Lecture week 9 - Networks

Question 1

What is Network Layer in the Internet?

Answer 1

The Internet is a collection of autonomous systems (ASes)
Major backbones connect regional networks, which
connect LANs

Question 2

What is Communication in the Internet?

Answer 2

The Internet uses the Internet Protocol (IP)
It aims to deliver datagrams from source to destination
on a “best effort” base — delivery not guaranteed

Transport layer takes data streams, and breaks them into datagrams, typically 1500 bytes

Network layer transmits the datagrams across the Internet

Each datagram might be fragmented, if an intermediate network has a smaller packet size

Each datagram is reassembled at the destination, and passed to the transport layer, which reassembles them into a data stream for the application

Question 3

What is the Summary?

Answer 3

The Internet uses IP to pass datagrams
IPv4 and IPv6 header
IP address = network number + host number

Routing in the Internet is based on autonomous systems
The interior gateway routing protocol (OSPF): intra-AS
routing
The exterior gateway routing protocol (BGP): inter-AS
routing