OSPF performs a lookup in its FIB table for a packet. If the tunnel ID in the matching entry is 0, the packet needs to be forwarded through a tunnel, such as an MPLS tunnel.

Question

Options

• ATRUE
• BFALSE
• C
• D

• A
  8% (3)
• B
  72% (26)
• C
  3% (1)
• D
  17% (6)

Explanation

Option B (FALSE) is correct because a tunnel ID of 0 in an OSPF FIB entry means the packet should be forwarded natively (no tunnel), not through a tunnel like MPLS. A non-zero tunnel ID is what indicates the packet must traverse a tunnel - 0 is essentially the "no tunnel" sentinel value.

Why A is wrong: The statement inverts the logic. Tunnel ID = 0 signals a normal, untunneled forwarding path. Requiring a tunnel would be indicated by a positive (non-zero) tunnel ID in the FIB entry.

Memory tip: Think of 0 as "zero tunnels" - the packet goes straight through without any encapsulation. Any number above 0 means "tunnel this packet." The question tries to trick you by associating 0 with a special action (tunneling), when in fact 0 means the absence of that action.

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