Sun Microsystems Gigabit Ethernet MMF/UTP Adapter - Manual (Page 72)

38 Sun PCI-Express Dual Gigabit Ethernet MMF/UTP Adapter Installation and User’s Guide • June 2006
data can be communicated. Two physical layer parameters control whether your
side is the master or the slave, or whether mastership is negotiated with the link
partner.
Caution – Do not adjust the link clock mastership parameters unless you clearly
understand the settings of the link partner. Incorrect link clock mastership
configuration results in link-up failure.
Interpacket Gap Parameters
The ipge device supports a programmable mode called enable_ipg0.
When an instance receives a packet with enable_ipg0 set (the default), The
instance adds an additional time delay before transmitting the packet. This delay, set
by the ipg0 parameter, is in addition to the delay set by the ipg1 and ipg2
parameters. The additional ipg0 delay helps reduce collisions.
If enable_ipg0 is disabled, the value of ipg0 is ignored and no additional delay is
set. Only the delays set by ipg1 and ipg2 will be used. Disable enable_ipg0 if
other systems keep sending a large number of back-to-back packets. Systems that
have enable_ipg0 set might not have enough time on the network.
TABLE 3-7 Forced Mode Parameters
Parameter Description
master-cfg-enable Determines whether or not during the autonegotiation process
the link clock mastership is setup automatically.
master-cfg-value • If the master-cfg-enable parameter is set, then the
mastership is not set up automatically but depends on the
value of master-cfg-value.
• If the master-cfg-value is set, then the physical layer
expects the local device to be the link master.
• If the master-cfg-value is not set, then the parameter
expects the link partner to be the master.
• If autonegotiation is not enabled, then the value of master-
cfg-enable is ignored and the value of master-cfg-value
is key to the link clock mastership.
• If the master-cfg-value is set, then the physical layer
expects the local device to be the link master.
• If the master-cfg-value is not set, then the parameter
expects the link partner to the master.