© 2009 Pearson Education, Inc. Publishing as Prentice Hall An Introduction to Networking Chapter 1 Updated January 2009 Raymond Panko’s Business Data Networks and Telecommunications, 7th edition May only be used by adopters of the book

© 2009 Pearson Education, Inc. Publishing as Prentice Hall1-2 Builds Slides with the blue mouse icon in the upper right hand corner are “build” slides Not everything on the slide will appear at once Each time the mouse click icon is clicked, more information on the slide will appear The number by the mouse icon gives the number of builds on the slide (the number of mouse clicks) 2

© 2009 Pearson Education, Inc. Publishing as Prentice Hall : Black Box View of Networks What Is a Network? –Preliminary definition: A network is a communication system that allows application programs on different hosts to work together Application 1 Application 2 Host A Host B Network

© 2009 Pearson Education, Inc. Publishing as Prentice Hall 1-4 Hosts –Any computer attached to a network is called a host –Including client PCs, servers, mobile phones, etc. Host Cat (Ignores Internet)

© 2009 Pearson Education, Inc. Publishing as Prentice Hall Networked Applications

© 2009 Pearson Education, Inc. Publishing as Prentice Hall What are Networked Applications? Applications that can only exist because of networking The World Wide Web Facebook YouTube Etc. 1-6

© 2009 Pearson Education, Inc. Publishing as Prentice Hall 1-7 Application Standards Application standards govern communication between application programs –Allow products from different vendors cannot talk to one another For example, the Hypertext Transfer Protocol (HTTP) standardizes communication between any browser and any Web servers –Different applications use different standards uses the Simple Mail Transfer Protocol (SMTP) and other standards …

© 2009 Pearson Education, Inc. Publishing as Prentice Hall 1-8 Application Standards Application standards govern communication between application programs –Standards are also called protocols Many standards have “protocol” in their names Example: Hypertext Transfer Protocol –HTTP is an open standard (not controlled by any vendor) Open standards drive down product costs –Vendor-controlled standards are called proprietary standards

© 2009 Pearson Education, Inc. Publishing as Prentice Hall : Hypertext Transfer Protocol (HTTP) Client Host Web server Program Browser HTTP Request Message (Asks for File) HTTP Response Message (Contains the Requested File) HTTP is a Client/Server Protocol –The client is the browser; it sends a request –The server is the Web server; it sends a response –Most application standards are client/server protocols 1

© 2009 Pearson Education, Inc. Publishing as Prentice Hall : The ARPANET and the Internet ARPANET –Some of the first networked applications were created for the ARPANET –Created by the Defense Advanced Research Projects Agency (DARPA) around 1970 Served researchers doing business with DARPA Connected many sites around the United States

© 2009 Pearson Education, Inc. Publishing as Prentice Hall : The ARPANET and the Internet Soon, Many Similar Networks Appeared –CSNET in computer science –BITNET in business and the social sciences –Tower of Babel situation—no interconnection –This was frustrating to users

© 2009 Pearson Education, Inc. Publishing as Prentice Hall : The ARPANET and the Internet Next, DARPA Created the Internet in 1980 to Connect Networks Together –Initially, commercial activity was forbidden –Became commercial in 1995 –Today, the Internet is almost entirely commercial –Almost no government money flowing in to run the Internet

© 2009 Pearson Education, Inc. Publishing as Prentice Hall : Traditional Internet Applications File Transfer Protocol (FTP) The World Wide Web (WWW) E-Commerce –Buying and selling on the Internet

© 2009 Pearson Education, Inc. Publishing as Prentice Hall : The Internet Versus the World Wide Web (and Other Applications) World Wide Web (Application) (Application) FTP (Application) Other Applications The Internet (Transmission System) The Internet is a global transmission system. The WWW, , etc., are applications that run over the Internet global transmission system

© 2009 Pearson Education, Inc. Publishing as Prentice Hall : Newer Internet Applications Instant Messaging (IM) Streaming Audio and Video –No need to wait until the entire file is downloaded before beginning to see or hear it Voice over IP (VoIP) –Telephony over the Internet or other IP networks Peer-to-Peer (P2P) Applications –Growing processing power of PCs allows PCs to serve other PCs directly 3

© 2009 Pearson Education, Inc. Publishing as Prentice Hall : Newer Internet Applications Web 2.0 –A hazy term that focuses on using the Internet to facilitate communication among people –Including the creation of communities –In addition, the users themselves typically generate the content –Blogs, wikis, podcasts –Examples: community building sites such as MySpace and Facebook, video sharing sites such as YouTube, virtual worlds such as Second Life, and specific information sharing sites, such as craigslist

© 2009 Pearson Education, Inc. Publishing as Prentice Hall : Corporate Network Applications Corporate Network Applications are Specific to Businesses –Can consume far more corporate network resources than traditional and new Internet applications combined Transaction-Processing Applications –Simple, high-volume repetitive clerical transaction applications –Accounting, payroll, billing, manufacturing, etc. –Not all corporate network applications are transaction- processing applications

© 2009 Pearson Education, Inc. Publishing as Prentice Hall : Corporate Network Applications Enterprise Resource Planning (ERP) Applications –Serve individual business functions while providing integration between functional modules Sales Purchasing Manufacturing Shipping Warehousing Accounting Billing Inter-Function Transaction Inter-Function Transaction Inter-Function Transaction

© 2009 Pearson Education, Inc. Publishing as Prentice Hall : Corporate Network Applications Organizational Communication Applications – , etc. –Groupware Integrate multiple types of communication, organize communication for retrieval, and provide multiple ways to disseminate and retrieve information

© 2009 Pearson Education, Inc. Publishing as Prentice Hall : Corporate Network Applications Converged Networks –Voice and data traditionally have needed different networks –Convergence: Moving voice/video and data networks to a single network –Can save the corporation a great deal of money by only having a single network –Many technical issues remain

© 2009 Pearson Education, Inc. Publishing as Prentice Hall : File Service File Server 1. User saves data file to file server, which is backed up nightly 2 2. Later, user can retrieve the data file from any other computer 3. Others can retrieve the file and even edit it if they are given permission

© 2009 Pearson Education, Inc. Publishing as Prentice Hall : File Service File Server 1. A program is Installed on the file server; Less expensive than installing it on many individual PCs 2. A multiuser version of the program is required 3 4. Note that the program is executed on the client PC, not on the file server! 4. Note that the program is executed on the client PC, not on the file server! 3. For execution, a copy is downloaded from the file server

© 2009 Pearson Education, Inc. Publishing as Prentice Hall Quality of Service (QoS)

© 2009 Pearson Education, Inc. Publishing as Prentice Hall : Network Quality of Service (QoS) Quality of Service (QoS) –Indicators of network performance –Speed, etc. Metrics –Ways of measuring specific network quality-of-service variables –The metric for speed is bits per second

© 2009 Pearson Education, Inc. Publishing as Prentice Hall : Transmission Speed Measuring Transmission Speed –Measured in bits per second (bps) –In metric notation: Increasing factors of 1,000 … –Not factors of 1,024 Kilobits per second (kbps)-note the lowercase k Megabits per second (Mbps) Gigabits per second (Gbps) Terabits per second (Tbps)

© 2009 Pearson Education, Inc. Publishing as Prentice Hall : Transmission Speed Measuring Transmission Speed –What is 23,000 bps in metric notation? –What is 3,000,000,000 bps in metric notation? –What is 15,100,000 bps in metric notation? Occasionally measured in bytes per second –If so, written as Bps, rather than bps –Usually seen only in file downloads

© 2009 Pearson Education, Inc. Publishing as Prentice Hall : Transmission Speed Writing Transmission Speeds in Proper Form –The rule for writing speeds (and metric numbers in general) in proper form is that there should be 1 to 3 places before the decimal point –23.72 Mbps is correct (2 places before the decimal point) –2,300 Mbps has four places before the decimal point, so it should be rewritten as 2.3 Gbps (1 place) –0.5 Mbps has zero places to the left of the decimal point. It should be written as 500 kbps (3 places) Leading zeros do not count 3

© 2009 Pearson Education, Inc. Publishing as Prentice Hall : Transmission Speed Writing Transmission Speeds in Proper Form –How to convert 1,200 Mbps to proper form, to Gbps NumberSuffix 12,020Mbps Must divide number by 1,000 So must multiply suffix by 1,000 12,020  12.02Mbps  Gbps

© 2009 Pearson Education, Inc. Publishing as Prentice Hall : Transmission Speed Writing Transmission Speeds in Proper Form –How to convert.2346 Mbps to proper form, to kbps NumberSuffix Mbps Multiply by 1,000Divide by 1,  234.6Mbps  kbps

© 2009 Pearson Education, Inc. Publishing as Prentice Hall : Transmission Speed Writing Transmission Speeds in Proper Form –How should you write the following in proper form? kbps 0.47 Gbps 11,200 Mbps.0021 Gbps

© 2009 Pearson Education, Inc. Publishing as Prentice Hall : Transmission Speed Rated Speed –The speed in bits per second that you should get (advertised or specified in the standard) Throughput –The speed you actually get –Almost always lower than the rated speed On Shared Transmission Lines –Aggregate throughput—total throughput for all users –Individual throughput—the individual user’s share of the aggregate throughput

© 2009 Pearson Education, Inc. Publishing as Prentice Hall : Cost Network Demand, Budgets, and Decisions –Figure 1-12 shows that network demand is growing explosively, while network budgets are growing slowly –This creates a cost squeeze that affects every decision –Overspending in one area will result in the inability to fund other projects Figure 1-12

© 2009 Pearson Education, Inc. Publishing as Prentice Hall : Cost Systems Development Life Cycle Costs –Hardware: Full price: advertised base price plus necessary options –Software: Full price: advertised base price plus necessary options –Labor costs: Networking staff and user costs –Outsourcing development costs –Total development investment

© 2009 Pearson Education, Inc. Publishing as Prentice Hall : Cost Systems Life Cycle (SLC) Costs –System development life cycle (SDLC) versus system life cycle (SLC) SLC has ongoing costs after development –Total cost of ownership (TCO) Total cost over entire life cycle SLC includes carrier costs –Carrier pricing is complex and difficult to analyze –Must deal with leases, which lock the firm in for months or years 1

© 2009 Pearson Education, Inc. Publishing as Prentice Hall : Other Quality-of-Service Metrics We Have Already Seen Speed and Cost Availability –The percentage of time a network is available for use –“Our availability last year was 99.9%” Downtime is the amount of time a network is unavailable –Measured in minutes, hours, etc. –“In July, we had five minutes of downtime.”

© 2009 Pearson Education, Inc. Publishing as Prentice Hall : Other Quality-of-Service Metrics Error Rates –Packet error rate: the percentage of packets lost or damaged –Bit error rate: the percentage of bits lost or damaged

© 2009 Pearson Education, Inc. Publishing as Prentice Hall : Other Quality-of-Service Metrics Latency and Jitter –Latency Delivery delay, measured in milliseconds –For instance, 250 ms is a quarter of a second Bad for real-time applications –Voice and video –Network control messages

© 2009 Pearson Education, Inc. Publishing as Prentice Hall : Other Quality-of-Service Metrics Latency and Jitter –Jitter Variation in latency between successive packets Makes voice sound jittery Figure 1-14

© 2009 Pearson Education, Inc. Publishing as Prentice Hall : Other Quality-of-Service Metrics Service Level Agreements –Customers want guarantees for performance –Provider pays penalties if the network does not meet its service metrics guarantees –Often specified on a percentage basis At least 100 Mbps 99.5% of the time To guarantee this speed 100% of the time would be impossible, and even 99.99% would be far more expensive

© 2009 Pearson Education, Inc. Publishing as Prentice Hall : Other Quality-of-Service Metrics Service Level Agreements –Specify a worst case –Speed SLAs Low speed is the worst case So an SLA would guarantee a lowest speed that would be delivered E.g., no worse than 1 Mbps) Customer would like higher speeds But wants no less than 1 Mbps

© 2009 Pearson Education, Inc. Publishing as Prentice Hall : Other Quality-of-Service Metrics Service Level Agreements –Latency SLAs Would an SLA specify a lowest latency or a highest latency? Ask yourself, “Which is worse: large latency or small latency?” The answer: Large latency is worse So specify a maximum latency No more than 100 ms 99% of the time

© 2009 Pearson Education, Inc. Publishing as Prentice Hall : Other Quality-of-Service Metrics Service Level Agreements –What would an SLA guarantee for availability?

© 2009 Pearson Education, Inc. Publishing as Prentice Hall : Other Quality-of-Service Metrics Service Level Agreements –What would an SLA guarantee for error rates?

© 2009 Pearson Education, Inc. Publishing as Prentice Hall : Network Security Security –Security attacks can be extremely expensive –Companies need to install defenses against attacks –Chapter 9 discusses network security in depth

© 2009 Pearson Education, Inc. Publishing as Prentice Hall : Network Security Authentication –Goal is to stop impostors –Supplicant attempts to prove its identity to a verifier –Example: user logging into a server is a supplicant; the server is a verifier –Proofs of identity are called credentials Supplicant: True User? Verifier: Server Credentials: Password

© 2009 Pearson Education, Inc. Publishing as Prentice Hall : Network Security Cryptographic Protections –Eavesdroppers may intercept your messages Read and even change messages Send new messages impersonating the other side –Cryptography is the use of mathematics to protect information in storage or in transit –Encryption for confidentiality An eavesdropper cannot read encrypted messages The legitimate receiver, however, can decrypt the message 2

© 2009 Pearson Education, Inc. Publishing as Prentice Hall : Network Security Firewall –Examines each packet passing through it –Drops and logs provable attack packets –It lets other packets get through, even if suspicious Arriving Packet Arriving Packet Provable Attack Packet Provable Attack Packet Other Packets Other Packets Drops Passes

© 2009 Pearson Education, Inc. Publishing as Prentice Hall : Network Security Host Hardening –Some attacks will inevitably get past safeguards and reach hosts –Hosts must be “hardened” to withstand attacks –Hardening is a set of protections we will see in Chapter 9 Example: installing antivirus software on the host Example: downloading security updates …

© 2009 Pearson Education, Inc. Publishing as Prentice Hall Switched Networks

© 2009 Pearson Education, Inc. Publishing as Prentice Hall1-50 Figure 1-16: Ethernet Switch Operation Ethernet Switch A1-44-D5-1F-AA-4C B2-CD-13-5B-E4-65 D C4-B6-9F C3-2D-55-3B-A9-4F In switched networks, Messages are called frames Host A1-… wishes to send a frame to Host C3 The frame must pass Through the switch In switched networks, Messages are called frames Host A1-… wishes to send a frame to Host C3 The frame must pass Through the switch Switch connectors are called ports Switch connectors are called ports

© 2009 Pearson Education, Inc. Publishing as Prentice Hall1-51 Figure 1-16: Ethernet Switch Operation UTP Ethernet Switch A1-44-D5-1F-AA-4C B2-CD-13-5B-E4-65 D C4-B6-9F C3-2D-55-3B-A9-4F Frame To C3… Host A1-… sends the frame to the switch Host A1-… sends the frame to the switch

© 2009 Pearson Education, Inc. Publishing as Prentice Hall1-52 Figure 1-16: Ethernet Switch Operation Switching Table Port Host 10 A1-44-D5-1F-AA-4C 13 B2-CD-13-5B-E C3-2D-55-3B-A9-4F 16 D C4-B6-9F UTP Ethernet Switch A1-44-D5-1F-AA-4C B2-CD-13-5B-E4-65 D C4-B6-9F C3-2D-55-3B-A9-4F Frame To C3… The switch reads the destination address in the frame. It looks up the address (C3-…) in the switching table. It reads the port number (15) The switch reads the destination address in the frame. It looks up the address (C3-…) in the switching table. It reads the port number (15)

© 2009 Pearson Education, Inc. Publishing as Prentice Hall1-53 Figure 1-16: Ethernet Switch Operation Switching Table Port Host 10 A1-44-D5-1F-AA-4C 13 B2-CD-13-5B-E C3-2D-55-3B-A9-4F 16 D C4-B6-9F Ethernet Switch A1-44-D5-1F-AA-4C B2-CD-13-5B-E4-65 D C4-B6-9F C3-2D-55-3B-A9-4F Frame To C3… The switch sends the frame out Port 15, to the destination host. The switch sends the frame out Port 15, to the destination host.

© 2009 Pearson Education, Inc. Publishing as Prentice Hall : Switched Network in a Multistory Building On each floor, hosts connect to a workgroup switch via wire or wireless transmission A core switch connects the workgroup switches to each other

© 2009 Pearson Education, Inc. Publishing as Prentice Hall : Switched Network in a Multistory Building Router Core Switch Workgroup Switch 2 Workgroup Switch 1 Wall Jack To WAN Wall Jack Server Client Frames from the client to the server go through Workgroup Switch 2, through the Core Switch, through Workgroup Switch 1, and then to the server 3

© 2009 Pearson Education, Inc. Publishing as Prentice Hall 1-56 Figure 1-18: Four-Pair Unshielded Twisted Pair (UTP) Copper Wiring

© 2009 Pearson Education, Inc. Publishing as Prentice Hall : Packet Switching and Multiplexing In packet switching, the sending host breaks each message into many smaller packets Sends these packets out one at a time Packets are routed to the destination host In packet switching, the sending host breaks each message into many smaller packets Sends these packets out one at a time Packets are routed to the destination host

© 2009 Pearson Education, Inc. Publishing as Prentice Hall : Packet Switching and Multiplexing Multiplexing reduces cost. Each conversation only has to pay for its share of the trunk lines it uses Multiplexing reduces cost. Each conversation only has to pay for its share of the trunk lines it uses

© 2009 Pearson Education, Inc. Publishing as Prentice Hall Routed Networks (Internets)

© 2009 Pearson Education, Inc. Publishing as Prentice Hall : Routed Networks The 1980s: A Switched Tower of Babel –At first, there were only switched networks –Soon, there were many incompatible switched networks –Users on different switched networks could not communicate with each other SW Switched Network 1 Switched Network 2

© 2009 Pearson Education, Inc. Publishing as Prentice Hall : Routed Networks Routers and Routed Networks –Routers were created connect different switched networks together –Routed networks are also called internets SW Switched Network 1Switched Network 2 Router Routed Network (Internet)

© 2009 Pearson Education, Inc. Publishing as Prentice Hall : Routed Networks Routers and Routed Networks –Routers are more complex (and expensive) than switches Designed to work no matter how complex the internet Require more hands-on administration than switches SW Switched Network 1Switched Network 2 Router Routed Network (Internet)

© 2009 Pearson Education, Inc. Publishing as Prentice Hall 1-63 Terminology Capitalization of “Internet” –“Internet” with a capital “I” is used for the global Internet we all use each day –“internet” with a lower-case “i” is used when talking about a smaller internet or about internets in general –In all cases, capitalized at the beginning of a sentence Internet internet

© 2009 Pearson Education, Inc. Publishing as Prentice Hall : Routed Networks Originally, only switched network addresses existed –Different switched network technologies used different address schemes –A universal address scheme was necessary to represent any host on any network in the world. Cerf and Kahn Created this Universal Address –These were called IP address –32 bits long –Usually expressed in dotted decimal notation, such as –Host IP addresses are globally unique 1

© 2009 Pearson Education, Inc. Publishing as Prentice Hall : Routed Networks So Hosts on an Internet Have Two Addresses Example –The author’s computer has the Ethernet address AF-23-B9-C8-4E-38 This is its address on its Ethernet switched network –The author’s computer also has the IP address This is its globally unique IP address

© 2009 Pearson Education, Inc. Publishing as Prentice Hall : Routed Networks Packets and Frames –Packets are called frames in switched networks –Packets are called packets in routed networks –A packet is carried in a frame within each switched network Packet Frame

© 2009 Pearson Education, Inc. Publishing as Prentice Hall 1-67 Routers, Frames, and Packets A frame arrives at a router –The frame contains a packet The router takes the packet out of the frame –The router puts the packet into a new frame appropriate for the next network and sends it out –The packet continues; the frame does not Router Packet Frame 1 Packet Frame 2 Packet Network 2

© 2009 Pearson Education, Inc. Publishing as Prentice Hall : Routed Network (Internet) 2. Packet travels through three switched networks 2 1. When a packet is sent, the packet travels all the way from the source host to the destination host 3. The packet travels in three frames—one in each switched network

© 2009 Pearson Education, Inc. Publishing as Prentice Hall : Routed Network (Internet) In this example, the internet has three networks –When a packet is sent, –That one packet goes all the way from the source host to the destination host –The packet travels in three different frames along the way, one in each network –A frame only travels through a single network

© 2009 Pearson Education, Inc. Publishing as Prentice Hall : Routed Network (Internet) Suppose that a packet has to travel through seven networks –When a packet was sent, –How many packets go from the source host to the destination host? –How many frames will there be along the way?

© 2009 Pearson Education, Inc. Publishing as Prentice Hall : The Global Internet 1. User PC Host Computer 1. Web server Host Computer 4 Router 2. User PC’s Internet Service Provider ISP Access Line 3. Web server’s Internet Service Provider ISP Access Line 4. Internet Backbone (Multiple ISP Carriers) ISP 5. NAPs = Network Access Points Connect ISPs NAP

© 2009 Pearson Education, Inc. Publishing as Prentice Hall : The Global Internet How is the Internet Financed? –Through ISP subscriber payments Residences typically pay $10 to $100 per month Business typically pay thousands or tens of thousands of dollars per month –Like the telephone network The telephone network is supported by customer payments to telephone carriers –Almost no government money involved

© 2009 Pearson Education, Inc. Publishing as Prentice Hall : The Internet The TCP/IP Standards –The set of protocols that governs the Internet –Standards for both applications and packet delivery –Created by the Internet Engineering Task Force (IETF)

© 2009 Pearson Education, Inc. Publishing as Prentice Hall : Domain Name System (DNS) Domain Name System (DNS) –IP addresses are official addresses on the Internet and other internets –Hosts can also have host names (e.g., cnn.com) Not official—like nicknames –If you only know the host name of a host that you want to reach, your computer must learn its IP address DNS servers tell our computer the IP address of a target host whose name you know –Like looking up someone’s name in a telephone directory

© 2009 Pearson Education, Inc. Publishing as Prentice Hall : Domain Name System (DNS) Host NameIP Address…… Voyager.cba.hawaii.edu … Host NameIP Address…… Voyager.cba.hawaii.edu … DNS Table 1. Client Host wishes to reach Voyager.cba.hawaii.edu; Needs to know its IP Address 2. Sends DNS Request Message “The host name is Voyager.cba.hawaii.edu” Voyager.cba.hawaii.edu Local DNS Host 1

© 2009 Pearson Education, Inc. Publishing as Prentice Hall : Domain Name System (DNS) Host NameIP Address…… Voyager.cba.hawaii.edu … Host NameIP Address…… Voyager.cba.hawaii.edu … DNS Table 4. DNS Response Message “The IP address is ” Voyager.cba.hawaii.edu Client sends packets to DNS Host looks up the target host’s IP address DNS Host 2

© 2009 Pearson Education, Inc. Publishing as Prentice Hall LANs and WANs

© 2009 Pearson Education, Inc. Publishing as Prentice Hall : LANs and WANs (Study Figure) CategoryLocal Area NetworksWide Area Networks AbbreviationLANWAN Distance SpanCustomer premises (apartment, office, building, campus, etc.) Between sites within a corporation or between different corporations Wide Area Network Building LAN Home LAN Campus LAN

© 2009 Pearson Education, Inc. Publishing as Prentice Hall : LANs and WANs CategoryLocal Area NetworksWide Area Networks Can use switched network technology? Yes Can use routed network technology? Yes, especially in large LANs Yes, in fact, that is what the Internet is Many students are surprised that LANs can be routed and that WANs can be switched Many students are surprised that LANs can be routed and that WANs can be switched

© 2009 Pearson Education, Inc. Publishing as Prentice Hall : LANs and WANs CategoryLocal Area NetworksWide Area Networks ImplementationDo it yourselfMust use a carrier with rights of way Ability to choose technologies HighLow Need to manage technologies HighLow

© 2009 Pearson Education, Inc. Publishing as Prentice Hall : LANs and WANs CategoryLocal Area NetworksWide Area Networks Cost per bit transmittedLowHigh with arbitrary Changes unrelated to costs Therefore, typical transmission speed Usually 100 Mbps to 10 Gbps About 256 kbps to 50 Mbps In economics, you learned that when unit price goes up, people will purchase less of the product Because WANs cost much more per bit, companies learn to live with fewer bits per second

© 2009 Pearson Education, Inc. Publishing as Prentice Hall Network Management

© 2009 Pearson Education, Inc. Publishing as Prentice Hall : Network Management Strategic Network Management –As far as possible, build a coherent roadmap –Pay special attention to decisions that lock you in for long periods of time –Legacy technologies are technologies selected previously that limit services today For upgrading, service benefits must exceed update costs

© 2009 Pearson Education, Inc. Publishing as Prentice Hall : Network Management Product Selection with Multicriteria Decision Making –The entire systems development life cycle (SDLC) must be followed –For network products, corporations buy instead of make network elements Must use multicriteria decision making (Figure 1-26) Select purchasing criteria (speed, cost, etc.) Give each criterion an importance weight Rate each product on each purchasing criteria

© 2009 Pearson Education, Inc. Publishing as Prentice Hall : Multicriteria Decision Making in Purchase Decisions Product AProduct B CriterionCriterion Weight (Max: 5) Criterion Rating (Max: 10) Criterion Score Product Rating (Max: 10) Criterion Score Functionality Availability27147 Cost Ease of Management Electrical Efficiency Total Score120126

© 2009 Pearson Education, Inc. Publishing as Prentice Hall : Network Management Ongoing Management –After the SDLC ends –The most important (and expensive) part of the systems life cycle –Often discussed in terms of OAM&P –Operations, administration, maintenance, and provisioning

© 2009 Pearson Education, Inc. Publishing as Prentice Hall : Network Management Ongoing Management (OAM&P) –Operations Moment-by-moment traffic management Network operations center (NOC) using SNMP (see Figure 1-29)

© 2009 Pearson Education, Inc. Publishing as Prentice Hall : Network Management Ongoing Management (OAM&P) –Maintenance Fixing things that go wrong Conducting preventative maintenance Should be separate from the operations staff

© 2009 Pearson Education, Inc. Publishing as Prentice Hall : Network Management Ongoing Management (OAM&P) –Provisioning (Providing Service) Includes physical installation Includes setting up user accounts and services Reprovisioning when things change Deprovisioning when accounts and services are no longer permitted Collectively extremely expensive

© 2009 Pearson Education, Inc. Publishing as Prentice Hall : Network Management Ongoing Management (OAM&P) –Administration High end: planning Middle: analysis of operations to indicate needed changes Low: paying bills, managing contracts, etc.

© 2009 Pearson Education, Inc. Publishing as Prentice Hall Simple Network Management Protocol (SNMP)

© 2009 Pearson Education, Inc. Publishing as Prentice Hall : Simple Network Management Protocol (SNMP) Network Management Software (Manager) Managed Device Managed Device The manager manages multiple managed devices from a central location Collects information about each managed device Can sometimes reconfigure managed devices remotely

© 2009 Pearson Education, Inc. Publishing as Prentice Hall1-93 Figure 10-13: Simple Network Management Protocol (SNMP) Network Management Software (Manager) Managed Device Network Management Agent (Agent), Objects Manager talks to a network management agent on each managed device—not to the managed device directly

© 2009 Pearson Education, Inc. Publishing as Prentice Hall1-94 Manager collects data about each device; stores the data in a Management Information Base (MIB) Figure 10-13: Simple Network Management Protocol (SNMP) Management Information Base (MIB) Network Management Software (Manager) Data

© 2009 Pearson Education, Inc. Publishing as Prentice Hall1-95 Figure 10-13: Simple Network Management Protocol (SNMP) Network Management Software (Manager) Simple Network Management Protocol (SNMP) Messages Managed Device 1. Command (Get, Set, etc.) 2. Response 3. Trap (Alarm) Initiated by a Managed Device

© 2009 Pearson Education, Inc. Publishing as Prentice Hall : Simple Network Management Protocol (SNMP) Notes –Remote management can greatly reduce the TCO by reducing labor costs, despite the higher cost of managed devices Central Management No Central Management Device costsHigherLower Labor costsMuch LowerMuch Higher TCOLowerHigher

© 2009 Pearson Education, Inc. Publishing as Prentice Hall 1-97 Key Points Perspective –Definition of a network –Networked applications –Quality of Service Network Technology –Switched versus routed networks (internets) –The global Internet –LANs versus WANs Network Management

© 2009 Pearson Education, Inc. Publishing as Prentice Hall 1-98 All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of the publisher. Printed in the United States of America. Copyright © 2009 Pearson Education, Inc. Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall