computer network

3. Transport Layer


Computer
Networking: A Top
Down Approach
6th edition
Jim Kurose, Keith Ross
Addison-Wesley
March 2012
All material copyright 1996-2012
J.F Kurose and K.W. Ross, All Rights Reserved


Transport Layer 3-1

,3. Transport Layer: Goals
our goals:
v understand v learn about Internet
principles behind transport layer protocols:
transport layer § UDP: connectionless
services: transport
§ multiplexing, § TCP: connection-oriented
demultiplexing reliable transport
§ reliable data transfer § TCP congestion control
§ flow control
§ congestion control



Transport Layer 3-2

,3. Transport Layer: Outline
3.1 transport-layer 3.5 connection-oriented
services transport: TCP
3.2 multiplexing and § segment structure
demultiplexing § reliable data transfer
3.3 connectionless § flow control
transport: UDP § connection management
3.4 principles of reliable 3.6 principles of congestion
data transfer control
3.7 TCP congestion control



Transport Layer 3-3

, Transport services and protocols
application
transport
v provide logical communication network
data link
between app processes physical

running on different hosts
v transport protocols run in
end systems
§ send side: breaks app
messages into segments,
passes to network layer
§ recv side: reassembles application
segments into messages, transport
network
passes to app layer data link
physical

v more than one transport
protocol available to apps
§ Internet: TCP and UDP
Transport Layer 3-4