SUMMARY of Days 20-36 of CPSC 441 L01
=====================+===============

<Day 20 recap:>
  "The Network Layer provides addressing, routing, and inter-networking
  functionality to support host-to-host delivery of datagrams."

<Day 21 recap:>
  Midterm exam on Chapters 1-3 (overview, AL, and TL)
  
<Day 22 recap:>
  "They who control the routers control the Internet."

<Day 23 recap:>
  "The Internet is a network of networks, built using the magic of IP,
  which is a connection-less best-effort datagram NL protocol."

  "An IPv4 address has k bits of network ID, and 32-k bits of host ID."

<Day 24 recap:>
  "DHCP and NAT are two clever techniques to extend the longevity of IPv4,
  by supporting temporal and/or spatial reuse/sharing of IP addresses."

<Day 25 recap:>
  "Link-state routing requires a global view of the network topology,
  and calculates good routes using Dijkstra's algorithm."

<Day 26 recap:>
  "Distance-vector routing is a distributed routing algorithm that combines
  local state information with information gathered from neighbouring routers."

  "Internet routing happens in two stages: inter-domain and intra-domain."

<Day 27 recap:>
  "BGP is an inter-domain routing algorithm that uses policy-based routing."

<Day 28 recap:>
  "Software-Defined-Networking (SDN) is a new paradigm for Internet routing,
  providing great flexibility via flow tables and generalized forwarding."

<Day 29 recap:>
  "The Datalink Layer provides node-to-node (hop-by-hop) delivery
   of frames across a link, using LLC and MAC protocols."

  "Cyclic Redundancy Check (CRC) is an extremely powerful
   error detection mechanism used in many DLL protocols."

<Day 30 recap:>
  "Medium Access Control (MAC) protocols are used to arbitrate
   access to a shared channel in broadcast-based link technologies."
  "MAC protocols provide many tradeoffs between channel access delay,
   collisions, and efficiency."

<Day 31 recap:>
  "Ethernet is the dominant technology for wired LANs."

  "ARP provides the IP-to-MAC address mapping information
  required for the final step of local datagram delivery."
  
<Day 32 recap:>
  "Ethernet switches are layer-2 devices that use flooding, self-learning,
  and selective forwarding to deliver frames at the datalink layer."

<Day 33 recap:>
  "IEEE 802.11 WiFi is a ubiquitous solution for wireless network access,
   with CSMA/CA (a.k.a. Distributed Coordination Function) at the MAC layer."

  "Because of the higher error rate on WLANs, WiFi uses a connection-less
  ACKed service model, unlike Ethernet's connection-less unACKed service."

<Day 34 recap:>
  "Supporting mobility within a single WLAN is quite easy,
  but mobility across different provider networks is more challenging."

  "IETF Mobile IP allows an MH to maintain its IP identity while roaming."

<Day 35 recap:>
  "There is a never-ending 'arms race' between the good guys and the bad guys."

  "Internet censorship is a known/challenging issue in several countries."

<Day 36 recap:>
  "Large online social media platforms have grown to have undue influences
   on political, economic, legal, and social aspects of our personal lives."

  "Deep space networking faces many technical challenges, making it like
   the Internet in some ways, and completely different in other ways."