Node Credit Based Efficient Flooding (NCBEF) Method for Mobile Ad-hoc Networks

Effective routing is one important research issue for mobile ad-hoc network where gadgets have confined resources. Due to non-foreseeing network topology, frequent link failure occurred that drives route break, partitions and high routing overhead issue. These issues result superfluous resource wastage and diminish network life. Existing reactive routing algorithm helps nodes to discover route via broadcast of route request to all these reachable nodes. Receiving node of route request further forward to all its neighbours’ nodes that lead flooding. Here broadcasting of route request results several issues such as wastage of resources, congestions, redundancy of route request and broadcast storm problem. Though to maximize resource utilization and minimize broadcast storm problem, efficient broadcast method in routing algorithm is required. Numerous contributions have done towards efficient broadcasting which concentrate different aspects. In this paper, NCBEF method is presented that motive was to do efficient flooding. NCBEF method enables node to broadcast route request to some neighbours instead of all. To do this, NCBEF method, determine high creditable neighbours during hello signal transmission. Few hypotheses were formulated to evaluate and test NCBEF method. Hypotheses were evaluated by simulation of NCBEF method in network simulator software on the basis of certain criteria.


Flooding
Flooding initiated via broadcasting of routing packets by a node that require route for communication.At this moment receiving node rebroadcast received packets to its covering nodes.Further broadcasting of routing packets spreads throughout the network that results flooding.This method enables routing protocols to tell a node for receiving routing packets and rebroadcast further [1].Simple scenario of flooding presents in figure 3.

Figure 3. Network Scenarios for Flooding
In above figure, network with seven devices is illustrate where each device labelled with unique number like device 1, 2, 3, 4 etc.Here device begin forwarding of routing messages to its neighbours 2 and 3.Each neighbour receives messages and further forwards to its successor.When device receive same message from all neighbours then process first one and discard others.For example, device 1 receive message from device 1 and 3 then it processes message of device 1 instead of device 3. Likewise, same phenomena follow by all the devices which results flooding.At another site, each device receives messages from those preceding devices and further forwards to those successor devices which are reachable.If network is large then this procedure results storm of messages named broadcast storm problem which impact network functioning or denying services.Figure 4 shows the scenario of storm problem where each device forward to all its successor devices.Node Credit Based Efficient Flooding (NCBEF) Method for Mobile Ad-hoc Networks DSR [2], AODV [3], LAR [4], ZRP [5] etc.Every routing protocol is responsible for route discovery, repair and topology update.Thus, appropriate flooding methods are required to accomplish routing with less overhead [6,7].Various category of flooding method depicted in figure 5.

Figure 5. Various category of Flooding Simple Flooding
This method defines common properties between all the devices of the network where each one forward routing messages without knowing of neighbours.

Following sub-category comes in this.
Blind flooding -Blind flooding method alternatively known as pure flooding where every device forwards broadcasting message during route discovery phase [8] [9].In this, when a device receive forwarding message then it is require to forward further.

Probabilistic flooding -Earlier method resulted
broadcast storm problem which leads wastage of network resources.To sort out this problem, a method suggested that referred as probabilistic [9].This was employed concept of probabilistic rebroadcast.
Therefore, it categorized in counter based, distance based [9], location based [10] and cluster based [11].This scheme advantages control of redundant transmission of packets over blind method [12].This category method offers knowledge of neighbor's information for every device of the network.Every device gathers and shares its 1-hop neighbor knowledge via exchanging of HELLO message [13].

Flooding
To choose forwarding nodes, two alternatives are possible.First is, sender node deciding neighbors list for the further forwarding which named sender based.
Another one is receiving node decides list of neighbors for further broadcasting which named as receiver based.The schemes expressed in [14] [15] [16] are sender-based, while the schemes proposed in Various flooding approach [24] [25] [26] falls in 1hop neighbor knowledge method that ensure about entire message delivery.

2-Hop or More Neighbor Knowledge Methods
In this method, it has assumed that every device contains the record of two-hop neighbors.The onehop neighbor knowledge gathers by the use of HELLO message in MAC sub-layer of DLL layer.To keep up-to date information about topology, HELLO messages periodically exchanged between devices.

Relevant Work
In preceding section, basic flooding operation and its traditional methods have presented.In few decades, more efforts have putted to contribute resourceful flooding.Here, individual were focused on different parameters and aspects like 0-hop, 1-hop and k-hop neighbour knowledge information.Following section highlight few contributions for the fruitful flooding.
Authors in [24] expressed that a one-hop flooding approach accomplishes complete when each device like 1 the neighbor's scope of 1 can be come to by F (1), where F( 1) is characterized as a subset of 1's neighbors that are chosen to forward the flooding message (F(1) incorporates 1 itself).The neighbor's region of a node 1 is the entire shadow zone appeared in Figure 6, where 2, 3, 4 is the entire neighbors of 1's. Figure 6 shows Neighbor's area of node 1.

Figure 6. Neighbour's area of node
Another method was advised named as Flooding with Self-pruning [27] in which 1-hop neighbour information used.Accordingly, to this method, device forward message by enclosing complete list of 1-hop neighbours.At the receiving site, each node who receive flooding message compare its neighbours with list enclosed in message.Ultimately device either discard forwarding message when it's all 1-hop neighbours is available in the list, or forwards the message further.
Self pruning leads redundant transmission to exchange neighborhood information.To control this, every node maintains received adjacent neighbor records in memory [28].
Further, to offer more efficient flooding an Edge Forwarding [29] method was suggested that uses knowledge of 1-hop neighbor.This method effort to control flooding traffic through geographical knowledge results limited broadcasting within range of each device.
In this method, communication area of node is divided into six uniform subareas.Suppose node 1  Therefore, Xian long Jiao et al in [31] advised CEF method to optimize performance of routing protocols use of directional antenna.Initially authors expected every node offered inclusive a single-beam directional antenna in EFDA [32], and afterward proposed CEF which is a calculation enhanced EFDA.
Authors [32] stated that for the ad-hoc networks Information and Adaptive Holding)" [33].
Further-more an approach advised in which every device aware about the network topography of 2-hop radius.Inappropriately, finding minimum set of devices was NP-hard.Therefore, Amir Qayyum et al. [34] suggested a heuristic method to determine the solution named Multipoint Relays (MPR).

Therefore, three-hop horizon pruning (THP)
algorithm was the first heuristic to take into account 3-hop information in the selection of relay nodes for broadcast packets [35].
To achieve efficiency, selective rebroadcasting approach is further extended in another one referred as MISTRAL [36].This resulted compensation between overhead and end delivery of messages.
Forward error correction technique was adapted to accomplish compensation.
Moreover, another method was designed that known as ASTRAL [37].A forward and backward packet recovery method was used here.Hemant Kumar Gianey, Tanupriya Choudhury, Ahmed A. Elngar decision on the basis of amount and timestamps of packets.
Global Queue Pruning [40] method was presented that restricts the overhead of the transmission and to enable delivery of packets to each node.It considered virtual topology where few nodes work as forwarders.
At the last but not least, Selective Epidemic Broadcast Algorithm [41]

Proposed Methodology
Apart from discussed all flooding methods, to enable efficient flooding for routing protocols by concentrating limited resource constraints a method is proposed.method known as Node Credit Based Efficient Flooding (NCBEF).NCBEF method uses one hop neighbour information concept to broadcast routing packets for route discovery.algorithm that represents in pseudo code form.

Algorithm
NCBEF method achieves its goal via taking input, processing and resulting output.Thus, node coverage area, stay time and power backup takes as input.
Credit calculation defined as process and higher credit value neighbors list as output.The complete process illustrates in below pseudo code.Hemant Kumar Gianey, Tanupriya Choudhury, Ahmed A. Elngar evaluate and analyze with the existing blind flooding method.Though, experiment will perform with the help of simulation software or tools.Next section defines the whole thing about experiment of proposed method.

Experiment of NCBEF Method
In previous section, NCBEF method described hypothetically.
Here experimental setup and simulation of proposed method presented.NCBEF method is practically simulated in network simulator software i.e.NS-2.To simulate NCBEF method, various network matrices like packet size, traffic type, number of devices etc. are considers.Table 2 presents network characteristics in form of matrices.Means, forumlated hypotheses are accepted as per reults.May be some hypotheses rejects for the same.

Conclusion
Due to non-anticipating network topology, frequent link failure occurred that leads route break, partitions and high routing overhead issue.These issues results unnecessary assets wastage and diminish network life.Existing reactive routing algorithm encourages nodes to discover route through communicate of course solicitation to all these reachable nodes.
Receiving node of route request further forward to all its neighbours' nodes that lead flooding.Here communicating of course solicitation results a few issues, for example, wastage of assets, blockages, excess of course solicitation and communicate storm issue.However, NCBEF technique empowers hub to communicate course solicitation to certain neighbors rather than all.To do this, NCBEF strategy, decide high respectable neighbors during hello signal transmission.Few hypotheses were formulated to evaluate and test NCBEF method which was accepted.
As correspondence bearer point of view, network classifies in wired and wireless form.Further wireless network likewise had some expertise in EAI Endorsed Transactions on Industrial Networks and Intelligent Systems Research Article EAI Endorsed Transactions on Industrial Networks and Intelligent Systems Online First 1 foundation less on the interest of uses and conditions.

Figure 1
Figure 1 presents classification of network in in setting of correspondence bearer.In the figure coloured arc highlight the concern which will be discussed in this work.

Figure 1 .
Figure 1.Category of networks

Figure 2 .
Figure 2. MANET Scenario With the presence of finite resource constraints of devices, ad-hoc network becomes more concentrating field of study and research.Flooding resulted replications of the same packets where each device receives multiple copies of packets which lead numerous problems such as wastage of resource, congestion and many more.In case of large network, flooding results unnecessary transmission of same routing messages which leads wastage of bandwidth and power, congestions and collisions.Replications of message occurred bandwidth choke and congestion issues.Below figure illustrates discussed issue.

Figure 7 .
Figure 7. Transmission range of node 1 directional antenna was benefited to optimize the performance.A hybrid flooding strategy was additionally proposed which consolidates "Neighbor learning based flooding and Area-based flooding called FONIAH (Flooding in light of One-bounce Neighbor NCBEF assists sender or any other node to select some appropriate neighbours instead of all for further broadcasting.According to NCBEF, sender or any node select high creditable neighbours to broadcast routing packets during routing.The creditability of node is defined by credit (C) which is determined by weight calculation.Therefore, to determine a credit coverage area, stay time and power backup of node have considered.However, Credit (C) is factorized in c1, c2 and c3 with the respect of coverage area, stay time, power backup.The value of c1, c2 and c3 is constant and the sum of all is should be 1.A formula to calculate credit (C) of node defines in below equation.CA is coverage area of node ST-ST is stay time of node at any place PB-PB is power backup of node c1, c2 and c3 are credit factors NCBEF functions in in two steps.First, each node of network determines its credit via calculating weight.Then nodes exchange their credit value with the neighbours to maintain record.Nodes credit exchange achieve through periodic exchange of modified hello signal.In general hello signal leads neighbour discovery in wireless communication.Hello signal is broadcasted in form of message that has number of fields.General format of hello message defined below.For the NCBEF method, hello message modified by defining new field i.e.C_Val in existing format.The modified hello message shows below.

Figure 8 .
Figure 8.A mobile ad-hoc networks scenario

Figure 10 .
Figure 10.Comparative network life Routing Efficiency -Routing Efficiency is characterized as proportion of information transmitted to the aggregate routing requests and information packets.Comparative routing efficiency

Figure 11 .
Figure 11.Comparative routing efficiency Throughput -NCBEF method results more throughput comparatively blind method.Throughput is data units received successfully per unit time at the receiver.Figure 12 show routing efficiency comparison of both methods.

Figure 12 .
Figure 12.Comparative throughput Node Credit Based Efficient Flooding (NCBEF) Method for Mobile Ad-hoc Networks EAI Endorsed Transactions on Industrial Networks and Intelligent Systems Online First communication range is divided in six subareas as 11, 12, 13, 14, 15, 16, illustrate in below figure.

11 12 13 14 15 16
[39]offering decision capability to nodes for rebroadcasting or discarding receiving packets, a method[39]was advised.In these nodes made 1 EAI Endorsed Transactions on Industrial Networks and Intelligent Systems Online First 6

Table 2 .
Simulation matrices Network Simulator-2 (NS-2) is function evaluation software for the network which is free available and open source.It is event based that designed and