Chapter 3: Transport Layer Chapter goals: Chapter Overview: o understand principles o transport layer services behind transport layer o multiplexing/demultiplexing services: o connectionless transport: UDP o multiplexing/demultiplex Ing o principles of reliable data transfer o reliable data transfer o flow control o connection-oriented transport o congestion control TCP g instantiation and o reliable transfer implementation in the f| ow contro Internet o connection management o principles of congestion contro o TCP congestion control
Comp 361, Spring 2005 3: Transport Layer 1 Chapter 3: Transport Layer last revised 16/03/05 Chapter goals: understand principles behind transport layer services: multiplexing/demultiplex ing reliable data transfer flow control congestion control instantiation and implementation in the Internet Chapter Overview: transport layer services multiplexing/demultiplexing connectionless transport: UDP principles of reliable data transfer connection-oriented transport: TCP reliable transfer flow control connection management principles of congestion control TCP congestion control
Chapter 3 outline D 3.1 Transport-layer 0 3.5 Connection-oriented services transport: TCP 03.2 Multiplexing and o segment structure demultiplexing o reliable data transfer 03. 3 Connectionless flow control transport: UDP o connection management O 3.4 Principles of 口36 Principles of reliable data transfer congestion control 口3.7 TCP congestion contro
Comp 361, Spring 2005 3: Transport Layer 2 Chapter 3 outline 3.1 Transport-layer services 3.2 Multiplexing and demultiplexing 3.3 Connectionless transport: UDP 3.4 Principles of reliable data transfer 3.5 Connection-oriented transport: TCP segment structure reliable data transfer flow control connection management 3.6 Principles of congestion control 3.7 TCP congestion control
Transport services and protocols o provide logical communication lication between app processes running on different hosts data link networ data link o transport protocols run in end systems o send side: breaks app network data link messages into segments physical passes to network layer o rcv side: reassembles segments into messages application passes To app layer networ data link o more than one transport protocol available to apps o Internet: tcp and UDP
Comp 361, Spring 2005 3: Transport Layer 3 Transport services and protocols provide logical communication between app processes running on different hosts transport protocols run in end systems send side: breaks app messages into segments, passes to network layer rcv side: reassembles segments into messages, passes to app layer more than one transport protocol available to apps Internet: TCP and UDP application transport network data link physical application transport network data link physical network data link physical network data link physical network data link physical network data link network physical data link physical
Transport vs. network layer o network layer: logical Household analogy: communication 12 kids sending letters to between hosts 12 kids O transport layer: logical o processes kids communication D app messages letters between processes in envelopes o relies on, enhances g hosts houses network layer services 口 transport protocol Ann and Bil o network-layer protocol E postal service
Comp 361, Spring 2005 3: Transport Layer 4 Transport vs. network layer network layer: logical communication between hosts transport layer: logical communication between processes relies on, enhances, network layer services Household analogy: 12 kids sending letters to 12 kids processes = kids app messages = letters in envelopes hosts = houses transport protocol = Ann and Bill network-layer protocol = postal service
Transport-layer protocols Internet transport services: lication g reliable. in-order unicast data link networ delive ry (TCp) data link o congestion o flow contro o connection setup be, physical i network data link a unreliable (best-effort physical unordered unicast or 受 multicast delivery: UDP o services not available application o real-time networ data link o bandwidth guarantees o reliable multicast
Comp 361, Spring 2005 3: Transport Layer 5 Transport-layer protocols Internet transport services: reliable, in-order unicast delivery (TCP) congestion flow control connection setup unreliable (“best-effort”), unordered unicast or multicast delivery: UDP services not available: real-time bandwidth guarantees reliable multicast application transport network data link physical application transport network data link physical network data link physical network data link physical network data link physical network data link network physical data link physical