4. Access Layer End station entry pint to the network Access Layer Characteristics
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8. Application Presentation Session Transport Data Link Network Physical EXAMPLES Telnet HTTP ASCII, EBCDIC JPEG Operating System / Application Access Scheduling Role of Application Layers
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10. Application Presentation Session Transport Network Data Link Physical Data Data Upper layer data Upper layer data TCP Header Data IP Header LLC Header MAC Header 0101110101001000010 Encapsulation Data PDU Bits Frame Packet Segment
11. Application Session Presentation Transport Data Link Network P hysical Upper Layer Data Upper Layer Data TCP+Upper Layer Data IP+TCP+Upper Layer Data MAC Header TCP Header LLC Hdr+IP+TCP+Upper Layer Data LLC Header IP Header 0101110101001000010 De-Encapsulation Data
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13. Host 10 Base 2__ Thick Ehernet 10 Base 2__ Thick Ehernet Hub Hosts 10 Base T _ Twisted Pair Physical Layer :Ethernet/802.3
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15. Hubs: One Collision Domain More end stations means more collisions CSMA/CD is used
16. Data Link Layer Functions 802.2 HDLC Data Link Defines Physical source and destination address Higher layer protocol (Service Access Point) associated with frame Network topology Frame sequencing Flow control Connection-oriented or connectionless Physical Ethernet 802.3 EIA/TIA_232 V.35 Frame Relay
17. Data Link Layer Functions 0000.0c xx.xxxx 8 Preamble Dest Add Source Add Length Data FCS 6 6 2 Variable 4 Ethernet II uses “Type “ here and does not use 802.2 IEEE assigned Vender assigned MAC Layer -802.3 # Bytes