Ad-hoc TPE kursus: Datanet

warmersafternoonNetworking and Communications

Oct 23, 2013 (4 years and 21 days ago)

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Ad
-
hoc TPE kursus: Datanet

Formål:



At give den studerende viden om grundlæggende begreber,
principper og teknikker i moderne datanet(Internettet).



At eksemplificere anvendelse af 2 meget anvendte protokoller i
(programmeringssproget) C


Indhold :




Basale netværksbegreber (MM1)


-

Protokolbegreber, OSI
-
modellen versus TCP
-
implementationen


-

Lag 1 og 2: basal datatransmission, MAC, LLC, Ethernet, HDLC





Adressering i netværk (MM2)


-

IPv4/IPv6


-

Name Services(DNS)




Internet services og protokoller (MM3)


-

Datagram og forbindelses orienteret service


-

Protokoller: IP, UDP, TCP


-

Service primitiver, Tilstandsmaskine model





Protokol programmering (MM4 & 5)


-

TransportLayerInterface


-

Berkeley Sockets, TCP primitiver og eksempler


-

UDP primitiver og eksempel

Local Area Networks

Two broadcast networks


(a)

Bus : Ethernet collision prone


(b)

Ring : ArcNet collision free

Issues:

Topology

Arbitration

Allocation

Wide Area Networks


Relation between hosts on LANs and the
subnet.

Wide Area Networks (2)


A stream of packets from sender to receiver.



Store & Forward = Packet Switched




Routing

Network Software


Protocol Hierarchies


Design Issues for the Layers


Connection
-
Oriented and Connectionless Services


Service Primitives


The Relationship of Services to Protocols

Network Software

Protocol Hierarchies


Layers, protocols, and interfaces

Protocol Hierarchies (2)


The philosopher
-
translator
-
secretary
architecture.

Protocol Hierarchies (3)


Example information flow supporting virtual
communication in layer 5.

Design Issues for the Layers


Addressing


Error Control


Flow Control


Multiplexing


Routing

Connection
-
Oriented and Connectionless
Services


Six different types of service.

Service Primitives


Five service primitives for
implementing a simple connection
-
oriented service.

Service Primitives (2)


Packets sent in a simple client
-
server interaction on a connection
-
oriented network.

Services to Protocols
Relationship


The relationship between a service and a
protocol.

Reference Models


Reference Model Design Principles


The OSI Reference Model


The TCP/IP Reference Model


A Comparison of OSI and TCP/IP


A Critique of the OSI Model and Protocols


A Critique of the TCP/IP Reference Model

Reference Model Design
Principles

1.
Each layer should perform a well
-
defined function.

2.
The function of each layer should be chosen with an eye
toward defining internationally standardized protocols.

3.
The layer boundaries should be chosen to minimize the
information flow across the interfaces.

4.
A layer should be created where a different abstraction is
needed.

5.
The number of layers should be large enough that distinct
functions need not be thrown together in the same layer out of
necessity and small enough that the architecture does not
become unwieldy.

Reference Models

The OSI
reference
model.

Reference Models (2)


The TCP/IP reference model.

Reference Models (3)


Protocols and networks in the TCP/IP
model initially.

Comparing OSI and TCP/IP
Models

Concepts central to the OSI model


Services


Interfaces


Protocols

A Critique of the OSI Model and
Protocols

Why OSI did not take over the world


Bad timing


Bad technology


Bad implementations


Bad politics

Bad Timing


The apocalypse of the two elephants.

A Critique of the TCP/IP Reference
Model

Problems:


Service, interface, and protocol not distinguished


Not a general model


Host
-
to
-
network “layer” not really a layer


No mention of physical and data link layers


Minor protocols deeply entrenched, hard to
replace

Hybrid Model


The hybrid reference model to be used in
this book.

Example Networks


The Internet


Connection
-
Oriented Networks:



X.25, Frame Relay, and ATM


Ethernet


Wireless LANs: 802:11

Internet Usage

Traditional applications (1970


1990)


E
-
mail


News


Remote login


File transfer

New applications (1990


)


WWW


Too much to mention

Architecture of the Internet


Overview of the Internet.

Ethernet


Architecture of the original Ethernet.


Dorado @ Xerox Parc (84)

Ethernet


Ethernet Cabling


Manchester Encoding


The Ethernet MAC Sublayer Protocol


The Binary Exponential Backoff Algorithm


Ethernet Performance


Switched Ethernet


Fast Ethernet


Gigabit Ethernet


IEEE 802.2: Logical Link Control


Retrospective on Ethernet


Ethernet MAC Sublayer Protocol

Frame formats.
(a)

DIX Ethernet,
(b)

IEEE 802.3.



Ethernet MAC Sublayer Protocol (2)



Ethernet Performance


Efficiency of Ethernet at 10 Mbps with 512
-
bit slot times.

IEEE 802.2: Logical Link Control

(a)

Position of LLC.
(b)

Protocol formats.