Home|Cheat|Cram|Answers|Chat

CSC 718 Cram Sheet - last hour

Formulas

• BDP = bandwidth x RTT (bits; /8 = bytes).
• Queue delay d_q = q / C (queue size / link speed).
• Effective RTT = RTprop + B/C.
• Cubic: W(t) = C(t-K)^3 + W_max, C=0.4, beta=0.7.
• Mathis: throughput ~ (MSS/RTT) x (1.22 / sqrt(p)).
• PBFT: n >= 3f+1. DHT lookup: O(log N).

Numbers to remember

• 100 Mbps x 40 ms = 500,000 B; 2xBDP buffer = 80 ms; peak RTT = 120 ms.
• IPv6 header 40 B; 6LoWPAN ~2-7 B; 802.15.4 frame 127 B; IPv6 min MTU 1280 B.
• CoDel: 5 ms target, 100 ms interval.
• BGP TCP port 179; MQTT 1883/8883.

One-line summaries

• End-to-End: do real work at the endpoints; network helps speed only.
• BGP: policy routing between companies; RPKI adds proof of ownership.
• MPLS: strict but rigid; SD-WAN: flexible but best-effort.
• Cubic loss-based; BBR model-based; CoDel drops early.
• QUIC/HTTP3 over UDP, independent streams, fast secure handshake.
• SDN: brain out of the box; P4: program the data plane.
• Anycast: one IP, many servers, nearest wins.
• 6LoWPAN/RPL: squeeze IPv6 and route on noisy links.
• DHT: distributed phone book; IPFS: find by content; IoT: sign at sensor, ledger at gateway.

Home|Cheat|Answers|Top|Chat