Network Layer

Internetworking

A collection of networks to provide data delivery of host-to-host.

H# are hosts

R# are routers

Store and Forward Packet Switching

IP and Routing

Internet Protocol (IP)

Governs the transmission of data over the internet.

Responsible for Routing data packets.

• Sender

  • Encapsulates segments into datagrams and sends them from the sending host to the receiving host

• Receiver

  • Datagrams are delivered to the transport layer

• Every host and router

  • Network layer protocols that operate at the network, data link, and physical layers

• A router examines the header fields in all IP datagrams that pass through it

Network Layer

Encapsulation

segment

datagram

frame

• Routing Protocols

  • RIP, OSPF, BGP

• IP Protocol

  • Address

  • Datagram Format

  • Packet handling

• ICMP Protocol

  • Error reports

  • Router Signals

• Forwarding Table

Internet network Layer (disassembled) 

IP Datagram Format

• Internet Protocol Address
  • Identification for a device using the Internet Protocol
  • Location identification
• What are they?
  • A 32 bit number (IPv4)
  • A 128 bit number (IPv6)
• Who manages it?
  • Internet Assigned Numbers Authority (IANA)
    • Internet providers
  • Local administrators for a business or YOU at home

IP Address

Address Classes

• IPv4 addresses divided in
  • Network portion
  • Host ID
• At the beginning of IP protocol addresses were designed based on classes:
  • Class A
  • Class B
  • Class C
  • Class D
    • Multicasting
  • Class E
    • experimental

• Class A network range

  • 0-127

  • Really 0-126 as 127 is reserved

• Class B network range

  • 128-191

• Class C network range

  • 192-223

     

Network Ranges

• Class A supports 16777214 hosts
• Class B supports 65534 hosts
• Class C supports 254 hosts
  
   
• What if I only need 50 hosts or even worse 300?
  • IP wastage

SUBNETting

• To avoid IP wastage

• Create smaller networks (sub networks; subnets) inside large networks

• How?

  • Borrow bits from the Host ID

• Still have wastage but a lot more reduced

SUBNETting

• How do we know that 192.168.1.32 is an IP address or a subnet

• Subnet Masks

Class A: 255.0.0.0
Class B: 255.255.0.0
Class C: 255.255.255.0

• Subnet 192.168.1.32 is then represents as :

192.168.1.32  255.255.255.224 (or 192.168.1.32/27)

Router Architecture

datagrams journey

The concept of net neutrality is based on the idea that the internet should be an open and level playing field, where all users have equal access to information and online resources, regardless of their location, financial resources, or the type of device they use to access the internet.

If network neutrality is not enforced, ISPs could prioritize or block certain types of internet traffic, including specific websites, applications, or services. This could have significant implications for how routers function and how data is transmitted over the internet.

https://www.youtube.com/watch?v=fpbOEoRrHyU

https://worldpopulationreview.com/country-rankings/countries-without-net-neutrality

Network Neutrality