Network hop

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

A hop is one journey of a message from one network node to the next node along its path to a destination.

A network hop is one journey of a message from one network node to the next node along its path to a destination. Layer 2 provides hop-to-hop delivery, while Layer 3 provides end-to-end delivery. section 4.3.1 section 4.4

Three-hop journey

When PC1 sends a message to SRV1, the message makes three hops: PC1 to R1, R1 to R2, and R2 to SRV1. A switch may forward the message, but traveling through a switch does not count as a hop. section 4.3.1

At each hop:

• Layer 2 addresses the message to the next node using that node’s MAC address. section 4.3.1
• The destination MAC address changes for each hop, while the destination IP address remains the same from source host to destination host. section 4.4
• Layer 3 selects the destination host, and Layer 2 forwards the message to the next node in the path. section 4.3.1 section 4.4

Figure 4.2 TCP/IP Layer 2. A message sent from PC1 to SRV1 takes three hops through the network: from PC1 to R1, from R1 to R2, and from R2 to SRV1. At each hop, the message is addressed to the next hop’s MAC address. A message traveling through a switch does not count as a hop.

Trace the three-hop PC1-to-SRV1 path and see how each next hop is addressed. section 4.3.1

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

How deep it goes

Defines a hop, traces three forwarding steps, and distinguishes changing MAC addresses from persistent IP addressing.

Examples

Uses a PC1-to-SRV1 route through R1 and R2, emphasizing that switch forwarding does not add a hop.

What it assumes

Assumes basic network nodes and addresses, while defining hops, MAC addresses, and the Layer 2 and Layer 3 delivery distinction.

What you can do after

Evaluate a network path by counting node-to-node journeys and identifying the MAC address used at each hop.

How it connects

Connects hops with the Data Link Layer, MAC addresses, routers, switches, IP addresses, and end-to-end delivery.

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Also explained in

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  Graph Neural Networks in ActionA graph hop is one traversal from a node to an adjacent node along an edge.

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Related concepts

• data link layerproduced by · The data link layer is the network-model layer that provides frame delivery and link addressing between nodes connected by the same physical or logical link.
• direct model embeddingaddressed by · A model-serving design in which model execution code is integrated with application logic and runs in the same process.
• neural network layerequivalent to · A neural network layer is a computational stage or component that transforms input representations into outputs within a neural network.
• message passingconfigured by · A technique in which computational entities exchange messages to communicate or propagate information, often coordinating work or updating state.

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.