1. ROUTING PROTOCOL IN WIRELESS

2. Wired Networks Vs Wireless Networks
Advantages Wired Network
A wired network offer connection speeds of 100Mbps to 1000Mbps
Physical, fixed wired connections are not prone to interference and fluctuations in available bandwidth, which can affect some wireless networking connections.
Disadvantages over wired networks
Expensive to maintain the network due to many cables between computer systems and even if a failure in the cables occur then it will be very hard to replace that particular cable as it involved more and more costs.
When using a laptop which is required to be connected to the network, a wired network will limit the logical reason of purchasing a laptop in the first place.

3. Wired Networks Vs Wireless Networks
Advantages of Wireless Networks
Mobile users are provided with access to real-time information even when they are away from their home or office.
Setting up a wireless system is easy and fast and it eliminates the need for pulling out the cables through walls and ceilings.
Network can be extended to places which can not be wired.
Wireless networks offer more flexibility and adapt easily to changes in the configuration of the network.
Disadvantages of Wireless Networks
Interference due to weather, other radio frequency devices , or obstructions like walls.
The total Throughput is affected when multiple connections exists.

4. Problems in Wireless communications
Multipath propagation
when a signal travels from its source to destination, in between there are obstacles which make the signal propagate in paths beyond the direct line of sight due to reflections (pantulan), refraction (pembiasan), absorbtion (penyerapan), and diffraction (pembelokan) and scattering.
Path loss
attenuation of the transmitted signal strength as it propagates away from the sender.
Interference
Limited frequency spectrum.
frequency bands are shared by many wireless technologies and not by one single wireless technology

5. Behavior of Radio Waves
The longer of the wavelength, the more distant radio waves propagate.
The longer of the wavelength, the more easily the wave through or around the barrier.
The shorter of the wavelength, the more data that can be sent.

6. Routing?
Routing is the act of moving information from a source to a destination.
The routing concept basically involves, two activities: firstly, determining optimal routing paths and secondly, transferring the information groups (called packets) through the network.

7. Routing?

8. Routing ?

9. Routing protocol GOAL?
Determine “good” path (sequence of routers) thru network from source to destination.
“good” path:
❍ typically means minimum cost path
❍ link cost: delay, $ cost, or congestion level

10. Classification of Dynamic Routing Protocols
Distance Vector Protocols
Link-State Protocols
Distance vector routing aims to determine the direction or vector, and the distance to the other links in an internetwork.
While the link-state routing aims to recreate the correct topology on an internetwork.

11. Traditional routing algorithms
Distance Vector
Periodic exchange of messages with all physical neighbors that contain information about who can be reached at what distance
Selection of the shortest path if several paths available
Every node maintains the distance of each destination
Link State
Periodic notification of all routers about the current state of all physical links
Router get a complete picture of the network
Each node maintains a view of the network topology
Example
ARPA packet radio network (1973), DV-Routing
every 7.5s exchange of routing tables including link quality
updating of tables also by reception of packets
routing problems solved with limited flooding

12. Distance-Vector
Known also as Distributed Bellman-Ford or RIP (Routing Information Protocol)
Every node maintains a routing table
all available destinations
the next node to reach to destination
the number of hops to reach the destination
Periodically send table to all neighbors to maintain topology

13. Distance Vector (Tables)1 2 A B C
Dest.
Next
Metric … A B 1 C 3
Dest.
Next
Metric … A 1 B C 2
Dest.
Next
Metric … A B 3 2 C

15. Distance Vector (Update)
B broadcasts the new routing information to his neighbors
Routing table
is updated
(A, 1)
(B, 0)
(C, 1)
(A, 1)
(B, 0)
(C, 1) 1 1 A B C
Dest.
Next
Metric … A B 1 C
3 2
Dest.
Next
Metric … A 1 B C
Dest.
Next
Metric … A B
3 2 1 C

16. Distance Vector (New Node)
broadcasts to update tables of C, B, A with new entry for D
(A, 1)
(B, 0)
(C, 1)
(D, 2)
(A, 2)
(B, 1)
(C, 0)
(D, 1)
(D, 0) 1 1 1 A B C D
Dest.
Next
Metric … A B 1 C 2 D 3
Dest.
Next
Metric … A 1 B C D 2
Dest.
Next
Metric … A B 2 1 C D

17. Link-State Like the shortest-path computation method
Each node maintains a view of the network topology with a cost for each link
Periodically broadcast link costs to its outgoing links to all other nodes such as flooding

18. Link-State
Link-state algorithms are also known as Dijkstra's algorithm or algorithms shortest path first (SPF).
These algorithms improve the information database of topology information.
Distance vector algorithms have information that is not specifics about the network distance and do not know the distance router.
While the link-state algorithms improve knowledge of the distance router and how they inter-connections.

19. Link-State Features that are owned by the link-state routing are:
Link-state advertisement (LSA) - are small packets of information routing sent between routers
Topological database - is a collection of information of LSA-LSA
SPF algorithm - is the calculation in the database as a result of the SPF tree
Routing table - a list of routes and interfaces

20. Link-State A
link costs F H B E C G D

21. Link-State

22. Link-State

23. Single Source Shortest Path Algorithm
There are two kinds of algorithms used in solving problems of single source shortest path, namely:
Bellman-Ford algorithm is used to solve a single problem that has the shortest path to the edge of negative weights.
Djikstra Algorithm is used to solve a problem that has a single shortest path edge with positive weights.

24. Dijkstra Algorithm
Dijkstra's algorithm determines the distances (costs) between a given vertex and all other vertices in a graph. This may be useful to determine alternatives in decision making.
Dijkstra's algorithm begins at a specific vertex and extends outward within the graph, until all vertices have been reached.
Dijkstra's algorithm stores the total cost from a source vertex to the current vertex.
More simply, Dijkstra's algorithm stores a summation of minimum cost edges.

25. DIJKSTRA Algorithm Method
Initialization s (source)
Select one vertex as the source
Then d (s) = 0
Label 0 at vertex s
For each edge e ЄE
 If i is the endpoint of e properly labeled and j is the endpoint that is not labeled, it p (i, j) is = d (i) + w (i, j)

26. DIJKSTRA Algorithm Method
e is edge for T that has the smallest value of P
 if i is endpoint of e that is added the label and j is endpoint that is not added yet the label then added e and vertex j to tree T
 d(j)=P(ij)
 Give label d(j) to vertex j
Return to number 2

27. Example 1
Determine the shortest path from A to each v in the following a graph G:

28. Example 1

29. Example 1

30. Example 1

31. Example 1

32. Practices

33. Practices

34. Bellman-Ford Algorithm
Bellman-Ford algorithm calculates the shortest distance (from one source) at a weighted digraph.
It means of one source is that it calculates the shortest distance which all originated from one point node.
Dijkstra's algorithm can more quickly search for the same thing provided that no side (edge) that weighs negatives.
So the Bellman-Ford algorithm is only used if there is a weighty negative side.

35. The characteristics of the Bellman-Ford algorithm
Working with weights despite the negative edge.
Must be directed edge (otherwise the graph would have cycles by negative weights)
Iteration i find the whole shortest path by using I edge.
Can detect cycle with negative weighting if any.

36. Applications in routing
A distributed variant of Bellman-Ford algorithm is used in the Routing Information Protocol (RIP).
The algorithm is distributed because it involves a number of nodes (routers) within an Autonomous system, a collection of IP networks typically owned by an ISP.
It consists of the following steps:
Each node calculates the distances between itself and all other nodes within the AS and stores this information as a table.
Each node sends its table to all neighbouring nodes.
When a node receives distance tables from its neighbours, it calculates the shortest routes to all other nodes and updates its own table to reflect any changes.

37. Example Develop algorithm using the following working example
use a table to show changes in estimates of distances and predecessors
initialize table —no predecessors

38. example Revise estimates of distances Ulangi sebanyak v-1 kali
Untuk masing-masing edge (u, v) dalam graph, set d(v) = min[d(v), d(u) + w(u, v)]
Jika jarak direvisi, tentukan vertex predecessor baru
edges dapat diambil dengan berbagai cara misalnya sesuai dengan urutan abjad: (a, b), (a,c), (a, d), (b, a), (c, b), , (s, b)