Lines Matching full:the
6 The Binary Large Object (BLOB) Transfer models implement the Bluetooth Mesh Binary Large Object
8 from a single source to many Target nodes over the Bluetooth Mesh network. It is the underlying
9 transport method for the :ref:`bluetooth_mesh_dfu`, but may be used for other object transfer
10 purposes. The implementation is in experimental state.
12 The BLOB Transfer models support transfers of continuous binary objects of up to 4 GB (2 \ :sup:`32`
13 bytes). The BLOB transfer protocol has built-in recovery procedures for packet losses, and sets up
14 checkpoints to ensure that all targets have received all the data before moving on. Data transfer
17 BLOB transfers are constrained by the transfer speed and reliability of the underlying mesh network.
18 Under ideal conditions, the BLOBs can be transferred at a rate of up to 1 kbps, allowing a 100 kB
20 other limiting factors can easily degrade the data rate by several orders of magnitude. Tuning the
21 parameters of the transfer according to the application and network configuration, as well as
22 scheduling it to periods with low network traffic, will offer significant improvements on the speed
23 and reliability of the protocol. However, achieving transfer rates close to the ideal rate is
34 The BLOB Transfer Client is instantiated on the sender node, and the BLOB Transfer Server is
35 instantiated on the receiver nodes.
40 The BLOB transfer protocol introduces several new concepts to implement the BLOB transfer.
46 BLOBs are binary objects up to 4 GB in size, that can contain any data the application would like to
47 transfer through the mesh network. The BLOBs are continuous data objects, divided into blocks and
48 chunks to make the transfers reliable and easy to process. No limitations are put on the contents or
49 structure of the BLOB, and applications are free to define any encoding or compression they'd like
50 on the data itself.
52 The BLOB transfer protocol does not provide any built-in integrity checks, encryption or
53 authentication of the BLOB data. However, the underlying encryption of the Bluetooth Mesh protocol
54 provides data integrity checks and protects the contents of the BLOB from third parties using
60 The binary objects are divided into blocks, typically from a few hundred to several thousand bytes
61 in size. Each block is transmitted separately, and the BLOB Transfer Client ensures that all BLOB
62 Transfer Servers have received the full block before moving on to the next. The block size is
63 determined by the transfer's ``block_size_log`` parameter, and is the same for all blocks in the
64 transfer except the last, which may be smaller. For a BLOB stored in flash memory, the block size is
65 typically a multiple of the flash page size of the Target devices.
70 Each block is divided into chunks. A chunk is the smallest data unit in the BLOB transfer, and must
71 fit inside a single Bluetooth Mesh access message excluding the opcode (379 bytes or less). The
72 mechanism for transferring chunks depends on the transfer mode.
74 When operating in Push BLOB Transfer Mode, the chunks are sent as unacknowledged packets from the
76 sent, the BLOB Transfer Client asks each BLOB Transfer Server if they're missing any chunks, and
77 resends them. This is repeated until all BLOB Transfer Servers have received all chunks, or the BLOB
80 When operating in Pull BLOB Transfer Mode, the BLOB Transfer Server will request a small number of
81 chunks from the BLOB Transfer Client at a time, and wait for the BLOB Transfer Client to send them
82 before requesting more chunks. This repeats until all chunks have been transferred, or the BLOB
85 Read more about the transfer modes in :ref:`bluetooth_mesh_blob_transfer_modes` section.
92 In the BLOB Transfer models' APIs, the BLOB data handling is separated from the high-level transfer
94 applications. While the high level transfer is controlled directly by the application, the BLOB data
97 The BLOB stream is comparable to a standard library file stream. Through opening, closing, reading
98 and writing, the BLOB Transfer model gets full access to the BLOB data, whether it's kept in flash,
99 RAM, or on a peripheral. The BLOB stream is opened with an access mode (read or write) before it's
100 used, and the BLOB Transfer models will move around inside the BLOB's data in blocks and chunks,
101 using the BLOB stream as an interface.
106 Before the BLOB is read or written, the stream is opened by calling its
107 :c:member:`open <bt_mesh_blob_io.open>` callback. When used with a BLOB Transfer Server, the BLOB
111 For each block in the BLOB, the BLOB Transfer model starts by calling
112 :c:member:`block_start <bt_mesh_blob_io.block_start>`. Then, depending on the access mode, the BLOB
114 called repeatedly to move data to or from the BLOB. When the model is done processing the block, it
115 calls :c:member:`block_end <bt_mesh_blob_io.block_end>`. When the transfer is complete, the BLOB
121 The application may implement their own BLOB stream, or use the implementations provided by Zephyr:
132 Each BLOB Transfer Server may have different transfer capabilities. The transfer capabilities of
133 each device are controlled through the following configuration options:
140 The :kconfig:option:`CONFIG_BT_MESH_BLOB_CHUNK_COUNT_MAX` option is also used by the BLOB Transfer
141 Client and affects memory consumption by the BLOB Transfer Client model structure.
143 To ensure that the transfer can be received by as many servers as possible, the BLOB Transfer Client
144 can retrieve the capabilities of each BLOB Transfer Server before starting the transfer. The client
145 will transfer the BLOB with the highest possible block and chunk size.
153 Mode. In most cases, the transfer should be conducted in Push BLOB Transfer Mode.
155 In Push BLOB Transfer Mode, the send rate is controlled by the BLOB Transfer Client, which will push
156 all the chunks of each block without any high level flow control. Push BLOB Transfer Mode supports
157 any number of Target nodes, and should be the default transfer mode.
159 In Pull BLOB Transfer Mode, the BLOB Transfer Server will "pull" the chunks from the BLOB Transfer
162 in Pull BLOB Transfer Mode, the BLOB Transfer Server will request chunks from the BLOB Transfer
164 is repeated until the BLOB Transfer Server has received all chunks in a block. Then, the BLOB
165 Transfer Client starts the next block, and the BLOB Transfer Server requests all chunks of that
174 The timeout of the BLOB transfer is based on a Timeout Base value. Both client and server use the
177 The BLOB Transfer Server uses the following formula to calculate the BLOB transfer timeout::
182 For the BLOB Transfer Client, the following formula is used::
186 where TTL is time to live value set in the transfer.
191 This section contains types and defines common to the BLOB Transfer models.