Which of the following fields are included in the OSPF Hello packet? (Multiple choice)

Question

Options

• AOriginating router interface authentication type and authentication information
• BArea ID of the originating router interface
• CHello interval of the originating router interface
• DRouter ID of the originating router
• EThe MAC address of the originating router interface
• FMasks for DR and BDR

• A
  81% (13)
• F
  19% (3)

Explanation

Note: The provided answer key appears to contain an error - E should NOT be correct. MAC addresses are Layer 2 constructs; OSPF operates at Layer 3 and never includes MAC addresses in Hello packets. The correct answers are A, B, C, D.

OSPF Hello packets carry the Router ID (D) to identify the sender, the Area ID (B) to ensure neighbors belong to the same area, the Hello interval (C) so neighbors can verify timers match before forming adjacency, and authentication type/data (A) to validate peer identity and security. Option E is wrong because OSPF is a Layer 3 protocol - MAC addresses live at Layer 2 and are handled by Ethernet frames wrapping the OSPF packet, not inside it. Option F is wrong because the Hello packet includes the IP addresses of the DR and BDR (not masks), and the interface's subnet mask is a separate field used to verify common network membership.

Memory tip: Think of Hello packets as a "business card exchange" - routers share who they are (Router ID), where they live (Area ID), how often they'll call (Hello interval), and a password (authentication). Layer 2 details like MAC addresses never appear on a business card because they're envelope-level, not content-level.

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