Internet DRAFT - draft-bakht-maoddp

draft-bakht-maoddp



INTERNET-DRAFT					Dr. Humayun Bakht 
Expires: May 2014				Director of Studies
Request for Comments				London School of Commerce 
draft-bakht-maoddp-02.txt			Email: humayunbakht@yahoo.co.uk
			
	                        		
Category: Informational          			December 2013                              
                  
                                                   
                                         
           Fault Detection and Recovery in Wireless Sensors Network 
Abstract 
Wireless Sensors networks (WSNs) are type of wireless ad-hoc 
networks with reduced or no mobility. These networks combine 
wireless communication with minimal onboard computation facilities 
for sensing and monitoring of physical and environmental phenomena.
Much work has been reported on different aspects of wireless sensors 
networks;however,less attention has been paid on addressing fault 
detection and recovery in these networks.
Fault could be any thing which can lead communication break down as a 
whole or part of a wireless sensors network.Thus, detection of such 
fault attains a primary focus to support routine operations within 
such networks.
Mobile Ad-hoc On Demand Data Delivery Protocol (MAODDP) belongs to 
on-demand data delivery type routing family of mobile ad-hoc networks.
The contribution of this paper is to introduce an efficient fault 
detection and recovery mechanism for WSNs network. We believe proposed
two step model can offer a robust solution for the fault management 
in Wireless Sensors Network.   
    
Status of This Memo  
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RFC 		Fault Detection and Recovery in Wireless Sensors Network   December 2013






Table of Contents    

Abstract	1
Status of This Memo	1
2.   Introduction	2
3.   Fault Detection and Recovery in a Wireless Sensors Network3
3.1. Time State							3
3.2. Data Communication						3
3.3. Dead Node							3
3.4. Sleep Mode							4
3.5. Route Finder						4
4.   Discussion							4
5.   References							5

 

 1.   Conventions used in this document 
    
  The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 
     document are to be interpreted as described in "Key words for use 
    in RFCs to Indicate Requirement Levels". 

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RFC 		Fault Detection and Recovery in Wireless Sensors Network    December 2013

    
2.   Introduction
With the recent advances in technologies miniaturization of 
computing and sensing technologies enables the development of 
tiny, and low-cost sensors and controller [1]. There is an 
increasing focus on these systems is observed in the civil 
domain to monitor and to protect critical infrastructure such 
as bridges and tunnels etc [2]. Such wireless networks of 
distributed sensor nodes are commonly known as Wireless Sensor 
Networks (WSNs) [3]. WSNs have its origin from mobile 
ad-hoc network [4]. Mobile ad-hoc network is the collection 
of mobile nodes establishing network without requiring any 
supporting infrastructure [5]. 

Sensor link the physical world with the digital world by 
capturing, interacting and revealing real-world objects into a 
form that can be stored, processed and analyzed [6]. Sensor 
can help to monitor and avoid catastrophic infrastructure 
failures, conserve precious natural resources, increase 
productivity, and enable new applications such as smart homes 
and smart cities technologies [7,8].  

Mobile ad-hoc on-demand data delivery protocol (MAODDP) is an 
on-demand data delivery protocol focusing route establishment 
and data delivery one after the other simultaneously at the 
same time. MAODDP has been extended to support similar 
operations in related network. The contribution of this work is 
to introduce a novel two step model of fault management for WSNs. 
In this context, this work has been organized as follows. 
In section 3 A detail overview of the proposed two step model 
is presented and in section 4 A conclusive discussions on the 
presented model is covered. 

  
 
3.  Fault Detection and Recovery in a Wireless Sensors Network
The structure of wireless sensor network could take one of many forms 
therefore standard fault detection mechanisms might not be suitable 
under different scenarios or structure formation. However, types of 
faults to some extent directly related with specific structural 
deployment of a WSN. It is therefore important to know what types of 
fault could encounter in an established WSNs.  

Among the many types of faults, link breakage could be seen as one of 
the common faults which might be found in any wireless sensors network 
irrespective of which structure it follows. Such faults could happen in 
one of many situations which depend of various restrictions of devices 
participating in a network. Therefore, it is important that fault 
detection mechanisms should put minimum or in ideal case no extra 
burden on network available resources. Examples of some such resources 
are bandwidth and battery power as in the case of wireless sensors 
networks. 



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It has been mentioned that devices in a sensors network generally operate 
at a low battery power. Extra operational requirements may develop a 
situation where most of the available battery power consumes in tasks 
other then real communication. Similarly the same could pose additional 
requirements to the available bandwidth resulting slowing down 
communication or data transfer, thereby, degrading performance of a WSN.

It is quite understandable that the CLUSTER HEAD (CH) OR GROUP LEADER of a 
GROUP cannot all alone handle such failures OR errors. In due course, 
errors could also be some thing other then fault detection. However, this 
term has been used synonymously in place of faults in the available 
literature. CH can function better if a fault detection mechanism can 
follow a distributed set of an operation. Since, it is quite obvious that 
in most of the network life CH would be busy in communicating with SINK 
in order for collected data to be delivered at the base station.  It is 
off interest that there is one of many possible ways of CH selection as 
reported in the existing literature. However, in a general sense a NODE 
or a STATION with high power and storage capacity could be a standard 
choice. 

It is highly unlikely that a fault detection and recovery solution 
requiring some additional tasks for Cluster Head to perform could 
full-fill all the requirements. It is partially due to the same 
reasons that this particular area stands alone and requires some better 
mechanism of handling issue being discussed. 

Fault detection and fault recovery are interrelated with each other. On 
one hand where fault detection is considered on other side fault recovery 
has to be taken on board at the same time. A general principle as outlined 
in the above discussion has been followed in the proposed fault detection 
and recovery for WSNs and is as follows. 

3.1. Time State
It is in view of the above discussion a TIME state has been introduced 
as a part of HEADER of a data packet in MAODDP. Such factor could be used 
either to calculate or to determine a successful data delivery. It is 
important to mention that TIME factor is one of some novel factor of the 
presented mechanism.  Wireless node has also been made responsible to take 
necessary steps in case a node feels some communication disturbances. 
This model has been named as a two steps due to the above mentioned actions 
which are introduced to ensure error free communication.  TIME state T not 
only ensures effective communication but also validates known path entries 
of WSNs nodes. 

3.2. Data Communication
if an acknowledged or replied is not receive within the time T a wireless 
node regardless of status i.e. head or a member can either consider resending 
the data packet or a query could be initiated to the node closest to the 
desired destination.  A limit of maximum two reattempts has been added as a 
crucial part of the proposed scheme. In between these two attempts the first 
one must be done and the second is optional. Therefore, if the node is not in 
a position where it can make a second attempt subsequent retry is not required. 
 
A sensor node could chose to conserve power then to consume it in another 
attempt.  If after first or second retries NO STATUS UPDATE is received, 
such destination is MARKED as UNAVILABLE OR DEAD.  In order to minimize 
addition tasks, SOURCE node is not required to ISSUE any UPDATE notification 
about the DEAD node rather a NOVEL approach has been introduced. 



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3.3. Dead Node
In the adopted procedure in MAODDP, a node having information about a 
DEAD node, add a reference to it in the next communication to any node 
in the network. Such entries are marked with (D + MNO) where D 
represents a Dead node and MNO represent the dead node member number.  
A retry to any of the wireless node can alert all the nodes in the path 
to the destination node about a possible break. Such node would also 
follow the above procedure for minimum of one subsequent communication 
cycle. It is self explanatory that all group members became aware of a 
possible DEAD node in due time.  An account of SLEEPING MODE has also 
been considered; therefore a soft measure of RE-ALIVE Header has been 
added. In essence if a node misses a communication due to being 
in a sleep mode and discover again, any such discovering could be marked 
as (RAL+MNO), here RAL denotes re-alive and MNO is for member number. 
Such MARKS are added only once by all the nodes in the path in very next 
data transmission. 

3.4. Sleep Mode
In relation with SLEEP MODE depends on a wireless sensors network 
formation, a node might be given permission to switch into SLEEP MODE. 
In other words, during such mode nodes are considered in an active 
transmission. In addition to the above, though Status Time calculation 
can also reflect such situation, however, such precaution is added to 
avoid any minor possibility. In second step of a two steps model if a 
node does not hear delivery confirmation from the CH, it can follow 
the same procedure of retries as mentioned earlier in STEP one. 

3.5. Route Finder
Based on relation between CH and a member node retries does not mean 
that NODE should STOP sending collected data rather a ROUTE FINDER 
PACKET (RFP) is broadcast by a node who have lost path to the CH. 
Such measures are necessary to enable node performing primary tasks 
of such deployments. A ROUTE FOUND PACKET (RFP) is sent back to such 
node from any of the NODE having an active path to the CH.  
 
4.Discussion
It is evident from the above discussion that such approach is feasible 
in terms of refreshing route or communication path between the member 
nodes and the CH. Moreover, it is also beneficial in avoiding NETWORK 
REBOT option which could otherwise result in data lost. NETWORK 
REBOTTING is an available option if a WSNs suffers badly with huge 
faults resulting communication dropped at a large scale. Such situation 
could force a WSNs to reboot in order to reconfigure network topology. 
In worst scenarios, network formation pattern could also be taken into 
account. It can be concluded that proposed mechanism offer a reliable 
and quick FAULT detection and recovery for a WSN. Similarly, based on 
the given specification very less temporary additional tasks are taken 
to make it an effective solution for fault management in a wireless 
sensors network.





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5.  References 
    
[1]	I. F. Akyildiz, W. Su, Y. Sankarasubramaniam, and E. 
Cayirci, A survey on sensor networks," presented at the IEEE Communication 
Magazine, 2002.
[2]	H. Karl and A. Willig, Protocols and Architectures for Wireless Sensor 
Networks: John Wiley & Sons, Ltd, West Sussex, England, 2005.
[3]	B. krishnamachari, Networking Wireless Sensors: Cambridge University 
Press, New York, 2005.
[4]	K. Sohraby, D. Minoli, and T. Znati, Wireless Sensor Networks: 
Technology, Protocols, and Applications. 
[5]	 H.bakht Mobile Ad-hoc on-Demand Data 
Delivery Protocol (MAODDP), IETF draft, November 2010.
[6]	H.Bakht, Mobile Ad-hoc Networking, Create Space, January 2010.
[7]	C. Cordeiro and D. P. Agrawal, Ad hoc & sensor networks, Theory 
and Applications: World scientific publishing, 2006.
[8]		S. Gupta and N. Parveen, "Optimum Node Deployment Strategy for 
Heterogeneous Wireless Sensor Network by Estimating Network Lifetime," 
presented at the 2nd International Conference on Emerging Trends in 
Engineering and Technology (ICETET09), 2009.
  
 

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RFC 			Fault Detection and Recovery in Wireless Sensors Network     December 2013

Editors Addresses
Dr. Humayun Bakht
Director of Studies   
London School of Commerce     
United Kingdom