Seamless Media Streaming over Mobile IPenabled WLAN

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Seamless Media Streaming over Mobile IP-enabled
WLAN
Special Lab. Seminar
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Contents

• Research Overview
• Background Motivation
• Previous Approach Results
• Current Approach
• Related Works
• Expected Result

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Research Overview

• How to achieve seamless media streaming over
  Mobile IP-enabled wireless LAN?
• Limitations of current Mobile IP-enabled WLAN
  environments
• Scarce and limited network bandwidth of WLAN as
  compared to wired network
• Fluctuated packet transmission and burst packet
  loss due to the fading/shadowing of wireless
  channel and channel contention
• Security
• Power consumption of wireless terminals
• Mobility issues including handoff (transient
  packet loss and disruption)

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Background Motivation

• Handoff properties in Mobile IP-enabled WLAN
• Communicate with exactly one AP(access point)
  before and after a handoff ? Hard handoff
  (break-before-make)
• The initial service disruption while the new AP
  updates its host list (probe delay,
  authentication delay, re-association delay)
• The second service disruption while the Ethernet
  switch updates its central address table
  (bridging delay)
• IP layer handoff occurs after link layer handoff
  is finished
• Without link information, there exists handoff
  latency before the MN discovers a change in the
  point of attachment.
• The registration process takes some time
• Burst packet losses during handoffs ? hurts
  time-critical programs such as video streaming
  and video conferencing

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Previous Approach and Results

• To minimize packet losses during handoffs
• A packet forwarding with buffering mechanism in
  mobile agents
• Pre-buffering adjustment based on handoff
  transient time analysis in a streaming client

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Current Approach

• Link-layer assisted seamless handoff mechanism
  (soft handoff make-before-break)
• No packet transfer disruption during handoffs !!
• Can be extended to cross-layer optimization
  concept
• Performance evaluation using NS-2
• Assume that mobile node can associate with
  multiple APs (i.e., multiple channels)
• Propose handoff initiation algorithm

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Related Works

• Switched wireless Ethernet with soft handoff 1,
  2
• Only propose idea and procedure
• No handoff initiation algorithm
• No performance evaluation
• Current IEEE 802.11 WLAN explicitly forbids
  associating with more than one access point. ?
  Why?
• Methods to associate with multiple APs (i.e.,
  multiple channels)
• By using multiple NIC devices 3
• By software modification and revised 802.11 WLAN
  products 4
• Dont concentrate on handoff issue

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Expected Result

• Seamless Media Streaming over Mobile IP-enabled
  WLAN

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References

• 1 V. Kumar Choyi et al., Fast Handoff Scheme
  in Wireless LANs For Real-Time Systems, in Proc.
  The Third IEEE WLANs Workshop, September 2001.
• 2 Raheem A. Beyah et al.,A Mobility
  Enhancement for Switched Wireless Etherent with
  Soft Handoff, in Proc. IEEE MWSCAS 2002, August
  2002.
• 3 Behnaam Aazhang et al., Multitier Wireless
  Communications, in Kluwer Journal on Wireless
  Personal Communications, June 2001.
• 4 Ranveer Chandra el al., MultiNet Connecting
  to Multiple IEEE 802.11 Networks Using a Single
  Wireless Card, in Proc. IEEE INFOCOM 2004, March
  2004.