无线通信_BLE_9.2 L2CAP信道

 

目录

文档摘要

抓包数据

Channel ID: 0x0004  (Attribute Protocol)

Channel ID: 0x0006  (LE Security Manager Protocol)

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文档摘要

 L2CAP有个很简单的概念——信道。

信道是指一个数据包序列，连接两个设备上的一对服务。

在两个设备间允许同时启用多条信道。

信道标识符	用法
0x0000	保留:不能使用
0x0001	经典蓝牙信令信道
0x0002	“无连接”信道
0x0003	AMP管理协议
0x0004	属性协议(ATT)
0x0005	低功耗信令信道
0x0006	安全管理协议(SMP)
0x0007~0x003E	保留:日后可能使用
0x003F	AMP测试协议
0x0040~0xFFFF	面向连接信道

低功耗蓝牙一共使用了3条信道：

信道标识符为0x0004用于属性协议；

信道0x0005用于低功耗蓝牙命令信道；

信道0x0006用于安全管理； 

抓包数据

Channel ID: 0x0004  (Attribute Protocol)

LE BB:
	Header Length: 13
	Header Version: 3
	RF Channel: 37 - 2476 MHz
	Meets Predefined Filter Criteria for BT low energy devices: No
	Receive Status: Received without errors
	Decryption Initiated: No
	Signal Strength: 11 (strong)
	Access Address: 0xaf9a9513
LE PKT:
	CRC: 0x08abdb
LE DATA:
	LLID: Start
	NESN: 0
	SN: 0
	SN+NESN: 0
	MD: 0
	CP: No CTEInfo
	Payload Length: 11
L2CAP:
	PDU Length: 7
	Channel ID: 0x0004  (Attribute Protocol)
ATT:
	Signature Present: No
	PDU Type is Command: No
	Opcode: Read by Group Type Request
	Starting Attribute Handle: 1
	Ending Attribute Handle: 65535
	Attribute Group Type: Primary Service

 

Channel ID: 0x0006  (LE Security Manager Protocol)

LE BB:
	Header Length: 13
	Header Version: 3
	RF Channel: 14 - 2430 MHz
	Meets Predefined Filter Criteria for BT low energy devices: No
	Receive Status: Received without errors
	Decryption Initiated: No
	Signal Strength: 10 (strong)
	Access Address: 0xaf9a9513
LE PKT:
	CRC: 0x4bd89c
LE DATA:
	LLID: Start
	NESN: 1
	SN: 1
	SN+NESN: 3
	MD: 0
	CP: No CTEInfo
	Payload Length: 11
L2CAP:
	PDU Length: 7
	Channel ID: 0x0006  (LE Security Manager Protocol)
SMP:
	Code: Pairing Request
	IO Capabilities: KeyboardDisplay
	OOB data flag: OOB Authentication data not present
	AuthReq
		Bonding_Flags: Bonding
		MITM: MITM Protection:  Yes
		Secure Connection Pairing: Yes
		Keypress Notifications: No
		CT2: Supports h7 Function: Yes
	Maximum Encryption Key Size: 16 Octets
		EncKey: Initiator shall distribute LTK followed by EDIV and Rand
		IdKey: Initiator shall distribute IRK followed by its address
		Sign: Initiator shall distribute CSRK
		EncKey: Responder shall distribute LTK followed by EDIV and Rand
		IdKey: Responder shall distribute IRK followed by its address
		Sign: Responder shall distribute CSRK