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RFC 826 / PROTOCOL MECHANISMS

Resolve the next hop on a link

01

Routing first selects a local next hop; ARP then looks up that address on the selected link.

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RFC 826 · Packet GenerationEXAMPLE
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Resolve the next hop on a linkRouting first selects a local next hop; ARP then looks up that address on the selected link.hostgatewayremote IPlocal linkARP cache: gateway IP → ?gateway IP → MACframe to gatewayThe remote IP is not the local ARP target
03
Resolve the gateway and send the IP packet in a frame to it.

Resolve the gateway and send the IP packet in a frame to it.

Protocol participantThreat or exceptionProtocol controlSimplified drawings · precise section references
KEY POINT

ARP resolves a local link-layer address, not an entire routed path.

  • ARP resolves a local link-layer address, not an entire routed path.
  • For a remote IP destination, resolve the gateway’s local address rather than the remote host’s MAC address.
DETAILS

The drawing is a simplified worked example. Follow the linked RFC and its updates for implementation requirements.

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Privacy
All chapters in this RFC
  1. Resolve the next hop on a link
  2. Broadcast a question and receive a reply
  3. Read the variable-address packet
  4. Learn from the sender mapping
  5. Probe before claiming an IPv4 address
RFC 9700 / CHAPTERS

Chapters

For full details, tables, algorithms, and exceptions, read the original RFC.

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