Network Infrastructure Devices - What are Bridges and Switchs?
A bridge is a network device that operates at the Data Link layer (Layer 2) of OSI model. There are many different types of bridges and include Transparent bridges, Encapsulation bridges, Source-route bridges. Source-route bridges are for Token Ring network. Bridges allow segmenting a Local Network into multiple segments, thus reducing the network traffic. A bridge performs the segmenting function by examining the Data Link Layer (Layer 2) data packet (Ethernet Frame) and forwarding the packet to other physical segments only if necessary. Both swiches and bridges function using Data Link Layer (Layer 2) addressing system, also known as MAC addresses.
Bridge can connect only a few Networks, LANs or Hosts. A Bridge has comparatively less ports than a Switch. A Switch has usually 24 ports or 48 ports. Brides and Switches are considered to operate at Data Link Layer (Layer 2) of OSI model.
The following picture shows a 24 port, 10/100, Cisco 2950 Catalist Switch.
