looking forward chapter 12 copyright 2001 prentice hall revision 2: may 2001

Looking Forward

Chapter 12

Copyright 2001 Prentice HallRevision 2: May 2001

Budgeting and Procurement

Planning how to spend money

Selecting and purchasing technologies and services

3

The Budget Realities

Exploding demand but stagnant or slowly-growing budgets Must buy only what you really need in

every system

Time

Demand

Budget

4

CostsTotal Purchase Costs Base price misleading due to absence of

needed options Must cost out total purchase cost of fully

configured system

Initial Installation Cost The purchased product or service Labor needed to implement

Central staff labor User labor, including training costs Losses due to implementation disruptions

5

Costs

Ongoing Costs over Life Span

Often exceed initial costs Labor

Upgrades

Especially high in immature products When possible, avoid the “bleeding edge”

6The Timing of Costs and Benefits

Discounting Money can be invested (I.e. opportunity

cost) If the investment rate is 20%, then

$1 invested today will bring $1.20 next year

So $1 received today is worth $1.20 received next year

Or, $1.20 received next year is worth $1 today

Or, $1 received next year is worth only $0.80 today


When Costs and Benefits Come Over Time Hurdle rate: minimum rate of return

expected by a corporation for investments Often around 20%

If the hurdle rate is i then Money received or spent a year from now

should be discounted (divided) by (1+i)

Money received or spent n years from now should be discounted (divided) by (1+i)n


Discounted Cash Flow Example (i=20%) Net Present Value (NPV) = 3,639 (sum of annual present values)

This Year Next YearYear After

Cash Flow In 2,000 3,000 4,000

Cash Flow Out 1,000 1,500 2,000

Net Cash Flow 1,000 1,500 2,000

Discount Ratio 1 1.2 1.44

Present Value 1,000 1,250 1,389

9

Procurement

User Needs

Must drive everything else Sometimes difficult to assess But the only way to drive evaluations

of alternatives

10

ProcurementRequest for Proposals (RFP) Call for proposals to bid on the project Specifies what should be provided RFP will form the basis for resolving

subsequent contract disputes Must be very detailed A legal document

If something is left out, negotiating for it after the contract is signed will be done at the contractor’s advantage

11

Procurement

Proposals

Several companies are likely to submit proposals

These proposals must be evaluated so that you can select the best one

You must lay out your evaluation criteria in the RFP and follow them in selection, or you can be sued by a loser

12

Procurement

Evaluating Proposals with Multicriteria Decision Making First, you must have specific criteria

For instance, price, performance, and reliability Same criteria must be applied to each proposal

Second, you must give a weight (importance) to each Often of 5-point or 10-point scale Same weights must be applied to each

proposal

13

Procurement

Evaluating Proposals with Multicriteria Decision Making Third, you must evaluate each

proposal on each criteria Perhaps on scale of 1 to 10 or some other

scale Score on each criterion will be different

for each proposal

14

ProcurementEvaluating Proposals with Multicriteria Decision Making Fourth, do the arithmetic for each proposal Highest total score should win

Proposal A Score Weight Product

Price 10 5 50

Performance 6 8 48

Reliability 5 4 20

118Total Score

15

ProcurementEvaluating Proposals with Multicriteria Decision Making Example: a different proposal Same criteria & weights, different scores,

total scoreProposal B Score Weight Product

Price 8 5 40

Performance 7 8 56

Reliability 8 4 32

128Total Score

16

Procurement

Negotiating before contractor selection

Often, negotiate with a few highly-rated proposers before selection for better terms

Proposers present their Best and Final Offers

Ongoing Monitoring Must monitor ongoing work to ensure

compliance

Renegotiating During Performance Sometimes must renegotiate during work; Bad

because buyer is at a disadvantage in negotiations

17

Types of Servers

Small Servers Usually are PCs Need a PC Server Operating System

(SOS) such as Microsoft Windows Server, Novell NetWare, LINUX

Large Servers Usually use Workstation Servers Usually run UNIX

18Symmetric Multiprocessing (SMP)

PC or workstation can have multiple microprocessors

Work is shared among the microprocessors through symmetric multiprocessing (SMP) to increase overall speed

However, if you have N microprocessors, your server is not N times faster than a single-microprocessor server because of problems in assigning work evenly

19

RAIDRedundant Array of Inexpensive (or Independent) Drives RAID controller controls multiple small

inexpensive disk drives Reads and writes in parallel for higher

speed despite low-cost drives Information usually is stored redundantly If one disk fails, lose no information Drives may even be hot-swappable

Do not have to turn off computer to replace

20

Server Farms

In large sites, one server is not enough Have several, even hundreds of

servers Called a server farm Many PC servers may be more cost-

effective than fewer workstation servers

ServerFarm

21

Server Farms

Load Balancing Approach Router or other device sends requests

to servers based on load

22

Server Farms

Server Clustering Approach Act as a single server without an

external load balancer

23

Server Farms

Reliability If one server’s hardware fails,

operation continues without interruption

However, software failures often take down all servers simultaneously

24

Server Configuration

When Server Operating System is Installed, it Must be Configured Complex task with many steps, many

of which require you to have conceptual knowledge

Requires training Valuable skill

25

Ongoing WorkServer Systems Administration is Labor-Intensive on a Continuing Basis Assisting users Adding/dropping Users Assigning and changing rights for users Data backup Upgrading and repairing servers Adding & maintaining application

programs …

26Network Management System

The Concept From a central computer, network

administrator can manage entire network Collect data Give commands

Moving gradually toward this ideal

Data

Command


Standards Most widely used is the Simple

Network Management Protocol (SNMP)

Other standards exist

SNMP


The Manager Software on network administrator's

computer Short for “network management

software” Implements network management

support

Managed Nodes Routers, client PCs, etc. that are managed

ManagerManaged

Node


Agents Network management agents Installed in managed nodes Communicate with the manager on

behalf of the node

Manager Agent

Managed Node


RMON Probes Remote MONitoring SNMP only Special type of agent Collects data on a LAN’s traffic:

packet sizes, error rates, etc.

Manager

LAN

RMON Probe


Objects Managed nodes have several objects

that are managed Example: Client PC, one object might be

status of TCP connection to particular server another may be status of router port

A managed node may have several “instances” of some objects; For instance, a router may have several ports Agent OBJ

OBJ

OBJ

OBJ


Management Information Base (MIB) Stores collected information Schema

The overall design Entities (objects) and attributes Object-oriented database

The actual stored information Confusingly, “MIB” is used to refer

both to the schema and the actual data

MIB


Management Information Base (MIB) Full MIB is stored on the central

administration computer Relevant portion of the MIB is also

stored by each Agent

Manager Agent

MIBMIB

34Network Management Protocol

Network management protocol standardizes Communication between manager and agent

Defines the schema of the MIB

Most popular is the Internet Engineering’s Simple Network Management Protocol (SNMP)

There are others


SNMP Requests and Responses Manager sends requests

Get: give me data Set: change your setting (e.g., turn off

Port 1)

Agent sends back responses The information Confirmation or reason for rejection

Manager Agent

MIBMIB

Get or SetRequest

Response


SNMP Traps Sometimes, agent can send a

message without a prior manager request

Message is called a trap in SNMP For instance, if the agent senses a

problemManager Agent

MIBMIB

Trap

37

Directory ServersInformation is Organized Hierarchically Hierarchy of objects X.500 Standard defines types of

objects and their propertiesOrganization (O) = xxx

Organizational Unit (OU) = yyy

Employee (E) = zzzCommon Name (CN)=Pat Lee

E-Mail (EM)=LeeDigital Certificate (DC)=Password (PW)=$^%@&

38

Directory Servers

LDAP Lightweight Directory Access Protocol Most popular directory access

protocol Governs user interaction with

directory server

DirectoryServer

LDAP

39

Directory Server Products

Directory Server Products

Novell Directory Services (NDS) From Novell Book incorrectly calls it NetWare

Directory Services Mature, widely used

Active Directory From Microsoft New

40Directory Servers and Security

Directory Server can store data and policies for security servers Digital certificates Passwords Policies

Centralizes managementand control

41

Converging Boxes

Today, Many Types of Devices Forwarding: Hubs, Switches, Routers Security: Firewalls, etc.

Difficult to Manage

Difficult to Integrate Forwarding and Security

42

Converging Boxes

Comprehensive Relay Devices are Needed Combine both forwarding and security Easier management Easier integration of forwarding,

security

CRD

CRD CRD

CRD

CRDCRD

43

Converging Boxes

Multi-Layer Packet Analysis

Comprehensive relay devices will analyze headers and data fields at all layers

For intelligent forwarding, like Layer 4 switches

For intelligent security, like firewalls This will reduce costs compared to

having separate devices

44

Converging Boxes

Processing Concerns

Multi-layer forwarding will be processing intensive

So will be multi-layer security

Processors must grow in power to keep up with increasing demand plus multi-layer processing and security

45

Policy Based Networking

Policy Servers will Store Policies and Related Data Will control individual forwarding,

security, and comprehensive relay devices

Uniformity in policy implementation

CRD

CRDPolicy

Policy

Policy Server

46

Policy Based Networking

COPS Common Open Policy Service Standardized way for policy servers to

talk with devices for which they set policy

CRD

CRDCOPS

COPS

Policy Server

47

Wireless Communication

Site Wireless Networking

802.11 For large site networks with many

stations

Bluetooth For a few devices close to one another Personal area networking

May Interfere with Each Other if Both are Implemented

48


Metropolitan Wireless Networking For an urban area Exists now, but slow (around 9,600

bps) Soon 100 kbps 3d Generation (3G) wireless service

up to 2 Mbps

Satellite Wireless Networking Megabit speeds anywhere

49


Cellular Systems Service area is broken

up into several smallareas called cells

Within each cell, there is a cellsite that transmits to and receives from cellular

devicesCellsite

50


Cellular Systems Channel reuse. Channels can be

reused in non-adjacent cells Very important due to limited available

frequencies Serves more subscriber with the same

amount of frequency spectrum

No

No

YesNo

Yes

NoNo

YesNo

UsesChannel

232

Can ReuseCh. 232?

Channel 232Used in 4 cells

51


The Wireless Revolution New freedom for users Anything, anytime, anywhere Likely to spawn new applications

52

Really Personal Computing

Both Desktop PCs and Notebook PCs are Large This limits their portability

Many Future Access Devices Will be Smaller Personal digital assistants (PDAs) Cellphones

53

Cellphone Access

Cellphones will be Very Popular for Internet Access Cellphones are very widespread

In Japan, the number of cellphones passed the number of wired phones in early 2000

This is happening in other countries aswell

The U.S. is somewhat behind becauseit did not settle on the world cellphonestandard, GSM

54

Cellphone Access

Starting to have small displays capable of showing a few lines of data

Good for short messages (Short Message Service or SMS)

Good for restricted Internet access Text only A few short lines only

55

Cellphone Access

Wireless Access Protocol (WAP)

Emerging standard for cellphone web access

Also for other small devices, such as personal digital assistants (PDAs)

Competition from i-mode technology created and popularized in Japan

56

Cellphone Access

Wireless Markup Language (WML)

Part of WAP

Way of formatting webpagesfor small displays

Simpler than HTML

Reformatting may be expensive

57

Cellphone Access


Device will communicate over the Internet with WAP server via WAP protocols rather than with webservers directly

WirelessCarrier

WAPProtocols

WAP Protocols

WAPServer

58

Cellphone Access


WAP server may get content from full webserver using full webservice protocols (HTTP, TCP), probably translating webpages to WML

WirelessCarrier WAP

Server

Webservice Protocols

Full Webserver

59Network Object-Oriented Processing

Traditional Object-Oriented Programming Programs consist of many objects

(forms, buttons, etc.) Objects send messages to one

another to ask others to do certain tasks by executingmethods OBJ

OBJOBJ

OBJ

Message

Application


Network Object-Oriented Programming (NOOP) Objects can run on multiple machines Still communicate by sending

messages

NOOP takes advantage of available capacity on computers on the network If computer has idle capacity, it will be

sent objects

OBJ

OBJ OBJ

OBJ

OBJ

OBJ

Message


NOOP Standards are Needed for Object-Object Communication Microsoft’s standard is DCOM CORBA is a competing consortium

standard

OBJ

OBJ

OBJ

OBJ

OBJ

OBJ

62

The Changing InternetToday’s Internet Speed too low Delays (Latencies) are too long Reliability is too slow

Need a “Business Class Internet” Faster Lower Latency High reliability

Two Classes of Service? Regular versus Business Class? Haves versus Have-Nots?

63

The Next Big Thing

The PC Revolution of the 1980s was not anticipated

The Internet Revolution of the 1990s was not anticipated

Will the future simply be an extension of the past, or will there be a Next Big Thing?

looking forward chapter 12 copyright 2001 prentice hall revision 2: may 2001

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