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TomS_
Git-r-done
Premium,MVM
join:2002-07-19
London, UK
kudos:5
reply to Da Geek Kid

Re: [HELP] NO flash files

Oh man thats gotta be painful. Why does such a recent device not do TFTP (from ROMMON)....?!?

OP: I have done this once, with a Cat 2900. I accidentally loaded a 2900XL image on to it, because I thought thats what I had bought. Oops.

One tip I have for xmodem transfer ... ramp up the speed to 57600bps. This will make it faster, thus saving some of your sanity. I tried 115200bps, but this resulted in too many errors and the transfer would fail.

You could always try 115200bps though, and if it gives you grief, just drop down to the next lowest speed.



Da Geek Kid

join:2003-10-11
::1
kudos:1
Reviews:
·Callcentric

reason for tftp is that it requires a CPU. Cat switches are ASIC based and cannot support TFTP function in ROMMON. that's why the tftp is on high end 4500s 6500s and all routers...

edit: actually any new device that has the Mgmt port can be used with TFTP feature on the Cat switches as well...



TomS_
Git-r-done
Premium,MVM
join:2002-07-19
London, UK
kudos:5

Then how does IOS run on it? There must be some kind of basic CPU in there.



Da Geek Kid

join:2003-10-11
::1
kudos:1
Reviews:
·Callcentric

1 edit

We are talking about ROMMON here... The ROMMON on the switches are far less powerful than the ROMMON on some routers. The ROMMONs on the routers or Cat4500/Cat6500 which have CPU as well as ASIC can utilize this function. ROMMON is there to allow to load the bin file in the memory so that they system can run.

edit: have you ever turned on a Cisco switch that did not see anything from the Console? That means the ROMMON chip is fried most likely



TomS_
Git-r-done
Premium,MVM
join:2002-07-19
London, UK
kudos:5

Still doesnt make sense.

ROMMON is boot loader software. It has to run on a CPU in order to load IOS and launch it. Just like a PC uses a boot loader to launch your OS, it all runs on the system CPU.

If an "ASIC" is capable of running ROMMON, then it must be capable of running IOS too, and this makes it less ASICy. And if it does that, then its got a general purpose CPU of some kind in there somewhere, either built in to the ASIC kind of like a SoC, or as a separate chip on the board.

As far as larger modular switches go, the processor modules run ROMMON and IOS on its CPU like any other device, but by being modular provide the ability to swap out a module if it fails, and provide redundancy through a second module. Its not so much about providing extra software features.



Da Geek Kid

join:2003-10-11
::1
kudos:1

No. ROMMON itself is a separate chipset which can be replaced. It's actually more like a BIOS than a boot loader...



TomS_
Git-r-done
Premium,MVM
join:2002-07-19
London, UK
kudos:5

ROMMON is software stored in a ROM, just like the BIOS in a PC is software stored in a ROM (though most likely an EEPROM or similar as it can be updated these days.)

That software still has to be executed by something, it cant execute on its own. And yes, most likely held in a replaceable chip.

And the BIOS in a PC is still a boot loader of sorts (I think more correctly a bootstrap), only a very basic low level one. It (among other things like allowing you to edit various settings) finds the boot loader on the preferred boot device and loads it into RAM and tells the processor to start executing that code which locates the OS and starts loading it.

And re your previous edit, if the ROMMON chip is fried of course it wont boot. Just like a PC wont boot if the BIOS ROM is fried. If the processor cant execute the code contained within it, youre not going very far.



Wily_One
Premium
join:2002-11-24
San Jose, CA
Reviews:
·AT&T U-Verse
reply to Da Geek Kid

said by Da Geek Kid:

reason for tftp is that it requires a CPU. Cat switches are ASIC based...

That reasoning doesn't wash. Just because a switch uses an ASIC for some wire-speed functions does not imply it doesn't also have a CPU.



cramer
Premium
join:2007-04-10
Raleigh, NC
kudos:9
reply to Da Geek Kid

The CLI with which you are interacting is running on a CPU. The limitation is one of complexity in reaching an outside port -- i.e. initialization of the Cisco ASIC, or Broadcom SoC.

(As a point of reference, Netgear and HP manage to do it, but I don't know how big their bootroms are.)



Da Geek Kid

join:2003-10-11
::1
kudos:1
Reviews:
·Callcentric
reply to TomS_

said by TomS_:

ROMMON is software stored in a ROM,...

Firmware yes, software no.

I believe what you guys are getting confused is that ROMMON is a binary code that functions very few commands. In order for it to understand an IP it would require access to ports. The ports are not loaded until the IOS gets loaded 1st. ROMMON does not have access to any port and hence you cannot connect to any of the ports 1 -48
On Switches with OOBM ports the ports is defined in the ROMMON which can be accessed.


Da Geek Kid

join:2003-10-11
::1
kudos:1
reply to Wily_One

Image is cute and irrelevant as 3560-X and 3750-X have Mgmt ports which do have tftp capability...



Wily_One
Premium
join:2002-11-24
San Jose, CA

Geek Kid,
Are you saying the 3560 has no CPU?



Da Geek Kid

join:2003-10-11
::1
kudos:1
Reviews:
·Callcentric

Maybe I should explain it a little differently. All devices may have some sort of CPU. What I mean by CPU vs. ASIC. ASIC based devices (i.e. switches) mean that the Chip deals with the port and not the "software".

Perfect example is 4500s and 6500s. During the ROMMON mode you cannot set the TFTP to communicate with your PC on port G3/47... The only ports available are the ones on the Sup Module. It goes the same with any router that the only one available is e0/0. Now as for a switch, since all ports are handled by a separate set of chipsets usually a set of 4 or 8 ports are handled by one chip. These chips are non functional in ROMMON. IOS has to loaded and small firmwares get loaded on them to communicate with the IOS. The only way to push a bin file to flash on a switch without a Mgmt port is thru Console's XModem.



TomS_
Git-r-done
Premium,MVM
join:2002-07-19
London, UK
kudos:5

If only you'd said that about 10 or so posts ago... :P

I think youre the one who is confused, but with your terminology. We tend to go through these back and forths before what you really meant to say comes out.