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Transmission Lines and Network Connections
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Communication Basics #03 Transmission Lines & Network Connections
Communication Basics #32 Worked Example: STM-1 + ATM Cells — Frame Efficiency, 83.17% Real Data
Communication Basics #33 Worked Example: STM-1 + 576-byte IP Packets — 90.87% Real Data
Communication Basics #34 Worked Example: STM-1 + Mixed 53/77-byte Payload — 85.19% Real Data
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Solution Notebook · EN
#03 Two/four-wire circuit equivalents, the channel-line-trunk hierarchy, PVC/SVC virtual circuits, and switched-leased-dedicated services
Solution Notebook · EN
#32 establish the 9×270-byte STM-1 frame and 155.52-Mbit/s line rate, the one-column VC-4 POH and 9×260-byte C-4 client container, and 149.76-Mbit/s ATM-cell capacity; show why cells cross C-4 frame boundaries and per-frame floor/tail-waste accounting is wrong; use the 47-byte user field only for conditional AAL1 non-P, yielding a theoretical 132.806-Mbit/s upper bound and 85.395% line efficiency; gate actual goodput on cell mix, AAL, service, QoS, and protection
Solution Notebook · EN
#33 retain the 155.52-Mbit/s STM-1 line rate and 9×260-byte C-4 container; distinguish RFC 791's 576-octet host acceptance rule from an MTU claim; treat 24+552 bytes as a conditional model; show under RFC 2615/RFC 1662 that the POS/PPP stream may cross VC boundaries; derive 143.52 Mbit/s and 92.284% only as zero-extra-overhead upper bounds; gate actual goodput on PPP, stuffing, MTU, loss, QoS, and protection
Solution Notebook · EN
#34 distinguish a 53-byte ATM cell from a hypothetical 77-byte unit; continuously map their alternating 130-byte pair into the correct 2,340-byte C-4; derive 18+18 pair-aligned units with zero tail; under the stated 47+72 user model calculate 17,136 bits/frame, 137.088 Mbit/s, and 88.148% line-efficiency upper bounds; use gross-byte weights for mixture efficiency; gate actual goodput on mapping, AAL/PDU, traffic mix, OAM/idle, QoS, and protection