KYUNG-HWA%20KIM

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DYSWIS

• KYUNG-HWA KIM
• HENNING SCHULZRINNE
• 12/09/2008
• INTERNET REAL-TIME LAB,
• COLUMBIA UNIVERSITY

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Do You See What I See?
Do you see what I see?
End user
Internet
End user
End user
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Outline

• Overview
• Fault Detection
• Peer Selection
• Probing
• Problem
• Implementation
• Demo

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Overview

• Overview
• DYSWIS Do you see what I see
• Distributed network fault detection and analysis
  system
• Motivation
• Different causes for a particular network fault
• Need different view from other sources for the
  fault
• End-to-end diagnosis
• Need user-friendly interface
• Current Problem
• Centralized management schemes
• Complexity in the user network and devices
• Failed to solve the service quality problem
• Approach
• Collaborate with other end users
• P2P based
• Remote probing

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For Quick Understanding
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Fault Detection

• Automatic fault detection
• Network raw packet capturing
• Analyze network packet and protocol
• Raw packet capturing
• Check error response
• Check timeout
• Check TCP congestion
• Monitoring TCP sequence numbers
• Define fault cases
• Automatic vs. Manual
• FSM approach
• pre-define
• learning

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FSM - Approach
Automatic Protocol Failure Detection Using
Finite State Machines Zhifeng Wang , Kai X.
Miao, Tao Zuo, Henning Schulzrinne, Kyung Hwa
Kim, Vishal Kumar Singh
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FSM - Approach
Automatic Protocol Failure Detection Using
Finite State Machines Zhifeng Wang , Kai X.
Miao, Tao Zuo, Henning Schulzrinne, Kyung Hwa
Kim, Vishal Kumar Singh
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Peer Selection

• Peer Selection
• DHT or Database
• Register myself to DHT network
• AS number, subnet, first hop, AP.
• Search probing nodes
• Inner nodes and outer nodes

You can contact to B. His IP address is
218.59.21.16 and port number is 9090
I need some nodes who can help me. Who is in
same subnet with me?
A
B
DHT
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Peer Selection - DHT (key, value)
ltkeygt lttypegtnodelt/typegt ltasngt14ltasngt
ltsubnetgt128.59.0.0/16lt/subnetgt lt/keygt
ltvaluegt lttypegtnodelt/typegt ltipgt128.59.21.15lt/ip
gt ltportgt9090lt/portgt ltprotocolgtudplt/protocolgt lt
/valuegt
I need some nodes who can help me. Who is in
same subnet with me?
ltkeygt lttypegtnodelt/typegt ltasngt9880ltasngt
ltsubnetgt45.45.45.0/24lt/subnetgt
ltfirewallgtnolt/firewallgt ltnatgtnolt/natgt lt/keygt
ltvaluegt lttypegtnodelt/typegt ltipgt128.59.21.15lt/ip
gt lthostnamegtkkh.cs.columbia.edult/hostnamegt
ltportgt9090lt/portgt ltprotocolgttcplt/protocolgt lt/val
uegt
A
B
DHT
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Remote Probing

• Distributing modules
• Detecting and probing modules should be added and
  updated
• Dynamic class loading
• Dynamic module distributing
• Modules can be created and updated separately.
• XMLRPC

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Probing Scenarios

• HTTP
• Causes Dead web-server , page moved, low
  bandwidth
• Check DNS query
• TCP connection
• Ask other node to try same query
• Check TCP congestion
• DNS
• Causes Dead DNS server , resolution failed, udp
  is not working ,
• Check other DNS server
• Ask other node to try to connect my DNS server
• Ask other node to query same host to another DNS
  server
• SIP/RTP
• Causes NAT, DNS, proxy server, authentication
• Proxy connectivity test
• Ask other node to try same action.

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Probing Scenarios

• Connection problem
• Causes Dead server, firewall, wrong port number
  
• Traceroute Check routers
• Ask other node to try to connect the server
• Ask other node to check my port
• TCP Congestion
• Causes Queuing delay, dead routers
• Traceroute , ping
• Try to find bottleneck

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Probing Scenarios
A
B
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Data Gathering

• Problem
• We have resources Other machines
• But how do we use them efficiently?
• We need real data
• Approach
• Collecting data
• Collecting Scenarios
• Implementing prototype

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Implementation

• Architecture

http//wiki.cs.columbia.edu/display/res/DYSWIS
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For the detail, visit http//wiki.cs.columbia.e
du/display/res/DYSWIS
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Demo

• Demo

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Future work

• Implementation
• http//www.cs.columbia.edu/khkim/project/dyswis
• Coming soon Mac Linux
• Testbed - PlanetLab
• Mature research for analysis
• Support real time protocols
• How to find solutions for end users

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backup

• Check local network.
• Select two nodes, one from same subnet, another
  one from outer subnet.
• Let the nodes try to connect the server.
• If both nodes failed to connect the server, log
  this fault as server failure.
• If only internal node failed, execute traceroute
  to check where the packet is blocked.
• If internal node succeeded, it is possible that
  this problem is caused by local firewall or
  something else.
• Check incoming/outgoing port Let other nodes
  open same port, and try to connect there. Check
  the remote node received packet or not. Check the
  ACK from remote node came back.