300-365 · Question #87
When CAPWAP protocol runs over IPv4, which UDP port numbers are used for control and data traffic,respectively?
The correct answer is C. control 5246, data ?5247. CAPWAP running over IPv4 uses UDP port 5246 for control traffic and UDP port 5247 for data traffic, as standardized in RFC 5415.
Question
When CAPWAP protocol runs over IPv4, which UDP port numbers are used for control and data traffic,respectively?
Options
- Acontrol 5246, data ?UDP-Lite(IP Protocol 136)
- Bcontrol 5247, data ?5246
- Ccontrol 5246, data ?5247
- Dcontrol 5247, data ?UDP-Lite(IP Protocol 136)
How the community answered
(29 responses)- B3% (1)
- C93% (27)
- D3% (1)
Why each option
CAPWAP running over IPv4 uses UDP port 5246 for control traffic and UDP port 5247 for data traffic, as standardized in RFC 5415.
UDP-Lite (IP Protocol 136) is used for the CAPWAP data plane when running over IPv6, not over IPv4 where both channels use standard UDP ports.
The port assignments are reversed - 5246 is the control port and 5247 is the data port, not 5247 for control and 5246 for data.
RFC 5415 defines UDP port 5246 as the CAPWAP control channel, which carries management messages, configuration updates, and keepalives between the WLC and APs, and UDP port 5247 as the CAPWAP data channel, which carries encapsulated 802.11 client data frames - both transported over standard UDP when CAPWAP runs on IPv4.
Port 5247 is assigned to CAPWAP data, not control, and UDP-Lite applies to IPv6 CAPWAP deployments rather than IPv4.
Concept tested: CAPWAP IPv4 UDP port assignments for control and data
Source: https://www.rfc-editor.org/rfc/rfc5415
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