jumbo packets on em card.

[Jeremy Chadwick]

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 |