The Internet:a "service"view Infrastructure that provides mobile network services to applications: national or global ISP Web,streaming video,multimedia teleconferencing,email,games,e- Streaming commerce,social media,inter- Skype video connected appliances,.. local or provides programming interface regionaMSP to distributed applications: home network content provider "hooks"allowing sending/receiving HTTP network datacenter apps to“connect'”to,use Internet network transport service provides service options,analogous enterprise to postal service network Introduction:1-6
▪ Infrastructure that provides services to applications: • Web, streaming video, multimedia teleconferencing, email, games, ecommerce, social media, interconnected appliances, … The Internet: a “service” view Introduction: 1-6 mobile network home network enterprise network national or global ISP local or regional ISP datacenter network content provider HTTP network Skype Streaming video ▪ provides programming interface to distributed applications: • “hooks” allowing sending/receiving apps to “connect” to, use Internet transport service • provides service options, analogous to postal service
What's a protocol? Human protocols: Network protocols: ·“what's the time?” computers(devices)rather than humans .“I have a question” all communication activity in Internet ·introductions governed by protocols ..specific messages sent Protocols define the format,order of ..specific actions taken when message received, messages sent and received among or other events network entities,and actions taken on msg transmission,receipt Introduction:1-7
What’s a protocol? Introduction: 1-7 Human protocols: ▪ “what’s the time?” ▪ “I have a question” ▪ introductions … specific messages sent … specific actions taken when message received, or other events Network protocols: ▪ computers (devices) rather than humans ▪ all communication activity in Internet governed by protocols Protocols define the format, order of messages sent and received among network entities, and actions taken on msg transmission, receipt
What's a protocol? A human protocol and a computer network protocol: TCP connection request Hi TCP connection response Got the time? GET http://gaia.cs.umass.edu/kurose_ross 4一2：00 <file> time Q:other human protocols? Introduction:1-8
What’s a protocol? Introduction: 1-8 A human protocol and a computer network protocol: Q: other human protocols? Hi Hi Got the time? 2:00 time TCP connection response <file> TCP connection request GET http://gaia.cs.umass.edu/kurose_ross
Chapter 1:roadmap -What is the Internet? ■What is a protocol? Network edge:hosts,access network, physical media Network core:packet/circuit switching,internet structure Performance:loss,delay,throughput Security Protocol layers,service models ■History Introduction:1-9
Chapter 1: roadmap Introduction: 1-9 ▪ What is the Internet? ▪ What is a protocol? ▪ Network edge: hosts, access network, physical media ▪ Network core: packet/circuit switching, internet structure ▪ Performance: loss, delay, throughput ▪ Security ▪ Protocol layers, service models ▪ History
A closer look at Internet structure mobile network Network edge: national or global ISP hosts:clients and servers servers often in data centers local or regionalsp home network content provider network datacenter network enterprise network Introduction:1-10
A closer look at Internet structure Introduction: 1-10 mobile network home network enterprise network national or global ISP local or regional ISP datacenter network content provider network Network edge: ▪ hosts: clients and servers ▪ servers often in data centers