150 likes | 299 Vues
Multipath Routing: Proxy Selection. By Joseph A LaConte CS 591 – Semester Project December 07, 2005. Presentation Goals. Define the problem Provide brief background information Explain an overview of the solution Discuss issues associated with solution. Assumptions.
E N D
Multipath Routing: Proxy Selection By Joseph A LaConte CS 591 – Semester Project December 07, 2005
Presentation Goals • Define the problem • Provide brief background information • Explain an overview of the solution • Discuss issues associated with solution
Assumptions • Multiple path routing is available. • Future Internet has a set of proxy servers available to users.
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
Proxy Based Multipath Routing Each packet is transmitted over one of many paths using IP–IP encapsulation then forwarded by the proxy server.
Why Proxy Selection? A bad choice can route your packet far out of the way or to an overloaded proxy server.
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)
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 -> Colorado -> US West -> US) [break down similar to DNS: cs -> uccs -> edu]
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.
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
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).
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.
Future Work • Implementation • Multiple proxy hops • Benefit of n paths over x distance • Wireless
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.pdf Sacerdoti, Federico D. 2004. Tcphealth: TCP Connection Monitoring in Linux. http://heron.ucsd.edu/tcphealth/ Sarolahti, Pasi. 2002. Linux TCP. Seminar on Linux Kernel. http://www.cs.helsinki.fi/u/kraatika/Courses/sem02a/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 with Multiple Path Routing. Master’s thesis, University of Colorado at Colorado Springs.