Internet of things - zigbee network function
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This document outlines Zigbee network architecture in the context of the Internet of Things, detailing the formats for Zigbee PHY and MAC frames, device addressing, and operations for joining a personal area network (PAN). It explains the roles of coordinators, routers, and end devices, as well as the various types of communication such as broadcast and unicast transmissions. Additionally, it discusses the process of energy scanning, beacon requests, and the management of device joins and their attributes.
Internet of things - zigbee network function
- 1. Internet of Things ( IoT ) ZigBee Network Function - Session 3
- 2. Zigbee Network Architecture ZC ZR ZR ZEDZED ZED ZED External Network
- 3. Zigbee PHY Frame Format 4 Bytes (32 bits) 1 Byte 1 Byte Bytes Variable ( 0 – 127 ) Preamble SFD PHR Payload Synchronization Header PHY Frame Header PHY Payload
- 4. ZigBee MAC Frame Format 2 Byte 1 Byte 2 Byte 2 Byte 2 Byte 2 Byte Variable (0 – 102) 2 Byte Frame Control Seq Num Dest PAN Dest Address Source PAN Source Address Frame Payload FCS Network Addressing MHR MSDU MFR
- 5. ZigBee Device Addressing • 64 bit address – Uniquely identifies the node and is permanent • 16 bit address – Assigned to a node when node joins a network – Network address is unique to each node in network – Network addresses are not static – Address changes • When end device leaves & join back with the network • Device type changes from router to end device or vice- versa
- 6. Personal Area Network • Co Ordinator selects a channel & PAN ID • Routers and End Devices will join the PAN • PAN ID is selected by the co-ordinator, when it starts the PAN • The device like router & end device will be part of the PAN, when they join the network. • Supports mesh routing – Data traverse multiple nodes to reach the destination – All devices will receive 16 bit address when it joins the network – 16 bit address of coordinator is always 0
- 7. Coordinator Starting a PAN • Must have a coordinator present • Different Scan – Energy Scan – PAN Scan • Energy Scan – Performs energy scan to discover level of RF activity on different channels – Avoids the channels with high energy levels
- 8. PAN Scan Co Ord New Coord Co Ord Beacon Request Beacon Beacon Request Beacon
- 9. PAN Scan • Coordinator send a one hop beacon request • All nearby coordinator & routers will respond back with beacon frame. • Beacon Frame Contains – Sender PAN ID – Whether device is allowing joining – Active or beacon scan • Allows the coordinator to detect nearby PAN IDs to avoid duplicate PAN IDs
- 10. Beacon Frame 2 Bytes 1 Byte 4 or 10 2 Byte Variable Variable Variable 2 Bytes Frame Control Beacon Seq Number SRC ADDR INFO Super Frame Spec GTS Fields Pending Addr Fields Beacon Payload Frame Check Seq
- 11. Beacon Super Frame Specifier Bits 0 – 3 Bits 4 -7 Bits 8 – 11 Bits 12 Bits 13 Bits 14 Bits 15 Beacon Order Super Frame Order Final CAP Slot Battery Life Extension Reserved PAN Coordinat or Asso Permit
- 12. Command Identifier CMD ID Command Name 0x01 Association Request 0x02 Association Response 0x03 Disassociation Notification 0x04 Data Request 0x05 PAN ID Conflict Notification 0x06 Orphan Notification 0x07 Beacon Request 0x08 Coordinator realignment 0x09 GTS Request 0x0a – 0xff Reserved
- 13. Joining a PAN • Router and end devices must discover & join • Starts with PAN Scan • Receives list of beacons from nearby devices • Parse this list to find valid zigbee network • Configured to join any PAN or only with certain PAN ID • Must find a coordinator & router that allows • Each beacon contains – PAN ID = XXXX – Allow Join = True / False
- 14. Joining PAN Router New Router Co Ord Beacon Request Beacon Beacon Request Beacon Association Req Association Response
- 15. Allow Joining • Allow joining depends on two things – Permit Joining attribute – Number of end device it already has • Permit Joining Attribute – Configured to allow join – Allow join for a short time – Not allow for any more time • End Device Children – Each router will support finite number of end children – Once device exceeded, device will not be allowed to join
- 16. Broadcast Transmission • Intended to propagate entire zigbee network • All devices receives this, retransmit 3 times • Local entry of broadcast • Each entry persists for 8 seconds • Broadcast transmission table holds 8 entries • As it get transmitted all the network, broadcast should be used sparingly
- 17. Unicast Transmission • Data transmission use 16 bit network address • Must discovered when it joins the PAN • Sends broadcast network address discovery – Contains 64 bit address – Address matching • Response will contain 16 bit network address. • Can use to start transmit the data