CONET MODULE 1 ETHERNET BASED I/O SYSTEMS LECTURE NOTES Onur Akbatı Levent Ucun Galip Cansever 1 Contents 1. ETHERNET ....................................................................................................................................................................................4 1.1 FOUR BASICS OF ETHERNET ....................................................................................................................................................5 1.1.1. NETWORK CORE : CIRCUIT SWITCHING & PACKET SWITCHING CIRCUIT SWITCHING ................................................................13 1.1.2. OVERVIEW OF DELAY IN PACKET SWITCHED NETWORKS .........................................................................................................17 2. LAYERS ......................................................................................................................................................................................18 2.1. OSI REFERENCE MODEL ........................................................................................................................................................18 2.1.1. SEVEN LAYER ISO-OSI REFERENCE MODEL .........................................................................................................................20 2.1.1.1. APPLICATION LAYER .........................................................................................................................................................20 2.1.1.2. PRESENTATION LAYER ......................................................................................................................................................20 2.1.1.3. SESSION LAYER ................................................................................................................................................................21 2.1.1.4. TRANSPORT LAYER ...........................................................................................................................................................21 2.1.1.5. NETWORK LAYER ..............................................................................................................................................................21 2.1.1.6. DATA LINK LAYER .............................................................................................................................................................21 2.1.1.7. PHYSICAL LAYER ..............................................................................................................................................................22 2.2. FIVE LAYER INTERNET PROTOCOL .........................................................................................................................................22 2.2.1. APPLICATION LAYER ..............................................................................................................................................................22 2.2.2. TRANSPORT LAYER ................................................................................................................................................................22 2.2.3. NETWORK LAYER ...................................................................................................................................................................23 2.2.4. DATA LINK LAYER ..................................................................................................................................................................23 2.2.5. PHYSICAL LAYER ...................................................................................................................................................................23 2.3. APPLICATION LAYER ..............................................................................................................................................................24 2.3.1. HTTP (H YPER TEXT TRANSPORT PROTOCOL ) .......................................................................................................................24 2.3.1.1. NON -PERSISTENT AND PERSISTENT CONNECTIONS ..........................................................................................................25 2.3.2. FTP (F ILE TRANSFER PROTOCOL ) .........................................................................................................................................28 2.3.3. SMTP (S IMPLE MAIL TRANSFER PROTOCOL ) .........................................................................................................................30 2.3.4. DNS (D OMAIN NAME SERVICE ) ..............................................................................................................................................30 2.4. TRANSPORT LAYER ................................................................................................................................................................32 2.4.1. MULTIPLEXING AND DEMULTIPLEXING ....................................................................................................................................34 2.4.2. CONNECTIONLESS TRANSPORT : UDP (U SER DATAGRAM PROTOCOL ) ...................................................................................34 2.4.3. CONNECTION -ORIENTED TRANSPORT (T RANSMISSION CONTROL PROTOCOL ) .......................................................................37 2.4.3.1. TCP SEGMENT STRUCTURE .............................................................................................................................................38 2.4.3.2. SEQUENCE NUMBERS AND ACKNOWLEDGE NUMBERS .......................................................................................................41 2.4.3.3. PRINCIPLES OF RELIABLE DATA TRANSFER .......................................................................................................................42 2.4.3.4. ARQ ALGORITHMS ............................................................................................................................................................42 2.5. NETWORK LAYER ...................................................................................................................................................................48 2.5.1. INTERNET PROTOCOL (IP V4)..................................................................................................................................................48 2.5.1.1. IP ADDRESSING ................................................................................................................................................................48 2.5.1.2. ASSIGNING ADDRESSES ....................................................................................................................................................51 2.5.1.3. TRANSPORTING A DATAGRAM FROM SOURCE TO DESTINATION .........................................................................................52 2.5.1.4. DATAGRAM FORMAT .........................................................................................................................................................54 2.5.1.5. IP FRAGMENTATION AND REASSEMBLY ..............................................................................................................................57 2.5.1.6. INTERNET CONTROL MESSAGE PROTOCOL (ICMP)...........................................................................................................59 2.6. LINK LAYER AND LOCAL AREA NETWORKS (LAN) ...................................................................................................................60 2.6.1. ERROR -DETECTION AND CORRECTION TECHNIQUES ..............................................................................................................64 2.6.1.1. PARITY CHECKS ................................................................................................................................................................65 2.6.1.2. CHECKSUM METHODS .......................................................................................................................................................66 2.6.1.3. CYCLIC REDUNDANCY CHECK (CRC)................................................................................................................................66 2.6.2. LINK LAYER ADDRESSING .......................................................................................................................................................66 2.6.2.1. ADDRESS RESOLUTION PROTOCOL (ARP ) .......................................................................................................................68 2.6.2.2. SENDING A DATAGRAM TO A NODE OFF THE LAN ..............................................................................................................70 3. BRIDGES AND SWITCHES ............................................................................................................................................................72 3.1. HUBS .....................................................................................................................................................................................72 3.2. BRIDGES ................................................................................................................................................................................74 3.2.1. FORWARDING AND FILTERING ................................................................................................................................................74