FSR special link state packages where each nodes

FSR is
an inferred proactive routing protocol. It uses the “fisheye” technique
proposed by klein rock & Stevens FSR4 (where the technique was used to
reduce the size of information required to represented graphical data) fishes
do have 3600  vision eye of
the fish captures with high details the distance near focal point  grows. Based on these concept a table driven
proactive protocol. Fish eye routing generates accurate routing decisions by
taking advantage of the global networks information. It takes the shorter
routes, class sensitive to traffic load, less sensitive to topology. It is
easier to debug & Account for routes since the entire network topology
& route tables are stored at each node. For the above stated reasons table
driven scheme is chosen for routing. Reactive protocols are distance vector
based where as proactive protocol like FSR is link & state based and has
faster speed of convergence & starter lived routing loops. In link state
topology information is disseminated in special link state packages where each
nodes receives a global view of the network rather than the view seen by nodes
neighbor. Fisheye routing takes advantages of this feature by implementing a
novel updating mechanism to reduce control overhead traffic.

FSR
is chosen to be the appropriate protocol for the present study; FSR is a link
state proactive protocol. Why fish eye protocol is the best?

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1)      
Fish eye is a proactive routing protocol
which maintains routes to all destinations, instead of whether or not these
routes are needed. The main advantage of this category of protocols is that
hosts establish a session.

2)      
Through updating link state information
with different frequencies depending on the scope distance, FSR scales well to
large network size & keeps overhead low without comprising route
computation accuracy when the destination is near.

3)      
As mobility increases, routes to remote
destinations become less accurate. However, when a package approaches its
destination, it finds increasingly accurate routing instructions as it enters
sectors with a higher refresh rate.

4)      
The control overhead is greatly reduced
in FSR average no of neighboring nodes is independent from network size since
node density is kept constant. The reason why FSR reduces  O/H is that only a fraction of the entries
are updated each time. In a two level fisheye hierarchy, the smaller radius,
the smaller fraction of entries updated in the “fast” interval & the lower
the control O/H.

5)      
FSR is more desirable for large mobile
network where mobility is high & the BW is low. By choosing proper no of
scope levels & radius size, FSR proves to be a flexible solution to the
challenge of maintaining accurate routes in ad-hoc network.

6)      
In a wireless environment, a radio link
between  mobile nodes may experience
frequent disconnects & reconnects. The Ls protocol release a link state
update for each such change, which floods the network & causes excessive
overhead. FSR avoids this problem by using periodic, instead of event driven,
exchange of the topology map greatly reducing the control message overhead.

7)      
FSR scales  well to large network size & keeps
overhead low without compromising route computation accuracy when the
destination is near. By retaining a routing entry for each destination, FSR
avoids the extra work of finding the destination & thus maintains low
single package transformer latency. (As mobility increases, routes to remote
destinatios become less accurate. However, when a package approaches its
destination, it finds increasingly accurate routing instructions as it enters
sectors with a higher refresh rate)

8)      
Throughput of FSR also increases as it
uses multilevel fish eye scope. This technique results in lower overhead &
less consumption of BW which is a major plus point for throughput. FSR if
highly scalable as it uses different frequencies for different scope that is at
different time intervals.

 

Another
characteristic of FSR is it uses different frequency in exchanging link state
information. (One hop neighbors are classified as scopes) scope is defined in
terms of the nodes that can be reached in a certain no of hopes.         

The
center nodes has most accurate information about all nodes in the circle &
because less accurate with each outer circle

Even
through a node does not have accurate information about distance nodes, the
package are routed correctly because the route information becomes more &
more accurate as the package moves closer to destination The reduction of
routing messages is achieved by updating the network information for nearby
nodes at a higher frequency & remote nodes at lower frequency. As a results
considerable amount of LSPs are suppressed.

FSR
reduces significantly the consumed BW as the link state updating packets are
exchange only among neighboring nodes. The routing overhead is also reduced due
to different frequencies of updates among nodes of different scopes.

 FSR manages to reduce the message size of the
topology information due to removal of topology information concerned far away
nodes.