1. Stanford University TCP Switching: Exposing circuits in the Internet Pablo Molinero-Fernández Nick McKeown Stanford University

2. Why was the Internet packet- switched (PS) in the first place? 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

3. Stanford University How the Internet really is SONET/SDH IP Routers IP Routers Your Local Central Office Your Local Central Office

4. Stanford University Need to optimize processing rather than link efficiency Source: SPEC95Int; Prof. Miller, Stanford Univ., 2000 2x / 2 years2x / 7 months Slow Routers Fast Links

5. Stanford University How is the Internet today 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

6. Stanford University TCP SWITCH: Using TCP connections to establish circuits Ingress TCP-SW Core TCP-SW Egress TCP-SW Destina- tion Source SYN SYN+ACK DATA ACCEPTED IP Routers TCP Switches Expose circuits to IP Optimize for the common case –TCP traffic –Data packets

7. Stanford University TCP SWITCH: Using TCP connections to establish circuits Ingress TCP-SW Core TCP-SW Egress TCP-SW Destina- tion Source SYN SYN+ACK DATA ACCEPTED IP Routers TCP Switches

8. 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

9. 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