Project Presentation

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• Project Presentation
• Quality of service
• in
• ad-hoc networks

Presented By Abbas Agane ELG 5125 - University
of Ottawa November 29, 2005
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Agenda

• Introduction
• Ad-hoc Network definition
• Overview Ad-hoc networks
• Network architecture
• Applications of ad-hoc networks
• Ad-hoc networks characteristics and requirements
• Overview QoS
• What is QoS ?
• The need of QoS in MANETs
• Why QoS is hard in MANETs
• Current Solutions for Support in MANETs
• Flexible QoS Model for MANETs
• INSIGNIA-MANETs QoS Signaling
• Cluster-based Routing Protocol
• SWAN for MANETs

• Ad-hoc QoS interconnectivity with Fixed Network
• Domain services
• Model for QoS ad-hoc interaction with the host
  domain
• Mechanism of operation
• Ad-hoc QoS interaction with the host domain
  architecture
• End-to-end Qos in MANETs connected to Fixed
  Networks
• (DS-SWAN)
• DS-SWAN for upstream
• Conclusions
• QA

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Ad Hoc Network definition

• An ad-hoc network is a wireless LAN, in which
  some devices are part of the network only for the
  duration of a communication session or while in
  some close proximity to the rest of the network.
• A "mobile ad hoc network" (MANET) is an
  autonomous system of mobile routers (and
  associated hosts) connected by wireless links
  forming an arbitrary graph. Routers are free to
  move randomly and organize themselves
  arbitrarily network topology may change rapidly
  and unpredictably. May operate in a stand-alone
  fashion, or may be connected to the Internet.
• An ad hoc network can be regarded as a
  spontaneous network a network that
  automatically emerges when nodes gather together

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MANET Mobile Ad hoc NETworks
C
B
A
D

• - Mobility - Self configuring and healing -
  Rapid Deployment
• High capacity - Independent of public
  infrastructure - Relaying
• Internet compatible standards-based wireless
  systems

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Network Architecture

• Multi-layered network infrastructure

• Flat network infrastructure

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Applications of Ad Hoc Networks

• Personal communications
  
• cell phones, laptops
• Cooperative environments
• taxi cab network
• meeting rooms
• Emergency operations
  
• policing and fire fighting
• Military environments
• Battlefield
• Network of sensors or floats over water

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Ad Hoc Networks Characteristics and Requirements

• Autonomous and spontaneous nature of nodes
• Distributed Algorithms to support security,
  reliability and consistency of exchanged and
  stored information
• Time-varying network topology (no pre-existing
  infrastructure or central administration)
• Scalable routing and mobility management
  techniques to face network dynamics
• Fluctuating link capacity and network resources
• Enhanced functionalities to improve link layer
  performance, QoS network support and end-to-end
  efficiency
• Low-power devices
• Energy conserving techniques at all layers

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What is QoS ?

• Hard to agree on a common definition of QoS
• A QoS enabled network shall ensure
• That its applications and/or their users have
  their QoS parameters fulfilled, while at the same
  time ensuring an efficient resource usage
• That the most important traffic still has its QoS
  parameters fulfilled during network overload
• What are the most important QoS parameters
• Throughput, availability, delay, jitter and
  packet loss

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The need for QoS in MANETs

• Applications have special service requirements
• VoIP delay, jitter, minimum bandwidth
• Needs intelligent buffer handling and queueing
• High mobility of users and network nodes
• Routing traffic is important
• No retransmission of lost broadcast messages
• Routing contol messages must be prioritized
• For use in emergency and military operations
• User traffic prioritization is needed
• user, role, situation etc
• Wireless bandwidth and battery capacity are
  scarce resources
• Need efficient resource usage
• E.g. only route high priority traffic through
  terminals that are low on power
• Need QoS aware routing

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Why QoS is Hard in Mobile Ad Hoc Networks?

• Dynamic network topology
• Flow stop receiving QoS provisions due to path
  disconnections
• New paths Must be established, causing data loss
  and delays
• Imprecise state information
• Link state changes continuously
• Flow states change over time
• No central control for coordination
• Error-prone shared medium
• Hidden terminal problem
• Limited resources availability
• Bandwidth, battery life, storage, processing
  capabilities
• Insecure medium

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Current Solutions for QoS support in Mobile Ad
Hoc Networks

• Because of the unique characteristics of the
  ad-hoc environment three models provide some good
  insight into the issues of QoS in MANETs
• These models provide a comprehensive solutions,
  namely
• INSIGNIA
• FQMM
• SWAN

• FQMM
• INSIGNIA
• SWAN

Flexibility!
Can be integrated with multiple routing
protocols
?
?
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Flexible QoS Model for MANETs (FQMM)

• First QoS Model proposed in 2000 for MANETs by
  Xiao et al
• Proposes a hybrid provisioning that combines
  the per-flow granularity on IntServ and per-class
  granularity of DiffServ
• Adopts DiffServ, but improves the per-class
  granularity to per-flow granularity for certain
  class of traffic
• Built over IntServ and DiffServ models, it can
  operate with extranet traffic
• Classification is made at the source node
• QoS provisioning is made on every node along the
  path
• FQMM Model provisions the traffic into two
  portions
• the highest priority is assigned per-flow
  granularity.
• the rest is assigned per-class granularity.
• Three types of nodes defined
• Ingress (transmit)
• Interior (forward)
• Egress (receive)

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INSIGNIA MANETs QoS Signaling

• First signaling protocol designed solely for
  MANETs by Ahn et al. 1998
• In-band signaling
• Base and enhanced QoS levels
• Per-flow management
• Resources management adapted as technology
• Intelligent packet scheduling
• Flow reservation, restoration and adaptation
• QoS reports periodically sent to source node
• Source node takes action to adapt flows to
  observed network condition
• Routing
• Any routing protocol can be used
• Route maintenance procedure will affect
• In-band signaling
• Establish, adapt, tear down reservations
• Control information embedded in data packets

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INSIGNIA OPTION Field

• Supports in-band signaling by adding a new option
  field in the IP header to carry the signaling
  control
• Reservation Mode (REQ/RES) indicates whether
  there is already a reservation for this packet.
• If no, the packet is forwarded to INSIGNIA
  Module which in coordination with a AC may
  either
• grant resources ? Service Type RT (real-time).
• deny resources? Service Type BE (best-effort).
• If yes, the packet will be forwarded with the
  allowed resources.
• Bandwidth Request (MAX/MIN) indicates the
  requested amount of bandwidth.

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INSIGNIA Bottleneck Node

• During the flow reservation process a node may be
  a bottleneck
• The service will degrade from RT/MAX -gt RT/MIN.

• If M2 is heavy-loaded it may also degrade the
  service level to BE/MIN where there is actually
  no QoS.

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Cluster-based Routing Protocol for Mobile Ad hoc
Networks

• When network size increase, flat routing schemes
  become infeasible. ? hierarchical routing
• Explicit hierarchy
• Group nodes geographically close to each other
  into explicit clusters
• Clusterhead
• Communicate to other nodes on behalf of the
  cluster
• Clustering is a distributed, efficient, scalable
  protocol
• Use clustering approach to minimize on-demand
  route discovery traffic
• use local repair to reduce route acquisition
  delay and new route discovery traffic
• suggest a solution to use uni-directional links

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Cluster Formation
routing showing a data path from source to
destination
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Cluster Formation

• Objective
• Form small, stable clusters with only local
  information

• Mechanism
• Variations of min-id cluster formation
  algorithm.
• Nodes periodically exchange HELLO pkts to
  
• maintain a neighbor table
• neighbor status (C_HEAD, C_MEMBER, C_UNDECIDED)
• link status (uni-directional link,
  bi-directional link)
• maintain a 2-hop-topology link state table

HELLO message format
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SWAN Stateless Wireless Ad Hoc Networks

• An alternative to INSIGNIA with improved
  scalabilities properties
• Is a stateless network scheme designed
  specifically for MANETs with no need to process
  complex signaling, or to keep per-flow
  information, to achieve scalability and
  robustness
• Promotes rate control system that can be used at
  each node to treat traffic either as real-time or
  best-effort
• Excessive real-time traffic is automatically
  demoted to best-effort
• While provides a model that deals with traffic on
  a per-class , it uses merely two level of
  service, best-effort and real-time traffic
• Both level of service can be mapped to DCSPs with
  known PHB (based on bandwidth requirement) to
  facilitate extranet QoS
• May decide to demote part of the real-time
  traffic to best-effort service due to lack of
  resources
• The transmission rate for the best-effort traffic
  is locally estimated and adjusted to accommodate
  the bandwidth required by Real Time traffic
• Supports source-based admission control and
  distributed congestion control for real-time
  traffic
• Uses explicit congestion notification (ECN)

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ad-hoc QoS interconnectivity with fixed network

• Ad-Hoc network needs to cling to a host network
  in order to gain access to the internet
• Co-operation between ad hoc network and the host
  network can facilitate end-to-end QoS support
• Framework proposed by Morgan and Kunz defines a
  solution for interaction between ad hoc and host
  networks
• This framework is not affected by the specific
  QoS model implemented on either side
• Ad-Hoc network may decide to implement INSIGNIA,
  SWAN, or FQMM, while host network may decide to
  implement DiffServ or IntServ
• Ad-hoc networks rely on the host network
  resources and services in order to access to the
  outside world
• The host network provides support for the ad-hoc
  by providing access to specific domain services
  and agreements
• Domain services are expressed in terms of three
  major components

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Domain services

• Service Level Agreement (SLA) Fixed networks
  define SLA as a contract between a customer and
  service provider that specifies, what services
  the network service provider will furnish
• Ad hoc domain may decide to use any protocol
  such as SLP (service Location Protocol ) to
  locate specific services such as a mail server,
  based on individual needs
• Traffic Conditioning Agreement (TCA) Specifying
  classifier rules and any corresponding traffic
  profiles and metering and shaping rules which are
  to apply the traffic streams selected by the
  classifier
• An example of TCA is the DSCP mapping, and packet
  fragmentation
• Ad Hoc network need to adopt a set of DSCP codes
  in order to be able to deal with DiffServ QoS
  traffic
• Service Provisioning Policy how traffic
  conditioners are configured on domain boundary
  nodes and how traffic streams are mapped to
  behaviour aggregates to achieve a range of
  services

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Model for QoS ad-hoc interaction with host domain
Network Elements 1,2
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Mechanism of Operation

• The GW to the proposed friendly domain can use
  SLA and TCA proposed by its fixed domain only
• GW(A) adopts SLA and TCA proposed by domain DS
• While GW(A) adopts SLA and TCA proposed by
  domain DS
• The GW has to achieve a compromise between the
  costs using different services
• When a GW looses link connectivity during a
  per-class, extranet packets have to be rerouted
  to an alternate GW
• Otherwise it will return to the originating node
  with a proper error code
• GWs have to create a table of the in-service DSCP
• This table provides a way of finding an alternate
  GW
• When a GW looses link connectivity during a
  per-flow session, extranet packets have to be
  returned to the sender with an error report

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Aggregate RSVP

• Is used to solve the scalability issues of RSVP
  protocol
• It is particular efficient for inter-domain
  reservations
• The terminal ad hoc network is good to employ
  aRSVP
• Since, all ad-hoc extranet traffic have to pass
  through an access network
• aRSVP is used to configure an aggregate PHB
  between nodes A, A, on one hand and D, D on
  the other hand
• All end-to-end reservations that use RSVP will
  use the same aggregate if they belong to the same
  class
• All same class reservations will share resources
  reserved by a single aRSVP
• This raises the problem of dealing with bursty
  traffic, because it will simply eat up the
  resources of other flow
• Because, Bursty traffic will simply eat up
  resources of other flows
• Proved that the performance degradation due to
  bursty flow comes with performance enhancement in
  the form of reduction of delay in the tail of the
  delay distribution

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Pro-active and reactive approach

• Proactive approach, by allowing the first or best
  AN to place an aRSVP request to reserve all
  classes of traffic (i.e. DSCP)
• Then other users will use pre-configured
  services, and only solicit a request for upgrade
  when needed
• Problem is the reservation of unused resources in
  anticipation of future need
• Unused resources can be released until needed.
  When needed, they can simply activated
• Reactive approach, by reserving services only
  when needed
• When services for a new DSCP are needed, the GW
  will broadcast a solicit message requiring all
  ANs to reply with the level of service and cost
  they can obtain from a specified host domain
• GW then will apply a selection criteria to choose
  which AN should provide aRSVP connection
• Reactive approach does not reserve unused
  resources like the proactive one
• However, a certain delay is expected to find the
  right AN, and to perform versus reactive aRSVP
  reservation can be determined from the service
  policy-provisioning repository

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Ad-hoc QoS interaction with host domain
Architecture
Architecture Elements 1, 2

• Ad-hoc may employ FQMM, SWAN, or INSIGNIA, and
  may be using dRSVP
• Ad-hoc will have a traffic forwarding algorithm,
  which will use the service policies in order to
  perform QoS routing
• SLA, TCA, and service provisioning policies, are
  all imported
• GW has a common access to SLA, TCA, and service
  provisioning policies

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End-To-End QoS in MANETs Connected to Fixed
NetworksDS-SWAN (Diff-SWAN)

• New protocol proposed by Remondo, designed to
  support end-to-end QoS in ad-hoc networks
  connected to fixed DiffServ domain
• DS-SWAN warns nodes in the ad-hoc networks when
  congestion is excessive for the correct
  functioning of real-time applications
• These nodes react by slowing down best-effort
  traffic
• DS-SWAN significantly improves end-to-end delays
  for real-time flows without starvation of
  background traffic
• DS-SWAN, the ingress edge router periodically
  monitors the number of Expedited Forwarding (EF)
  packets that are dropped by its token bucket
  meter
• On the other hand, the corresponding nodes in the
  fixed IP network periodically monitor the average
  end-to-end delays of the real-time flows
• DS-SWAN has been designed to combat the effect of
  congestion due to excess of best-effort traffic
  on end-to-end delay real-time flows

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DS-SWAN for upstream traffic

• For Real-time traffic, the DiffServ service
  class is the Expedite Forwarding
• PHB (Peer-Hop Behaviour)
• The number of dropped packets at the ingress edge
  router and the end-to-end
• delay of the real-time connection are associated
  with the QoS parameters of
• the SWAN model in the ad hoc network
• If the rate of the best-effort leaky bucket
  traffic shaper is lower, then best-
• effort traffic is more efficiently restricted
  and real-time traffic is not so much
• influenced by best-effort traffic, thereby
  maintaining the required QoS

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DS-SWAN for upstream traffic (cont)

• When a destination node detects that the
  end-to-end delay of one VoIP flow approached the
  threshold (i.e. becomes greater than 140ms), it
  sends a QoS_LOST warning to the ingress edge
  route
• When the edge router sends a QoS_LOST to the ad
  hoc network, it sends the message only to the
  VoIP sources generating flows that have problems
  to keep their end-to-end delay under 150ms, which
  will obviously also arrive at the intermediate
  nodes along the routes
• All these nodes forward the QoS_LOST message to
  all their neighbours because they may be
  contending with them for medium access

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DS-SWAN for upstream traffic (cont)

• The nodes in the ad hoc network use priority
  scheduling at the MAC layer to prioritize routing
  packets and QoS_LOST packets
• When a node in ad hoc network receives the
  QoS_LOST message, it will react by modifying the
  parameter value in the AIMD rate control
  algorithm
• Every time that a QoS_LOST message is received ,
  the node decreases the value of c by ?c-bit/s
  with a certain minimum value
• When no QoS_LOST message is received during T
  seconds the node increases the value of c by
  ?cbit/s unless the initial value of c has
  reached
• For r is opposite of the above results
• r-gt ?r-bit/s/ ?cbit/s

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Conclusion

• In this project, I have presented different
  existing QoS model for wireless ad-hoc networks
  and a proposed frameworks for ad-hoc
  interconnectivity with fixed domains
• INSIGNIA, SWAN, FQMM and DS-SWAN, each model
  provide the basics for a more comprehensive model
• Mobile nodes can connect to the Internet gateways
  of different types, providing different QoS
• Classified different approach with respect to
  different mobility scenarios
• Furthermore, I presented existing classified
  different level of QoS for hybrid fixed networks
• In order to achieve an end-to-end QoS approach,
  QoS information in both fixed and ad-hoc networks
  should be involved
• This demands an interaction between the sections

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References

• 1 Towards End-to-End QoS in Ad-Hoc Networks
  Connected to Fixed Networks David Remondo
  Catalonia Univ. of Technology (UPC)
• 2 An architectural framework for MANET QoS
  interaction with access domains Yasser Morgan
  and Thomas Kunz, Carleton University
• 3A proposal for an ad-hoc network QoS gateway
  Yasser Morgan and Thomas Kunz, Carleton
  University
• 4 A Glance at Quality of Services in Mobile
  Ad-Hoc Networks Zeinalipour-Yazti Demetrios
  (csyiazti_at_cs.ucr.edu)
• 5 Quality of Service in Ad-Hoc Networks Eric
  Chi, Antoins Dimakis el (smartnets_at_uclink.berkeley
  .edu)
• 6 QoS in Mobile Ad Hoc Networks Prasant
  Mohapatra, Jian Li and Chao Gui, University of
  California
• 7 QoS-aware Routing Based on Bandwidth
  Estimation for Mobile Ad Hoc networks Lei Chen
  and Wendi Heinzelman, University of
  Rochesterchenlei, wheinzel_at_ece.rochester.edu
• 8 Dynamic Quality of Service for Mobile Ad-Hoc
  Networks
• M. Mirhakkak, N. Schult, D. Thomson, The
  MITRE Corporation
• 9 Network Architecture to Support QoS in Mobile
  Ad Hoc Networks
• Lei Chen and Wendi Heizelman, University of
  Rochester

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QA
Thank You! Questions?