2621 router ios upgrade using tftp

Can someone please explain to me why when doing an ios upgrade on a 2621 10/100mb ethernet I have to use a 10mb connection to complete the tftp download?  I was doing the tftp over a 100mb switch and got an error about an arp failure code 1.  When I changed the switch to 10mb everything worked okay.

Please explain in some detail if possible.

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lrmooreConnect With a Mentor Commented:
I've never had a problem with that if the switchport is set to auto...As I said, if the switchport is set to 100/full then it probably won't negotiate speed/duplex and will fall back to a default 10mb half duplex..
Using rommon>tftpdownload ?
If yes, then if the switchport was in autosense mode, you should not have any problem.
If you have the switchport set to 100M/Full, the router is in a default state with autonegotiation enabled.
Anytime you have auto on one end and hard-set on the other, you have problems.
benje02Author Commented:
So the router will download at 100mb if the router and switch were both set at 100mb?
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If the router is up and running, with the FastEthernet port set to 100/full-duplex and the switchport is also set to 100/full-duplex, and you use copy tftp command, then yes, it will work just fine:
 router#copy tftp flash:
benje02Author Commented:
I had to use the tftpdownload command from the rommon mode to load the ios because I was upgrading the memory and rom.  When the router boots into rommon mode are the ethernet ports set to autosense and will work at 10mb or 100mb?  I thought the problem might be that in rommon they only worked at 10mb.

benje02Author Commented:
Okay, thanks for the help.
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