Thesis Proposal Defense

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Thesis Proposal Defense
Performance and Security in a Distributed
Wireless Networking Environment
Committee Dr. Andrew Yang Dr. Alfredo
Perez-Davila Ms. Wei Ding

• Presented by
• Karthik Sadasivam

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Motivation and Background

• Wireless networks are being used in almost every
  organization today
• Latest trend in wireless networks is pervasive
  and ubiquitous computing catering to both
  nomadic and fixed users anytime and anywhere
• 802.11 or Wi-fi standards for Wireless Local
  Area Networks ( 802.11a, 802.11b, 802.11g,
  802.11i) is most commonly used in enterprises
  today
• Distributed wireless networks are deployed over a
  wide geographic area and consist of mobile
  clients and base stations
• Two factors of prime importance in these networks
  Performance and Security
• Achieving an optimal balance between these two
  factors in such networks is an ongoing research
  problem

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Wireless Networks A Taxonomy

1. Single-hop cellular networks

1. Multi-hop cellular networks

1. Ad hoc networks

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Wireless Local Area Networks (WLANs)

• A Wireless Local Area Network consists of a set
  of mobile clients communicating via an access
  point (AP).
• IEEE 802.11 - adopted international standard for
  wireless LANs
• Transmission speeds ranging from 1 Mbps to 54
  Mbps in either the 2.4 GHz or 5 GHz frequency
  bands
• Various standards for IEEE 802.11 802.11a,
  802.11b, 802.11g, 802.11i
• 802.11 protocol has been found to be vulnerable
  to several types of attacks such as DoS, WEP key
  vulnerability, rogue APs

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Ultra WideBand (UWB) Networks

• Latest standard for high speed wireless networks
  (200-400 Mbps range)
• It works on impulse radio (short pulses of
  picoseconds duration) rather than carrier based
  radio
• US FCC has allocated a spectrum between 3.1 and
  10.6 GHz
• Initially it was used in radar communications
• Current research aims at the development of
  Physical and higher layer protocols for its use
  in WPANs and WMANs (IEEE 802.15 group for WPANs
  for PHY layer)

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Distributed Wireless Networks

• Usage Scenarios enterprise-wide wireless
  network management, Battlefield, geographic
  survey operations, search and rescue operations

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Typical Configurations

• Fixed Access Point - Single Hop Networks
• Fixed path mobile clients

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Typical Configurations (contd.)

• Fixed Access Point - Single Hop Networks
• Variable path (roaming) mobile clients

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Typical Configurations (contd.)

• Mobile Access points Multi Hop Networks

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Performance Factors

• The following are factors which affect
  performance of wireless networks in general
• Number of nodes Since bandwidth is shared
  equally among all nodes, the performance and
  throughput decreases as more nodes enter the
  network
• The underlying protocol Each layer of the
  TCP/IP protocol suite adds its own header, which
  tends to affect the performance considerably.
• The topology In case of a dynamically changing
  topology (for example, in ad hoc networks), the
  nodes have to maintain routing tables, which have
  to be recalculated every time a node leaves a
  current network and enters a new network

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Performance Factors (contd.)

• Fixed Access Point - Single Hop Networks
• In addition to the factors listed above, the
  following factors are specific to these type of
  networks
• In the case of fixed path clients, the distance
  of the clients from the access point plays an
  important role in determining the performance
• In the case of roaming mobile clients ,
  re-authentication is needed whenever a client
  moves away from the range of one access point to
  enter the range of another access point (known as
  handoff)

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Performance Factors (contd.)

• Performance in Mobile Access Point - Multi Hop
  Networks
• The following factors have been found to affect
  the performance of multi hop wireless networks-
• Routing protocols Most of the routing protocols
  used for ad hoc networks demand considerable
  bandwidth and power
• Node speed With increase in node mobility, the
  routing overhead and the bit error rate increases
  
• Traffic sources In multi hop networks, the
  source of traffic keeps varying constantly. At a
  particular instant of time, if we measure the
  bandwidth for a particular traffic source, it may
  not remain constant over a period of time as the
  topology changes.

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Performance Metrics

• Measurement of performance in a wireless network
  involves many interdependent factors. We consider
  the packet-level metrics only for sake of
  simplicity
• End-to-End Throughput - Measure of the number of
  packets successfully transmitted to their final
  destination per unit time.
• End-to-End Delay - Average time a packet takes to
  reach its destination
• Link Utilization - Long term proportion of time
  or probability that there is transmission on the
  link.
• Packet Loss - Ratio of transmitted packets that
  may have been discarded or lost in the
  network.

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Security issues

• In a distributed wireless network composed of
  both wired and wireless segments, the threat to
  the network is doubled.
• Some of the threats are common to both wireless
  and wired networks such as-
• invasion and resource stealing
• traffic redirection
• Denial of Service (DoS)
• Others are specific to wireless networks such as
  Rogue APs, WEP key vulnerability, MAC address
  spoofing, etc.
• Ad hoc networks introduce more security issues in
  routing since there are no inherent security
  mechanisms.

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Security issues (contd.)

• Authentication is one of the most important
  security issues for distributed wireless
  networks. The following are types of
  authentication methods used
• Mutual authentication Both the authenticator
  and the user must be able to mutually
  authenticate each other, in order to prevent
  threats such as rogue access points.
• Self-protecting A wireless node must protect
  itself from eavesdropping and impersonation
• Immune to dictionary attacks
• Secure session keys - Session keys provide
  message authentication, confidentiality and
  integrity for the user session.
• User-level authentication
• Fast re-authentication important in the case of
  roaming clients

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Security issues (contd.)

• Classification of Authentication methods
• Certificate based methods Such methods use
  public key infrastructure (PKI) to authenticate
  users. E.g PEAP and EAP
• Disadvantage
• cost of administration
• provides device authentication rather than
  user-level authentication
• Password based methods They are based on
  password authentication mechanism. E.g Ciscos
  LEAP
• Disadvantage
• more prone to attacks such as the
  Man-in-the-Middle (MITM)

.
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Security issues (contd.)

• Security in Fixed Access Point - single hop
  networks
• Reauthentication is a major issue in such
  networks
• centralized certificate-based authentication
  (RADIUS)
• Authentication Methods such as EAPOL (EAP over
  LAN) used

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Security issues (contd.)

• Security in Mobile Access point Multi Hop
  Networks
• Inter-Access Point authentication required in
  this case. Inter Access Point Protocol is used
  for this purpose
• Security in routing between mobile hosts-
• No centrally administered secure routers
• No strict security policies
• Highly dynamic nature of MANETs
• Current ad hoc protocols trust all participating
  nodes.

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Research Plan

• The study of performance will mostly be
  simulation-based
• A comparison of various factors affecting the
  performance will be done and most important ones
  will be derived
• Test cases will be drawn for these factors
• The major security issues in distributed networks
  will be studied and the impact of them on the
  performance will be analyzed
• The results of the security and performance
  analysis from these cases will be aggregated and
  compared to determine the tradeoffs between these
  two factors, so that an optimal solution may be
  achieved.

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Methods and instrumentation

• Hardware
• Pentium IV or higher machine with 512 MB RAM and
  wireless network adapter
• Cisco Wireless Access Point
• Software
• Operating Systems Windows 2K/ XP, Linux
• Network simulators
• Ns-2
• OPNET
• Programming platform Java SDK 1.4.2
• Cisco Aironet client utility (ACU)

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Acknowledgements
My sincere thanks to Dr. Andrew Yang for his
support and guidance and the NSF for funding my
position
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Thank you!

• Any Questions?