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Chapter 2 Overview

Chapter 2 Overview. Why is network mgmt necessary? Network managers job Network management vocabulary Network management principles Example implementation New approaches to network mgmt Evolution of network mgmt. What is Network Mgmt?. In the past network was small, local

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Chapter 2 Overview

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  1. Chapter 2 Overview • Why is network mgmt necessary? • Network managers job • Network management vocabulary • Network management principles • Example implementation • New approaches to network mgmt • Evolution of network mgmt Chapter 2  Overview of Network Management 1

  2. What is Network Mgmt? • In the past network was small, local • Managers job included… • Attach PC’s, etc., to LAN using NIC’s • Configure NIC’s, protocol stack, user app’s, shared printers, etc. • Ping was sufficient to “manage” network • Job was manageable Chapter 2  Overview of Network Management 2

  3. What is Network Mgmt? • Above only deals with configuration • Ongoingmaintenance issues • Improve performance • Handle failures, changes to network • More capacity/bandwidth may be needed • May need to account for usage • Security needs to be addressed • Highlighted terms: ISO mgmt categories Chapter 2  Overview of Network Management 3

  4. What is Network Mgmt? • In past, one network manager might be able to handle all responsibilities • Today there are specializations • Network architect • Installation, configuration, etc. • Ongoing maintenance, security, etc. • Different certifications for these Chapter 2  Overview of Network Management 4

  5. What is Network Mgmt? • Today, networks not local, more complex, so more demands on network manager • Mgmt tools are needed • Network-based mgmt tools: use the network to manage the network • Simple Network Management Protocol (SNMP) • Management Information Base (MIB) • Network Management System (NMS) • Remote Monitor (RMON) Chapter 2  Overview of Network Management 5

  6. A Note on RFCs • RFC == Request for Comments • Officially, an RFC is a proposed standard • In reality, an RFC is a de facto standard • Time for “comments” is before RFC is issued • IETF is responsible for RFCs • All RFCs available on the Web • IEEE and ISO also important sources for standards-related information Chapter 2  Overview of Network Management 6

  7. Network Mgmt Vocabulary • Network mgmt: local and remote • Local management station • Remote management agent Chapter 2  Overview of Network Management 7

  8. Network Mgmt Vocabulary • Mgmt agent provides information on the device and/or local environment • Can be hosted on a workstation, laptop, hub, switch, router, … • Mgmt station runs the Network Management System (NMS) • NMS displays/analyzes info from agents Chapter 2  Overview of Network Management 8

  9. Mgmt App Agent Process Agent Protocol Mgmt Process Mgmt Protocol Presentation Presentation Session Session Transport Transport Network Network Data Link Data Link Physical Physical Management Station Management Agent Mgmt and Agent Processes • Mgmt process is software on the Mgmt Station • Interface to SNMP • Agent process is software on the Mgmt Agent • Collects info Chapter 2  Overview of Network Management 9

  10. NMS Overview • NMS includes all management apps • Agent processes run on any device • PC, server, hub, switch, router, etc. • Agent collects info at request of mgmt station • The database of information is a Management Information Base (MIB) • Mgmt application queries agent’s MIB Chapter 2  Overview of Network Management 10

  11. Network Mgmt Example • To get value of MIB variable from mgmt agent • Mgmt app (part of NMS) on mgmt station passes request to mgmt process • Mgmt process calls network mgmt protocol (SNMP) • SNMP constructs Get-Request packet • Mgmt agent receives Get-Request • Agent process accesses requested value • SNMP constructs Get-Response packet • Mgmt process on mgmt station receives response • Mgmt process passes data to mgmt application Chapter 2  Overview of Network Management 11

  12. Network Mgmt Overhead • There is overhead in terms of • CPU cycles to generate and process information/packets • May require dedicated Management Station • Bandwidth usage for sending request and receiving responses • A tradeoff between cost and benefit Chapter 2  Overview of Network Management 12

  13. Additional Mgmt Capabilities • For efficiency, can request multiple values in a single Get-Request • Can traverse MIB in logical order • Mgmt agent can send unsolicited msgs • These are known as traps • For example, if a device goes down • Can request info from device or probe • Probe is a remote monitor (RMON) Chapter 2  Overview of Network Management 13

  14. Additional Mgmt Capabilities • RMON might monitor a network segment • Source/destination addresses • Protocols used • Usage statistics, etc. • Management station accesses RMON info • Using steps 1 thru 8, above • May also routinely poll RMON Chapter 2  Overview of Network Management 14

  15. Network Mgmt History • In 1977 International Organization for Standards (ISO) began work on Open Systems Interconnection (OSI) reference model • Purpose was to “provide a common basis for the coordination of standards developments for the purpose of system interconnection, while allowing existing standards to be placed in perspective within the overall Reference Model” • OSI model published in 1984 (7 years!) Chapter 2  Overview of Network Management 15

  16. Network Mgmt History • In March 1987, effort to develop Simple Gateway Monitoring Protocol (SGMP) • SGMP out by November 1987 • Could “get” and “set” variable values • About same time Common Mgmt Information Protocol (CMIP) developed for OSI model • CMIP is roughly SMNP for the OSI model • Effort to develop CMIP Over TCP (CMOT) as alternative to SGMP Chapter 2  Overview of Network Management 16

  17. Network Mgmt History • CMIP uses Remote Operations Services Elements (ROSE) • ROSE is for communication with distributed apps in OSI model • OSI mgmt process is richer and more comprehensive than that provided by SNMP • But OSI approach is more complex and took longer to develop • SNMP: “keep it simple”, and it’s good enough • So SNMP won out in practice Chapter 2  Overview of Network Management 17

  18. Network Mgmt History • Due to controversy/delays in OSI approach, Internet Activities Board (IAB) held meeting in 1988 • Decided to pursue both CMOT and SGMP • Eventually abandoned CMOT (complexity) • Eventually, three RFCs resulted… Chapter 2  Overview of Network Management 18

  19. Network Mgmt History • The three RFCs • Structure of Management Information (SMI), uses Abstract Syntax Notation One (ASN.1) • Management Information Base (MIB), the data structure on the mgmt agent • Simple Network Management Protocol (SNMP) • By 1989, SNMP was the de facto standard for management of TCP/IP networks Chapter 2  Overview of Network Management 19

  20. Network Management History Chapter 2  Overview of Network Management 20

  21. TCP/IP Development • TCP/IP (and SNMP) were viewed as temporary, since OSI was coming… • TCP/IP was part of Berkeley Unix • Corporations started using Unix (and hence TCP/IP, SNMP, etc.) so that OSI model was DOA Chapter 2  Overview of Network Management 21

  22. Chapter 2 Summary • Overview of network management • Responsibilities of network manager • Need for remote monitoring • Terminology • Basic principles • Simple example • History Chapter 2  Overview of Network Management 22

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