Administrator Guide

Over 127B packets: 0 0 pps 0
Over 255B packets: 0 0 pps 0
Over 511B packets: 0 0 pps 0
Over 1023B packets: 0 0 pps 0
Error statistics:
Input underruns: 0 0 pps 0
Input giants: 0 0 pps 0
Input throttles: 0 0 pps 0
Input CRC: 0 0 pps 0
Input IP checksum: 0 0 pps 0
Input overrun: 0 0 pps 0
Output underruns: 0 0 pps 0
Output throttles: 0 0 pps 0
m - Change mode c - Clear screen
l - Page up a - Page down
T - Increase refresh interval t - Decrease refresh interval
q - Quit
Maintenance Using TDR
The time domain reectometer (TDR) is supported on all Dell Networking switch/routers. TDR is an assistance tool to resolve link
issues that helps detect obvious open or short conditions within any of the four copper pairs. TDR sends a signal onto the physical
cable and examines the reection of the signal that returns. By examining the reection, TDR is able to indicate whether there is a
cable fault (when the cable is broken, becomes unterminated, or if a transceiver is unplugged).
TDR is useful for troubleshooting an interface that is not establishing a link, that is, when the link is apping or not coming up. Do not
use TDR on an interface that is passing trac. When a TDR test is run on a physical cable, it is important to shut down the port on
the far end of the cable. Otherwise, it may lead to incorrect test results.
NOTE: TDR is an intrusive test. Do not run TDR on a link that is up and passing trac.
To test the condition of cables on 100/1000/10000 BASE-T modules, follow the below steps using the tdr-cable-test
command.
Step
Command Syntax Command Mode Usage
1.
tdr-cable-test tengigabitethernet <slot>/
<port>
EXEC Privilege To test for cable faults on the TenGigabitEthernet
cable.
• Between two ports, you must not start the
test on both ends of the cable.
• Enable the interface before starting the test.
• The port must be enabled to run the test or
the test prints an error message.
2.
show tdr tengigabitethernet <slot>/<port> EXEC Privilege Displays TDR test results.
Flow Control Using Ethernet Pause Frames
An Aggregator auto-congures to operate in auto-DCB-enable mode (Refer to Data Center Bridging: Auto-DCB-Enable Mode). In
this mode, Aggregator ports detect whether peer devices support converged enhanced Ethernet (CEE) or not, and enable DCBX
and PFC or link-level ow control accordingly:
• Interfaces come up with DCB disabled and link-level ow control enabled to control data transmission between the Aggregator
and other network devices.
• When DCB is disabled on an interface, PFC, ETS, and DCBX are also disabled.
• When DCBX protocol packets are received, interfaces automatically enable DCB and disable link level ow control.
• DCB is required for PFC, ETS, DCBX, and FCoE initialization protocol (FIP) snooping to operate.
Link-level ow control uses Ethernet pause frames to signal the other end of the connection to pause data transmission for a certain
amount of time as specied in the frame. Ethernet pause frames allow for a temporary stop in data transmission. A situation may
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Interfaces