Ethernet Network Devices

Repeater:
A repeater receives a digital signal and reamplifies or regenerates that signal and then forwards the digital signal out to all active ports without looking at any data. Layer 2 Device.


Hub:

• Multiple-port repeater.
• Layer 2 Device, does not break up Collision Domain.
• Devices share the same bandwidth.
• All devices in the same Collision domain and in the same Broadcast domain.
• Hubs allow only one device to communicate at a time.

Bridge:

• Layer 2 Device, Breaks up Collision Domain.
• Each port is its own Collision Domain
• Does not break up Broadcast domains.

Switch:

• Multiport-Bridge, Layer 2 Device.
• Hardware-based bridging – application-specific integrated circuit (ASIC).
• Build filter table.
• Each port is its own Collision Domain
• Does not break up Broadcast domains.
• Each connected device plugged into a switch can transmit simultaneously.

Router:

• Layer 3 (Network Layer) devices provide connection between virtual LANs (VLANs).
• Routers, by default, will not forward any broadcast or multicast packets.
• Routers use the logical address in a Network layer header to determine the next hop router to forrward the packet to.
• Routers can use access lists, created by an administrator, to control security on the types of packets that are allowed to enter or exit an interface.
• Routers can provide layer 2 bridging functions if needed and can simultaneously route through the same interface.
• Routers can provide quality of service (QoS) for specific types of network traffic.