Download Internet Transport Protocols

The Transport Layer
Chapter 6
6.5 - 6.7
The Internet Transport Protocols: TCP (1)
a) Introduction to TCP
b) The TCP service model
c) The TCP protocol
d) The TCP segment header
e) TCP connection establishment
f) TCP connection release
Computer Networks, Fifth Edition by Andrew Tanenbaum and David Wetherall, © Pearson Education-Prentice Hall, 2011
The Internet Transport Protocols: TCP (2)
a) TCP connection management modeling
b) TCP sliding window
c) TCP timer management
d) TCP congestion control
e) TCP futures
Computer Networks, Fifth Edition by Andrew Tanenbaum and David Wetherall, © Pearson Education-Prentice Hall, 2011
The TCP Service Model (1)
a)
Some assigned ports
Computer Networks, Fifth Edition by Andrew Tanenbaum and David Wetherall, © Pearson Education-Prentice Hall, 2011
The TCP Service Model (2)
(a) Four 512-byte segments sent as separate IP diagrams
(b) The 2048 bytes of data delivered to the application in a single
READ call
Computer Networks, Fifth Edition by Andrew Tanenbaum and David Wetherall, © Pearson Education-Prentice Hall, 2011
The TCP Segment Header
a)
The TCP header.
Computer Networks, Fifth Edition by Andrew Tanenbaum and David Wetherall, © Pearson Education-Prentice Hall, 2011
TCP Connection Establishment
(a) TCP connection establishment in the normal case.
(b) Simultaneous connection establishment on both sides.
Computer Networks, Fifth Edition by Andrew Tanenbaum and David Wetherall, © Pearson Education-Prentice Hall, 2011
TCP Connection Management Modeling (1)
a)The states used in the TCP connection
management finite state machine.
Computer Networks, Fifth Edition by Andrew Tanenbaum and David Wetherall, © Pearson Education-Prentice Hall, 2011
TCP Connection Management Modeling (2)
a)TCP connection management
finite state machine.
b)The heavy solid line is the
normal path for a client. The
heavy dashed line is the normal
path for a server. The light lines
are unusual events. Each
transition is labeled by the event
causing it and the action
resulting from it, separated by a
slash.
Computer Networks, Fifth Edition by Andrew Tanenbaum and David Wetherall, © Pearson Education-Prentice Hall, 2011
TCP Sliding Window (1)
a)
Window management in TCP
Computer Networks, Fifth Edition by Andrew Tanenbaum and David Wetherall, © Pearson Education-Prentice Hall, 2011
TCP Sliding Window (2)
a)
Silly window syndrome
Computer Networks, Fifth Edition by Andrew Tanenbaum and David Wetherall, © Pearson Education-Prentice Hall, 2011
TCP Timer Management
(a) Probability density of acknowledgment arrival times in data link
layer. (b) … for TCP
Computer Networks, Fifth Edition by Andrew Tanenbaum and David Wetherall, © Pearson Education-Prentice Hall, 2011
TCP Congestion Control (1)
a)
Slow start from an initial congestion window of 1 segment
Computer Networks, Fifth Edition by Andrew Tanenbaum and David Wetherall, © Pearson Education-Prentice Hall, 2011
TCP Congestion Control (2)
a)Additive increase from an initial congestion
window of 1 segment.
Computer Networks, Fifth Edition by Andrew Tanenbaum and David Wetherall, © Pearson Education-Prentice Hall, 2011
TCP Congestion Control (3)
a)
Slow start followed by additive increase in TCP Tahoe.
Computer Networks, Fifth Edition by Andrew Tanenbaum and David Wetherall, © Pearson Education-Prentice Hall, 2011
TCP Congestion Control (4)
a)
Fast recovery and the sawtooth pattern of TCP Reno.
Computer Networks, Fifth Edition by Andrew Tanenbaum and David Wetherall, © Pearson Education-Prentice Hall, 2011
Performance Issues
a) Performance problems in computer networks
b) Network performance measurement
c) System design for better performance
d) Fast TPDU processing
e) Protocols for high-speed networks
Computer Networks, Fifth Edition by Andrew Tanenbaum and David Wetherall, © Pearson Education-Prentice Hall, 2011
Performance Problems in Computer
Networks
a)The state of transmitting one megabit from San Diego to Boston.
(a) At t = 0. (b) After 500 μ sec.
(c) After 20 msec. (d) After 40 msec.
Computer Networks, Fifth Edition by Andrew Tanenbaum and David Wetherall, © Pearson Education-Prentice Hall, 2011
Network Performance Measurement (1)
a) Steps to performance improvement
b) Measure relevant network parameters,
performance.
c) Try to understand what is going on.
d) Change one parameter.
Computer Networks, Fifth Edition by Andrew Tanenbaum and David Wetherall, © Pearson Education-Prentice Hall, 2011
Network Performance Measurement (2)
a)
b)
c)
d)
e)
f)
g)
h)
Issues in measuring performance
Sufficient sample size
Representative samples
Clock accuracy
Measuring typical representative load
Beware of caching
Understand what you are measuring
Extrapolate with care
Computer Networks, Fifth Edition by Andrew Tanenbaum and David Wetherall, © Pearson Education-Prentice Hall, 2011
Network Performance Measurement (3)
a)
Response as a function of load.
Computer Networks, Fifth Edition by Andrew Tanenbaum and David Wetherall, © Pearson Education-Prentice Hall, 2011
System Design for Better Performance (1)
a) Rules of thumb
b)
c)
d)
e)
f)
g)
7.
8.
CPU speed more important than network speed
Reduce packet count to reduce software overhead
Minimize data touching
Minimize context switches
Minimize copying
You can buy more bandwidth but not lower delay
Avoiding congestion is better than recovering from it
Avoid timeouts
Computer Networks, Fifth Edition by Andrew Tanenbaum and David Wetherall, © Pearson Education-Prentice Hall, 2011
System Design for Better Performance (2)
a)Four context switches to handle one packet
with a user-space network manager.
Computer Networks, Fifth Edition by Andrew Tanenbaum and David Wetherall, © Pearson Education-Prentice Hall, 2011
Fast TPDU Processing (1)
a)The fast path from sender to receiver is shown with a heavy
line. The processing steps on this path are shaded.
Computer Networks, Fifth Edition by Andrew Tanenbaum and David Wetherall, © Pearson Education-Prentice Hall, 2011
Fast TPDU Processing (2)
a)(a) TCP header. (b) IP header. In both cases, the shaded fields
are taken from the prototype without change.
Computer Networks, Fifth Edition by Andrew Tanenbaum and David Wetherall, © Pearson Education-Prentice Hall, 2011
Protocols for High-Speed Networks (1)
a)
A timing wheel
Computer Networks, Fifth Edition by Andrew Tanenbaum and David Wetherall, © Pearson Education-Prentice Hall, 2011
Protocols for High-Speed Networks (2)
a)Time to transfer and acknowledge a
1-megabit file over a 4000-km line
Computer Networks, Fifth Edition by Andrew Tanenbaum and David Wetherall, © Pearson Education-Prentice Hall, 2011
Delay Tolerant Networking
a) DTN Architecture
b) The Bundle Protocol
Computer Networks, Fifth Edition by Andrew Tanenbaum and David Wetherall, © Pearson Education-Prentice Hall, 2011
DTN Architecture (1)
a)
Delay-tolerant networking architecture
Computer Networks, Fifth Edition by Andrew Tanenbaum and David Wetherall, © Pearson Education-Prentice Hall, 2011
DTN Architecture (2)
a)
Use of a DTN in space.
Computer Networks, Fifth Edition by Andrew Tanenbaum and David Wetherall, © Pearson Education-Prentice Hall, 2011
The Bundle Protocol (1)
a)
Delay-tolerant networking protocol stack.
Computer Networks, Fifth Edition by Andrew Tanenbaum and David Wetherall, © Pearson Education-Prentice Hall, 2011
The Bundle Protocol (2)
a)
Bundle protocol message format.
Computer Networks, Fifth Edition by Andrew Tanenbaum and David Wetherall, © Pearson Education-Prentice Hall, 2011
End
a)Chapter 6
Computer Networks, Fifth Edition by Andrew Tanenbaum and David Wetherall, © Pearson Education-Prentice Hall, 2011