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-clithe Enhanced CLI from legacy mode, type exit

at the command prompt. To return to 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

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Lucent Technologies P550R, P220 manual M5520-TX Loopback Tests During Cold Start, Oversized Packets