Difference between CPLD, FPGA and ROMMON

[Kiley]

Hello there,

For reference, I am using the "Release Notes for Cisco Catalyst 9400 series Switches, Cisco IOS XE Cupertino 17.9.x Upgrading the Switch Software".

I will be upgrading our 9407 from IOS-XE 16.12.8 to 17.9.4. From what I've been able to see, it's a straight shot from the current IOS to the new (without having to jump to an intermediary one).  What the upgrade document indicates is that the ROMMON gets upgraded when going from 16.12.8 to 17.9.4.  As a part of that ROMMON upgrade is an upgrade of the CPLD/FPGA, which, when looking at the googles, are two different logic chips that I'm assuming, reside on the sup modules. 

It appears I need to upgrade the IOS first so the new ROMMON will get installed on the primary flash.  The Cisco upgrade guide indicates that ROMMON will ONLY be upgraded on the primary flash - I have to manually upgrade the ROMMON to the back-up flash (located in the Golden flash device).  However, before I can upgrade the back-up ROMMON, I need to upgrade the FPGA. 

In order to upgrade the FPGA, it indicates that I need to upgrade the CPLD.  CIsco says the command to upgrade the CPLD is upgrade hw-programmable cpld ........

However, when I do the command to see what options are available for "upgrade hw-programmable ?"  cpld AND fpga are options but there is no indication that I am to upgrade the FPGA in the document.  Is it not necessary to upgrade FPGA and that upgrading only CPLD takes care of FPGA?

What is real difference between ROMMON and the CPLD/FPGA anyway?  I had always thought that the ROMMON was like the BIOS for a cisco device.

And only then, if I am to understand correctly, can I then upgrade the back-up ROMMON to the Golden flash device.  

I apologize for the long query but any clarifications would be so greatly apprecaited.

Thank you very much!

Kiley

[Leo Laohoo]

I am not sure about the automatic ROMMON upgrade but if there is a console attached to supervisor card, a micro-code upgrade (express as "ucode") will also happen.  This process will take about 5 minutes on top of the regular upgrade process.  

So think about adding about 11 minutes on top of the 5 minutes.

[M02@rt37 · Accepted solution]

Hello @Kiley 

ROMMON serves as the bootstrap program for the device. The upgrade process involves updating the ROMMON image. This occurs during the IOS upgrade. ROMMON upgrade is done on the primary flash, and you may need to manually upgrade the backup ROMMON.

CPLD is a programmable logic device that controls certain functions on the switch. Upgrading the CPLD is essential for compatibility with newer software versions. The command you mentioned (upgrade hw-programmable cpld) is used for upgrading the CPLD.

FPGA is another type of programmable logic device with configurable logic blocks. FPGA upgrade might be part of the same process as CPLD upgrade. Cisco sometimes bundles these upgrades together for simplicity.

ROMMON is indeed similar to BIOS in the sense that it provides basic functionality for the device to boot.
CPLD and FPGA, on the other hand, are programmable logic devices that handle various functions and configurations beyond the basic boot process.

Typically, you would upgrade the IOS first, which may include the ROMMON upgrade.
Upgrading the CPLD is usually done next to ensure compatibility with the new software.
FPGA upgrade might be included in the CPLD upgrade process or could be a separate step.

[Kiley]

Ah, that makes sense - thank you, M02@rt37 - and Leo; although Leo, if there is another upgrade hidden within the upgrade, good gads!  I am greatly appreciative for your quick replies.

Kiley

[Kiley]

Hi guys,

This past weekend I completed the upgrade of the Catalyst 9407.  The instructions (noted above in the original post) were very clear, concise and extremely helpful.  What is significant is, if you have dual sups running in HA mode.....this upgrade took over 2 hours to complete - and that was with everything going right.  Make sure you plan for that amount of time.  First order of business:

Upgrade the IOS - with install mode, it went fairly quickly, approximately 20 minutes total. However, be aware that the ROMMON that gets upgraded to the primary flash does not actually get implemented until the switch (chassis) gets reloaded.  It’s a statement that flashed by fairly quickly. If I had known there would be a lot of switch reloads as a part of the CPLD upgrade process, I would not have reloaded the switch at this point, but I did not so I reloaded the switch.

The reboot process, each time, takes about 10 or so minutes.

Upgrade the CPLD - if you’re running dual sups in HA mode, the standby sup gets reloaded first – this process is a good 15 or so minutes to come back to standby (Hot).  After the standby gets upgraded, force a switchover so the standby becomes primary, and the primary becomes standby and upgrade the standby.  Another 15 or so minutes.

After both the CPLD on both sups have been upgraded, there is now an inconsistency between the CPLD version on the sups AND the CPLD version of the line cards.  You must reload the switch (chassis) again to update the line cards to the version to match the sup modules – another 15 or so minutes.

Now, and only now, can you upgrade the ROMMON to the golden/back up flash (which resides on both sup modules). The only tweak I needed was to the command structure for the actual upgrade; in the document, the command provided: “upgrade rom-monitor capsule golden switch” is not correct with this IOS. The correct command to use is: “upgrade rom-monitor capsule golden rp standby”.  This upgrades the standby sup, and it takes approximately 15 minutes or so for the switch to return to standby (Hot).  Once again, force a switchover to make the standby sup primary and the primary sup standby and rerun the command again; another 15 or so minutes will go by.

Good luck for anyone who has a Catalyst 9407 and needs to upgrade!

Thanks,

Kiley

[Julian Ortiz]

Hi Kiley,

I wish you read this message because I am in the same situation and I am very confused about the process. I will write my doubts:

Upgrade the IOS - with install mode, it went fairly quickly, approximately 20 minutes total. However, be aware that the ROMMON that gets upgraded to the primary flash does not actually get implemented until the switch (chassis) gets reloaded.  It’s a statement that flashed by fairly quickly. If I had known there would be a lot of switch reloads as a part of the CPLD upgrade process, I would not have reloaded the switch at this point, but I did not so I reloaded the switch.

The reboot process, each time, takes about 10 or so minutes.

Clear.

Upgrade the CPLD - if you’re running dual sups in HA mode, the standby sup gets reloaded first – this process is a good 15 or so minutes to come back to standby (Hot).  After the standby gets upgraded, force a switchover so the standby becomes primary, and the primary becomes standby and upgrade the standby.  Another 15 or so minutes.

CPLD upgrade is automatic or you have to upgrade with the command 2upgrade hw-programmable cpld filename"?

After both the CPLD on both sups have been upgraded, there is now an inconsistency between the CPLD version on the sups AND the CPLD version of the line cards.  You must reload the switch (chassis) again to update the line cards to the version to match the sup modules – another 15 or so minutes.

Clear.

Now, and only now, can you upgrade the ROMMON to the golden/back up flash (which resides on both sup modules). The only tweak I needed was to the command structure for the actual upgrade; in the document, the command provided: “upgrade rom-monitor capsule golden switch” is not correct with this IOS. The correct command to use is: “upgrade rom-monitor capsule golden rp standby”.  This upgrades the standby sup, and it takes approximately 15 minutes or so for the switch to return to standby (Hot).  Once again, force a switchover to make the standby sup primary and the primary sup standby and rerun the command again; another 15 or so minutes will go by.

The ROMMON is upgraded automatically in the primary SPI flash according to the documentation, but it must be done manually on the golden SPI flash. Is it mandatory to upgrade the ROMMON on the golden SPI flash?

Regards,

Julián

[Leo Laohoo]

ROMMON, CPLD, FPGA, microcode are mandatory -- The platform (router, switches, WLC) cannot be upgraded if the ROMMON/CPLD/FPGA or microcode is not upgraded first.   

Golden capsule is optional -- It is in the likely event the microcode gets corrupted, the golden capsule will "save the day".  The switch firmware can still be upgraded without upgrading the golden capsule.

[Julian Ortiz]

Hi Leo,

You say ROMMON, CPLD, FPGA, microcode are mandatory before firmware can be upgraded? But the guide says after firmware upgrade:

You can upgrade the ROMMON before, or, after upgrading the software version.

CPLD version upgrade process must be completed after upgrading the software image.

https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst9400/software/release/17-9/release_notes/ol-17-9-9400/upgrading_the_switch_software.html#concept_ycv_jdf_3mb

Regards,

Julián