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TCP Switching: Exposing circuits in the Internet. Pablo Molinero-Fern á ndez Nick McKeown Stanford University. PS uses the link bandwidth very efficiently PS networks are robust due to the little state kept at the intermediate nodes.
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TCP Switching: Exposing circuits in the Internet Pablo Molinero-Fernández Nick McKeown Stanford University Stanford University
PS uses the link bandwidth very efficiently PS networks are robust due to the little state kept at the intermediate nodes Current Internet shows very low link utilization, so there is no need to be efficient SONET can reroute in 50 ms vs. several seconds for IP. Robustness is not unique to PS Why was the Internet packet-switched (PS) in the first place? Stanford University
How the Internet really is Your Local Central Office Your Local Central Office IP Routers IP Routers SONET/SDH Stanford University
Need to optimize processing rather than link efficiency Slow Routers Fast Links 2x / 2 years 2x / 7 months Source: SPEC95Int; Prof. Miller, Stanford Univ., 2000 Stanford University
There is a lot of circuit switching (CS), in the form of SONET Today we are interested in the completion time of our browsing requests CS is out there, but IP sees it as static point-to-point links CS can provide smaller completion times How is the Internet today Stanford University
Source Ingress TCP-SW Core TCP-SW Egress TCP-SW Destina-tion SYN ACCEPTED SYN+ACK ACCEPTED DATA TCP Switches IP Routers TCP SWITCH: Using TCP connections to establish circuits • Expose circuits to IP • Optimize for the common case • TCP traffic • Data packets Stanford University
Source Ingress TCP-SW Core TCP-SW Egress TCP-SW Destina-tion SYN ACCEPTED SYN+ACK ACCEPTED DATA TCP Switches IP Routers TCP SWITCH: Using TCP connections to establish circuits Stanford University
Objectives of TCPSwitch • Primary goals: • Expose circuits to IP • Optimize for the common case • TCP traffic (90% of packets) • Data packets (1 out of 10) • Secondary goals: • Interoperability with existing equipment • Use of optics and off-the-shelf switches • QoS and best-effort Stanford University
TCPSwitch results • Implementation of ingress TCPSwitch • Linux 2.4 router, inside kernel • Data switching: similar performance as a router with a classifier (e.g. policer) • Simulation of TCPSwitch network • In ns-2 • Avg response time between 1/2 and 1/10, for some blocking prob (0%-3%) • Some TCP inefficiencies noticeable with very short flows • Work in progress Stanford University