Routing Algorithms in computer Networks and different types

1. Routing Algorithms in
Computer Networks

2. What ‘s Routing Algorithms in Computer Networks?
• In computer networks, routing is the process of selecting the path
along which the data will be transferred from the source node(device)
to the destination node
• This path is determined by the help of Routing Algorithms in
Computer Networks.
• This article aims to provide an overview of routing algorithms in
computer networks, the types of routing algorithms, and their
advantages and disadvantages

3. Categories of Routing Algorithm
• We have two types Nonadoptive routing algorithms and adaptive routing
algorithms
• on-adaptive routing algorithms are also known as static
routing algorithms. Static routing is a type of routing that does not change
the route taken based on network conditions. This means that the same
route is always taken, regardless of whether there are any changes in
network conditions.
• Adaptive routing algorithms allow packets to take multiple paths to avoid
congestion and flatten the on-chip network traffic distribution. Fully
adaptive algorithms, which permit non-minimal routes, can further
improve NoC efficiency as they allow packets to turn around to avoid
becoming blocked in congested regions.

5. Isolated
In these types of algorithms, each node determines its routing
decisions based on the information it receives without consulting other
nodes.
The sending nodes have no information of the state of a specific link.
The drawback is that packets may be routed over a busy network,
causing delays.
Example: Hot potato routing and backward learning.

6. Centralized
In these types of routing Algorithms, a centralized node has all network
information and makes all routing decisions.
The benefit is that only one node is necessary to retain the information
of the whole network, but the disadvantage is that if the central node
fails, the entire network is destroyed.
Example: The link state algorithm is sometimes referred to as a
centralized algorithm as it contains information of all the nodes present
in the network.

7. Distributed
• In Distributed Adaptive Routing Algorithms in Computer Networks,
the node collects information from its neighbors before deciding how
to route the packets.
• One disadvantage is that the packet may be delayed if the intervals at
which it receives information and delivers packets change.

8. Flooding
• Flooding
The flooding technique uses the practice of sending every incoming
packet on every outgoing line except the one from which it arrived.
One disadvantage of this algorithm is that packets can get stuck in a
loop, leading a node to receive duplicate packets.
• These issues can be solved using sequence numbers, hop counts, and
spanning trees.
•

9. Random Walk
• Each node in the network sends the data packet to a randomly picked
neighbor in the random walk algorithm. This is repeated until the
packet arrives at the target node.
• Random walk is a simple algorithm, however, it might result in
inefficient routing and unnecessary traffic.

10. Link State Routing Algorithm
•
Each node in the network keeps a map of the network topology and
uses Dijkstra’s algorithm to determine the most efficient path for data
packets in the link-state routing algorithm.
• The map is updated regularly based on information received from
neighboring nodes.

11. Distance Vector Routing Algorithm
• In the distance vector routing algorithm, each node in the network
has a table that records the distance and the next hop for each
destination node.
• The table is periodically updated based on information received from
surrounding nodes. The Bellman-Ford method is used to select the
best route for data packets.

14. Flooding
Flooding is used when source don’t have any idea about destination and should send a broadcast message to know to
destination

18. Problems of distance vector routing
• It is delay metric was queue length, it did not take line bandwidth into
account when choosing routes
• Count to infinity problem
(So, It is replaced by link state routing),
(Each router must do the following )
• Learn their neighbors and their network address
• Measure delay or cost to each of its neighbors
• Construct packet telling all it has learned
• Send this packet to all other routers
• Compute shortest path to every other router
• Learning about neighbors

19. Link State Routing (Learning about neighbors)

20. Link State Routing (Learning about neighbors and Measuring Line cost)
Learning about neighbors: use to know their neighbor routers
Measuring line Cost: use to measuring the distance neighbors

21. What is the link state packet?
• Link State Packet (LSP) is a packet of information generated by a
network router in a link state routing protocol that lists the router's
neighbors. Link state packets can be further defined as special
datagrams that determine the names of and the cost or distance to
any neighboring routers and associated networks.
• LSAs are distributed throughout a defined area by the process of
reliable flooding
• When a router receives a new LSA in a Link State Update packet, it
installs the LSA in its database and then forwards the packet on all its
interfaces except the one on which the Update packet was received.

22. LINK STATE ROUTING
Distributing Link State Packets: determine the names of and the cost or distance to any neighboring routers
Computing new routers: use for constructing subletting graphs which help to detect shortest paths

23. • Hierarchical routing is the procedure of arranging routers in a hierarchical manner.
• A good example would be to consider a corporate intranet. Most corporate intranets consist of a high speed
backbone network. Connected to this backbone are routers which are in turn connected to a particular workgroup.

24. References
• https://www.geeksforgeeks.org/classification-of-routing-algorithms/
• https://www.sciencedirect.com/topics/computer-science/adaptive-
routing#:~:text=Adaptive%20routing%20algorithms%20allow%20pac
kets,becoming%20blocked%20in%20congested%20regions.