SKR 3201: Internetworking (Antara Rangkaian)

Fahrul Hakim

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Introduction

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Lecture name : Fahrul HakimRoom Number : A 1.29Tel Number : 017-6886542Email : http:skr3201.blogspot.com

Email :fahrulhakim@gmail.comCredit : 3(3 + 0)Contact hours : 3 x 1 jam kuliah semingguSemester : 2 (2008/09)Prerequisite : SKR 3200

Course Objective

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At the end of this course, student should be able

• To understand the main Internet protocol, its characteristics and functions.

Synopsis:

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This course covers addressing, binding, routing, Internet and application protocols, principles and architecture of the global Internet. Focus is given to the Transportation Control Protocol / Internet Protocol (TCP/IP) Suite.

(Kursus ini merangkumi pengalamatan, pengikatan, penghalaan, protokol applikasi dan Internet,prinsip dan senibina Internet sejagat. Tumpuan diberikan kepada Sut transportation control protocol / Internet protocol (TCP/IP))

Teaching Planning

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SKR3201 (Sem.1 (08/09) Teaching Plan

Chapter 1 : Introduction and Overview

fahrulhakim

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• Terminology (including acronyms)• Concepts and principles

– The underlying model– Encapsulation– End-to-end paradigm

• Naming and addressing• Functions of protocols including Address

Resolution Protocol (ARP), IP, TCP, UDP,SMTP, FTP, DHCP, and more

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Introduction

• Layering model– What do you understand about layering– Give an example

• Internet architecture and routing– Homework, find the “Internet Architecture”– Present in class

• Applications– www– Email and etc

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Introduction

What Is an Internetwork?

• An internetwork is a collection of individual networks, connected by intermediate networking devices, that functions as a single large network.

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Internetworking

• Internetworking (cisco) – refers to the industry, products, and procedures that

meet the challenge of creating and administering internetworks.

• Internetworking: Douglas E. Comer– an overview of concepts, terminology, and technology

underlying the TCP/IP Internet protocol suite and the architecture of an internet.

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Why Study TCP/IP?

• Before TCP/IP and the Internet– Two sources of network protocols

• Specific vendors such as IBM or Digital Equipment

• Standards bodies such as the ITU (formerly known as CCITT)

• TCP/IP– Vendor independence

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Why Study TCP/IP?

• The Internet is everywhere– What is “Internet”– What do you understand “everywhere”

• Most applications are distributed– Give an examples

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Who Built TCP/IP?

• Internet Architecture Board (IAB)– Originally known as Internet Activities Board

• Evolved from Internet Research Group

• Forum for exchange among researchers

• About a dozen members

• Reorganized in 1989 and 1993

• Merged into the Internet Society in 1992

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Components Of The IAB Organization

• Internet Architecture Board (IAB)– Board that oversees and arbitrates– URL is

http://www.iab.org/iab

• IRTF (Internet Research Task Force)– Coordinates research on TCP/IP and internetworking– Virtually defunct, but may re-emerge– URL

http://www.irtf.org/

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Components Of The IAB (continued)

• IETF (Internet Engineering Task Force)– Coordinates protocol and Internet engineering– Headed by Internet Engineering Steering Group

(IESG)– Divided into N areas (N is 10 plus or minus a

few)– Each area has a manager– Composed of working groups (volunteers)– URL is

http://www.ietf.org

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ICANN

• Internet Corporation for Assigned Names and Numbers

http://www.icann.org• Formed in 1998 to subsume IANA contract• Not-for-profit managed by international board• Now sets policies for addresses and domain names• Support organizations

– Address allocation (ASO)– Domain Names (DNSO)– Protocol parameter assignments (PSO)

http://www.icannwatch.org/

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World Wide Web Consortium

• Organization to develop common protocols for World Wide Web

• Open membership

• Funded by commercial members

• URL is http://w3c.org

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Internet Society

• Organization that promotes the use of the Internet

• Formed in 1992

• Not-for-profit

• Governed by a board of trustees

• Members worldwide

• URL is http://www.isoc.org

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Protocol SpecificationsAnd Documents

• Protocols – A protocol is a formal set of rules and conventions

that governs how computers exchange information over a network medium.

– documented in series of reports– Example; Network protocol, routing protocol, etc.

• Documents known as Request For Comments (RFCs)– Anyone know about RFCs

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RFCs

• Series of reports that include– TCP/IP protocols– The Internet– Related technologies

• Edited by IESG (Eng Steering group), but not peer-reviewed like scientific journals

• Contain:– Proposals– Surveys and measurements– Protocol standards

• Numbered in chronological order

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RFCs (continue)

• Host Requirements Documents– Major revision/clarification of most TCP/IP protocols– RFC 1122 (Communication Layers)– RFC 1123 (Application & Support)– RFC 1127 (Perspective on 1122-3)

• Router Requirements– Major specification of protocols used in IP gateways

(routers)– RFC 1812 (updated by RFC 2644)

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Internet Drafts

• Preliminary RFC documents• Often used by IETF working groups• Either become RFCs within six months or

disappear• Available via

– Email– FTP– World Wide Web

• http://www.ietf.org/

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Questions?

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History of Internetworking

• IBM’s Systems Network Architecture (SNA) and Digital’s network architecture.– time-sharing networks that used mainframes and attached

terminals.• Local-area networks (LANs)

– relatively small geographical area to exchange files and messages

– shared resources– such as file servers and printers.

• Wide-area networks (WANs)– interconnect LANs with geographically dispersed users to create– connectivity.

• High-speed LANs and switched internetworks– operate at very high speeds and support such high-bandwidth

applications as multimedia and videoconferencing.

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Open System Interconnection Reference Model

• The Open System Interconnection (OSI) reference model describes how information from a software application in one computer moves through a network medium to a software application in another computer.

• Divides the tasks involved• Each layer is reasonably self-contained• implemented independently.

– enables the solutions offered by one layer to be updated without adversely affecting the other layers

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The OSI Reference Model Contains Seven Independent Layers

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Upper layer(Application Layer)- Implemented only in software

Lower layer(Data transport Layer)- Implemented both in hardware and software

OSI Model Layers Communicate with Other Layers

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Service Users, Providers, and Service Access Points (SAPs) Interact at the Network and Data Link Layer

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– One OSI layer communicates with another layer to make use of the services

– The services help a given OSI layer communicate with its peer layer in other computer systems.

– Three basic elements are involved in layer services: – the service user,

– the service provider, and

– the service access point (SAP).

Service Users, Providers, and Service Access Points (SAPs) Interact at the Network and Data Link Layer

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– Service user is the OSI layer that requests services from an adjacent OSI layer.

– Service provider is the OSI layer that provides services to service users. OSI layers can provide services to multiple service users.

– The SAP is a conceptual location at which one OSI layer can request the services of another OSI layer.

Service Users, Providers, and Service Access Points (SAPs) Interact at the Network and Data Link Layer

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Chapter 2 Review of Underlying Network Technologies

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Basic Network Concept

• The TCP/IP Concept (Five layers; • Network hardware

–Connection-oriented– Connectionless

• Packet Switching Networks– Local Area Network (LAN)–Wide Area Network (WAN)–Point-to-point link–Set of bridged networks

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Two Basic CategoriesOf Network Hardware

• Connection oriented (circuit switching)–establish a connection with the desired service before passing any data–Operate by forming a dedicated connection or circuit between 2 points

• Paradigm •Form a ‘‘connection’’ through the network•Send / receive data over the connection•Terminate the connection

–Involves 3 phases: connection establishment, data transfer, and connection termination

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Connection oriented

• Can guarantee bandwidth–Dedicated circuit, 64 Kbps,128 Kbps, 1M, 2M etx.–monitor for lost packets and handle resending them –The protocol is generally also responsible for putting the packets in the right sequence before passing the data up the protocol stack –negotiate a connection, transfer data, and tear down the connection

• Proponents argue that it works well with real-time applications

–Independent use

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Connection oriented

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• Can guarantee bandwidth– Dedicated circuit, 64 Kbps,128 Kbps, 1M, 2M etx.– monitor for lost packets and handle resending them – The protocol is generally also responsible for putting the packets

in the right sequence before passing the data up the protocol stack

– negotiate a connection, transfer data, and tear down the connection

• Proponents argue that it works well with real-time applications– Independent use

Connectionless(Packet Switched Technology)

• Paradigm– Form ‘‘packet’’ of data– Pass to network(Data to be transferred across a network is divided into small pieces

called packed that are multiplexed onto high capacity inter-machine connections)

• Each packet travels independently– transfer can simply send the data without the added overhead of

creating and tearing down a connection • Packet includes identification of the destination

– Enables the network hardware to know how to send it to specific destination

• Each packet can be a different size• The maximum packet size is fixed (some technologies

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Connectionless

• Advantage– Multiple communication among computers

can proceed at the simultaneously with intermachine connection shared by all pairs of computer that are communicating

• Disadvantage– Overloaded the networks – computers must

wait before sending additional packets

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Broad Characterizations OfPacket Switching Networks

• Local Area Network (LAN)– Engineered for

– Low cost– High capacity

– Direct connection among computers– Limited distance

• Wide Area Network (WAN)– Engineered for

• Long distances• Indirect interconnection via special-purpose hardware

– Higher cost– Lower capacity (usually)

• Categories are informal and qualitative

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Local Area Networks

• What is LAN– A LAN is a high-speed data network that covers a relatively small

geographic area. It typically connects workstations, personal computers, printers, servers, and other devices. .

• Engineered for– Low cost– High capacity– Direct connection among computers– Limited distance– LANs offer computer users many advantages, including shared

access to devices and applications, file exchange between connected users, and communication between users via electronic mail and other applications

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Three LAN Implementations Are Used Most Commonly

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Wide Area Networks(Long Haul Networks)

• What is WAN– A WAN is a data communications network that covers a

relatively broad geographic area and that often uses transmission facilities provided by common carriers, such as telephone companies.

– WAN technologies generally function at the lower three layers of the OSI reference model: the physical layer, the data link layer, and the network layer

• Engineered for– Long distances– Indirect interconnection via special-purpose hardware– Higher cost– Lower capacity (usually)

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A Typical Point-to-Point Link Operates Through a WAN to a Remote Network

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http://www.cisco.com/univercd/cc/td/doc/cisintwk/ito_doc/

Examples Of PacketSwitched Networks

• Wide Area Nets– ARPANET, NSFNET, ANSNET– Common carrier services

• Leased line services– Point-to-point connections

• Local Area Nets– Ethernet– Wi-Fi

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ARPANET (1969-1989)

• Original backbone of Internet

• Wide area network around which TCP/IP was developed

• Funding from Advanced Research Project Agency

• Initial speed 50 Kbps

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NSFNET (1987-1992)

• Funded by National Science Foundation• Motivation: Internet backbone to connect all

scientists and engineers• Introduced Internet hierarchy

– Wide area backbone spanning geographic U.S.– Many mid-level (regional) networks that attach to

backbone– Campus networks at lowest level

• Initial speed 1.544 Mbps

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ANSNET (1992-1995)

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•Backbone of Internet before commercial ISPs•Typical topology

Abilene Network Backbone

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Current status of the Abilene network at 10Gbps.

Wide Area Networks AvailableFrom Common Carriers

• In telecommunications, T-carrier, sometimes abbreviated as T-CXR, is the generic designator for any of several digitally multiplexed telecommunications carrier systems originally developed by Bell Labs and used in North America, Japan, and Korea.

• Optical Carrier levels describe a range of digital signals that can be carried on Synchronous optical networking SONET fiber optic network.[1] The number in the Optical Carrier level is directly proportional to the data rate of the bitstream carried by the digital signal.

• The general rule for calculating the speed of Optical Carrier lines is when a specification is given as OC-n, that the speed will equal n × 51.8 Mbit/s.[2]

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Wide Area Networks AvailableFrom Common Carriers

• Point-to-point digital circuits

– T-series (e.g., T1 = 1.5 Mbps, T3 = 45 Mbps)– OC-series (e.g., OC-3 = 155 Mbps, OC-48 =

2.4 Gbps)

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Wide Area Networks AvailableFrom Common Carriers (cont.)

• OC-1 (Optical) = (1) STS1 on Optical facilitiesOC-3 = (3) OC-1s = 155.52mbits/secOC-9 = (9) OC-1s (not commonly used) = 466.56mbits/secOC-12 = (12) OC-1s or (4) OC-3s = 622.08mbits/secOC-18 = (18) OC-1s (not commonly used) = 933.12mbits/secOC-24 = (24) OC-1s (not commonly used) = 1.244gbits/secOC-36 = (36) OC-1s (not commonly used) = 1.866gbits/secOC-48 = (48) OC-1s or (4) OC-12s or (16) OC-3s = 2.488gbits/secOC-192= (192) OC-1s or (4) OC-48s or (16) OC-12s or (64) OC-3s = 9.953gbits/sec

• OC-256 13.271 Gbps• OC-768 40 Gbps• What is the latest OC ??? New DWDM systems are now in

development to run at at 10 trillion bits per second (10 Tbps) per fiber.

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Wide Area Networks AvailableFrom Common Carriers (Cont)

• Packet switching services also available– The size of network can be extended by

adding a new switch and another communication lines

– The larger the WAN becomes the longer it takes to route traffic across it

• Examples: ISDN, SMDS, Frame Relay, ATM

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2.4 Ethernet—A Brief History • The original Ethernet was developed as an experimental coaxial cable network in the

1970s by Xerox Corporation to operate with a data rate of 3 Mbps using a carrier sense multiple access collision detect (CSMA/CD) protocol for LANs with sporadic but occasionally heavy traffic requirements. Success with that project attracted early attention and led to the :

– 1980 joint development of the 10-Mbps Ethernet Version 1.0 specification by the three-company consortium: Digital Equipment Corporation, Intel Corporation, and Xerox Corporation.

• The original IEEE 802.3 standard was based on, and was very similar to, the Ethernet Version 1.0 specification. The draft standard was approved by the 802.3 working group in 1983 and was subsequently published as an official standard in 1985 (ANSI/IEEE Std. 802.3-1985). Since then, a number of supplements to the standard have been defined to take advantage of improvements in the technologies and to support additional network media and higher data rate capabilities, plus several new optional network access control features.

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Ethernet—A Brief History • Coaxial Cable – Original Wiring Scheme

• Twisted Pair Ethernet – Cat 5 (Because existing telephone wires uses same technology) – Cheaper and easier to install as compared to coaxial cable.

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Category 6 cable, commonly referred to as Cat 6, is a cable standard for Gigabit Ethernet and other network protocols that is backward compatible with the Category 5/5e and Category 3 cable standards. Cat-6 features more stringent specifications for crosstalk and system noise.

2.4.2 Fast and Gigabit Ethernet

• Extremely popular• Packet-switched LAN tech• Can run over

– Copper (twisted pair)– Optical fiber

Three generations– 10Base-T operates at 10 Mbps (also depends on the Network

Bandwidth)To overcome the throughput problem : - same wires at Cat 5, but

achieve more bandwidth by using more wires – 100Base-T (fast Ethernet) operates at 100 Mbps– 10/100 Ethernet (dual speed Ethernet)– 1000Base-T (gigabit Ethernet) operates at 1 Gbps– 1000 Base-X (fiber optics – Ethernet signals are converted to light

pulses) – 10 – 40 Gbps

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2.4.2 Fast and Gigabit Ethernet

• Technology known as 10/100/1000 Ethernet is available for NICs as well as for switches.

• Automatic negotiation and determination of the cables and maximum speed the other side of the connection can support

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2.4.2 Fact for the Day !

• 10BASE-T, one of several physical media specified in the IEEE 802.3 standard for Ethernet local area networks (LANs), is ordinary telephone twisted pair wire.

• 10BASE-T supports Ethernet's 10 Mbps transmission speed. In addition to 10BASE-T, 10 megabit Ethernet can be implemented with these media types:

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2.4.2 Fact for the Day ! (cont.)

• 10BASE-2 (Thinwire coaxial cable with a maximum segment length of 185 meters)

• 10BASE-5 (Thickwire coaxial cable with a maximum segment length of 500 meters)

• 10BASE-F (optical fiber cable) • 10BASE-36 (broadband coaxial cable carrying

multiple baseband channels for a maximum length of 3,600 meters)

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2.4.2 Fact for the Day ! (cont.)

• This designation is an Institute of Electrical and Electronics Engineers (IEEE) shorthand identifier.

• The "10" in the media type designation refers to the transmission speed of 10 Mbps.

• The "BASE" refers to baseband signalling, which means that only Ethernet signals are carried on the medium.

• The "T" represents twisted-pair; the "F" represents fiber optic cable; and the "2", "5", and "36" refer to the coaxial cable segment length (the 185 meter length has been rounded up to "2" for 200).

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Power over Ethernet

• Power over Ethernet (PoE) can send small amount of electrical power over the same copper cable used for Ethernet

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2.4.5 Properties of Ethernet

• Design for shared bus technology that supports broadcast– All station connect to a single, shared communication channel– Transmit a packet to all stations at the same time– Single segments up to 500m; with up to 4 repeaters gives 2500m max

length

– Max 100 stations/segment, 1024 stations/Ethernet

• Best effort delivery– Hardware provide no information to the sender about whether

the packet was delivered

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Properties of Ethernet

• CSMA/CD shared medium Ethernet• Ethernet originally used a shared coaxial cable (the shared medium)

winding around a building or campus to every attached machine. A scheme known as carrier sense multiple access with collision detection (CSMA/CD) governed the way the computers shared the channel. This scheme was simpler than the competing token ring or token bus technologies.

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Properties of Ethernet

• When a computer wanted to send some information, it used the following algorithm:

• Main procedure• Frame ready for transmission. • Is medium idle? If not, wait until it becomes ready and wait the interframe gap

period (9.6 µs in 10 Mbit/s Ethernet). • Start transmitting. • Did a collision occur? If so, go to collision detected procedure. • Reset retransmission counters and end frame transmission. • Collision detected procedure (aborts when it detects collisions) • Continue transmission until minimum packet time is reached (jam signal) to

ensure that all receivers detect the collision. • Increment retransmission counter. • Was the maximum number of transmission attempts reached? If so, abort

transmission. • Calculate and wait random backoff period based on number of collisions. (must

wait for a minimum idle time) • Re-enter main procedure at stage 1.

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2.4.7. Wireless Networks and Ethernet

• IEEE standards:• IEEE 802.11b – Wi-Fi (max 11Mbps)• IEEE 802.11a and 802.11g – 54Mbps• IEEE 802.16 – WiMax ; IEEE802.n – • 540 Mbps and 802.11i (Security)

• Enables multiple users to share a broadband connection

• Supports WiFi 802.11 b/g • Four RJ45 Local Area Network ports available

• Additional Home Voice Service • Easy to use - plug and play • Supports Windows™ 2000, XP and Vista only

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Topology

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Example Coaxial Bus Topology -limited to 500 meter-100 stations

Example Star-Connected Topology

repeater

Hub/switch

Ethernet Hardware Addresses

• 48-bit addressing scheme • Each NIC card is assigned a unique 48-bit

number known as an Ethernet Address• How?

– Ethernet hardware manufacturers purchase blocks of Ethernet technologies and assign them in sequence.

– Physical addresses– Recall, that when computers connect to a hub, each

computer receives a copy of every packet sent

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Ethernet Frame Format

• Layer 2 – thought of as link-level connection • Header format fixed (Destination, Source, Type fields)• Frame data size can vary from packet to packet

– Maximum 1518 octets– Minimum 64 octets

• Preamble and CRC (Cyclic Redundancy Check) removed by framer hardware before– frame stored in computer’s memory; both sender and receiver

calculate the CRCs and counter check• Self Identifying (used by the OS to determine which protocol –

therefore a system can have many protocols)– Determine which protocol software module should process the

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Example Ethernet Frame In Memory

• Octets shown in hexadecimal• Destination is 02.07.01.00.27.ba• Source is 08.00.2b.0d.44.a7• Frame type is 08.00 (IP)

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Point-to-Point Network

• Any direct connection between two computers– Leased line– Connection between two routers– Dialup connection

• Link-level protocol required for framing

• TCP/IP views as an independent network

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Bridge

• Hardware device that connects multiple LANs and makes them appear to be a single LAN

• Repeats all packets from one LAN to the other and vice versa (does not replicate noise, errors or malformed frames – must be valid frame)

• Introduces delay of 1 packet-time• Does not forward collisions or noise• Called Layer 2 Interconnect or Layer 2 forwarder• Makes multiple LANs appear to be a single, large LAN• Often embedded in other equipment (e.g., DSL modem)• Watches packets to learn which computers are on which• side of the bridge (adaptive bridges)• Uses hardware addresses to filter04/08/23 71

Layer 2 Switch

• Electronic device

• Computers connect directly

• Applies bridging algorithm

• Can separate computers onto virtual networks (VLAN switch)

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Local and Remote Bridges Connect LAN

Segments in Specific Areas

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Bridging & Switching

• Function– controls data flow, handles transmission errors,

provides physical (as opposed to logical) addressing, and manages access to the physical medium.

• by using various link layer protocols that dictate specific flow control, error handling, addressing, and media-access algorithms

• Task – analyze incoming frames, make forwarding decisions

based on information contained in the frames, and forward the frames toward the destination

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ATM – Asynchronous Transfer Mode

• Asynchronous Transfer Mode (ATM) is a cell relay, packet switching network and data link layer protocol which encodes data traffic into small (53 octets; 48 octets of data and 5 octets of header information) fixed-sized cells. ATM provides data link layer services that run over Layer 1 links. This differs from other technologies based on packet-switched networks (such as the Internet Protocol or Ethernet), in which variable sized packets (known as frames when referencing Layer 2) are used.

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Physical Networks AsViewed By TCP/IP

• TCP/IP protocols accommodate

– Local Area Network– Wide Area Network– Point-to-point link

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INTERNETWORKING CONCEPT

Content

• Properties of Internetworking

• Network Interconnection

• Physical connectivity

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Accommodating Heterogeneity

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•Application gateways

•Gateway forwards data from one network to another

•Step at a time

•Disadvantage

1. Limited Communication

2.Unrealiable communication

Network level Interconnection

• Network-level gateways– Delivers small packets of data from their original

source to their ultimate destination without using intermediate application program

• Gateway forwards individual packets

• Advantage

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1.Efficient – directly mapping 2.Separate data comm. activities

3. Flexible system 4.Unlimited communication

Desired Design Properties

• Universal service

• End-to-end connectivity

• Transparency

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Agreement Needed ToAchieve Desired Properties

• Data formats

• Procedures for exchanging information

• Identification– Services– Computers– Applications

• Broad concepts: naming and addressing

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