Transport Layer→ Understand Principles Of Transport Layer

→ Building Reliable Protocols from first principles

⇒ Case studies - TCP\ UDP

Transport Layer→ Understand Principles Of Transport Layer

↳ End to end

/ ↳ EZE Bandwidth estimation

→ Notion of reliability↳ Reliable over unreliable channel↳ ↳ Error detection / correction

k→ Reliable concerns↳ state machine

→ Building Reliable Protocols from first principles

⇒ Case studies - TCP\ UDP

Transport Layer 3-3

Transport services and protocolsr provide logical communication

between app processes running on different hosts

r transport protocols run in end systems m sender: breaks app messages into

segments, passes to network layer

m receiver: reassembles segments into messages, passes to app layer

r more than one transport protocol available to appsm Internet: TCP and UDP

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logical end-end transport

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Transport Layer 3-4

Transport vs. network layer

r network layer: logical communication between hosts

r transport layer: logical communication between processes m relies on, enhances, network

layer services

Household analogy:12 kids sending letters to 12 kidsr processes = kidsr app messages = letters in

envelopesr hosts = housesr transport protocol = Ann to Billr network-layer protocol = postal

service

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Transport Layer 3-5

Internet transport-layer protocols

r reliable, in-order delivery (TCP)m congestion control m flow controlm connection setup

r unreliable, unordered delivery: UDPm no-frills extension of “best-

effort” IP

r services not available: m delay guaranteesm bandwidth guarantees

applicationtransportnetworkdata linkphysical

applicationtransportnetworkdata linkphysical

networkdata linkphysical

networkdata linkphysical

networkdata linkphysical

networkdata linkphysicalnetwork

data linkphysical

logical end-end transport