Bridges, Switches and Routers will all separate collision domains.
A Router
Hubs are not collision domains but a networking device. Hubs have single collision domain that makes them very undesirable for modern networks.
switches
Network+ Guide to Networks answer: Bridge, Switch, Router
For any amount of clients connected to a hub you will get a total of 1 collision domain. A hub is a device that simply repeats all of the signals from the ports and does not separate clients into separate collision domains.
Hubs do not reduce collision domains. All devices connected to the hub are in a single collision domain, where as on a switch, each port is its own collision domain.
To determine the number of collision and broadcast domains in a network topology, one must analyze the devices involved. Each switch creates separate collision domains for each connected device, while a router or Layer 3 switch creates separate broadcast domains. Without a specific topology diagram or description, it's impossible to provide an exact count; however, generally, each switch adds collision domains, and each VLAN or router adds a broadcast domain.
No
in my opinion there is no any collision domain in the router......but switch has collision domains for each interfaces & hub has one collision domain
On shared-media networks (i.e. hubs or pure ethernets), routers break up broadcast domains and bridges break up collision domains. Routers also break up collision domains. On switched networks, routers break up broadcast domains, and every switch port is its own separate collision domain.
SwitchDescription: Network Switch a device that seperates the Broadcast domain of a LAN segment from other segments.
router