Which TLV value must be added to Option 43 when DHCP is used to ensure that APs join the WLC?

Question

Options

• A0x77
• BAAA
• C0xf1
• D642

• C
  96% (24)
• D
  4% (1)

Explanation

DHCP Option 43 and Wireless LAN Controllers

When configuring DHCP Option 43 to allow Cisco Access Points (APs) to discover and join a Wireless LAN Controller (WLC), the TLV (Type-Length-Value) type field must be set to 0xf1 (241 in decimal), which is the Cisco-specific sub-option that carries the WLC's IP address in the vendor-specific information field. This value is a Cisco proprietary standard that APs look for during their discovery process when DNS or broadcast methods fail.

• 0x77 (Choice A) is incorrect - 0x77 equals 119 in decimal and has no relevance to Cisco AP/WLC DHCP discovery.
• AAA (Choice B) is incorrect - AAA refers to Authentication, Authorization, and Accounting, which is a separate security framework unrelated to DHCP Option 43 configuration.
• 642 (Choice D) is incorrect - this decimal value has no standard association with DHCP Option 43 or Cisco WLC discovery; it may be a distractor referencing partial port numbers or other protocols.

Memory Tip: Think "0xf1 = Find 1 controller" - the hex value 0xf1 is how APs find their WLC via DHCP. Alternatively, remember that f1 looks like "F1" (Formula 1), and APs race to find the controller using this value!

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