Computer Networking Past Paper

0. Network and Architecture

Switching

• y2019p5q6 (a)
  • multiplexing in five layers
• y2016p5q6 (a)
• y2018p5q5 (a)
  • Packet switching and Circuit switching
• y2019p5q5 (a)
  • marshalling taking up transmission time vs propagation delay
  • TDM
• y2017p5q4 (b)
  • queueing, $\propto$ contention, $B=2T×C$
  • processing, unusual packets, $\approx0$
  • transmission, the capacity of the link, $size(pkg)$/Exception
  • propagation, $\propto$ distance, WAN

Architecture

• y2017p5q4 (a)
  • hop-by-hop vs end-to-end, encryption

1. Physical Layer

• y2014p5q5 (b)
  • Queueing
• y2013p5q4 (a)
  • Coding
• y2019p5q5 (b,c)
  • Coding, multilevel encoding
  • Error Correction, redundancy and FEC
  • CDMA, chipping / gold code

2. Data Link Layer

• y2013p5q4 (b)
  • CSMA/CD, CSMA/CA
• y2021p5q6 (b)
  • CDMA, CSMA/CA, VLAN

Switches

• y2021p5q4
  • Topology, Forwarding table, Troubleshooting
• y2020p5q4
• y2023p5q3 (a)(i,ii)
  • Spanning Tree

3. Network Layer

• y2020p5q5
  • fault finding
• y2020p5q6
  • DHCP, ARP
• y2021p5q5
  • ICMP, topology, ping, trace-route, whole-system debugging
• y2018p5q5 (c)
  • subnet
• y2021p5q6 (a)
  • subnet and IPv6
• y2016p5q5 (a)
  • IPv6 address
  • IPv4 vs IPv6, DHCP vs SLAAC
• y2023p5q3 (b)
  • IP Troubleshooting
• y2017p5q5 (b ii,iii)
  • Fault finding, Classless Inter-Domain Routing, trace-route

Routers

• y2018p5q6 （a,b)
  • a switch vs router
  • distance-vector
• y2017p5q5 (a)
  • Router Control vs Data Panel (line-card)
• y2022p5q1
  • shortest path in a satellite network
• y2023p5q3 (a)(iii,iv)
• y2018p5q5 (b)
• y2014p5q4
  • Link-state vs Distance Vector protocol

4. Transport Layer

Reliable Data Transfer

• y2011p5q5
• y2014p5q6
  • FSM

UDP(QUIC), TCP

• y2022p5q3 (a,b), y2009p5q7 (a), y2017p5q6
  • Flow-control and Congestion-control
• y2019p5q4
  • TCP, ARQ; QUIC
• y2022p5q2
  • TCP; QUIC
• y2016p5q6 (b)
  • TCP retransmission timeout
  • Exponential Average (EWMA filter), Jacobson/Karels Algorithm
• y2018p5q6 （c-e)
  • TCP, Karn-Partridge algorithm
  • Max-min fairness, limitations(cheat)
• y2017p5q5 (b i)
  • Fault finding, TCP

Network buffers

• y2013p5q4 (c)
  • $B = 2T × C$, assumptions
  • Reference: Buffer Size Rule, Stanford, Note on Buffer size BDP

5. Application Layer

• y2014p5q5 (a)
• y2019p5q6 (b,c)
  • DNS
• y2016p5q4 (a)
  • HTTP, Connections, latency, RTT, bandwidth,
• y2013p5q5
  • Cache, CDN
• y2022p5q3 (c,d)
  • Cache
• y2016p5q4 (b)
  • conditional GET