Planeamento e Gestão de Redes. Análise de Requisitos

Transcription

1 Planeamento 1 Planeamento e Gestão de Redes Análise de Requisitos Manuel P. Ricardo Faculdade de Engenharia da Universidade do Porto

2 Planeamento 2 Book Top-Down Network Design, Second Edition Priscilla Oppenheimer Cisco Press Chapters 1 to 4 Credits These slides are based on the material made available by Priscilla Oppenheimer on the book s site

3 Planeamento 3 Structured Network Design Set of best practices Layer 7 first Identification of Business/technical goals Groups of users/their locations Applications usage, generated traffic Layer 7 Layer 6 Layer 5 Layer 4 Layer 3 Layer 2 Layer 1 Application Presentation Session Transport Network Data Link Physical

4 Planeamento 4 Top-Down Network Design Process Analyze requirements Monitor and optimize network performance Develop logical Implement and test network Test, optimize, and document Develop physical

5 Phase 1 Planeamento 5 Analyze Requirements Analyze company business goals Analyze network technical goals Characterize the existing network Characterize network traffic Analyze requirement s Monitor and optimize network performance Develop logical The steps addressed in this set of slides Implement and test network Test, optimize, and document Develop physical

6 Phase 2 Planeamento 6 Logical Network Design Design a network topology Design models for addressing and naming Select switching and routing protocols Develop network security strategies Develop network management strategies Analyze requirements Monitor and optimize network performance Develop logical Implement and test network Test, optimize, and document Develop physical

7 Phase 3 Planeamento 7 Physical Network Design Select technologies and devices for the networks Analyze requirements Monitor and optimize network performance Develop logical Implement and test network Test, optimize, and document Develop physical

8 Phase 4 Planeamento 8 Testing, Optimizing, and Documenting the Network Design Optimize the network Document the network Analyze requirements Monitor and optimize network performance Develop logical Implement and test network Test, optimize, and document Develop physical

9 Phase 1 Planeamento 9 Analyze Requirements Analyze company business goals Analyze network technical goals Characterize the existing network Characterize network traffic Analyze requirement s Monitor and optimize network performance Develop logical Implement and test network Test, optimize, and document Develop physical

10 Planeamento 10 Business Goals What is the new (improved) network required for?» Help increase revenue?» Reduce operating costs?» Improve communications?» Shorten product development cycle?» Expand into worldwide markets?» Build partnerships with other companies?» Offer better customer support or new customer services?

11 Planeamento 11 The Scope of the Design Small in scope?» E.g. Allow sales people to access network via a VPN Large in scope?» E.g. An entire re of an enterprise network Use the OSI model to clarify the scope» Support of new financial reporting application?» Add routing?» Wireless access?

12 Planeamento 12 Gather Information What applications are expected to be used? How critical are they?» very critical, somewhat critical, not critical

13 Planeamento 13 Register Applications Name of Application Type of Application New Application? Criticality Comments

14 Phase 1 Planeamento 14 Analyze Requirements Analyze company business goals Analyze network technical goals Characterize the existing network Characterize network traffic Monitor and optimize network performance Analyze requirement s Develop logical Implement and test network Test, optimize, and document Develop physical

15 Planeamento 15 Key Technical Goals Scalability Availability Performance But also» Security, manageability,

16 Planeamento 16 Scalability Scalability refers to the ability of the network to grow Try to learn» Number of sites to be added» What will be needed at each of these sites» How many users will be added» How many more servers will be added

17 Planeamento 17 Availability Availability» percent uptime per year, month, week, day, or hour. For instance: 24h, 7 day/week operation; network up for 165 in 168 hour Availability = 98.21%» or, Availability = MTBF/(MTBF + MTTR) MTBF - mean time between failures MTTR - mean time to repair (MTTR) Some enterprises may want % (Five Nines) availability» may require triple redundancy ISP 1 ISP 2 ISP 3 Enterprise

18 Planeamento 18 Performance Key performance factors include» Throughput» Delay (latency), delay variation, response time

19 Planeamento 19 Factors Affecting Throughput Size of packets, distance, errors Protocols: layer 2, transport, applications, DNS Packets-per-second switched by network elements Network topology Client and server speeds 100 % of Capacity Throughput Ideal Actual Offered Load 100 % of Capacity

20 Planeamento 20 Delay Perspectives User s view» Response Time Depends on the application / equipment application is running; not just the network Most users expect to see something on the screen in 100 to 200 milliseconds Engineer s view» End-to-end delay, delay variation» Caused by Propagation delay Transmission delay Packet-switching delay Queuing delay

21 Planeamento 21 Queueing Delay - Example Switch has 5 users, each offering 10 pac/s Average packet length = 1024 bits Packet switch transmits this data over a 64 kbit/s WAN circuit Load = 5 x 10 x 1024 = bit/s Utilization = 51200/64000 = 80% Average number of packets in queue = (0.8)/(1-0.8) = 4 packets Average Queue Depth Average Utilization Number of packets in a queue increases exponentially as utilization increases

22 Network Applications Planeamento 22 Technical Requirements Name of Application Cost of Downtime Acceptable MTBF Acceptable MTTR Throughput Goal Delay Must be Less Than: Delay Variation Must be Less Than:

23 Phase 1 Planeamento 23 Analyze Requirements Analyze company business goals Analyze network technical goals Characterize the existing network Characterize network traffic Monitor and optimize network performance Analyze requirement s Develop logical Implement and test network Test, optimize, and document Develop physical

24 Characterize the Existing Planeamento 24 Internetwork Its infrastructure» Logical structure (modularity, hierarchy, topology)» Physical structure Addressing and naming Wiring and media

25 Planeamento 25 Get a Network Map Medford Fast Ethernet 50 users Frame Relay CIR = 56 Kbps DLCI = 5 Frame Relay CIR = 56 Kbps DLCI = 4 Roseburg Fast Ethernet 30 users Grants Pass HQ Fast Ethernet 75 users Gigabit Ethernet Grants Pass HQ 16 Mbps Token Ring FEP (Front End Processor) T1 IBM Mainframe Web/FTP server Eugene Ethernet 20 users T1 Internet

26 Characterize Addressing and Planeamento 26 Naming IP addressing for» major devices, client networks, server networks Addressing oddities, such as discontiguous subnets Strategies for addressing and naming» For example, sites may be named using airport codes San Francisco = SFO, Oakland = OAK

27 Planeamento 27 Characterize the Wiring and Media Single-mode fiber Multi-mode fiber Shielded twisted pair (STP) copper Unshielded-twisted-pair (UTP) copper Coaxial cable Microwave Laser Radio Infra-red

28 Planeamento 28 Campus Network Wiring Telecommunications Wiring Closet Horizontal Wiring Wallplate Work-Area Wiring Vertical Wiring (Building Backbone) Main Cross-Connect Room (or Main Distribution Frame) Intermediate Cross-Connect Room (or Intermediate Distribution Frame) Building A - Headquarters Campus Backbone Building B

29 Planeamento 29 Characterize Network Availability MTBF MTTR Date and Duration of Last Major Downtime Cause of Last Major Downtime Enterprise Segment 1 Segment 2 Segment n

30 Measure Network Utilization in Planeamento 30 Hour Intervals Network Utilization 13:00:00 14:00:00 Time 15:00:00 Series1 16:00:00 17:00: Utilization

31 Planeamento 31 Bandwidth Utilization by Protocol Relative Network Utilization Absolute Network Utilization Broadcast Rate Multicast Rate Protocol 1 Protocol 2 Protocol 3 Protocol n

32 Planeamento 32 Characterize Response Time Node A Node B Node C Node D Node A X Node B X Node C X Node D X

33 Phase 1 Planeamento 33 Analyze Requirements Analyze company business goals Analyze network technical goals Characterize the existing network Characterize network traffic Analyze requirement s Monitor and optimize network performance Develop logical Implement and test network Test, optimize, and document Develop physical

34 Planeamento 34 Network Traffic Factors Traffic flow Location of traffic sources and data stores Traffic load

35 Planeamento 35 User Communities User Community Name Size of Community (Number of Users) Location(s) of Community Application(s) Used by Community

36 Planeamento 36 Data Stores Data Store Location Application(s) Used by User Community(or Communities)

37 Planeamento 37 Traffic Flow Destination 1 Destination 2 Destination 3 Destination MB/sec MB/sec MB/sec MB/sec Source 1 Source 2 Source 3 Source n

38 Traffic Flow Example App 2 20 Kbps App 3 96 Kbps App 4 24 Kbps App 9 80 Kbps Total 220 Kbps Library and Computing Center 30 Library Patrons (PCs) 30 Macs and 60 PCs in Computing Center Server Farm Planeamento Mbps Metro Ethernet to Internet App Kbps App 2 60 Kbps App Kbps App 4 48 Kbps App Kbps Total 808 Kbps 50 PCs 25 Macs 50 PCs Administration 30 PCs App 1 30 Kbps App 2 20 Kbps App 3 60 Kbps App 4 16 Kbps Total 126 Kbps App 1 48 Kbps App 2 32 Kbps App 3 96 Kbps App 4 24 Kbps App Kbps App Kbps App Kbps Total 1900 Kbps 50 PCs Arts and Humanities Math and Sciences Business and Social Sciences

39 Planeamento 39 Types of Traffic Flow Terminal/host Client/server Thin client Peer-to-peer Server/server Distributed computing

40 Network Applications Planeamento 40 Traffic Characteristics Name of Application Type of Traffic Flow Protocol(s) Used by Application User Communities That Use the Application Data Stores (Servers, Hosts, and so on) Approximate Bandwidth Requirements QoS Requirements

41 Collection of Tables Planeamento 41

42 Planeamento 42 Register Applications Name of Application Type of Application New Application? Criticality Comments

43 Network Applications Planeamento 43 Technical Requirements Name of Application Cost of Downtime Acceptable MTBF Acceptable MTTR Throughput Goal Delay Must be Less Than: Delay Variation Must be Less Than:

44 Planeamento 44 Characterize Availability MTBF MTTR Date and Duration of Last Major Downtime Cause of Last Major Downtime Enterprise Segment 1 Segment 2 Segment n

45 Planeamento 45 Bandwidth Utilization by Protocol Relative Network Utilization Absolute Network Utilization Broadcast Rate Multicast Rate Protocol 1 Protocol 2 Protocol 3 Protocol n

46 Planeamento 46 Characterize Response Time Node A Node B Node C Node D Node A X Node B X Node C X Node D X

47 Planeamento 47 User Communities User Community Name Size of Community (Number of Users) Location(s) of Community Application(s) Used by Community

48 Planeamento 48 Data Stores Data Store Location Application(s) Used by User Community(or Communities)

49 Planeamento 49 Traffic Flow Destination 1 Destination 2 Destination 3 Destination MB/sec MB/sec MB/sec MB/sec Source 1 Source 2 Source 3 Source n

50 Network Applications Planeamento 50 Traffic Characteristics Name of Application Type of Traffic Flow Protocol(s) Used by Application User Communities That Use the Application Data Stores (Servers, Hosts, and so on) Approximate Bandwidth Requirements QoS Requirements