1. Network monitoring and measurement-2.ppt
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Network monitoring and measurement involves measuring network traffic and monitoring systems to detect outages. It provides information for understanding network behavior, planning, security, billing, and more. Both active and passive monitoring techniques are used, with active involving test traffic and passive observing live traffic. Key metrics include availability, connectivity, latency, throughput, and link utilization. Various software tools exist to help with network monitoring and management tasks.
1. Network monitoring and measurement-2.ppt
- 2. Definition • Network traffic measurement is the process of measuring the amount and type of traffic on a particular network. This is especially important with regard to effective bandwidth management. • Network monitoring describes the use of a system that constantly monitors a computer network for slow or failing systems and that notifies the network administrator in case of outages via email, pager or other alarms. It is a subset of the functions involved in network management.
- 3. Motivation ★ Needs of service providers: ★Understand the behavior of their networks ★Provide fast, high-quality, reliable service to satisfy customers and thus reduce churn rate ★Plan for network deployment and expansion ★SLA monitoring, Network security ★Usage-based billing for network users (like telephone calls) ★Marketing using CRM data ★ Needs of Customers: ★Want to get their money’s worth ★Fast, reliable, high-quality, secure, virus-free Internet access
- 4. Application • Network Problem Determination and Analysis • Traffic Report Generation • Intrusion & Hacking Attack (e.g., DoS, DDoS) Detection • Service Level Monitoring (SLM) • Network Planning • Usage-based Billing • Customer Relationship Management (CRM) • Marketing
- 5. The General Traffic Flow Measurement Process Classification & Flow Recording Store (TCPdump) Observation Point PAYLOAD HEAD PAYLOAD HEAD PAYLOAD HEAD PAYLOAD HEAD Packet Capturing Filtering Display (Ethereal) Sampling Visualize (FlowScan) Analysis by applications (TE, attack detect., QoS monitoring, accounting, …) … other … packets Filtering Sampling flow records flow records packets packets flow records flow records
- 6. Problems • Capturing Packets: ✴High-speed networks (Mbps ? Gbps ? Tbps) ✴High-volume traffic ✴Streaming media (Windows Media, Real Media, Quicktime) ✴P2P traffic ✴Network Security Attacks • Flow Generation & Storage: What packet information to save to perform various analysis? How to minimize storage requirements? • Analysis: How to analyze and generate data needed quickly? What kinds of info needs to be generated? -- Depends on applications
- 7. Goals • Capture all packets • Generate flows • Store flows efficiently • Analyze data efficiently • Generate various reports or information that are suitable for various application areas Develop a flexible, scalable traffic monitoring and analysis system for high-speed, high-volume, rich media IP networks
- 8. Network Monitoring Metrics • CAIDA Metrics Working Group (www.caida.org) ✴Latency ✴Packet Loss ✴Throughput ✴Link Utilization ✴Availability • IETF’s IP Performance Metrics (IPPM) Working Group ✴Connectivity (RFC 2687) ✴One-Way Delay (RFC 2679) ✴One-Way Packet Loss (RFC 2680) ✴Round Trip Delay (RFC 2681) ✴Delay Variation ✴Bulk transfer capacity
- 9. One way loss RT loss One way delay RT delay Capacity Bandwidth Throughput Delay variance Network Monitoring Metrics Availability Connectivity Functionality Loss Delay Utilization
- 10. • Availability: The percentage of a specified time interval during which the system was available for normal use. ✤Connectivity: the physical connectivity of network elements. ✤Functionality: whether the associated system works well or not. • Latency: The time taken for a packet to travel from a host to another. ✤Round Trip Delay = Forward transport delay + server delay + backward transport delay ✤Ping is still the most commonly used to measure latency. • Link Utilization over a specified interval is simply the throughput for the link expressed as a percentage of the access rate.
- 11. Monitoring Method • Active Monitoring • Passive Monitoring
- 12. Active Monitoring • Performed by sending test traffic into network • Generate test packets periodically or on-demand • Measure performance of test packets or responses • Take the statistics • Impose extra traffic on network and distort its behavior in the process • Test packet can be blocked by firewall or processed at low priority by routers • Mainly used to monitor network performance
- 13. Passive Monitoring • Carried out by observing network traffic • Collect packets from a link or network flow from a router • Perform analysis on captured packets for various purposes • Network device performance degrades by mirroring or flow export • Used to perform various traffic usage/characterization analysis/intrusion detection
- 14. Comparison of Monitoring Approaches Active monitoring Passive monitoring Configuration Multi-point Single or multi-point Data size Small Large Network overhead Additional traffic - Device overhead - No overhead if splitter is used Purpose Delay, packet loss, availability Throughput, traffic pattern, trend, & detection CPU Requirement Low to Moderate High
- 15. Software in Network Monitoring and Management • EPM • The ping program • SNMP servers • IBM AURORA Network Performance Profiling System • Intellipool Network Monitor • Jumpnode • Microsoft Network Monitor 3 • MRTG • Nagios (formerly Netsaint) • Netdisco • NetQoS • NetXMS Scalable network and application monitoring system
- 16. Software in Network Monitoring and Management • Opennms • PRTG • Pandora (Free Monitoring System) - Network and Application Monitoring System • PIKT • RANCID - monitors router/switch configuration changes • RRDtool • siNMs by Siemens • SysOrb Server & Network Monitoring System • Sentinet3 - Network and Systems Monitoring Appliance • ServersCheck Monitoring Software • Cacti network graphing solution • Zabbix - Network and Application Monitoring System • Zenoss - Network and Systems Monitoring Platform • Level Platforms - Software support for network monitoring