Re: full/half duplex problem

Casper,

I hate to tell you differently but, when I look at the IEEE 802.3-2005;
Part 3; Clauses 34 thru 43. Clauses 36 thru 40, they refer to the
physical layer connections and I thoroughly agree with you that auto
negotiation is required for these interfaces passing thru a PHY. The
Nortel GbESM does enforce this with links that pass thru a PHY (copper
and Fiber)

The IBM Chassis uses the GMII standard to connect across it's back
plane to the Blades. In the Gigabit Media Independent Interface (GMII)
standards defined in clause 35, there is no mention of an auto
negotiation. Based on this IBM originally specified that the interface
should be 1000/Full/Rx & Tx Flow Control fixed. The then at a later
time expanded thier specification to include auto negotiation.

I think that Chris' issue is that the Solaris 10 driver for the
Broadcom 5704 NIC allows turning off auto negotiation and fixing the
speed and duplex at 1000/full and this works until the signal is
removed from the driver. Once the signal is reapplied the device
driver then sets the link at 1000/half. If you go to the Broadcom Web
Site, there is a driver that fixes this but it does not support the
VLAN configuration from the Solaris.

This would appear to me to be a bug in the Solaris device driver.

Bill Nelson


Casper H.S. *** wrote:
cconnell_1@xxxxxxxxx writes:

The nortel gb switch side is fixed full duplex, you cant change it. You
can only change the flow control settings which dont make any
difference anyway. I changed the
adv_autoneg_cap to be on and now when I disable/enable the port it
comes up in full duplex on the solaris blade.

You can't have "fixed full duplex" in Gbit ethernet.

Autonegotiation is *required* for Gbit.

Now, it can be so that the Nortel switch will only autonegotiate
1000 FDX, but if it is configured not to autonegotiate it's not
a Gbit ethernet switch.

Boot solaris blade, link comes up as 1000 full duplex -- OK
Disable/enable a port on the nortel switch - link comes up as 1000 full
duplex -- OK
Both kstat report 2 as link_duplex

BUT

If you reboot the switch module 'after' the blade is up, the link
changes to half duplex mode, and when it comes all the way back up it
stays as half duplex (kstat reports 1)

So after the switch reboots, it goes to half-duplex mode? And what
does the switch think it is set at?

Make sure that you leave auto_neg_cap on but limit the advertised
capabilities to the one you want (full-duplex/1000mbit)

Casper
--
Expressed in this posting are my opinions. They are in no way related
to opinions held by my employer, Sun Microsystems.
Statements on Sun products included here are not gospel and may
be fiction rather than truth.

.

Loading