11. Network Layer


  1. The Internet Concept (1)
  2. The Internet Concept (2)
  3. Routers (1)
  4. Routers (2)
  5. Hosts and Routers
  6. Forwarding and Routing
  7. IP Addresses and Dotted-Decimal Notation
  8. IP Addressing
  9. Subnets
  10. Subnet Addressing
  11. Classful Addressing
  12. Obtaining a Block of Addresses
  13. Special IP Addresses
  14. Obtaining a Host Address
  15. Dynamic Host Configuration Protocol
  16. DHCP Client-Server Interaction
  17. Network Address Translation
  18. NAT Example
  19. Criticisms of NAT
  20. IP Datagrams
  21. Forwarding IP Datagrams
  22. Extracting Network Prefixes
  23. Best-Effort Delivery
  24. IP Datagram Format (1)
  25. IP Datagram Format (2)
  26. Encapsulation
  27. Transmission across an Internet
  28. Example of IP Header
  29. Maximum Transmission Unit (MTU)
  30. Datagram Fragmentation (1)
  31. Datagram Fragmentation (2)
  32. Datagram Reassembly
  33. Fragment Loss
  34. Internet Control Message Protocol (ICMP)
  35. ICMP Message Types
  36. Use of ICMP Messages
  37. Routing Algorithms
  38. Internet Routing Protocols
  39. Abstract Graph Model
  40. Open Shortest Path First
  41. OSPF Algorithm
  42. Example of OSPF Algorithm
  43. Links to more information

11.1. The Internet Concept (1)

The internet concept

11.2. The Internet Concept (2)

The internet concept

11.3. Routers (1)

Networks connected by a router

11.4. Routers (2)

An internet

11.5. Hosts and Routers

The network layer

11.6. Forwarding and Routing

11.7. IP Addresses and Dotted-Decimal Notation

Example addresses

11.8. IP Addressing

Interface addresses

11.9. Subnets

Subnets

11.10. Subnet Addressing

11.11. Classful Addressing

11.12. Obtaining a Block of Addresses

11.13. Special IP Addresses

Special IP addresses

11.14. Obtaining a Host Address

11.15. Dynamic Host Configuration Protocol

DHCP client-server scenario

11.16. DHCP Client-Server Interaction

For a newly arriving host, DHCP is a four-step process:

DHCP client-server interaction

11.17. Network Address Translation

11.18. NAT Example

Network address translation

11.19. Criticisms of NAT

11.20. IP Datagrams

11.21. Forwarding IP Datagrams

11.22. Extracting Network Prefixes

11.23. Best-Effort Delivery

11.24. IP Datagram Format (1)

IP datagram header

11.25. IP Datagram Format (2)

IP datagram header

11.26. Encapsulation

11.27. Transmission across an Internet

Traversing different networks

11.28. Example of IP Header

Packet capture showing IP header

11.29. Maximum Transmission Unit (MTU)

11.30. Datagram Fragmentation (1)

Fragmentation

11.31. Datagram Fragmentation (2)

11.32. Datagram Reassembly

11.33. Fragment Loss

11.34. Internet Control Message Protocol (ICMP)

11.35. ICMP Message Types

ICMP messages

11.36. Use of ICMP Messages

11.37. Routing Algorithms

11.38. Internet Routing Protocols

11.39. Abstract Graph Model

11.40. Open Shortest Path First

11.41. OSPF Algorithm

  Initialisation:
 1.  N' = {u}
 2.  for all nodes v
 3.    if v is a neighbour of u
 4.       then D(v) = c(u,v)
 5.       else D(v) = infinity

 6.  Loop
 7.    find w not in N' such that D(w) is a minimum
 8.    add w to N'
 9.    update D(v) for each neighbour v of w not in N':
10.      D(v) = min( D(v), D(w) + c(w,v) )
11.  until N' = N

11.42. Example of OSPF Algorithm

11.43. Links to more information

See Chapter 4 of [Kurose and Ross], Chapters 20, 21, 22 and parts of 23 of [Comer] and parts of Chapter 5 of [Tanenbaum].