looking forward chapter 12 copyright 2001 prentice hall revision 2: may 2001
TRANSCRIPT
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Looking Forward
Chapter 12
Copyright 2001 Prentice HallRevision 2: May 2001
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Budgeting and Procurement
Planning how to spend money
Selecting and purchasing technologies and services
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The Budget Realities
Exploding demand but stagnant or slowly-growing budgets Must buy only what you really need in
every system
Time
Demand
Budget
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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
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Costs
Ongoing Costs over Life Span
Often exceed initial costs Labor
Upgrades
Especially high in immature products When possible, avoid the “bleeding edge”
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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
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7The Timing of Costs and Benefits
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
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8The Timing of Costs and Benefits
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
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Procurement
User Needs
Must drive everything else Sometimes difficult to assess But the only way to drive evaluations
of alternatives
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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Server Farms
Load Balancing Approach Router or other device sends requests
to servers based on load
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Server Farms
Server Clustering Approach Act as a single server without an
external load balancer
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Server Farms
Reliability If one server’s hardware fails,
operation continues without interruption
However, software failures often take down all servers simultaneously
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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
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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 …
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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
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27Network Management System
Standards Most widely used is the Simple
Network Management Protocol (SNMP)
Other standards exist
SNMP
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28Network Management System
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
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29Network Management System
Agents Network management agents Installed in managed nodes Communicate with the manager on
behalf of the node
Manager Agent
Managed Node
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30Network Management System
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
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31Network Management System
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
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32Network Management System
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
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33Network Management System
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
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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
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35Network Management Protocol
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
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36Network Management Protocol
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
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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)=$^%@&
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Directory Servers
LDAP Lightweight Directory Access Protocol Most popular directory access
protocol Governs user interaction with
directory server
DirectoryServer
LDAP
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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
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40Directory Servers and Security
Directory Server can store data and policies for security servers Digital certificates Passwords Policies
Centralizes managementand control
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Converging Boxes
Today, Many Types of Devices Forwarding: Hubs, Switches, Routers Security: Firewalls, etc.
Difficult to Manage
Difficult to Integrate Forwarding and Security
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Converging Boxes
Comprehensive Relay Devices are Needed Combine both forwarding and security Easier management Easier integration of forwarding,
security
CRD
CRD CRD
CRD
CRDCRD
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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
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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
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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
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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
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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
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Wireless Communication
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
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Wireless Communication
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
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Wireless Communication
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
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Wireless Communication
The Wireless Revolution New freedom for users Anything, anytime, anywhere Likely to spawn new applications
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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
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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
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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
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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
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Cellphone Access
Wireless Markup Language (WML)
Part of WAP
Way of formatting webpagesfor small displays
Simpler than HTML
Reformatting may be expensive
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Cellphone Access
Wireless Access Protocol (WAP)
Device will communicate over the Internet with WAP server via WAP protocols rather than with webservers directly
WirelessCarrier
WAPProtocols
WAP Protocols
WAPServer
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Cellphone Access
Wireless Access Protocol (WAP)
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
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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
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60Network Object-Oriented Processing
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
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61Network Object-Oriented Processing
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
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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?
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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?