Lesson 1 - History and Internet Architecture Flashcards
Galactic Network
a 1962 vision of J.C.R Licklider from MIT. He envisioned that everyone could quickly access data through a set of interconnected computers.
ARPANET
First network connecting 4 nodes (UCLA, Stanford, UCSB, Univ. of Utah) created by MIT researcher Lawrence Roberts in 1969.
DARPA
Defense Advanced Research Projects Agency
One of the first application launched on the internet in 1972
The initial ARPANET Host-To-Host protocol introduced in 1970
Network Control Protocol (NCP)
Protocol developed 1973 as an evolution of NCP which introduced the idea of open-architecture networking so that individual networks may be independently designed and developed
TCP/IP
TCP original 1973 service features were
The Transmission Control Protocol focused on service features such as flow control and recovery from lost packets.
IP originally responsible for
Internet Protocol responsible for addressing and forwarding of individual packets
System designed in 1983 to translate domain names to IP addresses by a scaleable distributed mechanism.
Domain Name System (DNS)
Application first introduced by team of researchers lead by Tim Berners-Lee
World Wide Web
Advantages of internet layered architecture
scalability, modularity, flexibility
Disadvantes of layered protocol stack model
- Some layers’ functionality depends on the information from the other layers.
- One layer may duplicate lower layer functionalities.
- Overhead that is caused by the abstraction between layers.
OSI model layers proposed by the International Organization for Standardization (ISO)
- Application
- Presentation
- Session
- Transport
- Network
- Data Link
- Physical Layer
Internet Protocol Stack layers are:
- Application
- Transport
- Network
- Data Link
- Physical
What is the interface between the application and transport layer?
sockets
describe the Application Layer
includes multiple protocols (web, email, ftp, DNS) and multiple services.
What does the Presentation Layer do?
formats the information that it receives from the layer below and delivering it to the application layer.
The Session Layer is responsible for
The session layer is responsible for the mechanism that manages the different transport streams that belong to the same session between end-user application processes
In which layer do the TCP and UDP protocols reside
Transport Layer
Transport layer packet of information
segment
Network layer packet of information
datagram
Transport layer is responsible for
end-to-end communication between end hosts.
The Network Layer is responsible for
moving datagrams from one Internet host to another.
Which layer includes the Internet Protocol (IP) & routing protocols?
Network layer
Data Link layer packets of information
frames
Protocols in the Data Link Layer
Ethernet, PPP, WiFi
Describe the Physical Layer
The physical layer facilitates the interaction with the actual hardware
It is responsible for transferring bits within a frame between two nodes that are connected through a physical link.
What responsibility does the data link layer have?
data link layer is responsible to move the frames from one node (host or router) to the next nod
define encapsulation with respect to network data
the process of adding layer information to the proceeding layer.
The transport layer encapsulates the application message with a transport header to make a segment.
The network layer encapsulates the segment with network header information to make a datagram.
End-to-end principle
the network core should be simple and minimal, while the end systems should carry the intelligence.
What is OSI model
A 7-layer internet architecture model proposed by ISO
What are examples of a violation of the end-to-end principle?
firewalls, traffic filters, Network address translation box (sometimes home router),
What are the ramifications of the hourglass shape of the internet?
A. Many technologies that were not originally designed for the internet have been modified so that they have versions that can communicate over the internet (such as Radio over IP).
B. It has been a difficult and slow process to transition to IPv6, despite the shortage of public IPv4 addresses.
What is an EvoArch model?
an abstract model for studying protocol stacks and their evolution.
On which layers to repeaters, hubs, bridges, routers operate?
repeaters/hubs - physical layer - receive and forward digital signals to connect different Ethernet segments.
Bridges - Data Link layer (layer 2) Receive packets and forward them to the appropriate destination.
Routers - Network Layer (Layer 3)
What is the purpose of the Spanning Tree Algorithm?
The goal of the spanning tree algorithm is to have the nodes (bridges) select which links (ports) to use for forwarding eliminating loops.
Describe the steps of the Spanning Tree Algorithm.
The algorithm runs in “rounds” and at every round each node sends to each neighbor node a configuration message with three fields: a) the sending node’s ID, b) the ID of the roots as perceived by the sending node, and c) the number of hops between that (perceived) root and the sending node.
At every round, each node keeps track of the best configuration message that it has received so far, and it compares that against the configuration messages it receives from neighboring nodes at that round.
Name each of the 5 internet layer’s packet of information
application - message transport - segment, network - datagram data link - frame physical - ??
