Networking Concepts and Technology: A Designer's Resource

Packet Switch Internals

The terms router and switch are often confusing because of the marketing adaptations from vendor to vendor. Original routers performed Layer 3 packet forwarding decisions on general-purpose computing devices with multiple network interface cards. The bulk of the packet processing was performed in software. The inherent design of Ethernet has limited scalability. As the number of nodes increased on an Ethernet segment belonging to one collision domain, the latency increased exponentially, hence bridges were introduced. Bridges segregated Ethernet segments by only allowing broadcasts to certain segments and learning MAC addresses. This allowed the number of nodes to increase.

The next advance in network switches was introduced ...