Switching

Q: How deeply does Acing the CCNA Exam: Volume 1 Fundamentals and Protocols cover switching?

Defines Layer 2 forwarding, MAC learning, flooding, and routing contrast, but does not descend into switch implementation internals.

As explained in Acing the CCNA Exam: Volume 1 Fundamentals and Protocols

A forwarding decision is a router's selection of the next forwarding action for a packet based on its destination and routing information.

Switching is the Layer 2 process switches use to forward Ethernet frames to their proper destinations within a LAN. A switch examines the Ethernet header, learns device MAC addresses, and uses its MAC address table to choose where a frame should go. This differs from routing: routers use Layer 3 IP-header information to forward packets between networks. section 6.0 section 9.0

Follow the forwarding process across a network:

Use ARP when a host needs the MAC address associated with a local destination or its default gateway. section 6.0
Let switches learn connected MAC addresses and forward or flood frames as appropriate. section 6.0
Let routers select the best route between networks, then encapsulate the packet in a new frame for the next hop. section 10.0

PC1 sends a packet to PC3

PC1 prepares a packet addressed to PC3 and uses ARP to learn R1's default-gateway MAC address. It sends the packet in a frame to that MAC address. The switches forward or flood the frame according to their learned MAC information. At each routed hop, the IP packet remains addressed to PC3 while the Layer 2 frame is replaced and addressed to the next hop. section 10.0

How Acing the CCNA Exam: Volume 1 Fundamentals and Protocols covers it

Cover of Acing the CCNA Exam: Volume 1 Fundamentals and Protocols

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Related concepts

most specific matching routeuses · The most specific matching route is the route whose network prefix has the greatest number of bits matching a packet's destination IP address.
mac address tableuses · A MAC address table is a switch data structure that maps learned MAC addresses to the interfaces through which their devices are reachable.
routingequivalent to · Routing is the selection of a path, destination, or processing component to direct an item, request, or flow toward an intended endpoint.
network address translationused by · Network address translation is a networking technique that rewrites IP addresses and often transport-layer ports as traffic crosses a gateway or network boundary.
connected routeproduced by · A connected route is a route to a network directly attached to an interface with an IP address that is operationally up.
routing tableproduced by · A routing table is a data structure containing rules that map destinations, conditions, or peers to paths, next hops, services, or other forwarding targets.

This explainer was generated by Manning's knowledge graph from the text of Acing the CCNA Exam: Volume 1 Fundamentals and Protocols. The section links point to the parts of the book it draws on.