2

I am experiencing an unusual memory issue with a Cisco 7604 router, specifically the memory on the Supervisor Engine (SUP32-GE-3B) and how it pertains to IOS requirements.

I was preparing the router for a customer, but it crashed when attempting to load the required IOS version due to insufficient memory. The necessary IOS version (AdvIPservices) requires 512MB DRAM, 128MB flash; whereas the IOS version that loads successfully (IPservices) requires 512MB SDRAM, and only 64MB flash. The Supervisor Engine has a 256mb RAM module, and the MSFC2A has another 256mb RAM module. The bootflash card is 256MB.

Herein lies the problem: when I used "sh ver" to check the available memory and verify that the system meets the IOS minimum requirements, here's the memory it reports:

cisco CISCO7604 (R7000) processor (revision 2.0) with 458752K/65536K bytes of memory.

65536K bytes of Flash internal SIMM (Sector size 512K).

Those first two values add up to 512MB, which implies that the system has enough SDRAM, even though it does not (unless it combines the total RAM from the Supervisor and the MSFC). I ruled out the bootflash as being the problem by replacing it with a 512MB card, but the problem persisted.

To make things stranger, I compared this result with some log files from my previous 7604 build, and it reported the following:

cisco CISCO7604 (R7000) processor (revision 2.0) with 458752K/65536K bytes of memory.

65536K bytes of Flash internal SIMM (Sector size 512K)

Except that it reports this while running the AdvIPservices image. I assume that this router also has the two 512MB ram modules lised in the purchase configuration document because it was able to load the IOS image without any problems but, at the time, I had no cause to open the router and physically verify the RAM modules, and I no longer have access to that router.

The only memory difference I see between the two routers is this line that appears during boot-up:

Good Router:

Cat6k-Sup32 platform with 524288 Kbytes of main memory

'Bad' Router:

Cat6k-Sup32 platform with 262144 Kbytes of main memory

However, another line shows up during boot which is identical between each router:

Good Router:

Cat6k-MSFC2A platform with 524288 Kbytes of main memory

'Bad' Router:

Cat6k-MSFC2A platform with 524288 Kbytes of main memory

So here are my questions:

  1. Whare those two different "Cat6k" platform memory values refer to, in terms of hardware?

  2. If the Cat6k values correspond to the RAM modules, why does the 'bad' router state that the MSFC has 512MB RAM, when the MSFC only actually has a 256MB module?

  3. What do the "show version" memory values (specifically the 'Processor with xK/yK bytes of memory' values) correspond to? IE: both PBRs show the same memory values here, but different values for Cat6k-Sup32. How is that possible?

  4. Both the IPservices and AdvIPservices images require 512MB DRAM (according to the Cisco IOS comparison tool), yet the 'bad' router only loads the IPservices image due to running out of memory. Why is this? Is it possible that the memory requirements listed by Cisco are "padded out" for the IPservices image, and it actually only requires 256MB?

  5. The "min flash" size is the only memory requirement diffrerence between the two IOS versions, and the 'bad' router excedes the minmum requirements for both images; yet it will only boot the IPservices image. The problem persists regardless of whether the bootflash card's capacity is 256MB or 512MB.

  6. Is there a preferred command (IOS or ROMMON) I can use to verify memory requirements in the future? The Cisco docs recommend "show version", but I'd prefer a more reliable alternative if possible.

I appreciate any assistance anyone can offer; I have tried searching for information about these values, but my search results keep getting flooded with unrelated example documents, as these values appear during a healthy boot up. I am already planning on upgrading the RAM in the 'bad' router, but I would really like to understand these seemingly incongruous values I'm seeing.

Liesmith
  • 235
  • 2
  • 9
  • Did you by any chance purchase this unit grey/aftermarket rather than new from Cisco? The standard RAM fitout on the Sup32 changed a while ago (May 2006) to be 512MB. – Phil Jul 07 '14 at 23:36
  • I have no idea where my employer purchased it...I believe they use a vendor affiliated with Cisco. To my knowledge, this router has been sitting on a shelf for a very long time. I've only performed one other 7604 build (described as the "good" router in my original post), and its memory appeared to be fine. One thing I'm unsure of is the MSFC RAM; it doesn't have an actual Cisco part number sticker on it, so I'm going off the part numbers on the Infineon chips themselves, which appear to be 256MB, according to Google...but the same number appears in photos of the 512MB RAM module as well. – Liesmith Jul 08 '14 at 05:15
  • You'll probably find the same density of chip on two different modules; there will just be twice as many on the 512mb. – Phil Jul 08 '14 at 12:20
  • You know what, the only thing that changed to 512MB was the RP (reflected by you seeing 512MB on the RP). I think the current standard on the SP is still 256MB on these units (unless you order it with the required licence for an image that needs the heavier software, at which point they will supply it with the correct RAM as part of the licence cost). – Phil Jul 08 '14 at 13:06

1 Answers1

4

  1. You've already discovered that there's two sets of RAM on the 6500/7600 series supervisors - the switch processor or supervisor RAM, and the MSFC or "route processor" RAM. The terminology isn't helped by there being three different names for each of these two components.

    The "sh ver" output is for the MSFC (RP) (add the two values together).

    "remote command switch show version" will execute show version on the Supervisor SP).

  2. I suspect as per my comments to your original question that it's actually a 512MB part that's installed given you're basing the assumption that it's 256MB on the markings on the RAM chips themselves rather than a cisco part number.

  3. Essentially answered above; your MSFC and Supervisor have different amounts of RAM installed which accounts for the differences

  4. There might be enough RAM to boot the IPServices image but that might not mean it will reliably operate with all features enabled/in use; so there is going to be an element of "overhead" built into their "minimum specs" as you suggest.

  5. The bootflash is just that - a flash disk. It can't be used to run the image, it's just storage. Changing the bootflash won't fix your low RAM condition. You're likely only asking this question based on the assumption that IPServices "shouldn't work" on 256MB RAM, though (addressed in my answer to point 4).

  6. See my answer to part 1 to get the figures for both the MSFC and the Supervisor

You need to upgrade the RAM in your Supervisor - You want a MEM-SUP32-512MB. Consider MEM-MSFC3-1GB= at the same time, as that's the current recommended amount for the MSFC.

(Edited because markdown was screwing with the numbering of the points)

Phil
  • 1,222
  • 1
  • 7
  • 15
  • Thank you very much for this explanation. It sounds like I may have asked my employer for an extraneous memory module (since I thought both were 256MB). For clarification; both RAM modules appear to be identical (same number and arrangement of Infineon chips), except for the serial number on the individual chips: The SUP32 RAM chips are HYB250256800CT-6, and the MSFC chips are HYB39S256400DT-7. Both modules contain four such chips, and the SUP32 module has a stick labeling it as "MEM-XCEF720-256M". – Liesmith Jul 08 '14 at 16:51
  • 1
    HYB39S256400DT-7 are supposedly 256Mbit which means you'd need 8 of those to make a 256MByte memory module. You sure that they're not on both sides of the module? I can't find anything on a "HYB250256800CT-6" but I'm guessing they're supposedly 256mbit as well (the 256 in the part code would give that away) but you'd need 16 of those to yield 512mb. – Phil Jul 08 '14 at 17:00
  • Ok, I just popped open the router and took a closer look at those modules; you're exactly right. Each module has chips on the front and back, but the MSFC chips are double-stacked. From the top, the modules look identical, but when you look at the MSFC mod from the side, you can see that it has twice as many chips as the SUP32 module. Thank you so much for your assistance with this, I thought I was going crazy...it turns out I'm only going blind. – Liesmith Jul 08 '14 at 17:21
  • We've all been there. No worries :) – Phil Jul 08 '14 at 17:25