Troubleshooting and Diagnostics Guide

Fabric OS Troubleshooting and Diagnostics Guide 91
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Diagnostic Port (D_Port)
10
Understanding D_Port
The D_Port does not carry any user traffic, and is designed to run only specific diagnostics tests on
it for identifying link-level faults or failures. Basically, in order to bring up a port in D_Port mode, you
must configure both ends of the link between a given pair of switches (or switches configured as
Access Gateways), and you must disable the existing port before you can configure it as a D_Port.
Figure 3 illustrates an example D_Port connection between a pair of switches through SFPs (port
assignments will vary). (For all topologies supported, see “Supported topologies” on page 93.)
FIGURE 3 Example of a basic D_Port connection between switches
Once the ports are configured as D_Ports, the following basic test suite is executed in the following
order, depending on the SFPs installed:
1. Electrical loopback (with 16G SFP+ only)
2. Optical loopback (with 16G SFP+ only)
3. Link traffic (with 10G SFPs and 16G SFP+)
4. Link latency and distance measurement (with 10G SFPs and 16G SFP+)
NOTE
Electrical and optical loopback tests are not supported for ICLs.
The fundamentals of D_Port testing are as follows:
1. The user configures the desired ports on both ends of the connection.
2. Once both sides are configured, a basic test suite is initiated automatically when the link
comes online, conducting diagnostic tests in the following order: (1) electrical loopback, (2)
optical loopback, and (3) link traffic.
3. After the automatic test is complete, the user can view results (through CLI or GUI) and rectify
issues (if any) that are reported.
4. The user can also start (and restart) the test manually to verify the link.
Advantages of D_Port
Use the D_Port tests for the following situations:
• Testing a new link before adding it to the fabric
• Testing a trunk member before joining it with the trunk
• Testing long-distance cables and SFPs
Tests can be run with the following options:
• Number of test frames to transmit