Tap partners, and Port 3 and Port 4 are Tap partners. A frame received on one Tap partner is
transmitted out of the other Tap partner, which mimics the behavior of an Ethernet cable.
Note
For more information about Tap latency, refer to the
PXIe-8521
Specifications
.
When an input session is created using an XNET interface for either Tap partner, and the "/
monitor" suffix is used with the XNET interface, the session reads frames going through the
Tap partners. Output sessions are not supported in Tap mode.
Note
You only need to select the monitor of one port in the Tap pairing. If both
monitors are selected, you will receive the same data twice.
Setting one port to Tap mode will automatically set the port's Tap partner to Tap mode. The
PXIe-8521 supports two Taps (Ports 1/2 and Ports 3/4) using this mode. All four ports can also
be used simultaneously while one pair is in Tap mode and the other ports are in Direct mode.
The following diagram describes one Tap pair on the PXIe-8521.
Figure 6. Tap Mode
PHY
XNET
Monitor
PHY
PXIe-8521
DUT1
DUT2
User Application
XNET
XNET
PXIe Controller
PHY State
The PXIe-8521 PHY's master/slave state can be configured for communication with its peer
PHY. In traditional Ethernet networks, this master/slave state is negotiated automatically at the
PHY level. However, in Automotive Ethernet networks such as IEEE 100BASE-T1, the
master/slave state is commonly configured statically and is typically determined by the PHY
state setting of the connected DUT. Configure the PHY state of the PXIe-8521's port to the
opposite of the connected DUT's PHY state.
8
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PXIe-8521 User Manual
