Table of contents
CAPWAP packets carry information
Discovery packets (AP sends first)
Configuration Status message (AP sends first)
Change State message (AP sends first)
Echo packets (both AP and AC can send first)
WTP Event message (AP sends first)
Configure update message (AC sends first)
Keepalive message ((AP and AC can both send first))
STA data transmission packet encapsulation
CAPWAP protocol control packets (AC port 5246)
The source port is 5246 is sent by the AC, and the destination port is 5246 is sent by the AP
Discovery AP discovers AC
Join AP join AC
Image Data AP sends to AC to request version update
Configuration Status AP requests AC to deliver configuration
Change State AP confirmation configuration
Echo Control Tunnel Keep Alive
Reset AC sends to AP to request AP restart
WTP Event AP sends messages to AC (sends AP statistics, wireless user parameter information, etc.)
Configuration Update AC sends to AP, requesting AP to perform configuration update
CAPWAP protocol data packets (AC port 5247)
The source port is 5247 is sent by the AC, and the destination port is 5247 is sent by the AP
Keep-Alive data tunnel keep alive
22%2C%22rType%22%3A%22article%22%2C%22rId%22%3A%22132257205%22%2C%22source%22%3A%22m0_49864110%22%7DCAPWAP packets carry information
Capwap messages carry different information through TLV (the following only introduces the message format of some messages)
Discovery packets (AP sends first)
Discovery Request (executes the discovery of AC, mainly carrying the characteristic information of AP)
Required TLVs
Discovery Type
This AC address is explained by the AP how to get it
WTP Board Data
AP describes its own motherboard data information
WTP Descriptor
AP describes its own hardware and software information
WTP Name
AP name (UTF-8 encoded byte string)
WTP Frame Tunnel Mode
AP describes the tunnel mode it supports
WTP MAC Type
AP describes its own MAC method
optional field
Vendor Specific Payload
Manufacturer custom attributes
Discovery Response (required TLV) publishes service information to AP
CAPWAP Control IPv4 Address
Describe the management IP address of the AC and the number of APs currently connected
AC Name
AC name (UTF-8 encoded byte string)
AC Descriptor
Describe whether the DTLS data channel is enabled, and the hardware and software information of the AC
Join message (AP sends first)
Join Request (required TLV) AP requests to join AC service
Location Data
User-defined location information (UTF-8 encoded string)
WTP Board Data、WTP Descriptor、WTP Name、WTP Frame Tunnel Mode、WTP MAC Type
Session ID
128-bit random session ID
ECN Support
show congestion notification support
CAPWAP Local IPv4 Address
AP's local IPv4 address message
Join Response AC responds to AP's join request
Mandatory TLV
Result Code
32-bit integer representing the result of the Request message
AC Descriptor、AC Name、ECN Support、CAPWAP Control IPv4 Address
CAPWAP Local IPv4 Address
AC's local IPv4 address message
Optional TLV
Image Identifier
Indicates the software version that the AC wants to run on the AP
Configuration Status message (AP sends first)
Configuration Status Request (required TLV) AP requests AC configuration delivery
AC Name
AC name, here refers to the AC to which the configuration request is made
Statistics Timer
Statistics timer, how often AP reports statistics information to AC
WTP Reboot Statistics
The AP communicates the reason for its reboot
Configuration Status Response AC sends configuration to AP
CAPWAP Timers
CAPWAP timer
Idle Timeout
The timeout period for the AC to deliver the AP to the STA
WTP Fallback
Ability to support AC active/standby switchover (when used for AC redundancy, the AP detects its preferred AC and disconnects from the previous CAPWAP tunnel)
AC IPv4 List
Configure the latest AC list for the AP to join (for AC redundancy)
Change State message (AP sends first)
Change State Request
- After the AP receives the Configure Status Response, it reports the update information of the wireless configuration status and the application of the AC configuration.
- When the AP is running normally, when an unexpected action occurs, it will use this message to notify the AC
Result Code
32-bit integer representing the result of the Configure Status Response message
Change State Response is just a response message
Echo packets (both AP and AC can send first)
Echo Request is used to keep alive the control tunnel between AP and AC
Echo Response to answer
WTP Event message (AP sends first)
WTP Event Request
Portable parameters
WTP Radio Statistics delivers statistical information about STAs
Duplicate IPv4 Address indicates that an IP address conflict has been detected
Delete Station Delete STA terminal information
Decryption Error Report The AP notifies the AC that the AC decrypts an error
WTP Event Response
Configure update message (AC sends first)
Configure update request is sent by AC to AP, indicating that AC updates the configuration of AP
are optional fields
AC Name With Priority AC name with priority
AC Timestamp requires AP to perform time synchronization
Add Mac Acl Entry Add MAC filtering strategy
Delete Mac Acl Entry Delete MAC filtering policy
CAPWAP Times CAPWAP Timers
Statistics Times requires the statistical reporting period of AP
Active/standby switchover capability of WTP Fallback AC
wait
Configuration Update Response AP 's response to AC
Must contain Result Code result set
Keepalive message ((AP and AC can both send first))
The message format of AP and AC is the same (here is the message of AP)
Packet Encapsulation Format
CAPWAP control packet
No DTLS encryption (encapsulated management VLAN)
UDP port is 5246
With DTLS encryption (encapsulated management Vlan)
UDP port is 5246
CAPWAP data packet
No DTLS encryption (encapsulated management VLAN)
UDP port is 5247
With DTLS encryption (encapsulated management Vlan)
UDP port is 5247
STA data transmission packet encapsulation
Direct forwarding (encapsulated business VLAN)
normal datagram
Physical layer - data link layer - IP layer - transport layer - application layer
STA direct forwarding: the Tag carried by the data coming out of the AP is the business Vlan, and the source and destination IP is its own source plus destination address (that is, the data packet has not changed)
Tunnel forwarding (encapsulated management VLAN)
STA tunnel forwarding: the Tag carried by the data from the AP is the Vlan where the AP is located, the source IP is the address of the AP, and the destination IP is the tunnel source address of the AC
No DTL encryption
With DTLS encryption
