[U-Boot-Users] ethact, ethprim and NET_MULTI

Wolfgang Denk wd at denx.de
Fri Mar 9 01:18:58 CET 2007

In message <917337.93885.qm at web302.biz.mail.mud.yahoo.com> you wrote:
> > What is the rationale behind this moving active
> > interface at any
> > (quite possibly non intentional) disturbance?
> Well, I can't speak to the author's original
> intentions.  You've probably noticed that the TCP/IP
> capabilities of U-boot are very limited.  A board has
> a single address which is not bound to a specific
> interface.

I'm not  sure  what  you  mean  by  "single  address".  Each  network
interface  has  it's  own  MAC  address,  which  often  is  mapped to
different IP addresses (note that this is not  a  requirement  -  all
interfaces could use the same IP address, too).

> I expect that the most common use for Ethernet
> connectivity is TFTP.  I guess it's assumed that you
> have things cabled properly, and if not, you don't
> care which interface is used to get your image.

The intention is to provide support  for  redundant  network  connec-
tions.  In  a  system with sevral interfaces you will be able to boot
over the network even if one cablke breaks  or  one  TFTP  server  is
down. The chosen timeout is a compromise between ebing long enough to
allow for tempoorary network glitches and being short enough to allow
for a reasonable fast boot in case of network problems on the primary
/ current interface.

Note that the timeout is adjustable.

Best regards,

Wolfgang Denk

DENX Software Engineering GmbH, HRB 165235 Munich, CEO: Wolfgang Denk
Office:  Kirchenstr. 5,       D-82194 Groebenzell,            Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
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