Chapter 2 Overview
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Chapter 2 Overview of Network Management 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
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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 - PowerPoint PPT Presentation
Transcript of Chapter 2 Overview
Chapter 2 Overview of Network Management 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 2
What is Network Mgmt? In the past network was small,
local Managers job included…
o Attach PC’s, etc., to LAN using NIC’so Configure NIC’s, protocol stack, user
app’s, shared printers, etc.o Ping was sufficient to “manage”
network Job was manageable
Chapter 2 Overview of Network Management 3
What is Network Mgmt? Above only deals with configuration Ongoing maintenance issues
o Improve performanceo Handle failures, changes to networko More capacity/bandwidth may be neededo May need to account for usageo Security needs to be addressed
Highlighted terms: ISO mgmt categories
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What is Network Mgmt? In past, one network manager
might be able to handle all responsibilities
Today there are specializationso Network architecto Installation, configuration, etc.o Ongoing maintenance, security, etc.o Different certifications for these
Chapter 2 Overview of Network Management 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 networko Simple Network Management Protocol
(SNMP)o Management Information Base (MIB)o Network Management System (NMS)o Remote Monitor (RMON)
Chapter 2 Overview of Network Management 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
o Time for “comments” is before RFC is issued IETF is responsible for RFCs
o All RFCs available on the Web IEEE and ISO also important sources for
standards-related information
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Network Mgmt Vocabulary Network mgmt: local and remote
o Local management stationo Remote management agent
Management Agent Management Station
NMS
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Network Mgmt Vocabulary Mgmt agent provides information on the
device and/or local environmento Can be hosted on a workstation, laptop,
hub, switch, router, … Mgmt station runs the Network
Management System (NMS) NMS displays/analyzes info from agents
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Transport
Presentation
Data Link
Session
Network
Physical
AgentProcess
AgentProtocol
Management Agent
Presentation
Transport
Data Link
Session
Network
Physical
MgmtProcess
MgmtProtocol
Management Station
MgmtApp
Mgmt and Agent Processes
Mgmt process is software on the Mgmt Stationo Interface to SNMP
Agent process is software on the Mgmt Agento Collects info
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NMS Overview NMS includes all management apps Agent processes run on any device
o PC, server, hub, switch, router, etc.o Agent collects info at request of mgmt
stationo The database of information is a
Management Information Base (MIB) Mgmt application queries agent’s MIB
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Network Mgmt Example To get value of MIB variable from mgmt
agent1. Mgmt app (part of NMS) on mgmt station passes
request to mgmt process2. Mgmt process calls network mgmt protocol
(SNMP)3. SNMP constructs Get-Request packet4. Mgmt agent receives Get-Request5. Agent process accesses requested value6. SNMP constructs Get-Response packet7. Mgmt process on mgmt station receives response8. Mgmt process passes data to mgmt application
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Network Mgmt Overhead There is overhead in terms of
o CPU cycles to generate and process information/packets May require dedicated Management
Station
o Bandwidth usage for sending request and receiving responses
A tradeoff between cost and benefit
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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
o These are known as trapso For example, if a device goes down
Can request info from device or probeo Probe is a remote monitor (RMON)
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Additional Mgmt Capabilities
RMON might monitor a network segmento Source/destination addresseso Protocols usedo Usage statistics, etc.
Management station accesses RMON infoo Using steps 1 thru 8, aboveo May also routinely poll RMON
Chapter 2 Overview of Network Management 15
Network Mgmt History In 1977 International Organization for
Standards (ISO) began work on Open Systems Interconnection (OSI) reference modelo 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!)
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Network Mgmt History In March 1987, effort to develop Simple
Gateway Monitoring Protocol (SGMP)o SGMP out by November 1987o Could “get” and “set” variable values
About same time Common Mgmt Information Protocol (CMIP) developed for OSI modelo CMIP is roughly SMNP for the OSI model
Effort to develop CMIP Over TCP (CMOT) as alternative to SGMP
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Network Mgmt History CMIP uses Remote Operations Services
Elements (ROSE)o 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 developo SNMP: “keep it simple”, and it’s good enougho So SNMP won out in practice
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Network Mgmt History Due to controversy/delays in OSI
approach, Internet Activities Board (IAB) held meeting in 1988o Decided to pursue both CMOT and
SGMPo Eventually abandoned CMOT
(complexity) Eventually, three RFCs resulted…
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Network Mgmt History The three RFCs
o Structure of Management Information (SMI), uses Abstract Syntax Notation One (ASN.1)
o Management Information Base (MIB), the data structure on the mgmt agent
o Simple Network Management Protocol (SNMP)
By 1989, SNMP was the de facto standard for management of TCP/IP networks
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Network Managemen
t History
1964
1968
1972
1976
1980
1984
1988
1992
1996
2000
2004
Packet Switching(ARPA)
TCP/IP
Ethernet
OSI
Reference
Model
Development
SGMP
SGMP & CMIP SNMPv1SMI MIB1
MIB 2
RMON 1SNMPv2SNMPv2 MIB
RMON 2
SNMPv3
DMI
WebBasedMgmt
CMOT
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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
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Chapter 2 Summary Overview of network management Responsibilities of network manager Need for remote monitoring Terminology Basic principles Simple example History
