A Bridge/Switch is a network device that typically operates at the Data Link layer (Layer 2) of the OSI model. A bridge or switch performs the its job by examining the Data Link Layer (Layer 2) data packet (Ethernet Frame) and forwarding the packet to other devices based on Layer 2 addresses (MAC Addresses). Both switches and bridges function using Data Link Layer (Layer 2) addressing system, also known as MAC addresses.
Each port of a network switch is in a separate collision domain and therefore Switches are used to divide a big collision domain into multiple smaller collision domains.
Bridge has only few ports and connect only a few collision domains, 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 the Data Link Layer (Layer 2) of the OSI model. Click the following link to learn the exact differences between Bridges and Switches.
Following picture shows a 24 port, 10/100, Cisco 2950 Catalist Switch.
Following image shows a 24 port, 10/100, Cisco 2960 Switch.