Loopback Tests - Lucent Technologies Cajun Switch P220 Release Note

Loopback Tests

Loopback tests on ports may fail when there is traffic present on the link at start-up.
M5520-TX Loopback Tests During Cold Start
Occasionally M5520-TX (P/N M5520-100TX) boards with a Quality Phy will fail loopback tests
when the board initially is started. The problem corrects itself as the board warms up.
M5520-TX Auto-negotiation with Xircom Adapter Cards
M5520-TX (P/N M5520-100TX) boards manufactured with a Quality Phy do not autonegotiate
with Xircom brand adapter cards. If you are having this problem, disable auto-negotiation on
the affected ports, and set the port speed and duplex state manually.
Oversized Packets
Oversized packets are not counted in itemized statistics if the packet size is between 1519 and
1548 bytes.
Short Cables May Cause Auto-negotiation Problems
You may experience difficulties with auto-negotiation between some releases of the 10/
100Base-TX Module (M5510-100FX, M5520-100TX, M5510R-100FX, M5512R-100TX) and
adapter cards using physical interfaces manufactured by National Semiconductor. The symptom
is loss of connectivity. You can address this problem by either disabling auto-negotiation, or
using a patch cable longer that 5 meters. Use the following Enhanced Command Line Interface
command in legacy mode to correct the situation:
Cajun> port set NationalPhyMode <slot>.<port> enable
NOTE: To enter legacy mode, type legacy-cli at the command prompt. To return to
the Enhanced CLI from legacy mode, type exit at the command prompt.
NOTE: The factory default for ports now sets the National Phy mode to enabled.
Cajun P220, P550, P550R Switch Release Notes, Release 4.0.1 15