17 Questions
In the context of AODV, what is the purpose of the Route Reply (RREP) packet?
To establish a reverse path to the source node
How many transmissions are typically required before the first data packet is sent in AODV?
3
What is the purpose of Destination Sequence Numbers in AODV routing?
To avoid loops by maintaining freshness of routes
Which path does the Route Request (RREQ) packet follow in the AODV example provided?
1-3-5
What is the role of Forward Path Entry in AODV routing?
To record intermediate hops towards a destination
Why is flooding not a preferred method for route discovery in AODV networks?
It slows down the network due to excessive control traffic
What action can an intruder take in AODV to become part of the route to a destination?
Send a RREP packet with a new dest_seq number higher than the current dest_seq number
How can an intruder perform a blackhole attack in AODV?
Advertise itself as having the fresher route by sending a RREP packet with a higher dest_seq number
In AODV, what does a higher value of dest_seq indicate about a route?
A fresher route
What is one way for an intruder to manipulate routing in AODV?
Sending false RREP packets with higher dest_seq numbers
Why is it important to consider the destination sequence number in AODV routing?
To prevent intruders from advertising false routes
In the ZigBee Routing Protocol ZBR, what happens when a node becomes a cluster head?
Its Cskip value is set to 0.
What defines the shape of the topology in ZigBee Routing Protocol ZBR?
Cskip
Which of the following is true about routers in ZigBee's Cluster Tree?
Each router has an address pool for newly associated nodes.
What does the Cskip value equal when the depth of a router equals the maximum depth of the Cluster Tree?
0
How is the destination node determined in the ZigBee ZBR Algorithm when sending a message?
(Adr + 1) + (Adrdest - (Adr + 1))/Cskip(d)
When does the next hop become the parent node in the Cluster Tree?
Study Notes
AODV Protocol
- A relay needs energy and memory capacity to relay packets and maintain a routing table
- The residual energy at nodes is not taken into account
- A higher value of dest_seq means a fresher route
- An intruder can advertise itself as having a fresher route by sending a route reply (RREP) packet with a new dest_seq number larger than the current dest_seq number
- This allows the intruder to become part of the route to the destination (blackhole attack)
AODV Operations
- Hop counter is used to save and relay packets
- RREQ (Route Request) and RREP (Route Reply) packets are used to establish routes
- RREQ packet contains the destination address and origination address
- RREP packet contains the destination address, origination address, and hop count
AODV Exercise
- RREQ packet is sent from node 1 to node 10
- The route is established through nodes 1, 3, 5, 7, and 10
- 8 transmissions are needed before the first packet is delivered
- 12 RREQ and 3 RREP packets are sent in total
ZigBee Routing Protocol (ZBR)
- ZBR is a hierarchical routing protocol based on hierarchical addresses and topology (Cluster Tree)
- There are two types of nodes: routers and end-devices
- Routers can route messages and attribute addresses
- Each router has an address pool defined by a Cskip (Cluster skip) formula
- Cskip is based on four parameters: depth (d), maximum depth (Lm), maximum number of child nodes (Cm), and maximum number of child router nodes (Rm)
ZBR Algorithm
- The algorithm uses the Cskip formula to determine the next hop address
- The algorithm checks if the destination is a descendant, and if so, calculates the next hop address
- If the destination is an end device, the next hop address is the router address
- Otherwise, the next hop address is calculated using the Cskip formula
Cluster Tree Example
- The example shows a Cluster Tree with nodes A, B, C, D, E, F, G, H, I, and J
- Node E wants to send a message to node F
- The algorithm is used to determine the next hop address
Learn about the blackhole attack in Ad hoc On-Demand Distance Vector (AODV) routing protocol for wireless sensor networks. Understand how intruders can manipulate route discovery to deceive nodes and disrupt communication.
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