+ Project Physical A Final exam (1 hour) Data Link All equal - PowerPoint PPT Presentation

Networking 101 Networking 101 Course details Networking 101 Objectives Ma¨ el Auzias ◮ How do computers ENSIBS - UBS communicate? ◮ What are the mechanisms September 2015 under an HTTP request or a telegram message? ◮ Networks are all around us, better study them! Figure: teaching.auzias.net 1 / 107 2 / 107 Networking 101 Networking 101 Introduction Course details Presentation Outline Evaluation Introduction ◮ Short test at the end of each lesson + ◮ Project Physical A ◮ Final exam (1 hour) Data Link ◮ All equal weighting Network Material ◮ Slides available at teaching.auzias.net Transport (github too) 3 / 107 4 / 107

Networking 101 Networking 101 Introduction Introduction Definitions and presentation Definitions and presentation ◮ Network: an interconnected group or system ◮ HTTP: Hypertext Transfer Protocol , application-level protocol for distributed, collaborative, hypermedia information ◮ Internet: world wide interconnected system of networks systems draft HTTP2 (July 2014) RFC791 (September 1981) ◮ FTP: File Transfer Protocol promotes sharing of files, ◮ IP: Internet Protocol provides the functions necessary to encourages the use of remote computers RFC959 (October deliver a package of bits from a source to a destination over a 1985) network ◮ RFC: Request For Comments (Internet Draft (ID), RFC, ◮ (world wide) Web: network consisting of a collection of Internet Standard) Internet websites using HTTP 5 / 107 6 / 107 Networking 101 Networking 101 Introduction Introduction Definitions and presentation Definitions and presentation ◮ Router: network hardware providing routing services ◮ Node (network): any entity that can send packets to/receive ◮ Routing: algorithm processed to decide where to forward a packets from a network through a NIC packet ◮ Client: computer able to send requests to a server ◮ Forwarding: action of moving a packet from one NIC to ◮ Request: application message destined for a server ( order ) another ◮ Server: computer able to respond to a client’s requests ◮ NIC: Network Interface Card ◮ Response: application message destined for a client ( result ) ◮ Switch (hub): network hardware connecting systems using packet switching ◮ Fat client: application where most functions are processed ◮ Packet switching: forward-like method regardless of the by the client itself content (destination-based) ◮ Thin client: application where most functions are carried ◮ NAT: Network Address Translation, router modifying IP out on a central server address into another IP address (PAT). 7 / 107 8 / 107

Networking 101 Networking 101 Introduction Introduction Network classification Topologies ◮ BAN: Body Area Network ◮ PAN: Personal Area Network ◮ (W)LAN: (Wireless) Local Area Network (home, office, school or airport) ◮ MAN: Metropolitan Area Network, can cover a whole city ◮ WAN: Wide Area Network cover a broad area (Internet) Figure: upload.wikimedia.org 9 / 107 10 / 107 Networking 101 Networking 101 Introduction Introduction Topologies Bonus ◮ Point-to-point: two entities directly connected to each other (tunnel). ◮ Ring: data go around the ring, unidirectional way network. ◮ Mesh: all nodes cooperate in the distribution of data in the network 1 . ◮ Star: all messages go through the same central node, reducing network failure. ◮ Fully connected: all nodes are connected to all other nodes. ◮ Line: bidirectional link between two nodes. Node can only Figure: Disconnected MANET illustration send packet going through its neighbors. ◮ Bus: all nodes are connected to the same media. Only one can send a packet at a time, which all others then receive. ◮ Tree: hierarchical topology, such as a binary tree. 1 Hong Kong protesters used a mesh network to organize (2014) 11 / 107 12 / 107

Networking 101 Networking 101 Introduction Introduction Bonus Bonus Figure: Store-carry-and-forward Figure: Store-carry-and-forward 13 / 107 14 / 107 Networking 101 Networking 101 Introduction Introduction Bonus Bonus Figure: Store-carry-and-forward Figure: Store-carry-and-forward 15 / 107 16 / 107

Networking 101 Networking 101 Introduction Introduction HTTP request/response example HTTP request/response example Enter getbootstrap.com in your browser Enter getbootstrap.com in your browser Figure: DNS request/response 17 / 107 18 / 107 Networking 101 Networking 101 Introduction Introduction HTTP request/response example To read Enter getbootstrap.com in your browser https://github.com/alex/what-happens-when ◮ DNS lookup Figure: DNS request/response ◮ ARP process ◮ Opening of a socket ◮ TLS handshake ◮ HTTP protocol ◮ HTTP Server Request Handle Figure: HTTP request/response 19 / 107 20 / 107

Networking 101 Networking 101 Introduction Introduction How do messages reach their destination? More like this... Figure: acenk90.files.wordpress.com Figure: wikimedia.org 21 / 107 22 / 107 Networking 101 Networking 101 Introduction Introduction N th layer communicate with N th layer.. Models overview (OSI and TCP/IP) Application 7 Presentation 6 Application Application 7 Send and receive message formated for applications Presentation Presentation 6 Session 5 Context manager, transform data into application acceptable format Session 5 Session Transport Control dialogues. Start, control, close 4 connections between local and remote Transport Transport 4 Packets reassembling, packetizing 3 Network Network Network 3 Transfert datagram on the same network Data Link 2 2 Data Link Data Link MAC address, error checking/packet synchro RJ-25 cord with 3 pairs of conductors T3, pair 3, + pole, white color T2, pair 2, + pole, black color R1, pair 1, - pole, red color Physical T1, pair 1, + pole, green color Physical R2, pair 2, - pole, yellow color 1 R3, pair 3, - pole, blue color 01010100101011011010001011 Physical (colors by american Bell system) 1 Figure: OSI model 23 / 107 24 / 107

Networking 101 Networking 101 Introduction Introduction .. thanks to 3- th layers One single protocol, one single layer Application Application Application Application 7 7 HTTP, FTP, telnet, VOIP, IRC, SSH, SMTP Presentation Presentation Presentation Presentation 6 6 MIME, T ox 5 Session Session 5 Session Session SOCKS, named pipe, PPTP Transport Transport Transport Transport 4 4 TCP, UDP 3 Network Network 3 Network Network IP, ICMP, EIGRP Data Link Data Link Data Link Data Link 2 2 ARP, MAC, IS-IS Physical Physical Physical Physical 1 1 IEEE 802.11, USB, Bluetooth, RS-232, OTN 25 / 107 26 / 107 Figure: layers and routing Figure: protocols and layers Networking 101 Networking 101 Introduction Introduction Encapsulation Reading Reading list: Application Data ◮ ”Computer Networks” by A Tanenbaum, Andrew S., G ISBN 013162959X eme en C sous Linux” by C Blaess 2 , UDP UDP ◮ ”Programmation syst` Transport header data ISBN 978-2212110548 ◮ http://nmap.org/book/toc.html IP IP data Internet header ◮ http://blog.nodenexus.com/2014/11/28/a-shark-on-the- network/ Frame Frame Frame data Link footer header ◮ and many many other resources on the Internet freely available 3 ! If you can read it, knowledge is reachable 4 ! Figure: Encapsulation 2 Translator in French of many man pages 3 An Introduction to Computer Networks (21: Security) by Peter L Dordal 4 such as this example of Wireshark using or what-happens-when 27 / 107 28 / 107

Networking 101 Networking 101 Introduction Physical Watching Presentation Outline Introduction Watching list: Physical ◮ DEF CON 22 Hacking Conference Presentation By Christopher Soghoian - Blinding The Surveillance State 5 Data Link ◮ any other defcon ◮ Mr Robot, that’s a good serie! Network Transport 5 media.defcon.org 29 / 107 30 / 107 Networking 101 Networking 101 Physical Physical Aims Hardware medium ◮ IEEE 802.3 (a.k.a. Ethernet): < 100Gbit/s ◮ IEEE 802.11 (a.k.a. Wi-Fi): < 50 Mbit/s (802.11ad goes up ◮ Interface data link layer, to 6.75 Gbit/s) ◮ IEEE 802.15.1 (a.k.a. Bluetooth): < 1 Mbit/s ◮ (De)Encode, ◮ IEEE 802.15.4 (a.k.a. ZigBee): < 250 kbit/s ◮ Transmit: 1 after 0 (after 0 or 1, after 0... or 1) ◮ IEEE 802.16 (a.k.a. Wi-Max): < 40 Mbit/s ◮ IEEE 1394 (a.k.a. Firewire): < 3200 Mbit/s ◮ USB, serial port such as RS-232... 31 / 107 32 / 107

Networking 101 Networking 101 Physical Physical Hardware medium: IEEE 802.3 (Ethernet) Hardware medium: IEEE 802.15.1 (Bluetooth) Figure: RJ45 connector Figure: Bluetooth card 33 / 107 34 / 107 Networking 101 Networking 101 Physical Physical Hardware medium: IEEE 802.15.4 (ZigBee) Hardware medium: IEEE 802.16 (Wi-Max) Figure: ZigBee card Figure: Wi-Max antenna 35 / 107 36 / 107

Networking 101 Networking 101 Physical Physical Hardware medium: IEEE 1394 (Firewire) Encoding ◮ MLT3 (Multi-Level Transmit): state changes for 1s over 3 levels, stays in the same state for 0s ◮ AMI (Alternate Mark Inversion): state 0 for 0s, state +/-1 for 1s ◮ Manchester: voltage transition (rising/falling edge mean 1/0) ◮ BMC (Biphase Mark Code): change its state for 1s, stay on the same state for 0s ◮ and so on... Figure: Firewire connector 37 / 107 38 / 107 Networking 101 Networking 101 Physical Physical Encoding: Multi-Level Transmit Encoding: Alternate Mark Inversion Figure: Multi-Level Transmit Figure: Alternate Mark Inversion 39 / 107 40 / 107