1.
DILLA UNIVERSITY
COLLEGE OF ENGINEERING & TECHNOLOGY
School of Computing & Informatics
M. Sc in Computer Science & Networking
By
Chapter-03
COET, Dilla University 1
Course Number CN6117
Course Title Mobile Computing

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Mobile Computing
CHAPTER-03
1. Mobile ad-hoc networks
2. Mobile IP
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1. MOBILE AD-HOC NETWORKS
 MANET stands for Mobile adhoc Network also
called as wireless adhoc network or adhoc wireless
network that usually has a routable networking
environment on top of a Link Layer ad hoc network.
 They consist of set of mobile nodes connected
wirelessly in a self configured, self healing network
without having a fixed infrastructure.
 MANET nodes are free to move randomly as the
network topology changes frequently.
 Each node behaves as a router as they forward
traffic to other specified node in the network.
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4.
Cont..
 MANET may operate as standalone fashion or they can
be the part of larger internet.
 They form highly dynamic autonomous topology with
the presence of one or multiple different transceivers
between nodes.
 The main challenge for the MANET is to equipped each
devices to continuously maintain the information required
to properly route traffic.
 MANETs consist of a peer-to-peer, self-forming, self-
healing network MANET’s typically communicate at radio
frequencies (30MHz-5GHz).
 This can be used in road safety, ranging from sensors
for the environment, home, health, disaster rescue
operations, air/land/navy defense, weapons, robots, etc.
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MANET (Mobile Ad Hoc Networks)
• Formed by wireless hosts which may be mobile
• No pre-existing infrastructure
• Routes between nodes may potentially contain multiple hops
– Nodes act as routers to forward packets for each other
– Node mobility may cause the routes change
A
B
C
D
A
B
C
D
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• Advantages: low-cost, flexibility
– Ease & Speed of deployment
– Decreased dependence on infrastructure
• Applications
– Military environments
• soldiers, tanks, planes
– Civilian environments
• vehicle networks
• conferences / stadiums
• outside activities
– Emergency operations
• search-and-rescue / policing and fire fighting
Why MANET?
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• Collaboration
– Collaborations are necessary to maintain a MANET and its
functionality.
– How to collaborate effectively and efficiently?
– How to motivate/enforce nodes to collaborate?
• Dynamic topology
– Nodes mobility
– Interference in wireless communications
Challenges
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Comparison
• MANETs vs. Wired networks
– In MANETs, each node also works as router for
forwarding packets
– In wired networks, routers perform routing task
• MANETs vs. Managed wireless networks
– No infrastructure in MANETs
– Special node known as access point (AP) in managed
wireless networks
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MANETS
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Characteristics of MANET
 Dynamic Topologies
 Bandwidth constrained, variable capacity
links
 Autonomous Behavior
 Energy Constrained Operation
 Limited Security
 Less Human Intervention
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11.
Cont..
Dynamic Topologies: Network topology which is typically multi
hops, may change randomly and rapidly with time, it can form
unidirectional or bi-directional links.
Bandwidth constrained, variable capacity links: Wireless links
usually have lower reliability, efficiency, stability, and capacity
as compared to wired network. The throughput of wireless
communication is even less than a radio’s maximum
transmission rate after dealing with the constraints like
multiple access, noise, interference conditions, etc.
Autonomous Behavior: Each node can act as a host and router,
which shows its autonomous behavior.
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12.
Cont..
Energy Constrained Operation: As some or all the nodes
rely on batteries or other exhaustible means for their
energy. Mobile nodes are characterized with less
memory, power, and lightweight features.
Limited Security: Wireless network are more prone to
security threats. A centralized firewall is absent due
to its distributed nature of the operation for security,
routing, and host configuration.
Less Human Intervention: They require minimum human
intervention to configure the network, therefore they
are dynamically autonomous in nature.
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Types of MANETs
 Vehicular Ad hoc Network (VANETs)
 Smart Phone Ad hoc Network (SPANC)
 Internet based Mobile Ad hoc Network (iMANETs)
 Hub-Spoke MANET
 Military or Tactical MANETs
 Flying Ad hoc Network (FANETs)
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Cont..
Vehicular Ad hoc Network (VANETs)
• Enable effective communication with another vehicle or with the
roadside equipments.
• Intelligent vehicular ad hoc networks(InVANETs) deals with another
vehicle or with the roadside equipments.
Smart Phone Ad hoc Network (SPANC)
• To create peer-to-peer network without relying on cellular carrier
networks, wireless access points or traditional network
infrastructure.
• Here peer can join or leave the network without destroying it.
Internet based Mobile Ad hoc Network (iMANETs)
• It supports internet protocols such as TCP/UDP and IP.
• To link mobile nodes and establish routes distributed and
automatically.
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Cont..
Hub-Spoke MANET
• Multiple sub MANET’s may be connected in hub-spoke VPN to
create a geographically distributed MANET.
• Normal Ad-hoc routing algorithm does not apply directly.
Military or Tactical MANETs
• This is used by the military units.
• Emphasis on data rate, real time demand, fast re-routing during
mobility, security, radio range, etc.
Flying Ad hoc Network (FANETs)
• This is composed of unmanned aerial vehicle (commonly known as
drone).
• Provides links to remote areas and mobility.
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Benefits of MANET
 Highly suitable network in such circumstances where fixed
infrastructure is too much costly, untrustworthy, not trusted and
due to unavailability of such a network.
 Quickly installation with least possible user intervention.
 Detailed planning and installation of base stations is not required.
 Ad hoc networks can be attached to the WWW or Internet,
thereby incorporating many different devices and making possible
for other users to use available services.
 Capacity, range and energy arguments promote their use in
tandem with existing cellular infrastructures as they can extend
coverage and interconnectivity.
 MANET also fitted to use the 4G architecture and their services,
aims to provide ubiquitous computer environments that support
users in completing their tasks, accessing information and
communicating anywhere , anytime and from any device .
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Applications of MANET
Some distinctive MANET applications include:
• Military field
• Cooperative work
• Confined level
• PAN and Bluetooth
• Business Sector
• Sensor Networks
• Backup Services
• Educational sector
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Cont..
Military field:
Ad-Hoc networking can permit army to exploit benefit of conventional network
expertise for preserving any info network among vehicles, armed forces, and
headquarters of information.
Cooperative work:
To facilitate the commercial settings, necessity for concerted computing is very
significant external to office atmosphere and surroundings as compared to inner
environment.
People want getting outside meetings for exchanging the information plus
cooperating with each other regarding any assigned task.
Confined level:
Ad-Hoc networks are able to freely associate with immediate, in addition
momentary hypermedia network by means of laptop computers for sharing the info
with all the contestants’ e.g. classroom and conference.
Additional valid and confined level application may be in domestic network where
these devices can interconnect straight in exchanging the information.
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Cont..
PAN and Bluetooth:
A PAN(Personal Area Networks) is localized and tiny range network whose
devices are generally belong to a specified individual.
Limited-range MANET such as Bluetooth can make simpler the exchange
among several portable devices like a laptop, and a cell phone.
Business Sector:
Ad-hoc network could be used for rescuing and emergency processes for
adversity assistance struggles, for instance, in flood, fire or earthquake.
Emergency saving procedures should take place where damaged and non-
existing transmissions structure and quick preparation of a transmission
network is required.
Sensor Networks:
Managing home appliances with MANETs in both the case like nearby and
distantly.
Tracking of objects like creatures. Weather sensing related activities.
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Cont..
Backup Services: liberation operations, tragedy recovery,
diagnosis or status or record handing in hospitals,
replacement of stationary infrastructure.
Educational sector: arrangement of communications facilities
for computer-generated conference rooms or classrooms or
laboratories.
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Challenges in Mobile Environments
 Limitations of the Wireless Network
 packet loss due to transmission errors
 variable capacity links
 frequent disconnections/partitions
 limited communication bandwidth
 Broadcast nature of the communications
 Limitations Imposed by Mobility
 dynamically changing topologies/routes
 lack of mobility awareness by system/applications
 Limitations of the Mobile Computer
 short battery lifetime
 limited capacities
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Routing
 Routing is the process of selecting a path
for traffic in a network or between or across
multiple networks.
 Packet forwarding is the transit of network
packets from one network interface to
another.
 Intermediate nodes are typically network
hardware devices such as routers, gateways,
firewalls, or switches.
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Routing protocol
 A routing protocol specifies how routers
communicate with each other to distribute
information that enables them to select
routes between any two nodes on a computer
network.
 A routing protocol shares this information
first among immediate neighbors, and then
throughout the network.
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MANET Main Classification
Reactive
On-Demand
Proactive
Table-Driven Hybrid
•DSDV
•WARP
•DREAM
•DSR
•AODV
•TORA
•ZRP
•HARP
Ad Hoc Routing Protocols Main Classification
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Proactive Protocols
Proactive: maintain routing information
independently of need for communication
• Update messages send throughout the
network periodically or when network
topology changes.
• Low latency, suitable for real-time traffic
• Bandwidth might get wasted due to periodic
updates
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On-Demand or Reactive Routing
• Reactive: discover route only when you need it
• Saves energy and bandwidth during inactivity
• Can be bursty -> congestion during high activity
• Significant delay might occur as a result of route
discovery
• Good for light loads, collapse in large loads
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Hybrid Routing
• Proactive for neighborhood, Reactive for far
away (Zone Routing Protocol, Haas group)
• Proactive for long distance, Reactive for
neighborhood (Safari)
• Attempts to strike balance between the two
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MANET Routing Protocols Classification
Source: MINEMA
Uniform
routing
Proactive
routing
Wireless Routing Protocol (WRP)
Destination Sequence Distance Vector (DSDV) routing protocol
Fisheye State Routing (FSR)
Distance Routing Effect Algo. for Mobility (DREAM) Location-based routing
Reactive
routing
Dynamic Source Routing (DSR) protocol
Temporally-Ordered Routing Algorithm (TORA)
Adhoc On-demand Distance Vector Routing (AODV)
Location Aided Routing (LAR) Location-based routing
Associativity Based Routing (ABR) protocol Link-stability based routing
protocol
Signal Stability-base adaptive Routing (SSR) Link-stability based routing
protocol
Non-uniform
routing
Zone-based
routing
Zone Routing Protocol (ZRP) Hybrid routing protocol
Hybrid Adhoc Routing Protocol (HARP) Hybrid routing protocol
Zone-based Hierarchical Link State routing (ZHLS) Hybrid routing protocol
Grid Location Service (GLS) Location service
Cluster-based
routing
Clusterhead Gateway Switch Routing (CGSR)
Hierarchical State Routing (HSR)
Cluster Based Routing Protocol (CBRP)
Core-node
based routing
Landmark Adhoc Routing (LANMAR) Proactive routing
Core-Extraction Distributed Adhoc Routing (CEDAR) Proactive routing
Optimised Link State Routing protocol (OLSR) Proactive routing
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2. Mobile IP
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2. Mobile IP
Mobile IP (or MIP) is an Internet Engineering
Task Force (IETF) standard communications
protocol that is designed to allow mobile
device users to move from one network to
another while maintaining a permanent IP
address.
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Why Mobile IP?
• What do cellular networks and wireless LANs provide?
– Wireless connectivity
– Mobility at the data link layer
• What is Dynamic Host Configuration Protocol (DHCP)?
– It provides local IP addresses for mobile hosts
– Is not secure
– Does not maintain network connectivity when moving
around
• What they do not provide:
– Transparent connectivity at the network layer
– Mobility with local access

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What is Mobile IP?
• Mobile IP provides network layer mobility
• Provides seamless roaming
Ability that a user roams in a secure way
across, different networks while keeping
connected and not disturbing ongoing
sessions and conversations.
• ‘‘Extends’’ the home network over the entire
Internet

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What Mobile IP does:
• Mobile IP solves the following problems
– if a node moves without changing its IP address it will be
unable to receive its packets,
– if a node changes its IP address it will have to terminate and
restart its ongoing connections every time it moves to a new
network area (new network prefix).
• Mobile IP is a routing protocol with a very specific
purpose.
• Mobile IP is a network layer solution to node mobility in
the Internet.
• Mobile IP is not a complete solution to mobility, changes
to the transport protocols need to be made for a better
solution

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Requirements to Mobile IP (RFC 2002)
• Transparency
– mobile end-systems keep their IP address
– continuation of communication after interruption of link
possible
– point of connection to the fixed network can be changed
• Compatibility
– support of the same layer 2 protocols as IP
– no changes to current end-systems and routers required
– mobile end-systems can communicate with fixed systems
• Security
– authentication of all registration messages
• Efficiency and scalability
– only little additional messages to the mobile system required
(connection typically via a low bandwidth radio link)
– world-wide support of a large number of mobile systems in the
whole Internet
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Mobile IP Terminology
• Mobile Node (MN)
– system (node) that can change the point of connection to the network without
changing its IP address
• Home Agent (HA)
– system in the home network of the MN, typically a router
– registers the location of the MN, tunnels IP data grams to the COA
• Foreign Agent (FA)
– system in the current foreign network of the MN, typically a router
– forwards the tunneled datagrams to the MN, typically also the default router for
the MN
• Care-of Address (COA)
– address of the current tunnel end-point for the MN (at FA or MN)
– actual location of the MN from an IP point of view
– can be chosen, e.g., via DHCP
• Correspondent Node (CN)
– communication partner

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Mobile IP Diagram
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Cont..
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Mobile IP
• Three Mobile IP mechanisms
– 1. Discovering
– 2. Registering
– 3. Tunneling
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Mobile IP (cont)
1. Discovery
– Extension of ICMP Router Advertisement
– Home agents and foreign agents broadcast agent
advertisements at regular intervals
– Agent advertisement
Allows for the detection of mobility agents
Lists one or more available care-of addresses
Informs the mobile node about special features
Mobile node selects its care-of address
Mobile node checks whether the agent is a home
agent or foreign agent
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Mobile IP Agent Advertisement Message
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Mobile IP (cont)
• 2. Registration
– Once a mobile node has a care-of address, its home agent
must find out about it
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Registration request Message
Registration reply Message
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Mobile IP (cont)
• Secure the Registration Procedure
– The home agent must be certain registration was originated by
the mobile node and not by some malicious node
– Security association: Message Digest 5 (MD5)
– Replay attacks
A malicious node could record valid registrations for
later replay, effectively disrupting the ability of the
home agent to tunnel to the current care-of address
of the mobile node at that later time
Identification field that changes with every new
registration
Use of timestamp or random numbers
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Message Digest 5 (MD5)
• One-Way Hash Function
– With some good properties, …
– Produces a 128-bit message digest
• Example
– Two communicating parties A and B
– A and B share a common secret value SAB
– When A has a message (M) to send to B, it calculate MDM =
H(SAB || M)
– It then sends [ M || MDM ] to B
– Because B possesses SAB, it can re-compute H(SAB || M) and
verify MDM.
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Mobile IP (cont)
3. Tunneling to the care-of address
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Two Tunneling Methods
IP-within-IP Encapsulation Minimal Encapsulation
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Mobile IPv6
• Mobility support in IPv6
– Follows the design for Mobile IPv4, using encapsulation to
deliver packets from the home network to the mobile point of
attachment
• Route Optimization
– Similar to IPv4
– Delivering binding updates directly to correspondent nodes
(home address, care-of address, registration lifetime)
• Security
– IPv6 nodes are expected to implement strong authentication
and encryption features
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Problems facing Mobile IP
• Routing inefficiencies
– Asymmetry in routing: Triangle routing
– Route optimization requires changes in the correspondent
nodes that will take a long time to deploy
• Security issues
– Firewalls
Blocks all classes of incoming packets that do not
meet specified criteria
It presents difficulties for mobile nodes wishing to
communicate with other nodes within their home
enterprise networks
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References
Reference Text Books:
• J. Schiller, Mobile Communications, Addison
Wesley, 2003.
• Alexander Kukushkin, Introduction to Mobile
Network engineering GSM,3G-WCDMA, LTE
and the Road to 5G, Wiley
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50.
THANK YOU
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