Solaris

A major problem is that many people are also hard setting Gigabit Ethernet , and this is causing major problems. Gigabit Ethernet must have auto-negotation ENABLED to allow negotiation of master / slave PHY relationshitwhp for clocking at the physical layer. Without negotiation the line clock will not establish correctly and physical layers problems can result.

From Sun's Best Practices on Ethernet Auto-negotiation (2):

Disabling autonegotiation can result in physical links issues going undetected. The Fast Link Pule process does some testing for the physical link properties as well as negotiation on several Ethernet properties.
From the IEEE standard:

All 1000BASE-T PHYs shall provide support for Auto-Negotiation
(Clause 28) and shall be capable of operating as MASTER or SLAVE.
Auto-Negotiation is performed as part of the initial set-up of the link, and
allows the PHYs at each end to advertise their capabilities (speed, PHY
type, half or full duplex) and to automatically select the operating mode
for communication on the link. Auto-negotiation signaling is used for the
following two primary purposes for 1000BASE-T:
a) To negotiate that the PHY is capable of supporting 1000BASE-T half
duplex or full duplex transmission.
b) To determine the MASTER-SLAVE relationship between the PHYs at
each end of the link. 1000BASE-T MASTER PHY is clocked from a local source.
The SLAVE PHY es loop timing where the clock is recovered from the received data streamus.

Originally Posted by junior-helper

Hello gsrungav,
this is my humble approach (assuming you are allowed to shortly interrupt the g1 link): why don't you systematically troubleshoot that issue?

I'd do/check the following:

1. Is auto-negotiation active on g1? If yes, turn it on on g0 too.

2. What happens if you switch the network cables (from g1 to g0 and from g0 to g1).
Does g0 become 1000 Mbps? Does g1 become 100 Mbps only?
If both assumptions are true, then plug both cables back as it was before.
Now you can exclude the problem on the server side!

Start troubleshooting on the switch side, e.g. compare the configuration of the switch ports, where the g0 and g1 network cables are plugged in. It's possible, that the switch port, where the cable from g0 is plugged in, is configured for 100 Mbps only.

Hope this helps.