Multipath Routing: Proxy Selection

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Multipath Routing Proxy Selection

• By Joseph A LaConte
• CS 591 Semester Project
• December 07, 2005

2
Presentation Goals

• Define the problem
• Provide brief background information
• Explain an overview of the solution
• Discuss issues associated with solution

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Assumptions

• Multiple path routing is available.
• Future Internet has a set of proxy servers
  available to users.

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Requirements

• Users share the same set of proxy servers.
• Proxy selection is determined based on QoS and
  Security.
• Set of proxy servers can change during
  communication.
• QoS Quality of Service

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Proxy Based Multipath Routing
Each packet is transmitted over one of many paths
using IPIP encapsulation then forwarded by the
proxy server.
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Why Proxy Selection?
A bad choice can route your packet far out of the
way or to an overloaded proxy server.
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Basic Proposed Schema

• Edge servers (middle-man)
• Contain hierarchical topology
• Manage proxy information
• Advise clients / Collect network data
• DNS modification
• Add edge server assignment (topology)

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Edge Server Topology

• Break Internet into subdivisions based on regions
  and sub-regions.
• Each subdivision has n proxy servers which report
  to an edge server.
• Each level in the hierarchy has a root node
• (eg. Colorado Springs -gt Colorado -gt US West -gt
  US)
• break down similar to DNS cs -gt uccs -gt edu

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How does hierarchical topology help?

• Provides a mechanism to restrict the assignment
  of proxy servers.

Generalized Example Proxy selection between L.A.
to Washington D.C. is based on information from
the highest level that contains both then
filtering from sub-region(s) between.
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Determining Quality of Service

• Data collection
• Proxy server
• Average wait time for packets
• Statistics on time between packets based on
  regions
• Edge server
• Response time to external proxy
• Client
• Applications/Implementation specific

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Security Issues

• Proxy servers
• How do you know if compromised?
• IDS on proxy can be used to notify edge server.
• What happens if compromised?
• Edge server can remove from availability list.
• What happens if all proxy servers go down?
• Normal communication persists (i.e. direct
  routing).

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Security Benefits

• Man in the middle.
• Avoid areas of high congestion or denial of
  service in the internet (loss of service)
• Can use firewall on Proxy to filter problems such
  as Slammer virus.

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Future Work

• Implementation
• Multiple proxy hops
• Benefit of n paths over x distance
• Wireless

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References

• Cai, Yu. 2005. On the Proxy Server based
  Multipath Connection. PhD Dissertation
• Defense, University of Colorado at Colorado
  Springs.
• http//cs.uccs.edu/chow/pub/master/ycai/doc/phd_
  thesis_defense_yu_cai.ppt
• Casetti, C., Gerla, M., Lee S. S., Mascolo, S.,
  Sanadidi, M. 2000.
• TCP with Faster Recovery. http//www.cs.ucla.edu/
  NRL/hpi/tcpw/tcpw_papers/2000-milcom-0.pdf
• Eyler, Pat. 2001. Networking Linux A
  Practical Guide to TCP/IP.
• New Riders, Indianapolis, Indiana.
• Gerla, M., Lee, S. S., Pau, G. 2002.
• TCP Westwood Performance Over Multiple Paths.
• http//www.cs.ucla.edu/NRL/hpi/papers/2002-tr-0.p
  df
• Sacerdoti, Federico D. 2004. Tcphealth TCP
  Connection Monitoring in Linux.
• http//heron.ucsd.edu/tcphealth/
• Sarolahti, Pasi. 2002. Linux TCP. Seminar on
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• http//www.cs.helsinki.fi/u/kraatika/Courses/sem0
  2a/Linux-TCP.pdf
• Tanenbaum, Andrew S. 2003. Computer Networks,
  4th ed. Prentice Hall PTR, Upper Saddle River,
  NJ.
• Watson, Frank E. 2005. Enhanced TCP Performance
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• Masters thesis, University of Colorado at
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