[SYMBOL] [A] [B] [C] [D] [E] [F] [G] [H] [I] [J] [K] [L] [M] [N] [O] [P] [Q] [R] [S] [T] [U] [V] [W] [X] [Z] half-duplex half-duplex communications hardware cables 2nd Ethernet 2nd LEDs 2nd 3rd POST 2nd power failures 2nd troubleshooting headers ISL hierarchies models Access layer Core layer 2nd Distribution layer High Level Interface (HILI) high-latency devices HILI (High Level Interface) hold-down timers 2nd hop counts RIP 2nd 3rd 4th host-to-host connectivity ping command 2nd 3rd 4th 5th 6th hosts OSI 2nd Application layer Data Link layer 2nd Network layer 2nd Physical layer Presentation layer Session layer Transport layer subnets determining 2nd tracert command 2nd 3rd 4th hubs star topology 2nd |