Layer 2: Link Layer Framing and transmission of a collection of bits into individual messages sent across a Application single"subnetwork"(one physical technology Transport Might involve multiple physical Link links(e.g, modern Ethernet) Physical Often technology supports broadcast transmission(every node connected to subnet receives
Layer 2: Link Layer 7 4 3 2 1 Framing and transmission of a collection of bits into individual messages sent across a single “ s u bn etwork” (one physical technology) Might involve multiple physical links (e.g., modern Ethernet) Often technology supports broadcast transmission (every “ n ode” connected to subnet receives) 16 Application Transport (Inter)Network Link Physical
Layer 3: (Inter)Network Layer(P) Bridges multiple subnets to provide end-to-end internet connectivity between Application nodes Provides global addressing Transport Works across different link technologies Link Dififerent for each Physical Internet hop
Layer 3: (Inter)Network Layer (IP) 7 4 3 2 1 Bridges multiple “ s u bn ets” to provide end-to-end internet connectivity between nodes • Provides global addressing 17 Works across different link technologies }Different for each Internet“hop” Application Transport (Inter)Network Link Physical
Layer 4: Transport Layer End-to-end communication between processes Application Different services provided TCP reliable byte stream 432 Transport UDP unreliable datagrams Link (Datagram single packet message) Physical 18
Layer 4: Transport Layer 7 4 3 2 1 End-to-end communication between processes Different services provided: TCP = reliable byte stream UDP = unreliable datagrams (Datagram = single packet message) 18 Application Transport (Inter)Network Link Physical
Layer 7: Application Layer Communication of whatever you wish Application Can use whatever transport(s)is convenient Transport Freely structured Link E.g Physical Skype, SMTP(email) Http (wEb), Halo Bit Torrent
Layer 7: Application Layer 7 4 3 2 1 Communication of whatever you wish Can use whatever transport(s) is convenient Freely structured E.g.: Skype, SMTP(email), HTTP (Web), Halo, BitTorrent 19 Application Transport (Inter)Network Link Physical
Internet Layering(" Protocol Stack") Application Implemented only at hosts not at interior router Transport (dumb network") Link Physical 20
Internet Layering (“Protocol Stack”) 20 7 4 3 2 1 } Implemented only at hosts, not at interior router (“dumb network” ) Application Transport (Inter)Network Link Physical