What are two valid modes that Cisco Express Forwarding can operate in? (Choose two.)

The correct answer is A. Central CEF mode D. Distributed CEF mode. Cisco Express Forwarding (CEF) Operating Modes Cisco Express Forwarding operates in two valid modes: Central CEF (cCEF), where the Route Processor (RP) handles all forwarding decisions for the entire router, and Distributed CEF (dCEF), where line cards maintain their own copies o

Submitted by haruto_sh· Mar 6, 2026Infrastructure

Question

What are two valid modes that Cisco Express Forwarding can operate in? (Choose two.)

Options

ACentral CEF mode
BDense CEF mode
CSparse CEF mode
DDistributed CEF mode
ERouted CEF mode

How the community answered

(40 responses)

A
93% (37)
C
5% (2)
E
3% (1)

Explanation

Cisco Express Forwarding (CEF) Operating Modes

Cisco Express Forwarding operates in two valid modes: Central CEF (cCEF), where the Route Processor (RP) handles all forwarding decisions for the entire router, and Distributed CEF (dCEF), where line cards maintain their own copies of the Forwarding Information Base (FIB) and adjacency tables, allowing each card to forward packets independently - improving scalability on high-end platforms like the Cisco 12000 series.

Why the distractors are wrong: Options B (Dense) and C (Sparse) are forwarding modes associated with PIM multicast routing (Protocol Independent Multicast), not CEF - making them common traps for test-takers. Option E (Routed CEF) is simply a fabricated term with no basis in Cisco networking.

Memory Tip: Think "C and D for CEF" - Central and Distributed are the only two real CEF modes. If you see multicast-sounding terms like "Dense" or "Sparse" in a CEF question, they are always distractors borrowed from PIM terminology to confuse you.

Topics

#Cisco Express Forwarding#CEF modes#Central CEF#Distributed CEF

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