A.5.4 example 4 – router r2 connects to network, Avr2070 – Atmel AVR2070 User Manual
Page 39
AVR2070
39
8240B-AVR-06/09
C sends association response.
Table A-5-7. Associaton response (direct)
C FCF – assoc rsp
0x8C63
Seq
03
PID
0x1234
E1 MAC
0x3333444455556666
Coord SA
0x0000
MAC Cmd
02
R1 SA
0x0003
R1 stores two addresses: Parent (coord) SA and R1 SA.
A.5.3 Example 3 – Router R3 connects to Coordinator C
This example is identical to example 2, except that R3 receives a beacon from R1 as
well as C. Since the coordinator C node is accessible directly to R3, it ignores R1,
because the number of hops are higher than directly connecting to the coordinator C.
A.5.4 Example 4 – Router R2 connects to Network
This example shows a multi-hop node being configured. At the start, assume that
routers R1 and R3 are already associated to the network.
R2 powers up, and scans for routers. It gets a beacon from C, R1, and R3. Since C
is far away, its LQI is less than R1's LQI, so R2 ignores C and tries to connect to R1,
since its signal is stronger than R3's signal.
R2 sends an association request to R1. This is an “direct association request”
because the source address is long. All new nodes send a direct request, since they
do not yet have a short address.
Table A-5-8. Association request (direct)
R2 FCF –assoc req
0xC863
Seq
01
PID
0x1234
R1 SA
0x0003
R1 MAC addr
0x5555444433332222
MAC
01
Parent SA
0x0003
Type
0x02
R1 forwards the association request to C, after re-arranging the packet into an
“indirect association request”, which has both addresses as short.
Table A-5-9. Association request (indirect)
R1 FCF
–assoc
req 0x8863
Seq
02
PID
0x1234
C SA
0x0000
R1 SA
0x0003
MAC
CMD
01
Par SA
0x0003
R2 MAC addr
0x5555444433332222
Type
0x02
C stores R2's MAC address and assigns a short address to R2. It then sends back
an association response frame.
This is an “indirect association response” frame, since the response is sent through a
router and not directly to the end node. Indirect frames use short addresses for both
source and destination.
Table A-5-10. Association response (indirect)
C FCF – assoc rsp
0x8863
Seq
03
PID
0x1234
R1 SA
0x0003
C SA
0x0000
MAC
02
Parent SA
0x0003
R2 MAC ad
0x55554...
R2 SA
0x0006
R1 receives the frame from C, and notices that the Parent SA matches its own SA.
This causes R1 to re-package the frame into a “direct association response” frame,
and to store R2's SA in its child table before sending the association response on to
R2.