Question

Difficulty: EasyPhysical Interface and Cabling Types

A network technician is connecting legacy network devices in a lab environment where Auto-MDIX is explicitly disabled on all switch interfaces. Which two statements correctly describe the cable pinout requirements and cabling types for these connections? (Choose two.)

  1. Connecting two network switches directly via FastEthernet interfaces requires a crossover cable when Auto-MDIX is disabled.Answer
  2. An Ethernet crossover cable connects transmit pins 1 and 2 on one RJ-45 connector to receive pins 3 and 6 on the opposite connector.Answer
  3. C
    Connecting a switch port directly to a router Ethernet interface requires a crossover cable when Auto-MDIX is disabled.
  4. D
    A standard straight-through Ethernet cable maps pins 1 and 2 on one end to pins 3 and 6 on the opposite end.
  5. E
    A rollover cable must be used to connect two Ethernet switches together for standard data transmission.

Answer

Connecting two network switches directly via FastEthernet interfaces requires a crossover cable when Auto-MDIX is disabled, and an Ethernet crossover cable connects transmit pins 1 and 2 on one RJ-45 connector to receive pins 3 and 6 on the opposite connector.
When connecting identical network device types (such as switch-to-switch or router-to-router) without Auto-MDIX feature active, a crossover cable must be used so that the transmit pins (1 and 2) on one end link to the receive pins (3 and 6) on the opposite end.

Step-by-Step Solution

1
Identify the device types being connected
Connecting a switch to a switch involves two like devices (MDI-X to MDI-X).
Like devices transmit and receive on identical pin pairs.
2
Determine the required cable type without Auto-MDIX
A crossover cable is required for switch-to-switch connections.
Without Auto-MDIX to automatically swap transmit and receive signals, the physical cable must perform the crossover function.
3
Verify the pinout wiring for FastEthernet crossover cables
Pins 1 and 2 on one connector connect to pins 3 and 6 on the opposite connector.
FastEthernet (100BASE-TX) uses pairs 1/2 and 3/6 for transmit (Tx) and receive (Rx).

Key Concept

Ethernet Cable Pinouts and MDI/MDI-X Device Interfaces
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