revised spring 2006 chap 1 - large enterprise networks 1 large enterprise networks chapter 1 network...

Revised Spring 2006Revised Spring 2006 Chap 1 - Large Enterprise NetworChap 1 - Large Enterprise Networksks

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Large Enterprise Networks Large Enterprise Networks Chapter 1Chapter 1

Network Management, MIBs, and MPLSNetwork Management, MIBs, and MPLS

Stephen B. MorrisStephen B. MorrisStudent: Paul L. Martin III “Tre”Student: Paul L. Martin III “Tre”


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OverviewOverview

Chapter 1 presents a general overview of modern Chapter 1 presents a general overview of modern enterprise network managemententerprise network management Importance of Network ManagementImportance of Network Management Introduction to Network Management PyramidIntroduction to Network Management Pyramid Goals of Network Management Systems (NMSs)Goals of Network Management Systems (NMSs) Understanding Simple Network Management Protocol Understanding Simple Network Management Protocol

(SNMP)(SNMP)


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Large Enterprise NetworksLarge Enterprise Networks

What is a Business ENTERPRISE? A business enterprise is a collection of

organizations and people formed to create and deliver products to customers

What is an NETWORK? A group of stations (computers, telephones,

or other devices) connected by communications facilities for exchanging information. Connection can be permanent, via cable, or temporary, through telephone or other communications links. The transmission medium can be physical (ie fiber optic cable) or wireless (e.g. satellite).


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Enterprise Networks: DefinedEnterprise Networks: Defined

Two Main CategoriesTwo Main Categories Enterprise NetworkEnterprise Network

A networking system that allows communication and A networking system that allows communication and resource sharing among all of a company's business resource sharing among all of a company's business functions and workers. This can even include the functions and workers. This can even include the company's suppliers and distributors.company's suppliers and distributors.33

Service ProviderService Provider SP’sSP’s generate contractually repeating revenues for the generate contractually repeating revenues for the

services delivered to their customers over a network, services delivered to their customers over a network, typically the Internet. These services must be typically the Internet. These services must be commercially available to the general population. The commercially available to the general population. The price for such services must include the actual delivery price for such services must include the actual delivery of the service including accommodations for the cost of the service including accommodations for the cost of the infrastructure to deliver the service (e.g. of the infrastructure to deliver the service (e.g. hardware, software, data center, labor, IP).hardware, software, data center, labor, IP).44


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Main Goals of the Enterprise Main Goals of the Enterprise NetworkNetwork

Two Main Focus AreasTwo Main Focus Areas Provide or improve business processes Save the organization money rather than act as a

revenue source


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Enterprise Network CharacteristicsEnterprise Network Characteristics

LargeLarge in Size (Equipment & in Size (Equipment & Personnel)Personnel)

Can be Can be Geographically SeparatedGeographically Separated Can maintain Can maintain Legacy EquipmentLegacy Equipment Generally Generally Hard to ManageHard to Manage Network ScalabilityNetwork Scalability affects affects

Network Manageability & Network Manageability & Network UsabilityNetwork Usability

Generally Generally owned by one owned by one organizationorganization


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Enterprise Network Characteristics Enterprise Network Characteristics (Con’t)(Con’t)

Many usersMany users simultaneously supported simultaneously supported Wide Range of Wide Range of Multi-vendor devicesMulti-vendor devices Network Elements can contain other Network Elements can contain other

intelligent devicesintelligent devices Individual N.Es can provide Individual N.Es can provide multiple multiple

servicesservices Specialized Servers provide Specialized Servers provide advanced advanced

servicesservices (I.e., SAN servers) (I.e., SAN servers) All network services are used as All network services are used as

essential business process essential business process componentscomponents by organizational by organizational personnelpersonnel


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Enterprise Network Enterprise Network Functional ComponentsFunctional Components

Network Management Challenges include: Complex apps & services Ever-changing apps &

services Geographically-dispersed

locationsand Personnel

All Bold text boxes provide some type of service


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Enterprise Networks: AdvantagesEnterprise Networks: Advantages

Centralized computing facilitates data sharing Centralized computing facilitates data sharing Centralized computing facilitates data backupsCentralized computing facilitates data backups Centralized management of software & Centralized management of software &

resourcesresources Network Authentication/Authorization can be Network Authentication/Authorization can be

enforcedenforced Network Administrators can perform remote Network Administrators can perform remote

software installationssoftware installations Expensive devices (laser printers, scanners, Expensive devices (laser printers, scanners,

etc.,) can be sharedetc.,) can be shared Users can access their files from any Users can access their files from any

workstationworkstation


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Enterprise Networks: Enterprise Networks: DisadvantagesDisadvantages

Expensive to build, operate, maintain, Expensive to build, operate, maintain, and upgradeand upgrade

Require skilled maintenance & support Require skilled maintenance & support personnelpersonnel

Data & Voice traffic traditionally kept Data & Voice traffic traditionally kept separate – now mergingseparate – now merging


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What is Network Management?What is Network Management?

A set of activities (e.g. network monitoring, A set of activities (e.g. network monitoring, gathering and analyzing the statistics, adjusting gathering and analyzing the statistics, adjusting network configuration) performed in order to network configuration) performed in order to increase the network performance and availabilityincrease the network performance and availability55

The process and techniques of remotely or locally The process and techniques of remotely or locally monitoring and configuring networks. Under the monitoring and configuring networks. Under the OSI model network management takes account of OSI model network management takes account of five key areas: configuration management, fault five key areas: configuration management, fault management, performance management, management, performance management, accounting management, and security accounting management, and security managementmanagement6 6 ((FCAPSFCAPS))

http://www.answers.com/topic/fcaps


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What is Network Management?What is Network Management? Network management provides the means to Network management provides the means to

keep network up and running in as orderly a keep network up and running in as orderly a fashion as possible. fashion as possible. Functional areas required for effective network Functional areas required for effective network

management include: FCAPSmanagement include: FCAPS FaultFault – Detecting network errors/break – Detecting network errors/break

downsdowns ConfigurationConfiguration – The set up and fine tuning – The set up and fine tuning

of s/w & h/w into an existing infrastructureof s/w & h/w into an existing infrastructure AccountingAccounting – Financial responsibilities such – Financial responsibilities such

as paying SPs, verifying chargesas paying SPs, verifying charges PerformancePerformance – Ensuring the network is – Ensuring the network is

operating to standards/expectations; operating to standards/expectations; Evaluate current and future performance Evaluate current and future performance

metricsmetrics SecuritySecurity – Protect network vs. hackers, or – Protect network vs. hackers, or

malicious activitymalicious activity

Figure: Taken from the Telecommunications Management Network architecture definition created by the International TelecommunicationsUnion in 1988. Source: http://www.luteus.biz/Download/LoriotPro_Doc/V4/LoriotProV4Doc/N14Management_Goals/FCAPS_EN.htm#FaultManagement


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BML - Business Management LayerBML - Business Management Layer Manage the overall business, gaining Manage the overall business, gaining

return on investment, market share, return on investment, market share, employee satisfaction, community and employee satisfaction, community and governmental goal.governmental goal.

SML - Service Management LayerSML - Service Management Layer Manage the service offered to customer or Manage the service offered to customer or

internal users, meeting customer service internal users, meeting customer service level, service quality, cost and time-to-level, service quality, cost and time-to-market objectivesmarket objectives

NML - Network Management LayerNML - Network Management Layer Manage the network and systems that Manage the network and systems that

deliver those services, capacity, diversity, deliver those services, capacity, diversity, and congestionand congestion


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EML - Element Management LayerEML - Element Management Layer Mange the elements comprising the Mange the elements comprising the

networks and systemsnetworks and systems NEL - Network Element LayerNEL - Network Element Layer

Switches, routers, transmission, Switches, routers, transmission, distribution systemsdistribution systems


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The Management System PyramidThe Management System Pyramid

OSS – Operations Support SystemOSS – Operations Support System System that handles workflows, managementSystem that handles workflows, management

inventory details, capacity planning,inventory details, capacity planning,and repair functions for SPsand repair functions for SPs

OSS used by the business support systemOSS used by the business support system OSS uses underlying NMS to communicateOSS uses underlying NMS to communicate

with lower level deviceswith lower level devices Expensive to deploy and developExpensive to deploy and develop Approx. Cost: $1M+Approx. Cost: $1M+ Example: AceComm is an OSS vendorExample: AceComm is an OSS vendor


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NMS – Network Management SystemNMS – Network Management System Computer based SW application suite thatComputer based SW application suite that

manages N.Esmanages N.Es Provides abstractions (signaling links, Provides abstractions (signaling links,

virtual connections, etc), fault & networkvirtual connections, etc), fault & networkconfiguration, retrieve performance & configuration, retrieve performance & billing data, execute provisioning,billing data, execute provisioning,security, script management, audit trailssecurity, script management, audit trails

Network-wide oversight & usageNetwork-wide oversight & usage Oversight over many N.Es (not just one)Oversight over many N.Es (not just one)

Uses EMS to communicate with N.EsUses EMS to communicate with N.Es Approx. Cost: $10K+Approx. Cost: $10K+ Example: Altiris can be used as an NMSExample: Altiris can be used as an NMS


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EMS – Element Management SystemsEMS – Element Management Systems Manages one or more of a specific type of NEs Manages one or more of a specific type of NEs EMS allows the user to manage all the features EMS allows the user to manage all the features

of each NE individuallyof each NE individually Specific functions include:Specific functions include:

S/W upload/downloadS/W upload/download Configuration DB backup/restoreConfiguration DB backup/restore Alarm processing & storageAlarm processing & storage

Approx. Cost: $1K+Approx. Cost: $1K+


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Key Difference (NMS vs EMS)Key Difference (NMS vs EMS)

Easy to confuse NMS and EMS roles/functionsEasy to confuse NMS and EMS roles/functions Key general difference is:Key general difference is:

NMS operations involve more than one NE NMS operations involve more than one NE simultaneouslysimultaneously

EMS operations focus on a single NEEMS operations focus on a single NE The guiding principle is the same for any The guiding principle is the same for any

OSS/NMS/EMS:OSS/NMS/EMS: Make using the object of attention easier to useMake using the object of attention easier to use


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Why is Network Management Why is Network Management Important?Important?

Maintains Network Availability Maintains Network Availability Network keeps runningNetwork keeps running Law of Five NinesLaw of Five Nines: The definition of : The definition of

system uptime or availability as 99.999%, system uptime or availability as 99.999%, or an approx. downtime of 5 min/yror an approx. downtime of 5 min/yr

Good Network Management facilities Good Network Management facilities assist in all the lifecycle stagesassist in all the lifecycle stages

Overall Operational Costs are reducedOverall Operational Costs are reduced Manage multiple incompatible management systemsManage multiple incompatible management systems

SNMPv3 uses MIBs for network management of data objectsSNMPv3 uses MIBs for network management of data objects

http://www.techonline.com/community/ed_resource/feature_article/14206


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Why Use Network Management?Why Use Network Management?

Comprehensive Network OversightComprehensive Network Oversight Management systems maintain entire Management systems maintain entire

network oversight - N.Es typically do notnetwork oversight - N.Es typically do not Record & Audit Trail LoggingRecord & Audit Trail Logging

An NMS maintains useful records &An NMS maintains useful records &audit trails of past configuration actionsaudit trails of past configuration actions

Unsupported Management ProtocolsUnsupported Management Protocols If N.Es don’t support SNMP, If N.Es don’t support SNMP,

then a NMS can facilitate a superior CLIthen a NMS can facilitate a superior CLI Network-wide service implementationNetwork-wide service implementation

NMS can facilitate network wide service like NMS can facilitate network wide service like (I.e., traffic engineering, QoS, planning, modeling, & (I.e., traffic engineering, QoS, planning, modeling, & backup/restore)backup/restore)


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Why Use Network Management?Why Use Network Management?

Fast Fault RectificationFast Fault Rectification NMS enable fast access to faults. NMS enable fast access to faults. Some network faults can only be handled Some network faults can only be handled

by an NMSby an NMS Rebalancing FacilitationRebalancing Facilitation

NMS assist in rebalancing networks NMS assist in rebalancing networks after new hardware is addedafter new hardware is added

Network-wide Object SupportNetwork-wide Object Support Management system can provide Management system can provide

network wide object support for service profilenetwork wide object support for service profile


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Common Network Management Common Network Management ChallengesChallenges

Backward CompatibilityBackward Compatibility Rare to experience “forklift”Rare to experience “forklift”

upgradesupgrades General expectation: rich General expectation: rich

mixture of old & new N.Esmixture of old & new N.Es Result: Complex set of Result: Complex set of

MIBs deployed across MIBs deployed across networknetwork

Multiplicity of Management Multiplicity of Management SystemsSystems

Lack of Standards-based Lack of Standards-based management system management system consolidationconsolidation

OlderN.Es


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Advantages of Standards-Based Advantages of Standards-Based ConsolidationConsolidation

Fewer & simpler user Fewer & simpler user management interfaces management interfaces

Reduced IT staff training Reduced IT staff training timetime

Fast fault identification & Fast fault identification & problem resolutionproblem resolution

Easier integration of new Easier integration of new hardware/software to hardware/software to overall infrastructureoverall infrastructure

Management system can Management system can provide network wide object provide network wide object support for service profile support for service profile (lessons learned; case (lessons learned; case studies for future reference)studies for future reference)


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The Manageability FactorThe Manageability Factor For the number of reasons, not all NEs lend themselves For the number of reasons, not all NEs lend themselves

to flexible, integrated, centralized management. to flexible, integrated, centralized management. This tends to add to the cost of ownership due to the following This tends to add to the cost of ownership due to the following

range of reasons:range of reasons: The NE is a legacy device with proprietary management The NE is a legacy device with proprietary management

infrastructure infrastructure The NE implements only SNMPv1 with support for set operationsThe NE implements only SNMPv1 with support for set operations The NE implements only SNMPv1 without support for set (a set The NE implements only SNMPv1 without support for set (a set

operations is an update to a network-resident manage object operations is an update to a network-resident manage object operations)operations)

The NE supports SNMPv3, but it has been poorly implementedThe NE supports SNMPv3, but it has been poorly implemented The NE supports SNMP3 but has a number of low quality MIB The NE supports SNMP3 but has a number of low quality MIB

modulesmodules An NE is considered to have good manageability if it supports a An NE is considered to have good manageability if it supports a

well implemented SNMPv3 agent and a high-quality MIBwell implemented SNMPv3 agent and a high-quality MIB


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Operating & Managing Large Operating & Managing Large NetworksNetworks

Important Aspects of Network Management include:Important Aspects of Network Management include: Traffic-Management as # of services/apps increaseTraffic-Management as # of services/apps increase

Measuring traffic levels and checking for network congestionMeasuring traffic levels and checking for network congestion Bandwidth Management Bandwidth Management Network & N.Es AvailabilityNetwork & N.Es Availability Network & N.E Status Monitoring Network & N.E Status Monitoring Discovery and Asset Inventory managementDiscovery and Asset Inventory management Network Configuration – Network Configuration –

VLAN setup, SAN volume setup,storage VLAN setup, SAN volume setup,storage allocations, remote control softwareallocations, remote control software

Service level agreement (SLA) reporting, SLA verification Service level agreement (SLA) reporting, SLA verification between an enterprise and SPbetween an enterprise and SP

Security controlSecurity control Resistance to attacks from both sides of the firewallResistance to attacks from both sides of the firewall

Scalability – Scalability – handling increased numbers of users, traffic, NEs,handling increased numbers of users, traffic, NEs,

Disaster recoveryDisaster recovery


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SNMPSNMP

Layer 2, 3, and 2.5Layer 2, 3, and 2.5Ports and InterfacesPorts and Interfaces


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Understanding OSI Layer 2 & 3 Understanding OSI Layer 2 & 3

To understand Network Management, one must To understand Network Management, one must have a thorough comprehension of OSI Layer 2 have a thorough comprehension of OSI Layer 2 and Layer 3and Layer 3 Layer 2 – Data Link LayerLayer 2 – Data Link Layer

Defines rules for sending/receiving data across a physical Defines rules for sending/receiving data across a physical connectionconnection

Examples: ATM, Frame Relay, Ethernet SwitchExamples: ATM, Frame Relay, Ethernet Switch

Layer 3 – Network LayerLayer 3 – Network Layer Ensures packets of information reach destination across Ensures packets of information reach destination across

multiple point-to-point linksmultiple point-to-point links Interconnected networks joined by routersInterconnected networks joined by routers

Example Device: IP RouterExample Device: IP Router


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Layers 2, 3, and 2.5Layers 2, 3, and 2.5

Layer 2 – Data Link Layer 2 – Data Link LayerLayer

Layer 3 – Network LayerLayer 3 – Network Layer Layer 2.5Layer 2.5 has been has been

used to categorize used to categorize some protocols that some protocols that operate between layer operate between layer 2 and layer 3. 2 and layer 3.


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Layer 2, 3, and 2.5Layer 2, 3, and 2.5

The primary protocols that SNMP implements: User Datagram Protocol (UDP) and the Internet Protocol (IP)

SNMP also requires Data Link Layer protocols (e.g. Ethernet, Token Ring) to implement the communication channel between manager and agent Data Link Layer

Provides the means to transfer data between network entities and to detect and possibly correct errors that may occur in the Physical layer.

The addressing scheme is physical which means that the addresses (MAC address) are hard-coded into the network cards at the time of manufacture


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MPLS on Layer 2.5MPLS on Layer 2.5

Multiprotocol Label SwitchingMultiprotocol Label Switching A method used to increase the speed of network traffic A method used to increase the speed of network traffic

flow by inserting information about a specific path the flow by inserting information about a specific path the packet is taking en route to its destination. packet is taking en route to its destination.

Saves the time needed for a router to look up the address for Saves the time needed for a router to look up the address for the next receiving nodethe next receiving node

MPLS is multiprotocol in that it works with IP, ATM, and Frame MPLS is multiprotocol in that it works with IP, ATM, and Frame Relay communications methods Relay communications methods

MPLS has some Quality of Service features that make it an MPLS has some Quality of Service features that make it an attractive communications technique.attractive communications technique.

Supplemental Link: Click hereSupplemental Link: Click here


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How MPLS WorksHow MPLS Works

Click here for full article


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MPLS Advantages/DisadvantagesMPLS Advantages/Disadvantages

AdvantagesAdvantages Can be deployed on routersCan be deployed on routers Paths can be reserved before traffic arrives at the networkPaths can be reserved before traffic arrives at the network Different QoS options can be appliedDifferent QoS options can be applied

Ex: Higher QoS can be reserved for VoIP; lower for e-mailEx: Higher QoS can be reserved for VoIP; lower for e-mail Traditional IP routing protocols can be usedTraditional IP routing protocols can be used

Ex: OSPF, IS-IS, BGP4Ex: OSPF, IS-IS, BGP4 Congested route problems can be reduced through Congested route problems can be reduced through

dynamic traffic monitoring and engineeringdynamic traffic monitoring and engineering DisadvantageDisadvantage

All nodes in the path must run MPLS protocols – additional All nodes in the path must run MPLS protocols – additional burdenburden


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Ports and InterfacesPorts and Interfaces

Terms “Ports” and “Interfaces” often used interchangeably, which is not necessarily the case Ports – underlying hardware entities

Example: ATM or Ethernet ports Interfaces – Exist at a higher abstraction layer

Configured to run on top of ports Referred to as “logical ports” Interface examples include:

Routing such as OSPF, IS-IS, BGB-4 Signaling, such as RSVP-TE and LDP MPLS IP

General Difference: Ports work out of the box, interfaces must be configured


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SNMPSNMP

Simple Network Management ProtocolSimple Network Management Protocol

Providing Network Management CapabilityProviding Network Management Capability


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The Goal of a NMSThe Goal of a NMS

The difference between the The difference between the real-time network situation real-time network situation and the NMS picture of the and the NMS picture of the network situation must be as network situation must be as small as possiblesmall as possible Administrators constantly strive Administrators constantly strive

to know and/or be able to to know and/or be able to quickly find out what is going on quickly find out what is going on with their networkwith their network

The purpose of NMSs and SNMP:The purpose of NMSs and SNMP: Help administrators stay on top Help administrators stay on top

of network operations, events, of network operations, events, and faultsand faults


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What is SNMP?What is SNMP?

A A protocolprotocol used by network hosts to: used by network hosts to: Exchange information, Exchange information, Monitor and control network devices, and to Monitor and control network devices, and to Manage configurations, statistics collection, Manage configurations, statistics collection,

performance, and security used in the management of performance, and security used in the management of networks.networks.

SNMP network management is based on the SNMP network management is based on the client and server modelclient and server model

Used almost exclusively in TCP/IP networks, but Used almost exclusively in TCP/IP networks, but not limited to themnot limited to them

SNMP facilitates communication between network SNMP facilitates communication between network devices devices


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What is SNMP?What is SNMP?

An SNMP-Managed Network Consists of Managed Devices, Agents, and NMSs


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What does SNMP do?What does SNMP do?

Notify network administrators about network Notify network administrators about network status through “network notifications”status through “network notifications” Events

An indication from the network to the NMS of some item of interest

EX: User logging onto a NE via Command Line Interface (CLI)

Faults An indication of a service-affecting network problem

EX: Communication line link failure Alarms

An indication that a potentially service-affecting problem is about to occur

EX: Congestion threshold being exceeded


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Main SNMP ComponentsMain SNMP Components Principal Components of SNMP are:Principal Components of SNMP are:

1. Manager1. Manager An application that performs the operational roles of An application that performs the operational roles of

generating requests to modify and retrieve management generating requests to modify and retrieve management information, and receiving the requested information and information, and receiving the requested information and trap-event reports that are generated by the SNMP agenttrap-event reports that are generated by the SNMP agent

2. Agent2. Agent An application that performs the operational role of An application that performs the operational role of

receiving and processing requests, sending responses to receiving and processing requests, sending responses to the manager, and sending traps when an event occursthe manager, and sending traps when an event occurs


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Main SNMP ComponentsMain SNMP Components Four Principal Components of SNMP are: Four Principal Components of SNMP are:

3. Management Information Base (MIB)3. Management Information Base (MIB) The set of parameters (database) that an SNMP The set of parameters (database) that an SNMP

management station can query or set in the SNMP agent of management station can query or set in the SNMP agent of a networked device (e.g, router).a networked device (e.g, router).

The unique identifier of each managed object includes the The unique identifier of each managed object includes the type (such as counter, string, gauge, or address), access type (such as counter, string, gauge, or address), access level (such as read/write), size restrictions, and range level (such as read/write), size restrictions, and range information of the object.information of the object.

4. Protocol Data Units (PDUs)4. Protocol Data Units (PDUs) A data object exchanged by protocol machines (e.g. SNMP A data object exchanged by protocol machines (e.g. SNMP

agents) & consisting of both protocol control information agents) & consisting of both protocol control information and user dataand user data


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SNMP Manager Role (Explained)SNMP Manager Role (Explained)

SNMP managers are the entities that interact with the agent Establishing & obtaining

the values of MBI objects instances on agent

Receiving notifications from agents

Exchanging messages with other managers


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SNMP Manager Role (Explained)SNMP Manager Role (Explained)

Facilities offered by management systems are: FCAP A centralized database Reporting Capabilities Support for many simultaneous client users Topology discovery Full featured, multi-level Graphical User Interface (GUI)

representing the managed network

Click here to see Fujitsu’s NETSMART 500Network Element Manager

http://www.fujitsu.com/us/services/telecom/netsmart-1500.html


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SNMP Agent Role (Explained)SNMP Agent Role (Explained)

SNMP agent are the entities that reside on manage devices. Agent are the workhorses of

management & provide the following functionality

Implementing and maintaining MIB objects

Responding to management operations such as requests

Generating trap & inform notifications Security Implementation Set Access Policy for External

Managers


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SNMP Agent Role (Explained)SNMP Agent Role (Explained)

The SNMP agent listens on UDP port 161


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SNMP MIBs (Explained)SNMP MIBs (Explained)

Each management station or agent in an SNMP-Each management station or agent in an SNMP-managed network maintains a local database of managed network maintains a local database of information relevant to network management, information relevant to network management, known as the management information base known as the management information base (MIB)(MIB) An SNMP-compliant MIB An SNMP-compliant MIB

Contains definitions and information about the properties Contains definitions and information about the properties of managed resources and the services that the agents of managed resources and the services that the agents support.support.

Managed objects/Management variablesManaged objects/Management variables The manageable features of resourcesThe manageable features of resources

A management station gets and sets objects in the A management station gets and sets objects in the MIB, and an agent notifies the management station of MIB, and an agent notifies the management station of significant but unsolicited events called significant but unsolicited events called trapstraps


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SNMP MIBs (Explained)SNMP MIBs (Explained)

MIBsMIBs The most crucial/important NMS componentThe most crucial/important NMS component MIBs contain data definitions for managed objectsMIBs contain data definitions for managed objects SNMP managers & agents exchange object instances SNMP managers & agents exchange object instances

using SNMP protocolusing SNMP protocol Are Plain-text filesAre Plain-text files MIBs are compiled into agent source code -> executable MIBs are compiled into agent source code -> executable

filefile Textual ConventionsTextual Conventions

MIB refinements (similar to programming language data MIB refinements (similar to programming language data types or classes in Java or C++)types or classes in Java or C++)


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SNMP MIB (Explained)SNMP MIB (Explained)

The following keywords are used to define a MIB The following keywords are used to define a MIB object:object: Syntax Syntax

Defines the abstract data structure corresponding to the Defines the abstract data structure corresponding to the object typeobject type

Access Access Defines whether the object value may only be retrieved but Defines whether the object value may only be retrieved but

not modified (read-only) or whether it may also be modified not modified (read-only) or whether it may also be modified (read-write)(read-write)

Description Description Contains a textual definition of the object type. The definition Contains a textual definition of the object type. The definition

provides all semantic definitions necessary for interpretation; provides all semantic definitions necessary for interpretation; it typically contains information of the sort that would be it typically contains information of the sort that would be communicated in any ASN.1 commentary annotations communicated in any ASN.1 commentary annotations associated with the objectassociated with the object


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SNMP MIB (Explained)SNMP MIB (Explained)

Object Identifer (OID) – used Object Identifer (OID) – used by the management station by the management station to request the object's to request the object's value from the agentvalue from the agent OID - a sequence of integers OID - a sequence of integers

that uniquely identifies a that uniquely identifies a managed object by defining a managed object by defining a path to that object through a path to that object through a tree-like structure called thetree-like structure called the OID treeOID tree or registration tree or registration tree

When an SNMP agent needs to When an SNMP agent needs to access a specific managed access a specific managed object, it traverses the OID object, it traverses the OID tree to find the object. tree to find the object.

Lexicographic Ordering


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SNMP MIB & Lexicographic SNMP MIB & Lexicographic OrderingOrdering

The OID serves as a uniquename that represents a nodein the tree-based structure

All objects can be traced fromthe root in a process called“walking the MIB.”

During a walk, each branch of the MIB is traversed from leftto right, starting at the root


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SNMP PDUs (Explained)SNMP PDUs (Explained)

SNMP uses “very simple messaging protocol” Three basic commands

Fetch (GET) Store (SET) Notification/Inform Message

Each SNMP message has the format Version Number Community Name - kind of a password One or more SNMP PDUs - assuming trivial

authentication


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SNMP PDUs (Explained)SNMP PDUs (Explained)

SNMPv1 originally defined six PDUs These PDUs have been redefined over the years

The current SNMP Framework categorizes the PDUs into different classes.


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SNMP “Get” PDUSNMP “Get” PDU


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SNMP “Get-Next” PDUSNMP “Get-Next” PDU


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SNMP “Set” ProtocolSNMP “Set” Protocol


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SNMP “Trap” PDUSNMP “Trap” PDU


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SNMPv1SNMPv1

SNMPv1 is probably best known for its relative simplicitySNMPv1 is probably best known for its relative simplicity Much more complicated than following versionsMuch more complicated than following versions

SNMPv1 message format is simple & straight-forwardSNMPv1 message format is simple & straight-forward


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SNMPv2SNMPv2

Certain issues with SNMPv1 were noticed & areas Certain issues with SNMPv1 were noticed & areas for improvement identifiedfor improvement identified MIB object definitions MIB object definitions Protocol operationsProtocol operations securitysecurity

Several versions of SNMPv2 & several message formats Several versions of SNMPv2 & several message formats PDUPDU format is the same for all the SNMPv2 types, format is the same for all the SNMPv2 types, The overall The overall messagemessage format differs for each variant. format differs for each variant.

Click here to see SNMPv2 Message Format


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SNMPv3SNMPv3 Created in the late 1990s Created in the late 1990s SNMP version 3 resolved the problems that occurred SNMP version 3 resolved the problems that occurred

with the many different variations of SNMPv2 with the many different variations of SNMPv2 Adopts many components created in SNMPv2 Adopts many components created in SNMPv2

including:including: SNMPv2 protocol operations, SNMPv2 protocol operations, PDU types and PDU types and PDU format. PDU format.

Significant changes made in SNMPv3 include Significant changes made in SNMPv3 include more flexible way of defining security methods and more flexible way of defining security methods and

parameters – allowing the coexistence of multiple security parameters – allowing the coexistence of multiple security techniquestechniques

Click here to see SNMPv3 Message Format


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SNMP Management Systems & SNMP Management Systems & AgentsAgents

SNMP managerSNMP manager

Any computer that sends queries Any computer that sends queries for IP-related information to a for IP-related information to a managed computer managed computer

SNMP manager can send a request SNMP manager can send a request to an SNMP agent to change a to an SNMP agent to change a configuration value configuration value

SNMP agentSNMP agent Any computer or other network Any computer or other network

device that monitors and responds device that monitors and responds to queries from SNMP managersto queries from SNMP managers

Can send a trap message to the Can send a trap message to the manager when specified events manager when specified events (I.e., system reboots, illegal access (I.e., system reboots, illegal access notification)notification)


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SNMP Manager/Agent SNMP Manager/Agent CommunicationCommunication


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Chapter 1 SummaryChapter 1 Summary

Large Enterprise Networks require good enterprise management from both people/administrators and systematic/technical components

The goals of enterprise networks: Make organizational personnel more productive Save the organization money (not act as a revenue

producer) The goal of network management:

Maintain network availability “You can’t achieve the goals of enterprise networks if you

can’t use them.”


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Chapter 1 SummaryChapter 1 Summary

The Simple Network Management Protocol has become the de facto standard for internetwork management It is a simple solution, Requires little code to implement, Vendors can easily build SNMP agents to their products SNMP is extensible - allowing vendors to easily add network

management functions to their existing products SNMP separates the management architecture from the architecture of

the hardware devices, which Broadens the base of multi-vendor support


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Supplemental MaterialsSupplemental Materials

General Network Management General Network Management Article: “Network Management as Core Competency” Article: “Network Management as Core Competency”

Computerworld, 20 March 2006Computerworld, 20 March 2006 Article: “Cisco Moves to Support Network Management” Article: “Cisco Moves to Support Network Management”

Computerworld, 12 December 2005Computerworld, 12 December 2005 MPLSMPLS

Article: “Building Large Metro Ethernets requires MPLS”Article: “Building Large Metro Ethernets requires MPLS”Converge! Network Digest, 24 October 2004Converge! Network Digest, 24 October 2004

SNMPSNMP Article: “Is it time to re-engineer SNMP”Article: “Is it time to re-engineer SNMP”

Networkworld, 22 March 2004Networkworld, 22 March 2004

revised spring 2006 chap 1 - large enterprise networks 1 large enterprise networks chapter 1 network...

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