Pure(Unslotted )ALOHA o Unslotted Aloha: simpler, no synchronization o When frame first arrives o Transmitimmediately o Collision probabilityincreases o Frame sent at to collides with other frames sentin [to-1, to+1] will overlap will overlap with start of i with end of - i's frame→← is frame一 node i frame 0 t+1 5: DatPure (Unslotted) ALOHA  Unslotted Aloha: simpler, no synchronization  When frame first arrives  Transmit immediately  Collision probability increases:  Frame sent at t0 collides with other frames sent in [t0 -1,t0+1] 5: DataLink Layer 5-18