[CentOS] how to enable Flow Control on CentOS?

[Lamar Owen]

On Friday, July 08, 2011 07:06:06 PM Les Mikesell wrote:
>And the 
> gigabit spec requires auto-negotiation.

According to clause 37.1.4.4 "User Configuration with Auto-Negotiation" of IEEE 802.3-2008, auto-negotiation with 1000Base-X is optional, but encouraged.

In contrast, for 1000Base-T, we find the following information in clause 40.5.1:
"40.5.1 Support for Auto-Negotiation
All 1000BASE-T PHYs shall provide support for Auto-Negotiation (Clause 28) and shall be capable of operating as MASTER or SLAVE."

'Shall' being legal language for 'absolutely without a doubt must' in this case.  Overwise the PHY wouldn't be able to determine which PHY is the clock MASTER.