Assumption: When we use smart lighting system on out door condition: sensor might not working as we want i.e. light doesn't turn on when sensor detect sundown.
In case sensor don’t work correct by itself, we need to manual configure, control via wireless communication and make sure that the wireless connection is reliable even the changing environmental condition.
Additionally, the scalable network can expand to thousands of nodes by using IPv6.
2. Scenario
Assumption:When we use smart lighting system on out door
condition: sensor might not working as we want i.e. light
doesn't turn on when sensor detect sundown.
In case sensor don’t work correct by itself, we need to manual
configure, control via wireless communication and make sure
that the wireless connection is reliable even the changing
environmental condition.
Additionally, the scalable network can expand to thousands of
nodes by using IPv6.
5. Solution
o Goal: Build a wireless sensor network embedded Internet allow to manual
configuring, control, monitoring the lights system via Internet using IPv6
is identifier for sensor nodes.
o Criteria:
1. Flexibility: Change configuring the topology for adapting to environmental
conditions.
2. Scalability: The network is still stable when extend more and more sensor
nodes.
Provide services to manage the IPv6 wireless network
called RPL (IPv6 Routing protocol for LLNs)
8. RPL
IPv6 routing protocol for LLNs that specifies how to build logical routing
topology (graph) over physical network to meet specific criteria.
The network administrator decide to have multiple graphs active with
different set of requirements.
In this project, we set up the requirements:
Flexible manage the network dynamically as well as manually
Reliable connection between nodes
Easily expand number of nodes as demand to widen the network.
9. Graph building process
The gateway (root) starts
advertising the information about
the graph using DIO message.
Upon the receive message, node
compute the rank – indicate the
relative position of node respect to
the root.
Choose the best path toward to the
root by selecting the preferred
parents based on objective
function, metric (link quality, battery
node...)
This process will repeat to
advertising DIO, compute rank and
do parents selection until leaf node
where the process terminated.
10. UPWARD Routing
After this formation completed, each
node has routing entry toward its
parents also has reach-ability
toward the root UPWARD routing
We use this operation allow root
collect the information from all the
node of the network.
11. Link Reliability - ETX
ETX metric is the expected number of transmission required to
successfully transmit and acknowledge a packet on the link
This metric regards to the link reliability level to select parent that provides
delivery with the least number of transmission.
The objective function decide the minimum-ETX path indicate the reliable
connection between nodes.
formula: ETX= 1 / (Df * Dr) where Df is the measured probability that a
packet is received by the neighbor and Dr is the measured probability that
the acknowledgment packet is successfully received.
12. Repair
Principles: A node is not
allowed to select as a parent a
neighboring node whose rank
is greater specific value
defined by node-rank+
max_depth.
When link failure occur. A node
has no router parent will trigger
local repair to inform its child
nodes find another parent node
while itself find other node as a
parent (comply the rule).
13. DOWNWARD Routing
When we have the traffic from outside the LLN network, at the root A send
the packet destined to node B. The root choose next-hop to forward IPv6
packet. This require the root A look up its routing table that contained the
path to the destination B. We use this traffic in order to manual control,
query the lighting sensor node.
Routing table is built and populated by advertised DAO message.
Operation: Each node joined the graph it will send DAO to its parent set.
As received the DAO message, node processes the prefix information and
add a entry into routing table. This process continues until the prefix
information reach the root.
14. Conclusion
Solved the requirements set is setup when design the network.
The latency is quite great.
Development: Outdoor System is the key factor in Smart City with capable of
sense “things” in order to detect (or even predict) changes in the weather as
well as the congestion traffic in megacity.
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AverageResponseTime(s)
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