4. Layer Functions Application Presentation Session Transport Network Data Link Physical 1 2 3 4 5 6 7 Network processes to applications Data representation Inter host communication End-to-end connections Addresses and best path Access to media Binary transmission
5. Peer-to-Peer Communication Physical Data Link Network Transport Session Presentation Application Physical Data Link Network Transport Session Presentation Application segment packet frame bit
6. Data Encapsulation Application Presentation Session Transport Network Data Link Physical Host A Application Presentation Session Transport Network Data Link Physical Host B Data Network Header Data Frame Frame Header Trailer Network Header Data 010010011010101
8. Application Layer Word Processing Spreadsheet Database Design/Manufacturing Project Planning Others Browser Filezila Ms. Outlook Computer Application Electronic Mail File Transfer Remote Access Client/Server Process Network Management Others Network Application Electronic Data Interchange World Wide Web E-Mail Gateways Special-Interest Bulletin Boards Financial Transaction Services Internet Navigation Utilities Conferencing (Video, Voice, Data) Others Internetwork Apps Internetwork application can extend beyond the enterprise
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10. Session Layer Network File System (NFS) Structured Query Language (SQL) Remote-Procedure Call (RPC) X Window System AppleTalk Session Protocol (ASP) DNA Session Control Protocol (SCP) Service Request Service Reply Coordinates applications as they interact on different hosts
13. Segment Upper-Layer Applications Application Presentation Session Transport segments share traffic stream Transport Application port Data Application port Data Application port Data Electronic Mail File Transfer Terminal Session
18. Network Layer: Path Determination Layer 3 functions to find the best path through the internetwork Which Path?
19. Network Layer: Communicate Path Addresses represent the path of media connections 1 2 3 4 5 6 7 8 9 10 11
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22. Network-Layer Protocol Operations X Y A B C Application Presentation Session Transport Network Data Link Physical X Network Data Link Physical Network Data Link Physical Network Data Link Physical Application Presentation Session Transport Network Data Link Physical Y A B C Each router provides its services to support upper-layer functions
24. Physical and Data-Link Types Data Link (frames) Physical (bits, signals, clocking) E t h e r n e t 802.2 LLC 8 0 2 . 3 8 0 2 . 5 F D D I Dial on Demand SDLC HDLC X.25 Frame Relay ISDN PPP V.24 EIA/TIA-232 G.703 V.35 EIA/TIA-449 EIA-530 HSSI LAN WAN Separate physical and data link layers for LAN and WAN