fundamentals of ip networking communicating over the ...ip.eap.gr/pdf/lecture schrotter.pdf ·...

ERASMUS IP Summer Course 2009: WiCoNet IP Networking

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ERASMUS IP: WiCoNet IP Networking

IP NetworkingDipl.-Ing. Peter Schrotter

Institute of Communication Networks and Satellite Communications

Graz University of Technology, Austria

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Overview

� Fundamentals of IP Networking

� Communicating over the Network

� Application Layer Functionality and Protocols

� OSI Transport Layer

� OSI Network Layer

� Addressing the Network (IPv4)

� OSI Data Link Layer

� OSI Physical Layer

� Ethernet

� Planning and Cabling Networks

� Configuring and Testing the Network

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IP Networking - Part 1

�� Fundamentals of IP NetworkingFundamentals of IP Networking








� Ethernet



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Networks Impact Daily Life

� Instantaneous communication supports and improves

our lives.

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How Networks Impact Daily Life

� Popular communication media such as IM, Wikis,

Blogs, Podcasting, and Collaboration Tools

– Instant messaging

• Real time communicationbetween 2 or morepeople based on typed text

– Weblogs (Blogs)

• Web pages createdby an individual

– Podcasting

• Website that containsaudio files availablefor downloading

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� Information networks can be used in different ways of

sharing and collaborating

→ Improvement for teaching and learning


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� Communication over a network changes the way we

work

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� Communication over a network supports the way we

play

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Data Networking:Role, Components, and Challenges

� Basic characteristics of communication

– Rules or agreements are 1st established

– Important information may need to be repeated

– Various modes of communication may impact the effectiveness of getting the message across.

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� Various elements make up a network

– Devices

• These are used to

communicate w ith

one another

– Medium

• This is how the

devices are con-

nected together

– Messages

• Information that

travels over the medium

– Rules

• Governs how messages f low across netw ork

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� Converged networks in communications

– A type of network that can carry voice, video & data over the same network

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Network Architecture Characteristics

� Characteristics that are addressed by network

architecture design

– Fault tolerance

– Scalability

– Quality of service

– Security


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� Packet switching helps to improve the resiliency and

fault tolerance of the Internet architecture

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� Characteristics of the Internet → Easy scaling to meet

user demand

– Hierarchical

– Common standards

– Common protocols

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� Need for Quality of Service → Mechanisms to ensure it

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� QoS mechanisms ensure quality of service for

applications that require it

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� For each type of traffic the appropriate QoS strategy

has to be chosen

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� Some networks must be secure


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� Basic measures to secure data networks

– Ensure confidentiality through use of

• User authentication

• Data encryption

– Maintain communication integrity through use of

• Digital signatures

– Ensure availability through use of

• Firewalls

• Redundant networkarchitecture

• Hardware without a singlepoint of failure

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�� Communicating over the NetworkCommunicating over the Network







� Ethernet



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� 3 common elements of communication

– message source

– the channel

– message destination

� Network definition

– data or information networks capable of carrying many different types of communications

Network StructureIKS


Network Structure

� Data is sent across a network in small “chunks” called

segments

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Network Structure

� Definition of the components of a network

– Hardware

– Software

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� End devices are the interface between human network

and communications network

� Role of end devices:

– client

– server

– bothclientandserver

Network Structure


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� Role of an intermediary device in a data network is

different to the role of an end device

� Role of an intermediary device

– provides connectivity and ensures data flows across network

Network StructureIKS


Network Structure

� Network media and criteria for making a network media

choice

– Network media is the channel over which a message travels

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Network Types

� Local Area Networks (LANs)

– A network serving a home, building or campus is considered a Local Area Network (LAN)

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Network Types

� Wide Area Networks (WANs)

– LANs separated by geographic distance are connected by a network known as a Wide Area Network (WAN)

� Metropolitan Area Networks (MANs)

– Interconnection of urban LANs, distances betw. LANs & MANs

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Network Types

� Internet

The internet is defined as a global mesh of interconnected networks

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Network Types

� Network representations


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Function of Protocolin Network Communication

� The importance of protocols and how they are used to

facilitate communication over data networks

– A protocol is a set of predetermined rules

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� Network protocols

– are used to allow devicesto communicatesuccessfully

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� Protocol suites and industry standards

� A standard is

– a process or protocol that has been endorsed by the networking industry and ratified by a standards organization


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� Interaction of different protocols


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� Technology independent Protocols

– Many diverse types of devices can communicate using the same sets of protocols

– This is because protocols specify network functionality, not theunderlying technology to support this functionality


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� Benefits of using a layered model include

– assists inprotocol design

– fosterscompetition

– changes inone layer donot affectother layers

– provides acommonlanguage

Layers with TCP/IP and OSI Model


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� Describe TCP/IP Mode

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� The Communication Process

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� Protocol Data Units (PDU) and Encapsulation

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� Process of sending and receiving messages

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� Protocol and reference

models

– A protocol modelprovides a model that closely matches the structure of a particular protocol suite

– A reference modelprovides a common reference for maintaining consistency within all types of network protocols and services

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� Open Systems Interconnection Model (OSI) of ISO


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� Comparison of OSI and TCP/IP model

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Addressing and Naming Schemes

� Labels in encapsulation headers are used to manage

communication in data networks

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� Examples for addressing in different layers:

Layer 2: Ethernet MAC Addresses

Layer 3: IP Addresses

Layer 4: TCP/UDP Port numbers

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� Labels in encapsulation headers are used to manage

communication in data networks

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� Information in the encapsulation header is used to

identify the source and destination processes for data communication

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�� Application Layer Functionality and ProtocolsApplication Layer Functionality and Protocols






� Ethernet




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� Applications provide the means for generating and receiving data

that can be transported on the network

Applications – The Interfacebetween Human and Data Networks

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� Applications, services and protocols work together in convertingcommunication to data that can be transferred across the data network


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� Applications, services and protocols play different roles in transporting data through networks


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� Networking Protocols are able to identify several message properties that can be defined by a protocol


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� Client and server processes have different tasks in data networks

The Role of Protocols inSupporting Communication

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� Examples of Application Layers services and protocols



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� Different behaviors of client server networking compared with peer-to-peer networking and peer-to-peer applications


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� DNS protocol

Support of DNS services

Features, Operation, and Use of TCP/IP Application Layer Services

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� HTTP protocol

Supports delivery of w eb pages to the client


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� POP and SMTP protocols

Support of e-mail services


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� Telnet protocol

used for examining and managing netw orks


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� SMB protocol

File shar ing in Microsoft-based netw orks



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� Gnutella protocol

supporting P2P services


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�� OSI Transport LayerOSI Transport Layer





� Ethernet



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Transport Layer Role and Services

� Transport layer

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� Major functions of the transport layer and the role it

plays in data networks

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� Supporting Reliable Communication

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� Basic characteristics of the UDP and TCP protocols


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� Representation of port number

Description of port numbers in the TCP and UDP protocols

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� The role of segments in the transport layer

two principle ways segments can be marked for reassembly

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Application and Operationof TCP Mechanisms

� TCP reliability mechanism working as part of a session

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� Port numbers

Establishment of TCP sessions and directing segments to server process

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� Handshaking during establishment of TCP sessions

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� Handshake in the termination of TCP sessions


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Managing TCP Sessions

� TCP sequence numbers are used to reconstruct the

data stream with segments placed in the correct order

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� Usage of TCP sequence and acknowledgement numbers

for management of exchanges in a conversation

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� Retransmission remedy for lost data employed by TCP

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� Mechanisms in TCP are managing the interrelationship

between window size, data loss and congestion during a session

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UDP Protocol

� Characteristics of the UDP protocol

types of communication for which it is best suited

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UDP Protocol

� The process specified by the UDP protocol to

reassemble PDUs at the destination device


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UDP Protocol

� Servers are using port numbers to identify a specified

application layer process

directing segments to the proper service or application

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UDP Protocol

� UDP protocol and port numbers are utilized in client-

server communication.

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�� OSI Network LayerOSI Network Layer




� Ethernet



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Network Layer Protocolsand Internet Protocol (IP)

� Tasks of the Network Layer in data networks

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� Basic characteristics and the role of the IPv4 protocol

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� Implications for using the IP protocol: connectionless


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� Implications for using the IP protocol: unreliable delivery

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� Implications for using the IP protocol: media independence

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� Framing in the Transport Layer

segments are encapsulated as packets

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� Major header fields in the IPv4 protocol

Role of each field in transporting packets

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Grouping Devices into Networksand Hierarchical Addressing

� There can be different reasons for grouping devices

into sub-networks

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� Dividing a large network can increase network

performance


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� Dividing a large network can increase network security

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� Communication problems can emerge when very large

numbers of devices are included in one large network

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� Hierarchical addressing solves the problem of devices

communicating across networks of networks

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� Further subdividing networks into smaller networks

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Fundamentals of Routes, Next Hop Addresses and Packet Forwarding

� Intermediary gateway device

allowing devices to communicate across sub-divided networks

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� IP packets are traversing unchanged via routers from

sub network to sub-network


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� Gateway are using a simple route table in directing

packets toward their ultimate destinations

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� Definition of a route and its three key parts

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� The purpose and use of the destination network in a

route

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� The purpose and use of the next hop in a route

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� Example: several IP packets are routed through several

gateways from devices on one sub network to devices on other sub networks

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� Routing protocols

needed for both static and dynamic routes


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� Routes can be manually configured to build routing table

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� Routing protocols allow automatic learning of routes

→ Continuous update of the routing table

– updated routes

– new networks (hosts)

– new (redundant) routes for already known networks (hosts)

– routes to be deleted

� Examples for routing protocols

– RIP (Routing Information Protocol)

– IGRP and EIGRP (CISCO proprietary)

– OSPF (Open Shortest Path First)

– BGP (Border Gateway Protocol)

– IS-IS (Intermediate System - Intermediate System)

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�� Addressing the Network (IPv4)Addressing the Network (IPv4)



� Ethernet

� Planing and Cabling Networks


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IP Addressing Structure

� Dotted decimal structure of a binary IP address

8-bit binary in network addressing and Convertion to decimal

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� Converting 8-bit binary to decimal

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� Converting decimal to 8-bit binary


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Classification of IPv4 Addresses

� 3 types of addresses in the network

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Types of Communicationin the Network Layer

� Characteristics of the 3 types of communication

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Reserved IPv4 Address RangesIKS


Public and Private Addresses

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Historic IPv4 Address AssignmentIKS


Assigning Addresses to Hosts

� End user devices can obtain addresses either statically

through an administrator or dynamically through DHCP


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Assigning Addressesto Special Devices

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Assignment of Public IPv4 Addresses

� Regional agencies manage IP address registries via ISPs

– ISPs are further providing Internet connectivity

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IPv6 Addresses

� Need for migration from IPv4 to IPv6

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Subnetting (IPv4)

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Testing the Network Layerwith PING command

� Ping command is checking operability of IP protocol

– on a local host: ping 127.0.0.1

– between a local host and agateway across a LAN

– between a local host and agateway to a devicein remote network

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Testing the Network Layerwith TRACEROUTE

� Observation of the path between two talking devices


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�� OSI Data Link LayerOSI Data Link Layer


� Ethernet



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Data Link Layer Services

� Preparing communication for transmission on specific

media

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Data Link Layer ProtocolsControl of Media Access

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Data Link Layer Framing

� Preparing a packet for transmission on a given media

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Hardware and Software LayersIKS


Protocols and Standards used


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Media Access Control (MAC) Techniques for Shared Media

� Necessary to avoid collisions

– added overhead should be minimized

� Two media access control methods for shared media

– controlled access vs. contention-based access

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Media Access Control (MAC)Techniques for Non-shared Media

� Full Duplex and Half Duplex

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Logical TopologyIKS


MAC Addressing and Framing

� Packets are encapsulating into frames to facilitate the

entry and exit of data on media

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MAC Addressing: Header and Trailer

Trailer is very important on "non-reliable" media

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MAC Addressing not always needed


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�� OSI Physical LayerOSI Physical Layer

� Ethernet



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Physical Layer Protocols & Services

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Frames are represented by Bits

� during transport across the local media

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Signals on Physical Layer

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Physical Layer StandardizationIKS


Physical LayerSignaling and Encoding


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Physical Layer Encoding

� Transmission of bits, treating a collection of bits as a code

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Bandwidth, Throughput, and Goodput

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Characteristics of Ethernet Media IKS


Impact of Interference

� Proper cabling reduces interference

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Characteristics of Network Media

� Basic characteristics of UTP cable

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Wireless Network Media

� Security in wireless communications


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�� EthernetEthernet



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Characteristics ofEthernet Network Media

� The evolution of Ethernet: Topology and Standardization

(IEEE 802.3)

� Hub / Repeater:

electricalSignalRegeneration

increasedDistances

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Introduction of LAN Switches

� Key innovation for managing collisions on Ethernet-

based networks

� Bridge / Switch:

Point-to-Point links

Reduction of thenetwork load

Deletion ofcorrupted frames

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State-of-the-art Ethernet

� Fiber optical and Twisted Pair cabling

point-to-point topography

large distances

bandwidths upto 10 Gbit/s

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Standards and ImplementationIKS


Characteristics of Ethernetin first 2 OSI Layers


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Media Access Control (MAC) and Logic Link Control (LLC) Sublayer

Logic Link Control Sublayer

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Physical Implementations

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Media Access Control Method

� Function of MAC in Ethernet

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Ethernet Timing

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Layer 2 Addressing

� The Frame – Encapsulating the Packet

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� Comparing Layer 2 and Layer 3 Addressing

Layer 2 Addressing


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� Ethernet Unicast, Multicast and Broadcast

Layer 2 AddressingIKS


Legacy Ethernet using Hubs

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Ethernet using SwitchesIKS


Address Resolution Protocol (ARP)

� Mapping IP to MAC Addresses

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Address Resolution Protocol (ARP)

� ARP process

– ARP entry enables a frame to be sent

– Destinations Outside the Local Network

– Removing Address Mappings

– Broadcast issues (overhead / flood on the media)

– Security issues (spoofing)

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� Ethernet

�� PlaningPlaning and Cabling Networksand Cabling Networks



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Requirements for LAN Planning

� Selection of the appropriate hardware and LAN cabling

� Key aspects for devices

– cost

– ports

– speed

– expandable / modular

– managable

� type of cabling

– horizontal, backbone, patch cable

– for intermediate or end devices

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Switches and Redundancy

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Pinout for Connectors

� depending on straight-through or cross-over cabling

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Types of Connections in a LAN

� WAN connections differ from LAN connections

� Device management connections

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Design an Addressing Schemefor an Inter-network

� Assign ranges for hosts, network devices and the router

interface

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Calculate the Address Rangesfor Subnetworks


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� Ethernet


�� Configuring and Testing the NetworkConfiguring and Testing the Network

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Internetwork Operating System (IOS)

� wide usage for professional network devices providing

– Security

– Addressing

– Interfaces

– Routing

– QoS

– ManagingResources

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IOS Startup and Running ConfigIKS


IOS Mode Hierarchical Structure

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Identification of IOS ModesIKS


Basic IOS Command Structure

� Help, feedback and shortcuts are available in different IOS modes


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Variants of IOS Show commandIKS


Command Line Interface (CLI)

� Accessing various IOS configuration modes using CLI

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Basic Device Configuration

� Naming of devices is essential to avoid confusions

� Namingconventions

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Restricted Access with Passwords

� Virtual Terminal Password

� Enable Password

� Enable Secret Password

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IOS Startup Config

� Examine the startup config, make changes to config,

and replace the startup config with the running config

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Router Interfaces

� Multiple interfaces necessary (LAN, WAN)

– Assign interface descriptions


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Configuring Router InterfacesIKS


Host Addressing Parameters

� Master addressing scheme → assigning IP parameters

to a host

� Select, Apply, andVerify AppropriateAddressingParametersto a Host

– Ipconfig

– Ping

– Show ip int

– Traceroute

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Verification of Connectivity

� Ping command in

the CLI to test:

– if IP protocolis operational

– if IP protocol isproperly boundto a NIC

– if a host canactivelycommunicate across the local network

– if the local host can communicate acrossthe internetwork to a given remote host

– measure relative network performance by regularly checks

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Further Verification and Tests

� Traceroute: step by step connectivity tests

� Address Resolution Protocol (ARP)

verifying the knowledge of the physical addresses of the hosts

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Thank you very much for your kind attention !

Have an interesting ERASMUS IP Summer Course !

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fundamentals of ip networking communicating over the ...ip.eap.gr/pdf/lecture schrotter.pdf ·...

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