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350-401 · Question #604

In which two ways does TCAM differ from CAM? (Choose two.)

The correct answer is A. CAM is used to make Layer 2 forwarding decisions, and TCAM is used for Layer 3 address lookups. B. The MAC address table is contained in CAM, and ACL and QoS Information Is stored in TCAM.. TCAM vs CAM Explanation CAM (Content Addressable Memory) is designed for exact-match lookups and is used for Layer 2 forwarding decisions, storing the MAC address table that switches use to forward frames. TCAM (Ternary CAM) extends this by supporting three states (0, 1, and wild

Submitted by javi_es· Mar 6, 2026Architecture

Question

In which two ways does TCAM differ from CAM? (Choose two.)

Options

  • ACAM is used to make Layer 2 forwarding decisions, and TCAM is used for Layer 3 address lookups.
  • BThe MAC address table is contained in CAM, and ACL and QoS Information Is stored in TCAM.
  • CCAM Is used by routers for IP address lookups, and TCAM is used to make Layer 2 forwarding
  • DCAM is used for software switching mechanisms, and TCAM Is used for hardware switching
  • EThe MAC address table Is contained in TCAM, and ACL and QoS information is stored in CAM.

How the community answered

(39 responses)
  • A
    87% (34)
  • C
    3% (1)
  • D
    3% (1)
  • E
    8% (3)

Explanation

TCAM vs CAM Explanation

CAM (Content Addressable Memory) is designed for exact-match lookups and is used for Layer 2 forwarding decisions, storing the MAC address table that switches use to forward frames. TCAM (Ternary CAM) extends this by supporting three states (0, 1, and wildcard/X), making it ideal for Layer 3 lookups and storing complex entries like ACLs, QoS policies, and routing tables - this is why A and B are correct.

  • C is wrong because it reverses the roles - CAM handles Layer 2, not routers doing IP lookups.
  • D is wrong because both CAM and TCAM are hardware-based mechanisms; neither is used for software switching.
  • E is wrong because it swaps the storage locations - the MAC table lives in CAM, and ACL/QoS data lives in TCAM.

Memory Tip: Think of the T in TCAM as "Three states" and "Top-layer" (Layer 3+). CAM = simple, exact match, Layer 2; TCAM = flexible, wildcard-capable, Layer 3 and beyond (ACLs, QoS).

Topics

#CAM#TCAM#Forwarding decisions#Hardware architecture

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