1、RFC 5415 CAPWAP Protocol Specification March 2009 2. Protocol Overview The CAPWAP protocol is a generic protocol defining AC and WTP control and data plane communication via a CAPWAP protocol transport mechanism. CAPWAP Control messages, and optionally CAPWAP Data messages, are secured using Datagra
2、m Transport Layer Security (DTLS) RFC4347. DTLS is a standards-track IETF protocol based upon TLS. The underlying security-related protocol mechanisms of TLS have been successfully deployed for many years. The CAPWAP protocol transport layer carries two types of payload, CAPWAP Data messages and CAP
3、WAP Control messages. CAPWAP Data messages encapsulate forwarded wireless frames. CAPWAP protocol Control messages are management messages exchanged between a WTP and an AC. The CAPWAP Data and Control packets are sent over separate UDP ports. Since both data and control packets can exceed the Maxim
4、um Transmission Unit (MTU) length, the payload of a CAPWAP Data or Control message can be fragmented. The fragmentation behavior is defined in Section 3. The CAPWAP Protocol begins with a Discovery phase. The WTPs send a Discovery Request message, causing any Access Controller (AC) receiving the mes
5、sage to respond with a Discovery Response message. From the Discovery Response messages received, a WTP selects an AC with which to establish a secure DTLS session. In order to establish the secure DTLS connection, the WTP will need some amount of pre- provisioning, which is specified in Section 12.
6、5. CAPWAP protocol messages will be fragmented to the maximum length discovered to be supported by the network. Once the WTP and the AC have completed DTLS session establishment, a configuration exchange occurs in which both devices agree on version information. During this exchange, the WTP may receive provisioning settings. The WTP is then enabled for operation. When the WTP and AC have completed the version and provision exchange and the WTP is enabled, t
