1. Ya Bao School of Engineering, SBU ACS Ch1 Protocol and Architecture 1 Ch1. Protocols and Architecture 1.1 Protocols zUsed for communications between entities in a system zMust speak the same language zEntities yUser applications ye-mail facilities yterminals zSystems yComputer yTerminal yRemote sensor

2. Ya Bao School of Engineering, SBU ACS Ch1 Protocol and Architecture 2 1.2 Protocol Architecture

3. Ya Bao School of Engineering, SBU ACS Ch1 Protocol and Architecture 3 1.3 TCP/IP Protocol Suite An Internet According to TCP/IP TCP/IP considers all of the hosts to be connected to this larger logical network rather to their individual physical networks. zDominant commercial protocol architecture zSpecified and extensively used before OSI zDeveloped by research funded US Department of Defense zUsed by the Internet

4. Ya Bao School of Engineering, SBU ACS Ch1 Protocol and Architecture 4 TCP/IP and OSI TCP/IP and the OSI Model Encapsulation

5. Ya Bao School of Engineering, SBU ACS Ch1 Protocol and Architecture 5 TCP/IP Protocol Architecture zApplication Layer yCommunication between processes or applications zEnd to end or transport layer (TCP/UDP/…) yEnd to end transfer of data yMay include reliability mechanism (TCP) yHides detail of underlying network zInternet Layer (IP) yRouting of data zNetwork Layer yLogical interface between end system and network zPhysical Layer yTransmission medium ySignal rate and encoding

6. Ya Bao School of Engineering, SBU ACS Ch1 Protocol and Architecture 6 1.3.2 Network Layer IP Datagram variable-length packet (up to 65,536 bytes) two parts: header(20-60 bytes) and data

7. Ya Bao School of Engineering, SBU ACS Ch1 Protocol and Architecture 7 1.3.3 Addressing Physical address: local jurisdiction, easy to change. Internet address: universe jurisdiction, cannot change. Internet Address

8. Ya Bao School of Engineering, SBU ACS Ch1 Protocol and Architecture 8 Class Ranges of Internet Addresses IP Addresses in Decimal Notation

9. Ya Bao School of Engineering, SBU ACS Ch1 Protocol and Architecture 9 Nodes with more than one address

10. Ya Bao School of Engineering, SBU ACS Ch1 Protocol and Architecture 10 1.3.4 Subneting Two Levels of Hierarchy Three Levels of Hierarchy

11. Ya Bao School of Engineering, SBU ACS Ch1 Protocol and Architecture 11 Addresses with and without Subnetting Masking

12. Ya Bao School of Engineering, SBU ACS Ch1 Protocol and Architecture 12 Example. Find the class, netid and hostid for each address: ClassNetidHostid a.4.23.145.90 A 4 23.145.90 b.227.34.78.7 D N/AN/A c.246.7.3.8 E N/AN/A d.129.6.8.4 B129.6 8.4 e.198.76.9.23 C198.76.923 Boundary-Level Masking Nonboundary-Level Masking IP Addr: 45. 23. 21. 8213. 23. 47. 37 Mask255.255. 0. 0255.255.255.240 Subnet addr: 45. 23. 0. 0213. 23. 47. 32 Bit-wise AND

13. Ya Bao School of Engineering, SBU ACS Ch1 Protocol and Architecture 13 1.3.5 Other Protocols in Network Layer ARP: find physical address from IP address RARP: find IP address from physical address. ICMP: send notification back to the sender IGMP: identify the hosts that are members of a group. UnicastingMulticastingBroadcasting One-to-oneone-to-manyone-to-all

14. Ya Bao School of Engineering, SBU ACS Ch1 Protocol and Architecture 14 1.3.6 Transport Layer TCP and UDP( User Datagram Protocol ) Port Addresses IP: host-to-host, deliver a packet from one physical device to another TCP: port-to-port, (Buffer used by a particular process) IP addr: 32 bits-- in IP datagram Port addr: 16 bits—in TCP datagram

15. Ya Bao School of Engineering, SBU ACS Ch1 Protocol and Architecture 15 UDP UDP Datagram Format UDP only provides basic functions:port addr, checksum, length. It does not provide any sequencing or reordering functions, can not soeccify the damaged packet

16. Ya Bao School of Engineering, SBU ACS Ch1 Protocol and Architecture 16 TCP Segment Format TCP is a reliable stream transport port-to-port protocol. TCP generates a virtual circuit between sender and receiver that is active for the duration of a transmission. connection establishment and connection termination alert. Sequence number. position of the data in the original data stream. Header length (HLEN): 4 bits, TCP head length:20—60 bytes Control(6 bits) :independently. Window size: size of the sliding window used in ARQ.

17. Ya Bao School of Engineering, SBU ACS Ch1 Protocol and Architecture 17 1.4 Application Layer 1.4.1. Client-Server Model: (many-to-one) Client:a program running on the local machine requesting service from a server. A client program is finite. Server: a program running on the remote machine provides services to the clients. A server program is infinite.

18. Ya Bao School of Engineering, SBU ACS Ch1 Protocol and Architecture 18 1.4.2 BOOTP and DHCP Attach to a TCP/IP internet, must know: Its IP address, its subnet mask, the IP address of a router and the IP address of a name server which stored in a configuration file. BOOTP: provide information for a diskless or first time boot computer. DHCP: provide dynamic configuration. Moving, temporary IP addr. 1.4.3 Domain name system(DNS) – map name and address Generic Domains: first level 7 possible 3-character labels: com, edu, gov, int, mil, net, org. a few more labels have been proposed: arts, firm, info, nom(personal nomenclatures), rec(recreation), store, web. Country Domains: 2-character country abbreviations. Inverse Domain: used to map a address to a name.

19. Ya Bao School of Engineering, SBU ACS Ch1 Protocol and Architecture 19 1.4.4 TELNET Remote Login Network Virtual Terminal(NVT):universal interface between different OSs.

20. Ya Bao School of Engineering, SBU ACS Ch1 Protocol and Architecture 20 1.4.5 File Transfer Protocol (FTP) Two connections (Date, Control). Which use different strategies and different port numbers. 1.4.6 Trivial File Transfer Protocol (TFTP) – copy files 1.4.7 Simple Mail Transfer Protocol (SMTP) User Agent (UA) Mail Transfer Agent (MTA) Relaying Mail gateway

21. Ya Bao School of Engineering, SBU ACS Ch1 Protocol and Architecture 21 Figure 25-16 The Entire E-mail System

22. Ya Bao School of Engineering, SBU ACS Ch1 Protocol and Architecture 22 Multipurpose Internet Mail Extensions(MIME) SMTP: ASCII format MIME: extend SMTP to non-ASCII Post Office Protocol (POP) – download mail from server

23. Ya Bao School of Engineering, SBU ACS Ch1 Protocol and Architecture 23 1.4.8 Hypertext Transfer Protocol (HTTP) -- www HTTP Transaction Uniform Resource Locator (URL): method, host, port, path

24. Ya Bao School of Engineering, SBU ACS Ch1 Protocol and Architecture 24 PDUs in TCP/IP Some Protocols in TCP/IP Suite

25. Ya Bao School of Engineering, SBU ACS Ch1 Protocol and Architecture 25 Exercise: A site with a given network address and mask. The administration has divided the site into several subnetworks. Choose appropriate subneaddresses, host addresses, and router addresses (a) (b)

26. Ya Bao School of Engineering, SBU ACS Ch1 Protocol and Architecture 26 Solutions (a) (b)