RFC 5412
Lightweight Access Point Protocol
6. Control Channel Management
The Control Channel Management messages are used by the WTP and AC to create and maintain a channel of communication on which various other commands may be transmitted, such as configuration, firmware update, etc.6.1. Join Request
The Join Request is used by a WTP to inform an AC that it wishes to provide services through it. Join Requests are sent by a WTP in the Joining state after receiving one or more Discovery Responses. The Join Request is also used as an MTU discovery mechanism by the WTP. The WTP issues a Join Request with a Test message element, bringing the total size of the message to exceed MTU.
If the transport used does not provide MTU path discovery, the initial Join Request is padded with the Test message element to 1596 bytes. If a Join Response is received, the WTP can forward frames without requiring any fragmentation. If no Join Response is received, it issues a second Join Request padded with the Test payload to a total of 1500 bytes. The WTP continues to cycle from large (1596) to small (1500) packets until a Join Response has been received, or until both packets' sizes have been retransmitted 3 times. If the Join Response is not received after the maximum number of retransmissions, the WTP MUST abandon the AC and restart the discovery phase. When an AC receives a Join Request, it will respond with a Join Response. If the certificate-based security mechanism is used, the AC validates the certificate found in the request. If valid, the AC generates a session key that will be used to secure the control frames it exchanges with the WTP. When the AC issues the Join Response, the AC creates a context for the session with the WTP. If the pre-shared session key security mechanism is used, the AC saves the WTP's nonce, found in the WNonce message element, and creates its own nonce, which it includes in the ANonce message element. Finally, the AC creates the PSK-MIC, which is computed using a key that is derived from the PSK. A Join Request that includes both a WNonce and a Certificate message element MUST be considered invalid. Details on the key generation are found in Section 10. The following subsections define the message elements that MUST be included in this LWAPP operation.6.1.1. WTP Descriptor
The WTP Descriptor message element is defined in Section 5.1.2.6.1.2. AC Address
The AC Address message element is defined in Section 5.2.1.6.1.3. WTP Name
The WTP Name message element value is a variable-length byte string. The string is NOT zero terminated.
0
0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+
| Name ...
+-+-+-+-+-+-+-+-+
Type: 5 for WTP Name
Length: > 0
Name: A non-zero-terminated string containing the WTP's name.
6.1.4. Location Data
The Location Data message element is a variable-length byte string
containing user-defined location information (e.g., "Next to
Fridge"). The string is NOT zero terminated.
0
0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+
| Location ...
+-+-+-+-+-+-+-+-+
Type: 35 for Location Data
Length: > 0
Location: A non-zero-terminated string containing the WTP's
location.
6.1.5. WTP Radio Information
A WTP Radio Information message element must be present for every
radio in the WTP. This message element is defined in Section 5.1.3.
6.1.6. Certificate
The Certificate message element value is a byte string containing a
DER-encoded x.509v3 certificate. This message element is only
included if the LWAPP security type used between the WTP and the AC
makes use of certificates (see Section 10 for more information).
0
0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+
| Certificate...
+-+-+-+-+-+-+-+-+
Type: 44 for Certificate
Length: > 0
Certificate: A non-zero-terminated string containing the device's
certificate.
6.1.7. Session ID
The Session ID message element value contains a randomly generated
[4] unsigned 32-bit integer.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Session ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: 45 for Session ID
Length: 4
Session ID: 32-bit random session identifier.
6.1.8. Test
The Test message element is used as padding to perform MTU discovery,
and it MAY contain any value, of any length.
0
0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+
| Padding ...
+-+-+-+-+-+-+-+-+
Type: 18 for Test
Length: > 0
Padding: A variable-length pad.
6.1.9. XNonce
The XNonce is used by the WTP to communicate its random nonce during
the join or rekey phase. See Section 10 for more information.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Nonce |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Nonce |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Nonce |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Nonce |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: 111 for XNonce
Length: 16
Nonce: 1 16-octet random nonce.
6.2. Join Response
The Join Response is sent by the AC to indicate to a WTP whether it
is capable and willing to provide service to it.
Join Responses are sent by the AC after receiving a Join Request.
Once the Join Response has been sent, the Heartbeat timer is
initiated for the session to EchoInterval. Expiration of the timer
will result in deletion of the AC-WTP session. The timer is
refreshed upon receipt of the Echo Request.
If the security method used is certificate-based, when a WTP receives
a Join Response, it enters the Joined state and initiates either a
Configure Request or Image Data to the AC to which it is now joined.
Upon entering the Joined state, the WTP begins timing an interval
equal to NeighborDeadInterval. Expiration of the timer will result
in the transmission of the Echo Request.
If the security method used is pre-shared-secret-based, when a WTP
receives a Join Response that includes a valid PSK-MIC message
element, it responds with a Join ACK that also MUST include a locally
computed PSK-MIC message element.
The following subsections define the message elements that MUST be
included in this LWAPP operation.
6.2.1. Result Code
The Result Code message element value is a 32-bit integer value, indicating the result of the request operation corresponding to the sequence number in the message. The Result Code is included in a successful Join Response. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Result Code | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Type: 2 for Result Code Length: 4 Result Code: The following values are defined: 0 Success 1 Failure (AC List message element MUST be present)6.2.2. Status
The Status message element is sent by the AC to the WTP in a non- successful Join Response message. This message element is used to indicate the reason for the failure and should only be accompanied with a Result Code message element that indicates a failure. 0 0 1 2 3 4 5 6 7 +-+-+-+-+-+-+-+-+ | Status | +-+-+-+-+-+-+-+-+ Type: 60 for Status Length: 1 Status: The Status field indicates the reason for an LWAPP failure. The following values are supported:
1 - Reserved - do not use
2 - Resource Depletion
3 - Unknown Source
4 - Incorrect Data
6.2.3. Certificate
The Certificate message element is defined in Section 6.1.6. Note
this message element is only included if the WTP and the AC make use
of certificate-based security as defined in Section 10.
6.2.4. WTP Manager Data IPv4 Address
The WTP Manager Data IPv4 Address message element is optionally sent
by the AC to the WTP during the join phase. If present, the IP
Address contained in this message element is the address the WTP is
to use when sending any of its LWAPP data frames.
Note that this message element is only valid when LWAPP uses the
IP/UDP Layer 3 transport.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IP Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: 138 for WTP Manager Data IPv4 Address
Length: 4
IP Address: The IP address of an interface.
6.2.5. WTP Manager Data IPv6 Address
The WTP Manager Data IPv6 Address message element is optionally sent
by the AC to the WTP during the join phase. If present, the IP
Address contained in this message element is the address the WTP is
to use when sending any of its LWAPP data frames.
Note that this message element is only valid when LWAPP uses the
IP/UDP Layer 3 transport.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IP Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IP Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IP Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IP Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: 139 for WTP Manager Data IPv6 Address
Length: 4
IP Address: The IP address of an interface.
6.2.6. AC IPv4 List
The AC List message element is used to configure a WTP with the
latest list of ACs in a cluster. This message element MUST be
included if the Join Response returns a failure indicating that the
AC cannot handle the WTP at this time, allowing the WTP to find an
alternate AC to which to connect.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AC IP Address[] |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: 59 for AC List
Length: >= 4
AC IP Address: An array of 32-bit integers containing an AC's IPv4
Address.
6.2.7. AC IPv6 List
The AC List message element is used to configure a WTP with the
latest list of ACs in a cluster. This message element MUST be
included if the Join Response returns a failure indicating that the
AC cannot handle the WTP at this time, allowing the WTP to find an
alternate AC to which to connect.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AC IP Address[] |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AC IP Address[] |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AC IP Address[] |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AC IP Address[] |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: 141 for AC List
Length: >= 4
AC IP Address: An array of 32-bit integers containing an AC's IPv6
Address.
6.2.8. ANonce
The ANonce message element is sent by an AC during the join or rekey
phase. The contents of the ANonce are encrypted as described in
Section 10 for more information.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Nonce |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Nonce |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Nonce |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Nonce |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: 108 for ANonce
Length: 16
Nonce: An encrypted, 16-octet random nonce.
6.2.9. PSK-MIC
The PSK-MIC message element includes a message integrity check, whose purpose is to provide confirmation to the peer that the sender has the proper session key. This message element is only included if the security method used between the WTP and the AC is the pre-shared secret mechanism. See Section 10 for more information. When present, the PSK-MIC message element MUST be the last message element in the message. The MIC is computed over the complete LWAPP packet, from the LWAPP control header as defined in Section 4.2.1 to the end of the packet (which MUST be this PSK-MIC message element). The MIC field in this message element and the Sequence Number field in the LWAPP control header MUST be set to zeroes prior to computing the MIC. The length field in the LWAPP control header must already include this message element prior to computing the MIC. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | SPI | MIC ... +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Type: 109 for PSK-MIC Length: > 1 SPI: The Security Parameter Index (SPI) field specifies the cryptographic algorithm used to create the message integrity check. The following values are supported: 0 - Unused 1 - HMAC-SHA-1 (RFC 2104 [15]) MIC: A 20-octet Message Integrity Check.6.3. Join ACK
The Join ACK message is sent by the WTP upon receiving a Join Response, which has a valid PSK-MIC message element, as a means of providing key confirmation to the AC. The Join ACK is only used in the case where the WTP makes use of the pre-shared key LWAPP mode (see Section 10 for more information). Note that the AC should never receive this message unless the security method used between the WTP and the AC is pre-shared-secret- based.
The following subsections define the message elements that MUST be included in this LWAPP operation.6.3.1. Session ID
The Session ID message element is defined in Section 6.1.7.6.3.2. WNonce
The WNonce message element is sent by a WTP during the join or rekey phase. The contents of the ANonce are encrypted as described in Section 10 for more information. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Nonce | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Nonce | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Nonce | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Nonce | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Type: 107 for WNonce Length: 16 Nonce: An encrypted, 16-octet random nonce.6.3.3. PSK-MIC
The PSK-MIC message element is defined in Section 6.2.9.6.4. Join Confirm
The Join Confirm message is sent by the AC upon receiving a Join ACK, which has a valid PSK-MIC message element, as a means of providing key confirmation to the WTP. The Join Confirm is only used in the case where the WTP makes use of the pre-shared key LWAPP mode (see Section 10 for more information). If the security method used is pre-shared-key-based, when a WTP receives a Join Confirm, it enters the Joined state and initiates either a Configure Request or Image Data to the AC to which it is now
joined. Upon entering the Joined state, the WTP begins timing an interval equal to NeighborDeadInterval. Expiration of the timer will result in the transmission of the Echo Request. This message is never received, or sent, when the security type used between the WTP and the AC is certificated-based. The following subsections define the message elements that MUST be included in this LWAPP operation.6.4.1. Session ID
The Session ID message element is defined in Section 6.1.7.6.4.2. PSK-MIC
The PSK-MIC message element is defined in Section 6.2.9.6.5. Echo Request
The Echo Request message is a keepalive mechanism for the LWAPP control message. Echo Requests are sent periodically by a WTP in the Run state (see Figure 2) to determine the state of the connection between the WTP and the AC. The Echo Request is sent by the WTP when the Heartbeat timer expires, and it MUST start its NeighborDeadInterval timer. The Echo Request carries no message elements. When an AC receives an Echo Request, it responds with an Echo Response.6.6. Echo Response
The Echo Response acknowledges the Echo Request, and is only accepted while in the Run state (see Figure 2). Echo Responses are sent by an AC after receiving an Echo Request. After transmitting the Echo Response, the AC should reset its Heartbeat timer to expire in the value configured for EchoInterval. If another Echo request is not received by the AC when the timer expires, the AC SHOULD consider the WTP to no longer be reachable. The Echo Response carries no message elements.
When a WTP receives an Echo Response it stops the NeighborDeadInterval timer, and starts the Heartbeat timer to EchoInterval. If the NeighborDeadInterval timer expires prior to receiving an Echo Response, the WTP enters the Idle state.6.7. Key Update Request
The Key Update Request is used by the WTP to initiate the rekeying phase. This message is sent by a WTP when in the Run state and MUST include a new unique Session Identifier. This message MUST also include a unique nonce in the XNonce message element, which is used to protect against replay attacks (see Section 10). The following subsections define the message elements that MUST be included in this LWAPP operation.6.7.1. Session ID
The Session ID message element is defined in Section 6.1.7.6.7.2. XNonce
The XNonce message element is defined in Section 6.1.9.6.8. Key Update Response
The Key Update Response is sent by the AC in response to the request message, and includes an encrypted ANonce, which is used to derive new session keys. This message MUST include a Session Identifier message element, whose value MUST be identical to the one found in the Key Update Request. The AC MUST include a PSK-MIC message element, which provides message integrity over the whole message. The following subsections define the message elements that MUST be included in this LWAPP operation.6.8.1. Session ID
The Session ID message element is defined in Section 6.1.7.6.8.2. ANonce
The ANonce message element is defined in Section 6.2.8.
6.8.3. PSK-MIC
The PSK-MIC message element is defined in Section 6.2.9.6.9. Key Update ACK
The Key Update ACK is sent by the WTP and includes an encrypted version of the WTP's nonce, which is used in the key derivation process. The session keys derived are then used as new LWAPP control message encryption keys (see Section 10). The WTP MUST include a PSK-MIC message element, which provides message integrity over the whole message. The following subsections define the message elements that MUST be included in this LWAPP operation.6.9.1. WNonce
The WNonce message element is defined in Section 6.3.2.6.9.2. PSK-MIC
The PSK-MIC message element is defined in Section 6.2.9.6.10. Key Update Confirm
The Key Update Confirm closes the rekeying loop, and allows the WTP to recognize that the AC has received and processed the Key Update messages. At this point, the WTP updates its session key in its crypto engine, and the associated Initialization Vector, ensuring that all future LWAPP control frames are encrypted with the newly derived encryption key. The WTP MUST include a PSK-MIC message element, which provides message integrity over the whole message. The following subsections define the message elements that MUST be included in this LWAPP operation.6.10.1. PSK-MIC
The PSK-MIC message element is defined in Section 6.2.9.6.11. Key Update Trigger
The Key Update Trigger is used by the AC to request that a Key Update Request be initiated by the WTP.
Key Update Triggers are sent by an AC in the Run state to inform the WTP to initiate a Key Update Request message. When a WTP receives a Key Update Trigger, it generates a Key Update Request. The following subsections define the message elements that MUST be included in this LWAPP operation.6.11.1. Session ID
The Session ID message element is defined in Section 6.1.7.7. WTP Configuration Management
The Wireless Termination Point Configuration messages are used to exchange configuration between the AC and the WTP.7.1. Configuration Consistency
The LWAPP protocol provides flexibility in how WTP configuration is managed. To put it simply, a WTP has one of two options: 1. The WTP retains no configuration and simply abides by the configuration provided by the AC. 2. The WTP retains the configuration of parameters provided by the AC that are non-default values. If the WTP opts to save configuration locally, the LWAPP protocol state machine defines the "Configure" state, which is used during the initial binding WTP-AC phase, which allows for configuration exchange. During this period, the WTP sends its current configuration overrides to the AC via the Configure Request message. A configuration override is a parameter that is non-default. One example is that in the LWAPP protocol, the default antenna configuration is an internal-omni antenna. However, a WTP that either has no internal antennas, or has been explicitely configured by the AC to use external antennas would send its antenna configuration during the configure phase, allowing the AC to become aware of the WTP's current configuration. Once the WTP has provided its configuration to the AC, the AC sends down its own configuration. This allows the WTP to inherit the configuration and policies on the AC.
An LWAPP AC maintains a copy of each active WTP's configuration. There is no need for versioning or other means to identify configuration changes. If a WTP becomes inactive, the AC MAY delete the configuration associated with it. If a WTP were to fail, and connect to a new AC, it would provide its overridden configuration parameters, allowing the new AC to be aware of the WTP's configuration. As a consequence, this model allows for resiliency, whereby in light of an AC failure, another AC could provide service to the WTP. In this scenario, the new AC would be automatically updated on any possible WTP configuration changes -- eliminating the need for Inter- AC communication or the need for all ACs to be aware of the configuration of all WTPs in the network. Once the LWAPP protocol enters the Run state, the WTPs begin to provide service. However, it is quite common for administrators to require that configuration changes be made while the network is operational. Therefore, the Configuration Update Request is sent by the AC to the WTP in order to make these changes at run-time.7.2. Configure Request
The Configure Request message is sent by a WTP to send its current configuration to its AC. Configure Requests are sent by a WTP after receiving a Join Response, while in the Configure state. The Configure Request carries binding-specific message elements. Refer to the appropriate binding for the definition of this structure. When an AC receives a Configure Request, it will act upon the content of the packet and respond to the WTP with a Configure Response. The Configure Request includes multiple Administrative State message elements. There is one such message element for the WTP, and then one per radio in the WTP. The following subsections define the message elements that MUST be included in this LWAPP operation.7.2.1. Administrative State
The Administrative Event message element is used to communicate the state of a particular radio. The value contains the following fields.
0 1
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Radio ID | Admin State |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: 27 for Administrative State
Length: 2
Radio ID: An 8-bit value representing the radio to configure. The
Radio ID field may also include the value of 0xff, which is used
to identify the WTP itself. Therefore, if an AC wishes to change
the administrative state of a WTP, it would include 0xff in the
Radio ID field.
Admin State: An 8-bit value representing the administrative state
of the radio. The following values are supported:
1 - Enabled
2 - Disabled
7.2.2. AC Name
The AC Name message element is defined in Section 5.2.3.
7.2.3. AC Name with Index
The AC Name with Index message element is sent by the AC to the WTP
to configure preferred ACs. The number of instances where this
message element would be present is equal to the number of ACs
configured on the WTP.
0 1
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Index | AC Name...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: 90 for AC Name with Index
Length: 5
Index: The index of the preferred server (e.g., 1=primary,
2=secondary).
AC Name: A variable-length ASCII string containing the AC's name.
7.2.4. WTP Board Data
The WTP Board Data message element is sent by the WTP to the AC and contains information about the hardware present. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Card ID | Card Revision | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | WTP Model | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | WTP Model | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | WTP Serial Number ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Ethernet MAC Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Ethernet MAC Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Type: 50 for WTP Board Data Length: 26 Card ID: A hardware identifier. Card Revision: 4-byte Revision of the card. WTP Model: 8-byte WTP Model Number. WTP Serial Number: 24-byte WTP Serial Number. Reserved: A 4-byte reserved field that MUST be set to zero (0). Ethernet MAC Address: MAC address of the WTP's Ethernet interface.7.2.5. Statistics Timer
The Statistics Timer message element value is used by the AC to inform the WTP of the frequency that it expects to receive updated statistics.
0 1
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Statistics Timer |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: 37 for Statistics Timer
Length: 2
Statistics Timer: A 16-bit unsigned integer indicating the time, in
seconds.
7.2.6. WTP Static IP Address Information
The WTP Static IP Address Information message element is used by an
AC to configure or clear a previously configured static IP address on
a WTP.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IP Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Netmask |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Gateway |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Static |
+-+-+-+-+-+-+-+-+
Type: 82 for WTP Static IP Address Information
Length: 13
IP Address: The IP address to assign to the WTP.
Netmask: The IP Netmask.
Gateway: The IP address of the gateway.
Netmask: The IP Netmask.
Static: An 8-bit Boolean stating whether or not the WTP should use
a static IP address. A value of zero disables the static IP
address, while a value of one enables it.
7.2.7. WTP Reboot Statistics
The WTP Reboot Statistics message element is sent by the WTP to the AC to communicate information about reasons why reboots have occurred. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Crash Count | LWAPP Initiated Count | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Link Failure Count | Failure Type | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Type: 67 for WTP Reboot Statistics Length: 7 Crash Count: The number of reboots that have occurred due to a WTP crash. LWAPP Initiated Count: The number of reboots that have occurred at the request of some LWAPP message, such as a change in configuration that required a reboot or an explicit LWAPP reset request. Link Failure Count: The number of times that an LWAPP connection with an AC has failed. Failure Type: The last WTP failure. The following values are supported: 0 - Link Failure 1 - LWAPP Initiated 2 - WTP Crash7.3. Configure Response
The Configure Response message is sent by an AC and provides an opportunity for the AC to override a WTP's requested configuration. Configure Responses are sent by an AC after receiving a Configure Request.
The Configure Response carries binding-specific message elements. Refer to the appropriate binding for the definition of this structure. When a WTP receives a Configure Response, it acts upon the content of the packet, as appropriate. If the Configure Response message includes a Change State Event message element that causes a change in the operational state of one of the Radios, the WTP will transmit a Change State Event to the AC as an acknowledgement of the change in state. The following subsections define the message elements that MUST be included in this LWAPP operation.7.3.1. Decryption Error Report Period
The Decryption Error Report Period message element value is used by the AC to inform the WTP of how frequently it should send decryption error report messages. 0 1 2 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Radio ID | Report Interval | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Type: 38 for Decryption Error Report Period Length: 3 Radio ID: The Radio Identifier: typically refers to some interface index on the WTP. Report Interval: A 16-bit, unsigned integer indicating the time, in seconds.7.3.2. Change State Event
The WTP Radio Information message element is used to communicate the operational state of a radio. The value contains two fields, as shown. 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Radio ID | State | Cause | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: 26 for Change State Event
Length: 3
Radio ID: The Radio Identifier: typically refers to some interface
index on the WTP.
State: An 8-bit Boolean value representing the state of the radio.
A value of one disables the radio, while a value of two enables
it.
Cause: In the event of a radio being inoperable, the Cause field
would contain the reason the radio is out of service. The
following values are supported:
0 - Normal
1 - Radio Failure
2 - Software Failure
7.3.3. LWAPP Timers
The LWAPP Timers message element is used by an AC to configure LWAPP
timers on a WTP.
0 1
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Discovery | Echo Request |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: 68 for LWAPP Timers
Length: 2
Discovery: The number of seconds between LWAPP Discovery packets
when the WTP is in the discovery mode.
Echo Request: The number of seconds between WTP Echo Request LWAPP
messages.
7.3.4. AC IPv4 List
The AC List message element is defined in Section 6.2.6.
7.3.5. AC IPv6 List
The AC List message element is defined in Section 6.2.7.7.3.6. WTP Fallback
The WTP Fallback message element is sent by the AC to the WTP to enable or disable automatic LWAPP fallback in the event that a WTP detects its preferred AC, and is not currently connected to it. 0 0 1 2 3 4 5 6 7 +-+-+-+-+-+-+-+-+ | Mode | +-+-+-+-+-+-+-+-+ Type: 91 for WTP Fallback Length: 1 Mode: The 8-bit Boolean value indicates the status of automatic LWAPP fallback on the WTP. A value of zero disables the fallback feature, while a value of one enables it. When enabled, if the WTP detects that its primary AC is available, and it is not connected to it, it SHOULD automatically disconnect from its current AC and reconnect to its primary. If disabled, the WTP will only reconnect to its primary through manual intervention (e.g., through the Reset Request command).7.3.7. Idle Timeout
The Idle Timeout message element is sent by the AC to the WTP to provide it with the idle timeout that it should enforce on its active mobile station entries. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Timeout | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Type: 97 for Idle Timeout Length: 4 Timeout: The current idle timeout to be enforced by the WTP.
7.4. Configuration Update Request
Configure Update Requests are sent by the AC to provision the WTP while in the Run state. This is used to modify the configuration of the WTP while it is operational. When an AC receives a Configuration Update Request it will respond with a Configuration Update Response, with the appropriate Result Code. The following subsections define the message elements introduced by this LWAPP operation.7.4.1. WTP Name
The WTP Name message element is defined in Section 6.1.3.7.4.2. Change State Event
The Change State Event message element is defined in Section 7.3.2.7.4.3. Administrative State
The Administrative State message element is defined in Section 7.2.1.7.4.4. Statistics Timer
The Statistics Timer message element is defined in Section 7.2.5.7.4.5. Location Data
The Location Data message element is defined in Section 6.1.4.7.4.6. Decryption Error Report Period
The Decryption Error Report Period message element is defined in Section 7.3.1.7.4.7. AC IPv4 List
The AC List message element is defined in Section 6.2.6.7.4.8. AC IPv6 List
The AC List message element is defined in Section 6.2.7.
7.4.9. Add Blacklist Entry
The Add Blacklist Entry message element is used by an AC to add a blacklist entry on a WTP, ensuring that the WTP no longer provides any service to the MAC addresses provided in the message. The MAC addresses provided in this message element are not expected to be saved in non-volative memory on the WTP. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Num of Entries| MAC Address[] | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MAC Address[] | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Type: 65 for Add Blacklist Entry Length: >= 7 Num of Entries: The number of MAC addresses in the array. MAC Address: An array of MAC addresses to add to the blacklist entry.7.4.10. Delete Blacklist Entry
The Delete Blacklist Entry message element is used by an AC to delete a previously added blacklist entry on a WTP, ensuring that the WTP provides service to the MAC addresses provided in the message. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Num of Entries| MAC Address[] | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MAC Address[] | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Type: 66 for Delete Blacklist Entry Length: >= 7 Num of Entries: The number of MAC addresses in the array. MAC Address: An array of MAC addresses to delete from the blacklist entry.
7.4.11. Add Static Blacklist Entry
The Add Static Blacklist Entry message element is used by an AC to add a permanent Blacklist Entry on a WTP, ensuring that the WTP no longer provides any service to the MAC addresses provided in the message. The MAC addresses provided in this message element are expected to be saved in non-volative memory on the WTP. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Num of Entries| MAC Address[] | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MAC Address[] | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Type: 70 for Delete Blacklist Entry Length: >= 7 Num of Entries: The number of MAC addresses in the array. MAC Address: An array of MAC addresses to add to the permanent blacklist entry.7.4.12. Delete Static Blacklist Entry
The Delete Static Blacklist Entry message element is used by an AC to delete a previously added static blacklist entry on a WTP, ensuring that the WTP provides service to the MAC addresses provided in the message. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Num of Entries| MAC Address[] | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MAC Address[] | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Type: 71 for Delete Blacklist Entry Length: >= 7 Num of Entries: The number of MAC addresses in the array. MAC Address: An array of MAC addresses to delete from the static blacklist entry.
7.4.13. LWAPP Timers
The LWAPP Timers message element is defined in Section 7.3.3.7.4.14. AC Name with Index
The AC Name with Index message element is defined in Section 7.2.3.7.4.15. WTP Fallback
The WTP Fallback message element is defined in Section 7.3.6.7.4.16. Idle Timeout
The Idle Timeout message element is defined in Section 7.3.7.7.5. Configuration Update Response
The Configuration Update Response is the acknowledgement message for the Configuration Update Request. Configuration Update Responses are sent by a WTP after receiving a Configuration Update Request. When an AC receives a Configure Update Response, the result code indicates if the WTP successfully accepted the configuration. The following subsections define the message elements that must be present in this LWAPP operation.7.5.1. Result Code
The Result Code message element is defined in Section 6.2.1.7.6. Change State Event Request
The Change State Event is used by the WTP to inform the AC of a change in the operational state. The Change State Event message is sent by the WTP when it receives a Configuration Response that includes a Change State Event message element. It is also sent in the event that the WTP detects an operational failure with a radio. The Change State Event may be sent in either the Configure or Run state (see Figure 2). When an AC receives a Change State Event it will respond with a Change State Event Response and make any necessary modifications to internal WTP data structures.
The following subsections define the message elements that must be present in this LWAPP operation.7.6.1. Change State Event
The Change State Event message element is defined in Section 7.3.2.7.7. Change State Event Response
The Change State Event Response acknowledges the Change State Event. Change State Event Responses are sent by a WTP after receiving a Change State Event. The Change State Event Response carries no message elements. Its purpose is to acknowledge the receipt of the Change State Event. The WTP does not need to perform any special processing of the Change State Event Response message.7.8. Clear Config Indication
The Clear Config Indication is used to reset a WTP's configuration. The Clear Config Indication is sent by an AC to request that a WTP reset its configuration to manufacturing defaults. The Clear Config Indication message is sent while in the Run LWAPP state. The Reset Request carries no message elements. When a WTP receives a Clear Config Indication, it will reset its configuration to manufacturing defaults.
(page 66 continued on part 4)
