Network Management Functions - Performance Network Management 1
Lectures Schedule Week Week 1 Topic Computer Networks - Network Management Architectures & Applications Week 2 Network Management Standards Architectures & Applications Week 3 Simple Network Management Protocol - SNMP v1, ASN, MIB, BER Week 4 Network Management Functions - Fault Week 5 Simple Network Management Protocol - SNMP v2 - Configuration Week 6 Network Management Functions - Accounting Week 7 Midterm Week 8 Simple Network Management Protocol - SNMP v3 - Performance Week 9 Network Management Functions Security Week 10 Remote Network Monitoring RMON 1, SLA Week 11 Remote Network Monitoring RMON 2 Week 12 Management Tools, Systems and Applications Week 13 NM Project Presentations Week 14 NM Project Presentations Week 15 NM Project Presentations 2
Network Management OSI NM Architecture and Model Manager Organization Model Agent Object Information Model Communication Model Structure of Management Information (SMI) Management Information Base (MIB) Protocol Data Unit (PDU) Configuration Management (CM) Fault Management (FM) Functional Model Performance Management (PM) Security Management (SM)a Accounting Management (AM) 3
Network Management Functions Corporate Network Management Administration Mgmt Capacity Mgmt Provisioning Mgmt Accounting Mgmt Performance Mgmt Configuration Mgmt Fault Mgmt Security Mgmt Traffic monitoring Throughput Utilisation 4
SNMP Milestone SGMP SNMP SNMP Security SMP SNMPv2 (parties) SNMPv2 (community) SNMPv3 draft full standard implementation experience proposed standard draft standard proposed standard draft standard 5
Standard SMI (Structure of Management Information) Define how management information may look like SMIv1: RFC 1155 SMIv2: RFC2578 (currently used) MIBs (Management Information Bases) Tell what management information exists MIB-I: RFC1156 MIB-II: RFC1213 SNMP (Simple Network Management Protocol) Define how information is exchanged SNMPv1: RFC1157 SNMPv2: RFC1901, 1905, 1906 SNMPv3: RFC2571-2575 6
Structure 7
Performance Management Issues of concern to the network manager include: What is the level of capacity utilization? Is there excessive traffic? Has throughput been reduced to unacceptable levels? Are there bottlenecks? Is response time increasing? Network managers need performance statistics to help them plan, manage, and maintain large networks 8
Performance Monitoring After availability, the second most important characteristic of a network is performance Performance data must be available in sufficient detail to be able to assess the bottleneck that is causing the problem and to plan appropriate remedial action 9
Performance Management: Definition The Utilization of Network Resources with The Ability to meet User Service Level Objectives 10
Performance Management: Activities Information Gathering Current System (Traffic / Resources) System History (Logs) Performance Evaluation (Analysis) For Different States / Conditions Understanding / Reporting 11
Network: Performance Traffic Process Arrival (Rate) Load Service (Time) Busy Period Measures Errors Channel Quality Utilization Load / Capacity Delay Throughput Monitor Traffic Measures Load Limits 12
It's Not The Volume, It's The Time It Takes To Double... It s not the heat, it s the humidity Example: Daily Usenet News volume (e.g., ~200GB/day now, doubling every 6 mos.) 13
Performance Management Sub-Categories and Related Activities Collecting Baseline Utilization Data Measuring link utilization using a probe Counting packets received/transmitted by a specific device Measuring device processor usage Monitoring device queue lengths Monitoring device memory utilization Measuring total response times Collecting a History of Utilization Data Measuring utilization and response times at different times of the day Measuring utilization and response times on different days over an extended period Capacity Planning Manually graphing or using a network management tool to graph utilization as a function of time to detect trends Preparing trend reports to document projected need for and the cost of network expansion.
Performance Management Sub-Categories and Related Activities (cont.) Setting Notification Thresholds Having a network management tool poll devices for values of critical parameters and graphing these values as a function of time Setting polling intervals Setting alarms/alerts on those parameters when the threshold is reached or a percentage of it is reached Initiating an action when the threshold is reached such a sending a message to the network manager. Building Databases Having the network management tool create a database of records containing device name, parameter, threshold and time for off-line analysis. Using the database to extract time dependence of utilization Using the time dependence of parameters to decide when network upgrades will be necessary to maintain performance Running Network Simulations Using a simulation tool to develop a model of the network Using the model s parameters and utilization data to optimize network performance Latency Query/Response time interval
MRTG Multi Router Traffic Grouper (Oeticker and Rand) www.ee.ethz.ch/stats/mrtg/ Generates graphic presentation of traffic on Web Daily view Weekly view Monthly view Yearly view Chapter 12
Example of Performance Management
Obtaining Baseline Measurements Baseline: report of network s current state of operation Baseline measurements allow comparison of future performance increases or decreases caused by network changes with past network performance The more data gathered while establishing the baseline, the more accurate predictions will be Several software applications can perform baselining 18
Performance and Fault Management Performance management: monitoring how well links and devices are keeping up with demands Fault management: detection and signaling of device, link, or component faults Organizations often use enterprise-wide network management software At least one network management console collects data from multiple networked devices at regular intervals Polling 19
Performance and Fault Management (continued) Each managed device runs a network management agent Collects information about device s operation and provides it to network management application Definition of managed devices and data collected in a Management Information Base (MIB) Simple Network Management Protocol (SNMP): TCP/IP protocol used by agents to communicate 20
Performance and Fault Management (continued) 21
Performance and Fault Management (continued) Network management application can present an administrator with several ways to view and analyze data Network management applications are challenging to configure and fine-tune Multi Router Traffic Grapher (MRTG): command-line utility that uses SNMP to poll devices, collects data in a log file, and generates HTML-based views of data 22
Performance and Fault Management (continued) 23
Network Statistics Baseline Trouble shooting Capacity planning for the future Reports
Traffic Load: Source HostTopN Host 1 Host 2 Host 3 Host 4 Host 5 Host 6 Host 7 Host 8 Host 9 Host 10 0 100 200 300 400 Giga Octets
Traffic Load: Source/Destination
Protocol Distribution
Traffic Load: Source Chapter 12 Figure 12.16 Load Statistics: Monitoring of Sources
Traffic Load: Destination Chapter 12
Traffic Load: Conversation Chapter 12
Protocol Distribution Chapter 12 Figure 12.19 Protocol Distribution (NetMetrix)
Conclusions SLA Measure Performance Meet requirements Evaluations of the Behaviour & Cost-Effectiveness of Network Resources