tcp switching: exposing circuits in the internet
DESCRIPTION
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. - PowerPoint PPT PresentationTRANSCRIPT
Stanford University
TCP Switching: Exposing circuits in the Internet
Pablo Molinero-FernándezNick McKeown
Stanford University
Stanford University
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
Stanford University
How the Internet really is
SONET/SDH
IP Routers
IP Routers
YourLocal
CentralOffice
YourLocal
Central Office
Stanford University
Need to optimize processing rather than link efficiency
0,1
1
10
100
1000
10000
1985 1990 1995 2000 Fib
er C
apac
ity
(Gb
it/s
)
FiberopticsDWDM
Source: SPEC95Int; Prof. Miller, Stanford Univ., 2000
0,1
1
10
100
1000
10000
1985 1990 1995 2000
Pro
cess
ing
Po
wer
(S
pec
95In
t b
ench
mar
k) 2x / 2 years 2x / 7 months
Slow Routers Fast Links
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
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
ACCEPTED
IPRouters
TCPSwitches
•Expose circuits to IP
•Optimize for the common case
–TCP traffic
–Data packets
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
ACCEPTED
IPRouters
TCPSwitches
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