jumbo packets on em card.
Jeremy Chadwick
koitsu at freebsd.org
Tue Apr 29 12:02:10 UTC 2008
On Tue, Apr 29, 2008 at 04:13:13PM +0530, Sharad Chandra wrote:
> I am getting a problem in setting em card to 1000baseTX. It shows "active
> status" with 100baseTX but as soon as i run "ifconfig em1 media 1000baseTX
> mediaopt full-duplex", it says *no carrier*. how can i set it to 1000base?
The PHYs support auto-negotiation of speed and duplex, as per the 802.3
standard.
Do you have a gigabit switch? If so, does auto-negotiation (e.g. no
"mediaopt" or "media" settings) work? If not, is the switch a managed
switch? If so, try explicitly setting the port on the switch to
1000mbit, full duplex. If not, then consider buying another switch.
Many consumer/residential switches do not do auto-negotiation properly,
resulting in "no carrier" or worse (bad throughput).
> And is it possible any how to send *jumbo packets* on this card or on bge card
> (bge card is working with 1000base)? I tried nemesis tool, but i don't think
> it can send bigger packets. BPF also seems to have limitaion upto 2K.
man 4 em
man 4 bge
Keep in mind that if you use jumbo frames, your **entire network** needs
to use jumbo frames. You cannot mix-and-match frame sizes. Chances are
your ISPs or your co-lo provider doesn't support jumbo.
--
| Jeremy Chadwick jdc at parodius.com |
| Parodius Networking http://www.parodius.com/ |
| UNIX Systems Administrator Mountain View, CA, USA |
| Making life hard for others since 1977. PGP: 4BD6C0CB |
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