Red Hat Bugzilla – Bug 121961
Unable to set MTU on Broadcom 5704 1000Base-T NIC (bcm5700 driver)
Last modified: 2007-11-30 17:06:54 EST
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Description of problem:
Hello, I'm having a problem with a pair of Broadcom 5704 1000Base-T
ethernet cards. When I try to set up a fixed value for MTU, to lower
it to 1400 (to workaround a problem related with tunneling ADSL
lines), the network interface stops working (i.e. doesn't send or
The driver version is 'Broadcom Gigabit Ethernet Driver bcm5700 with
Broadcom NIC Extension (NICE) ver. 6.0.2 (02/14/03)' as shown in
I have tried the same with a laptop (with Red Hat Fedora on it) and
it works. May it be a problem with hardware/kernel driver...
Version-Release number of selected component (if applicable):
kernel 2.4.9-e.34smp, module bcm5700 6.0.2 (02/14/03)
Steps to Reproduce:
'ip link set eth0 mtu 1400'
Actual Results: The NIC stops working.
Expected Results: Reduce MTU to 1400 and continue working
The vendor says the 'mtu' parameter on *loadable module* only allows
values from 1500 to 9000 (to enable jumbo frames). But I'm not
touching this... (also tried but didn't happened anything).
this module isn't shipped and thus not supported by us; I recommend
using the tg3 driver instead.