Spirent SmartBits System, Reference Manual

Page: 211 / 278

Appendix B: Auto Negotiation
10/100/1000Mbps Copper Ethernet Auto Negotiation
SmartBits System Reference 203
process cannot determine the duplex setting at the DUT. Only the Force AN option permits
this verification to take place.
Force Auto Negotiation Option
In applications such as SmartApplications, AST II, SmartFlow, and SmartMulticastIP, the
Force AN option sets the appropriate registers to the user-selected flow control, speed, and
duplex settings. It sets Register 0 to enable auto negotiation on this port, and it sets the
appropriate bit to signal a restart of the auto negotiation process.
Registers Untouched Option
In applications such as SmartApplications, AST II, SmartFlow, and SmartMulticastIP, the
Registers Untouched auto-negotiation option has been developed for advanced, custom
test requirements. With this option, the software writes no values to the MII registers for
speed and duplex setting. The user must configure these settings before running the test.
(The application also does not alter the flow-control advertisement.)
This option is not recommended for normal test situations and should be used with care.
Although the application will make a “best attempt” to ensure that the link is up for both
interfaces, it is not possible to verify the link in every case, because there is no adequate
MII read-back capability for duplex mode.
Note: Do not select Registers Untouched unless you are certain that ports on the DUT are
configured correctly and match the values in the SmartCard setup parameters.
Operation After the Auto Negotiation Protocol Completes
After the flow-control, speed, and duplex settings have been set (and/or negotiated), but
before the test is started, SmartBits verifies that a communication link has been
established. Once this is done, the application begins the selected test.