Network Programming I Computer Network Design Flavio Esposito http://cs.slu.edu/~esposito/teaching/3650/ Lecture 2
Lecture Goals Get feel and terminology of some components of real nets More depth & details later in course especially on protocols and arch Approach: use Internet as example but mention other networks too
Kurose- Ross Chapter 1 1.1 What is the Internet? 1.2. Network Edge (and Edge Computing) 1.3 Network Core packet/circuit switching, Internet structure 1.4. Performance Delay, Loss and Throughput 1.5. Protocol layers service model 1.6. Networks under attack
What is the Internet? 1.1 What is the Internet? 1.2. Network Edge (and Edge Computing) 1.3 Network Core packet/circuit switching, Internet structure 1.4. Performance Delay, Loss and Throughput 1.5. Protocol layers service model 1.6. Networks under attack
INET is a Collection of SW & HW PC server hosts = end systems running network apps wireless laptop smartphone wireless links wired links communication links fiber, copper, radio, satellite Router and switches routers and switches forward packets (chunks of data)
INET is a Collection of SW & HW PC server wireless laptop smartphone hosts = end systems running network apps Not only computers and phones are connected wireless links wired links communication links fiber, copper, radio, satellite Router and switches routers and switches forward packets (chunks of data)
Fun devices connected to the Internet (according to Kurose- Ross) Web-enabled toaster + weather forecaster IP picture frame http://www.ceiva.com/ Slingbox: watch, control cable TV remotely Tweet-a-watt: monitor energy use Internet refrigerator sensorized, bed mattress Internet phones
Really? Where is the fun here? Web-enabled toaster + weather forecaster IP picture frame http://www.ceiva.com/ Slingbox: watch, control cable TV remotely Tweet-a-watt: monitor energy use Internet refrigerator sensorized, bed mattress Internet phones
Fun Device Connected to the Internet
Fun Devices Connected to the Internet Submarine Underwater Communication Internet of Things Saves Whales http://blogs.ptc.com/2014/10/01/in ternet- of- things- saves- whales/ International Space Station Delay- Tolerant Networks
IP over Avian Carriers Under RFC 1149, a homing pigeon can carry Internet Protocol traffic. (Delay tolerant - - - high delay) What is a Request For Comments?
Sad Example of Packet Lost Under RFC 1149, a homing pigeon can carry Internet Protocol traffic. (Delay tolerant - - - high delay)
Internet main principle is packet switching Packet Apps segment data into packets, adding an header, then reassembled at the destination. Switching Packet switches are routers and link- layer switches near the end user used in the core.
Not all networks have packets: telephone circuit switching switchboard, 1975 (aka, human switch) (Story of PRONTO )
Network of Networks Today INET hierarchy mobile network home network global ISP regional ISP Internet: network of networks Interconnected ISPs protocols control send & rx messages e.g., TCP, IP, HTTP, Skype, 802.11 Internet standards RFC: Request for comments IETF: Internet Engineering Task Force institutional network
What is a Protocol? Hi Hi Got the time? 2:00 Examples of Human protocols: what s the time? I have a question introductions specific messages sent specific actions taken when messages received
What is a Protocol? network protocols: machines rather than humans all communication activity in Internet governed by protocols TCP connection request TCP connection response Get http://www.slu.edu/ <file>
What is a Protocol? network protocols: machines rather than humans all communication activity in Internet governed by protocols TCP connection request TCP connection response Get http://www.slu.edu/ protocols define format, order of messages sent and received among network entities, and actions taken on message transmission, receipt <file>
So what is the Internet? Evolving collection of hardware and software managed by protocols
Closer look at network structure mobile network home network global ISP regional ISP network edge: hosts: clients and servers servers often in data centers access networks, physical media: wired and wireless links institutional network network core: interconnected routers network of networks
Network Edge 1.1 What is the Internet? 1.2. Network Edge (and Edge Computing) end- systems, access nets, link, edge computing 1.3 Network Core packet/circuit switching, Internet structure 1.4. Performance Delay, Loss and Throughput 1.5. Protocol layers service model 1.6. Networks under attack
Network Edge network edge: hosts: clients and servers servers often in data centers access networks, physical media: wired and wireless links network core: interconnected routers network of networks
Access Network: How to connect end- systems with edge routers? Digital Subscriber Line (DSL) Use Existing phone line < 2.5 Mbps upstream transmission rate (typically < 1 Mbps) < 24 Mbps downstream transmission rate (typically < 10 Mbps) (Asymmetric DSL) central office telephone network DSL modem splitter voice, data transmitted at different frequencies over dedicated line to central office DSLAM DSL Access Multiplexer ISP
Access Network: Cable Network Frequency Division Multiplexing (FDM): different channels transmitted in different frequency bands cable modem splitter Channels V I D E O V I D E O V I D E O V I D E O V I D E O V I D E O D A T A D A T A C O N T R O L 1 2 3 4 5 6 7 8 9 Note: Control & Data packets flow over separate channels - >
Access Network: Home Networks wireless devices often combined in single box wireless access point (54 Mbps) cable or DSL modem router, firewall, NAT wired Ethernet (1 Gbps)
Access Network: Home Networks wireless devices often combined in single box wireless access point (54 Mbps) cable or DSL modem router, firewall, NAT wired Ethernet (1 Gbps) Fiber To The Home (FTTH): Popular In some countries like Sweden: access network with fiber optic:
Enterprise Access Network (Ethernet or Infiniband) Ethernet switch institutional link to ISP (Internet) institutional router institutional mail, web servers Ethernet typically used in companies, universities, etc. 10 Mbps - 10Gbps transmission rates today, end systems typically connect into Ethernet switch Infiniband (IB) can get to almost 100 Gbps HPC Usually connects servers in private nets but not to INET
Wireless Access Network (Wi- Fi or xg) Shared wireless access network Connects end system to router via base station aka access point wireless LANs: within building (100 ft.) 802.11b/g/n (WiFi): 11, 54, 450 Mbps transmission rate wide-area wireless access provided by telco (cellular) operator, 10 s km between 1 and 10 Mbps 3G, 4G: Long-Term Evolution (LTE) to Internet to Internet
Wireless Access Network (5G) Currently under research Buzzword or keyword? Uses notions of SDN Centralized control for distributed nets to Internet Steer traffic to chain of Middleboxes (e.g., balancers, traffic accelerators)
Internet of Things Research area: find new vulnerabilities of IoT devices Often poor hw, lack of good OS, apps poorly developed (phones too BTW) Search engine for IoT devices https://www.shodan.io/ webcam, videogame consoles, refrigerators, turbines Mine data from IoT, or hack to improve their security search for webcams with babies for organ traffic exist
Edge Computing Motivation Some applications can t wait for the cloud Unacceptable delays, gain in preprocessing
Edge Computing Motivation Some applications can t wait for the cloud Unacceptable delays, gain in preprocessing Hot Topic Becoming a popular subfield of computer network First IEEE/ACM Symposium on Edge Computing (2016)
Edge Computing Motivation Some applications can t wait for the cloud Unacceptable delays, gain in preprocessing Hot Topic Becoming a popular subfield of computer network First IEEE/ACM Symposium on Edge Computing (2016) Applications real- time image recognition: military & medicine security, first responders, drone controllers
Network Programming I Computer Network Design Flavio Esposito http://cs.slu.edu/~esposito/teaching/3650/ Lecture 2