EnterPrise Networking Orientation

8/11/2019 EnterPrise Networking Orientation

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Introduction toEnterprise Networking


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Course Objective

To understand both the What and the Why of

networks in general and the Enterprise Model

specifically.

Note: This course is not specific to Engineers majors. It is

intended for a wide audience with little or no prior experience

with the Networks, or Internet in general.


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This course will develop fundamental concepts, protocols &

architecturesof Broadband and Enterprise Networking.

Broadband networking driven by the imminent convergenceof

telephony (voice), Internet (data), cable (video), and wireless

networks.

Fundamental ideas in telephone, networking, cable systems,

wireless

Convergence architectures: B-ISDN, ATM, Frame Relay,

Internet

Course Description Highlights


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Issues:

High-speed switching & router-design,

Quality of service (QoS) building blocks and architectures

Traffic engineering (MPLS, ATM, frame-relay),

Fiber optical communications,

Optical networking concepts,

Protection/restoration/survivability,

Optical link layers (SONET, WDM)



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LANs/MANs/Last-Mile:

Gigabit Ethernet,

802.11a/b and community/hot-spot networks

Cable-modem, DSL principles and economics

Free-space-optical networkMultihop/3G wireless data, smart antennas, OFDM

The course will involve substantial reading and a term project to help student

synthesize the variety of concepts and appreciate the broad techno-economic

challenges.



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Pre-requisites

Our assumptions about you:

Computer networks background.

Internet experience.

Access to a computer.Knowledge of Networking Devices

Basic Network Terms


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Answers to FAQ's

Lot of paper readings in the class (due every homework) + research case study(writing skills)

Informal quizzes given occasionally to complement homeworks. These are notgraded.

All homeworks due at the beginning of the class indicated on the coursecalendar

Up to one late submission: no penalty

Beyond that 20% penalty: only if submitted before solutions are posted (max oneweek grace period)

All quizzes are open-book and extremely time limited.

Quizzes consist of design qns, numerical, and short answer questions.


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Grading

Homework 25%

Term Project 15%

Exams 60%


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Whats an Enterprise Networking?


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OverviewConnectivity:

direct (pt-pt, N-users),

indirect (switched, inter-networked)

Telephony, Internet, Cable Networks: Basic Concepts

Concepts: Topologies, Framing, Multiplexing,Flow/Error Control, Reliability, Multiple-access,

Circuit/Packet-switching, Addressing/routing,Congestion control

Data link/MAC layer: SLIP, PPP, LAN technologies

Interconnection Devices


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Transporting Electrical Signals

Common types of transmission media

Wire pair

Coaxial cable

Fiber optic cable

Radio


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Problems?

Security!

Its much easier to protect centralized

resources than when they are distributed.Network itself as the target..


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Before the Internet

Postal network.

Delivers different types of objects (letters, packages, etc.) world-wide.

Relatively high delay but relatively cheap.

Sender and receiver identified by their postal address (name, number,

street, city, etc.).Telephone network.

Engineered to deliver real-time voice.

Also world-wide.

Low delay but more expensive.

Users identified buy telephone number.


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Telephone Network: What is It?

Specialized to carry voice traffic

Aggregates like T1, SONET OC-N can also carry data

Also carries

Telemetry, video, fax, modem calls

Internally, uses digitalsamples

Switches and switch controllers arespecial purpose computers

Pieces:

1. End systems

2. Transmission3. Switching

4. Signaling


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Telephone Network: What is It?

Single basic service: two-wayvoice

low end-to-end delay

guarantee that an accepted call will run to completion

Endpoints connected by a circuit, like an electrical circuit

Signals flow both ways (ful l duplex)

Associated with reservedbandwidth and buffer resources


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Telephone Network Design

Fully connected core

simple routing

telephone numberis a hint about how to routea call

But not for 800/888/700/900 numbers: these are pointers to a directory thattranslates them into regular numbers

hierarchically allocatedtelephone number space


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Telephone Network Design


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Evolution of Communications Networks

POTS network is not designed for other forms of

communications (audio, video, and data).

About 30 years ago, a second communications network was

created with the goal of providing a better transportmechanism for data.

In this class, we will study the technology underpinning data

networks.


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Whats a network?

Merriam-Webster Dictionary:

|A fabric or structure of cords or wires that cross at regular

intervals

A system of computers, terminals and databases connected by

communication lines

A computer network is defined as the interconnection of 2 or

more independent computers.


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Why network?

Before networks:

One large computer (mainframe) used for all processing in

businesses, universities, etc.Smaller, cheaper computers

Personal computers or workstations on desktops.

Interconnecting many smaller computers is advantageous! Why?


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Why network?

Resource sharing!

Hardware: printers, disks, terminals, etc.

Software: text processors, compilers, etc.

Data.

Robustness.

Fault tolerance through redundancy.

Load balancing.

Processing and data can be distributed over the network.

Location independence.Users can access their files, etc. from anywhere in the network.


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Transmission

Definition

Electrical transfer of a signal, message, or other form of

intelligence from one location to another

Co-exists withswitchingas being one of the two major disciplines oftelecommunication


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Connectivity...

Building Blocks

links: coax cable, optical fiber...

nodes: general-purpose workstations...

Directconnectivity:

point-to-point

multiple access


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Connectivity (Continued)

Indirect Connectivity

switched networks

=> switches

inter-networks

=> routers


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What is Connectivity ?

Direct or indirect accessto every other node in the

network

Connectivityis what you get instead of a direct physical

linkKey Tradeoff: Performance characteristics worse!


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Connectivity

Internet:

Best-effort

(no performance guarantees)

Packet-by-packet

A pt-pt link:Always-connected

Fixed bandwidth

Fixed delay

Zero-jitter

A hi


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Architecture

Digital Divide


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Digital DivideThe Flip-side of the Knowledge Era

Our objective is freedom from distance. We aredetermined to link all the villages of India not only

with good roads but also with good telecom and

internet services

------ Prime Minister of India15th Au ust 2001

Haves Have-Nots

Knows Know -Nots


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BITS for All


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Last Mile Technology Solutions : 802.11(b)

NIC-Centre

New AdministrativeBuilding

(

Mantralaya

(

500 Meters


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Informal Quiz: Prerequisites

T F (True or False)

Datalink refers to the 3rd layer in the ISO/OSI reference model

If peak rate = 10 Mbps, Avg rate = 2 Mbps and Service rate = 4 Mbps,multiplexing gain = 2.

An even parity bit value for the 8-bit string 01101010 is 0.

Packet forwarding is a control-plane function and routing is a data-plane

function. Bridges and switches in Ethernet allow separation of collision domains, and

reduce the degree of sharing of the physical media.

Finding path from one node to another in a large network is a transport layerfunction.

It is impossible to send 3000 bits/second through a wire which has a bandwidth

of 1000 Hz. Randomness (in service and arrival) is what causes queuing at buffers.

Littles law which relates expected queuing delay E(T) and expected # in thesystem E(n) is applicable only to M/M/1 queues.

Littles law also holds for instantaneous(as opposed to average) queuing delayand instantaneous number in the system


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Informal Quiz (Continued)

Bit stuffing is used so that framing characters do not occur in the framepayload.

CRC is based upon the idea that it is highly unlikely for an uncorrupted packetto be perfectly divisible by the CRC polynomial.

Random access MAC protocols tend to perform very well at low loads in termsof channel multiplexing; but suffer from high delay at high loads.

Taking turns or token-based protocols like token-ring offer a best of bothpartitioning and random access worlds.

For long delay paths, on-off flow control is better than window flow control.

Ethernet uses a CSMA/CD access method.

The packets sent in a connection-oriented network are called datagrams.

The distance-vector protocol involves checking neighbors distance vectorsand updating its own distance vector.

Address structure is required to recognize whether the destination is one-hopor multiple-hops away.


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Informal Quiz: Solutions

T F (True or False)

Datalink refers to the 3rd layer in the ISO/OSI reference model

If peak rate = 10 Mbps, Avg rate = 2 Mbps and Service rate = 4 Mbps,multiplexing gain = 2.

An even parity bit value for the 8-bit string 01101010 is 0.

Packet forwarding is a control-plane function and routing is a data-plane function.

Bridges and switches in Ethernet allow separation of collision domains, andreduce the degree of sharing of the physical media.

Finding path from one node to another in a large network is a transport layerfunction.

It is impossible to send 3000 bits/second through a wire which has a bandwidth of1000 Hz.

Randomness (in service and arrival) is what causes queuing at buffers. Littles law which relates expected queuing delay E(T) and expected # in the

system E(n) is applicable only to M/M/1 queues.

Littles law also holds for instantaneous(as opposed to average) queuing delayand instantaneous number in the system


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Informal Quiz Solutions

Bit stuffing is used so that framing characters do not occur in the framepayload.

CRC is based upon the idea that it is highly unlikely for an uncorrupted packetto be perfectly divisible by the CRC polynomial.

Random access MAC protocols tend to perform very well at low loads in termsof channel multiplexing; but suffer from high delay at high loads.

Taking turns or token-based protocols like token-ring offer a best of bothpartitioning and random access worlds.

For long delay paths, on-off flow control is better than window flow control.

Ethernet uses a CSMA/CD access method.

The packets sent in a connection-oriented network are called datagrams.

The distance-vector protocol involves checking neighbors distance vectors andupdating its own distance vector.

Address structure is required to recognize whether the destination is one-hop ormultiple-hops away.

Documents

EnterPrise Networking Orientation