Zigbee Foundamental

Device Type

• Coordinator
  
  • first device in network
  • scan RF env, choose a channel and a network identifier (PAN ID), then start network
  • also optionally to be used to assist in setting up security and application-level bindings
  • once start-up accomplished, Coordinator behaves like a Router node(or even go away)
• Router
  
  • allow other devices to join the network
  • multi-hop routing
  • assisting in communication for its childs
  • general expected to be active all the time, have to be mains-powered
• End-device
  
  • can sleep and wake up as chooses, battery-powered node
  • memory(RAM) requirements are lower
  • in Z-Stack, device type is usually determined at compile-time with compile options (ZDO-COORDINATOR and RTR_NWK)

Stack Profile

• set of stack parameters that need to be configured to specific value. comprise the stack profile defiend by ZigBee Alliance
• All devices in a network must conform to the same stack profile
• 3 types
  
  • ZigBee
    
    • defined by ZigBee Alliance
  • ZigBee Pro
    
    • defined by ZigBee Alliance
  • network-specific profile
    
    • self defiend, closed network
    • ZigBee and ZigBee Pro profile device can not interoperate.
• ID: 0 for network specified profile; 1 for ZigBee; 2 for ZigBee Pro.
  
  • configured by STACK_PROFILE_ID in nwk_globals.h
• Normally, a device of 1 profile (ex. ZigBee PRO) joins a network with the same profile. If a router of 1 profile (ex. ZigBee PRO) joins a network with a different profile (ex. ZigBee-2007), it will join as a non-sleeping end device. An end device of 1 profile (ex. ZigBee PRO) will always be an end device in a network with a different profile. (这一段不是太看得懂)

Addressing

• 2 types:
  
  • 64 bits IEEE(MAC address or Extended Address)
  • 16 bits network address(logical address or short address)
    
    • used on local network

Tree Addressing

• uses a distributed addressing scheme: make sure unique; only has to communicate with its parent
• defines: ZIgBee-2007 its(5, 20, 6)
  
  • MAX_DEPTH: max depth of network. coordinator=0,
  • MAX_CHILDREN;
  • MAX_ROUTERS: a subset of MAX_CHILDREN,
    
    • (MAX_CHILDREN-MAX_ROUTERS)= end devices
• change tree addressing
  
  • ensure new value legal
  • ensure to use network-specific profile (change STACK_PROFILE_ID in nwk_globals.c to NETWORK_SPECIFIC), set MAX_DEPTH in nwk_global.s
  • set array’s CskipChldrn and CskipRtrs in nwk_globals.c

Stochastic(Random) Addressing – ZigBee PRO

• random set a value, uses rest devices to unsure no duplicate
• joins process
  
  • receives randomly addr from parent
  • the new network node generates “Device Announce” (contains short and extended addr) to others
  • if short addr confilct, a node(router) send out a broadcast “Network-Status - Address Conflict” to entire network
  • conflicted device change its short addr, then send its own “Device Announce” to check again
• End device not participate “address conflict”, its parents do it for them
  
  • parent issue “Rejoin Response” to end device to change end devices short addr.
  • end device issues “Device Announce” to check new addr
• “Device Announce” recieved, association and binding tables updates, routing table info not updated(new router must be established).

Addressing in Z-stack

• AF_DataRequest() to send data to device. dest device is a type afAddrType_t(in zComDef.h)
• defines in Z-Stack Developer’s Guide Sec 3.3 P10
• send type
  
  • unicast: use Addr16Bit, dest addr is in packet
  • Indirect: use AddrNotPresent, dest addr is not specified. dest addr is looked up from “binding table”(in stack of sending device): its called Souce binding
  • when binding table looking up, it treated as a unicast packet.
• Broadcast: use AddrBroadcast, dest addr sets as:
  
  • NWK_BROADCAST_SHORTADDR_DEVALL (0xFFFF) – to all devices(including sleeping one)
    
    • sleeping one, hold in its parents until wake up or time out(NWK_INDIRECT_MSG_TIMEOUT in f8wConfig.cfg)
  • NWK_BROADCAST_SHORTADDR_DEVRXON (0xFFFD) all devices when idle (RXONWHENIDLE). all devices except sleeping devices
  • NWK_BROADCAST_SHORTADDR_DEVZCZR (0xFFFC). to all routers(includes coordinator)
• Group Addressing
  
  • send packet to a group of device: addr mode is afAddrGroup, addr.shortAddr=group identifier
  • group defination: aps_AddGroup() in the Z-Stack API doc
  • group used in conjunction with indirect addressing. dest in binding table can be unicast/group addr.

Addressing functions

• NLME_GetShortAddr()
• NLME_GetExtAddr()
• NLME_GetCoordShortAddr() : get its parents addr
• NLME_GetCoordExtAddr()