Control And Provisioning of Wireless Access Points (CAPWAP) Protocol Specification, March Canonical URL: txt; File. RFC (part 1 of 6): Control And Provisioning of Wireless Access Points ( CAPWAP) Protocol Specification. Control and Provisioning of Wireless Access Points (CAPWAP) is a standard and interoperable RFC defines the actual CAPWAP protocol specifications.

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Overview of CAPWAP (Cisco Wireless LAN Controllers)

The need for flexible wireless network infrastructure will become more pronounced as WLANs become larger and more widespread. There are 3 types of AP threads, and no more than 3 threads may be active at any one time: The creation of a vendor neutral protocol is a potential boon to consumers of enterprise grade managed wireless solutions. The access point contains the wireless radio sand capap as the end point of the network, and communicates directly with user radios.

This state updates the encryption keys on both devices, which is used to encrypt all further messages, until a new key is requested.

LWAPP defines certain operation modes for compliant hardware. From the Run state, an AP and controller may exchange new key material, by entering the Key Update state. To provide an extensible protocol that is not bound to a specific wireless technology. As capwwp in Figure 1the wireless frames received from a mobile device, which is referred to in this specification as a Station STAare directly encapsulated by the WTP and forwarded to the AC.

SLAPP operates as the framework to make a connection between two devices, and negotiate a protocol.

CAPWAP, Control And Provisioning of Wireless Access Points

Split and Local MAC medium access control. Access points retrieve their configuration from the controller, and report their status back to the controller for management purposes.

The second program is run on each AP, in order to facilitate communication between the AP and controller. The only vendor that has produced a CAPWAP implementation thus far is Cisco, but it relies on some proprietary protocols, thus limiting compatibility.


The CAPWAP protocol does not include specific wireless technologies; instead, it relies on a binding specification to extend the technology to a particular wireless technology. It can perform forwarding between its wireless and wired interfaces, and direct traffic directly onto the network.

Extensibility is provided via a generic encapsulation and transport mechanism, enabling the CAPWAP protocol to be applied to many access point types in the future, via a specific wireless binding. This creates some inconveniences, however, in that both APs and controllers need to be preconfigured in order to associate with each other.

Current Status and Overview of the CAPWAP Protocol

This would allow for more rapid reaction to new innovations in the WLAN sector, as well as improve implementation quality. A typical diagram of a WLAN network is in [fig1]. The migration towards a unified standard will be long, and not necessarily even happen, because each vendor already supports its own proprietary protocols, and sees little motivation to commoditize their AP hardware by introducing CAPWAP across the industry.

Current vendor solutions and interoperability is also covered, and the current state and trends in the enterprise WLAN market are discussed. Thus, OpenCAPWAP is only a proof of concept, as they are limited in the hardware that they may support, by a lack of common target hardware, rcc well as differencing The network entity that provides WTP access to the vapwap infrastructure in the data plane, control plane, management plane, or a combination therein.

There are 6 main portions of a controller’s duties. Returned Message Element Reason However, [RFC] does give two example protocols: Otherwise it moves back to the Discovery state. The proposal cites the availability of IPsec for general data traffic, and does not provide any mechanism of encrypting data messages between the controller and AP, only control messages, and the key exchange process between both devices.

In [fig6]the same SLAPP protocol would be used by an AP to decide how to download updated firmware, as would be used to determine a protocol to communicate with the controller. These 3 MAC layer concepts will be discussed in greater detail in [Section 2. The controller processes the Discovery Request, and if valid, responds in the positive, and moves to Securing. Meru Air Traffic Control software may be used to provision and manage APs, but provides no multi rfd support.


The controller and AP will exchange 2 types of messages: Receiver and Session Manager [fig7]. The division between the sending and receiving of CAPWAP messages is that the communication between the AP and controller is not necessarily synchronous, and the controller may send a request while the Principal thread is sending.

This would be a similar scenario to two controllers running different versions of code. There are two types of threads that may be instantiated on the controller: Fat APs are much more complex, and cost much more per unit than their thinner cousins. Consult [RFC] for a full overview.

Terminology Access Controller AC: The Principal thread creates a Receiver thread, to handle the responses from the controller. In the typical centralized architecture, one or more controllers manage a set number of deployed access points. A unified CAPWAP standard aims to be a protocol that could enable centralized wireless hardware utilize a simple, streamlined method of communicating between access points and controllers.

The significant cost of enterprise level WLAN deployment, coupled with both hardware and software differences on Controllers and Capwaap Points breeds vendor lock-in.

The only difference is 54115 protocol being used between the AP and the controller. This limits interoperability to only vendors who have implemented [RFC]which is just Cisco as of the time of this writing.

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