- Based on multiple level clustering
- Each cluster has its leader
- Clustering is organized in levels
> Physical : between nodes that have physical wireless one-hop links between them.
> Logical : based on certain relations
Node 8 is described as L0-8
- Node ID = 8
- It leads a cluster at zero level
Node 3 is described as L1-3
- Node ID = 3
- It leads a cluster at first level
The path between two cluster leaders is called virtual link
The path between L1-3 L1-12 is : (3 – 2 – 8 – 13 – 12 )
HSR address is <HID - nodeID>
- HSR Address of node 10 is : <12,12 - 10>.
Every node maintains information about its peers’ topology and the status of links to them.
- this information is broadcast to all the members of the cluster periodically
Cluster leaders exchange similar information with their peers
- each cluster leader broadcast the information to the lower level informing all the nodes about the hierarchical topology of the network.
Every node’s hierarchical address is stored in an HSR table and indicates its location in the hierarchy
- HSR table is updated by the routing update packets
- Route establishment
> forward the packet to the highest node in the hierarchy of the source
> sent to the highest node in the hierarchy of the destination
> forward from this node to the destination node.
Advantage:
using hierarchy information reduces the routing table size
Disadvantage:
the process of exchanging information concerned all the levels of the hierarchy as well as the process of leader election in every cluster makes it quite problematic for ad hoc networks
Route establishment:
- Go to highest node in the hierarchy
- Establish connections on virtual links
- Send data through channel
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