In RPL (Routing Protocol for Low Power and Lossy Networks) we can use ETX (Expected Transmission Count) as an OF (Objective Function) for rank computation.
Can anyone explain the relation between ETX and Path cost in RPL?
ETX is directly proportional to the communication cost of the link between two nodes in terms of energy particularly in Low Power networks. Designing a routing protocol considering ETX as an objective function can be achieved by first mathematically deriving ETX of a link in the network of your consideration. Consequently, you can proceed to obtained EXT for a routing path considering all the EXTs of that particular path. Once you will be able to derive EXT of a path, you can sue that mathematical formulation for taking routing decision or as an objective function in your routing protocol for low power networks. In lossy networks, EXT is one of the most effective parameter for routing.
hi my friend . you can see calculate about etx in this file in contiki operation system . rpl-mrhof.c.
if you want know about etx as on of i think this file help you .
best regard.
ETX of a path is the sum of etx of each link composing the route
So if we have a higher value of etx then we have a higher member of retransmission that means more consumption of energy. there is a trade off between ETX and Energy.
Wish that helps
what is the difference between hop count and expected transmission count (ETX)
Dear Mr. Dalvin vinoth kumar A Bob;
As an example, the Expected Transmission Count (ETX) is used as the Objective Function (OF) to calculate the rank of nodes which is commonly used in LLNs.
Rank (Node) = Rank (Parent(Node)) + ETX
For more info, please go through the attached file.
BR
Somehow the ETX acts as an inverse link cost which is always between zero and one.
Somehow the etx acts as an inverse link cost which is always between zero and one.
can you please explain where exactly calculation of etx is done in rpl code? Can you help me out ? Can you help me out with ETT also?
- Badges
- Science topic