Which device does NOT propagate collisions in a network?

Bridges do not propagate collisions in a network because they operate at the data link layer and use MAC addresses to forward traffic selectively. When a bridge receives a data frame, it analyzes the destination MAC address and determines if the frame should be forwarded to another segment or if it is meant for devices on the same segment. This selective forwarding minimizes the chances of collisions by isolating collision domains, unlike hubs and repeaters, which broadcast data to all connected devices, increasing the likelihood of collisions.

Switches operate similarly to bridges but are generally more efficient, as they can provide dedicated bandwidth to each port, further mitigating collision occurrences. Thus, bridges and switches help create separate collision domains, allowing for more efficient network communication without the propagation of collisions.