CANOGA PERKINS 9145E Network Interface Device - Manual (Page 47)

Troubleshooting 9145E Ethernet Network Interface Device User’s Manual
Loopback Diagnostics
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5.4 Loopback Diagnostics
Use Loopbacks to diagnose a fault on the optical link. The 9145E supports two loopback modes
that you can set at the local site for both the local and remote 9145Es. These modes loop the
data through either the physical layer on the User side or the Network side.
When performing loopback diagnostics, the 9145E uses a unique MAC address, designated as
the Loop Test MAC Address, which is displayed on the Loopback Setup Screen (reference
6913303, 9145E NID Software Version 1.0 Users Manual). When in loopback mode, the 9145E
filters and discards all service frames.
The 9145E is configurable to swap the origination and destination MAC Addresses and to recal-
culate the looped frame's CRC. Test packets are returned to the source according to the selected
options. To display current loopback status, initiate loopbacks, configure address swapping and
CRC recalculation options, and to run a loopback test, reference 6913303, 9145E NID Software
Version 1.0 Users Manual.
5.4.1 User Mode
User Mode loops data received on the local User Port Rx through the FPGA to the User Port Tx.
Data is not sent out the Network Port Tx and incoming data on the Network Port Rx is ignored
(see Figure 5-3). To set this mode, set the Loopback State for the Local Module to Local (refer-
ence 6913303, 9145E NID Software Version 1.0 Users Manual).
Figure 5-3. User Mode
Tx
Rx
Rx
Tx
USER
PORT NETWORK
PORT
LOCAL DEVICE
Tx
Rx
Rx
Tx
USER
PORT NETWORK
PORT
REMOTE DEVICE
NO DATA TRANSMISSION
DATA IGNORED