Cisco CCNA (200-301)Network AccessHard
During the AP join process to a WLC, the lightweight access point must establish a CAPWAP tunnel to send control messages and another to send encapsulated client data. Which UDP port numbers does CAPWAP use for the control and data channels, respectively?
- A67 and 68
- B5246 and 5247
- C1812 and 1813
- D2246 and 2247
Show answer & explanationAnswer & explanation
Correct answer: B. 5246 and 5247
CAPWAP uses UDP port 5246 for control messages and UDP port 5247 for data traffic between the AP and WLC. Ports 67/68 are DHCP, 1812/1813 are RADIUS authentication/accounting, and 2246/2247 were used by the older, now largely obsolete LWAPP protocol before CAPWAP replaced it.
Why the other options are wrong
- A. These are DHCP client/server ports, unrelated to CAPWAP.
- C. These are RADIUS authentication and accounting ports.
- D. These were the legacy LWAPP ports, superseded by CAPWAP's 5246/5247.
CAPWAP Ports
Control And Provisioning of Wireless Access Points (CAPWAP) is the standard tunneling protocol between lightweight APs and a WLC, using UDP 5246 for control and 5247 for data.
- UDP 5246 = CAPWAP control channel
- UDP 5247 = CAPWAP data channel
- Replaced the older proprietary LWAPP (ports 2246/2247)
- AP discovery can use broadcast, DHCP option 43, DNS, or static WLC IP
Memory trick: 5246 controls, 5247 follows — one number apart, control leads data.