Circuit switching in the Internet

1. IP routers Source Boundary TCP-SW Core TCP-SW Boundary TCP-SW Destina-tion SYN ACCEPTED SYN+ACK ACCEPTED No difference between CS and PS in core DATA Circuit sw Circuit sw Circuit sw Packet sw Packet sw Packet sw 99% of Circuits Finish Earlier A big file can kill CS if it blocks the link Flow BW Flow BW Flow BW 1 Gb/s 1 Mb/s 1 Gb/s 1 Mb/s 10 Mb/s 10Mb/s+1Gb/s TCP Switches Avg latency Avg latency Avg latency 109.9s 0.505 s 10.495 s 1.099 sec 1 s 109.9sec Packets One Circuit Packets Worst latency Worst latency 10.990 s 10,000 s 10.990 sec 10,000 sec Worst latency 1 s 1 s Modems, DSL Moore’s law X2/18 months LAN • More efficient • More robust • Simpler • Can provide QoS • Statistical multiplexing • No hard state • No signaling, no state • WFQ/DRR/DiffServ • Over-provisioning Router capacity X2.2/18 months Memory latency X1.1/18 months Link speed x2/7 months SONET/SDH DWDM File = 10Mbit • True, but links are lightly utilized anyways • SONET 99.999%, 50 ms • IP 99.78%, 30 min • Commercial cct sw’s are 4-10x faster than equivalent routers • Perfect traffic isolation with ccts • More efficient • More robust • Simpler • Can provide QoS 100 clients 1 server 1 Gb/s x 100 File = 10Gbit/10Mbit File = 10Gbit/10Mbit • Create a separate circuit for each flow • IP controls circuits • Optimize for the most common case • TCP (90-95% of traffic) • Data (9 out of 10 pkts) 100 clients 100 clients 1 server 1 server TCP Switching 1 Gb/s 1 Gb/s x 99 x 99 1 Mb/s Pablo Molinero-Fernández, Nick McKeown Technology trends How Textbooks Say The Internet Is What The Internet Is Really Like Today Circuit switching in the Internet IP will conquer the world, because it is Reality check for IP What is the performance of circuit switching? What is the performance of circuit switching? What is the performance of circuit switching? One proposal for integrating circuits in an evolutionary way TCP Switching Exposes Circuits to IP Let TCP Leave State Behind Feasibility of TCP Switching • Amount of state • Minimum circuit = 64 kb/s. • 156,000 circuits for OC-192. • Update rate • About 50,000 new entries per sec for OC-192. • Lookup rate for boundary router • Exact match lookup, similar to 10G Ethernet • Readily implemented in hardware or software.

2. File = 10Gbit/10Mbit File = 10Gbit/10Mbit File = 10Mbit IP routers 100 clients 100 clients 100 clients • Create a separate circuit for each flow • IP controls circuits • Optimize for the most common case • TCP (90-95% of traffic) • Data (9 out of 10 pkts) Source Boundary TCP-SW Core TCP-SW Boundary TCP-SW Destina-tion 1 server 1 server 1 server 1 Gb/s 1 Gb/s 1 Gb/s TCP Switching SYN x 99 x 100 x 99 1 Mb/s ACCEPTED SYN+ACK ACCEPTED No difference between CS and PS in core DATA Circuit sw Circuit sw Circuit sw Packet sw Packet sw Packet sw 99% of Circuits Finish Earlier A big file can kill CS if it blocks the link Flow BW Flow BW Flow BW 1 Gb/s 1 Gb/s 1 Mb/s 1 Mb/s 10Mb/s+1Gb/s 10 Mb/s TCP Switches Avg latency Avg latency Avg latency 10.495 s 0.505 s 109.9s 1.099 sec 1 s 109.9sec Packets One Circuit Packets Worst latency Worst latency 10.990 s 10,000 s 10,000 sec 10.990 sec Worst latency 1 s 1 s Modems, DSL LAN • More efficient • More robust • Simpler • Can provide QoS • Statistical multiplexing • No hard state • No signaling, no state • WFQ/DRR/DiffServ • Over-provisioning SONET/SDH DWDM • True, but links are lightly utilized anyways • SONET 99.999%, 50 ms • IP 99.78%, 30 min • Commercial cct sw’s are 4-10x faster than equivalent routers • Perfect traffic isolation with ccts • More efficient • More robust • Simpler • Can provide QoS Pablo Molinero-Fernández, Nick McKeown Circuit switching in the Internet What is the performance of circuit switching? What is the performance of circuit switching? What is the performance of circuit switching? Technology trends How Textbooks Say The Internet Is What The Internet Is Really Like Today Moore’s law X2/18 months Router capacity X2.2/18 months Memory latency X1.1/18 months Link speed x2/7 months IP will conquer the world, because it is Reality check for IP One proposal for integrating circuits in an evolutionary way TCP Switching Exposes Circuits to IP Let TCP Leave State Behind Feasibility of TCP Switching • Amount of state • Minimum circuit = 64 kb/s. • 156,000 circuits for OC-192. • Update rate • About 50,000 new entries per sec for OC-192. • Lookup rate for boundary router • Exact match lookup, similar to 10G Ethernet • Readily implemented in hardware or software.