, Version 15.0(1r)M8, RELEASE SOFTWARE (fc1)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 2010 by cisco Systems, Inc.

Total memory size = 1024 MB - DIMM0 = 512 MB, DIMM1 = 512 MB
Field Upgradeable ROMMON Integrity test 
_______________________________________ 
ROM: Digitally Signed Release Software
CISCO3925-CHASSIS with C3900-SPE100/K9 with 1048576 Kbytes of main memory
Main memory is configured to 72/72(dimm 0/1) bit mode with ECC enabled

Upgrade ROMMON initialized
program load complete, entry point: 0x4000000, size: 0x18fa0
program load complete, entry point: 0x4000000, size: 0x18fa0


IOS Image Load Test 
___________________ 
Digitally Signed Release Software 
program load complete, entry point: 0x4000000, size: 0x34b73a0
Self decompressing the image : ####################################################################################################################################################################################################################################################################################################################################################################################################################################################################################################### [OK]

Smart Init is enabled
smart init is sizing iomem
                 TYPE      MEMORY_REQ
          HWIC Slot 0      0x00200000
          HWIC Slot 1      0x00200000
               PVDM 0      0x00200000
               PVDM 1      0x00200000
            SM Slot 1      0x00600000
           OIR memory      0x00600000
    Onboard devices &
         buffer pools      0x0230F000 
-----------------------------------------------
               TOTAL:      0x0370F000

Rounded IOMEM up to: 56Mb.
Using 5 percent iomem. [56Mb/1024Mb]

Ok Cisco developers, you should know the difference between megabytes [MB] and megabites [Mb], right? Doesn’t seems so :/

I looked deeper if this “typo” is only made on bootup messages. Unfortunately not.

C3925-WLC-pwo#show memory statistics 
                Head    Total(b)     Used(b)     Free(b)   Lowest(b)  Largest(b)
Processor   11A4B8E4   769345308    28055316   741289992   719013612   683698364
      I/O   3C800000    58720256    19334640    39385616    39382912    39381980

Output of this command suggests that measurement is made in bites not bytes but we all know what units are used. It’s not like we all don’t know how to read outputs, it’s just networking company as Cisco should take care of using proper units in outputs.

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