1. Revised Spring 2006 Chap 1 - Large Enterprise Networks 1 Large Enterprise Networks Chapter 1 Network Management, MIBs, and MPLS Stephen B. Morris Student: Paul L. Martin III “Tre”

2. Revised Spring 2006 Chap 1 - Large Enterprise Networks2 Overview Chapter 1 presents a general overview of modern enterprise network management Chapter 1 presents a general overview of modern enterprise network management Importance of Network Management Importance of Network Management Introduction to Network Management Pyramid Introduction to Network Management Pyramid Goals of Network Management Systems (NMSs) Goals of Network Management Systems (NMSs) Understanding Simple Network Management Protocol (SNMP) Understanding Simple Network Management Protocol (SNMP)

3. Revised Spring 2006 Chap 1 - Large Enterprise Networks3 Large 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).

4. Revised Spring 2006 Chap 1 - Large Enterprise Networks4 Enterprise Networks: Defined Two Main Categories Two Main Categories Enterprise Network Enterprise Network A networking system that allows communication and resource sharing among all of a company's business functions and workers. This can even include the company's suppliers and distributors. 3 A networking system that allows communication and resource sharing among all of a company's business functions and workers. This can even include the company's suppliers and distributors. 3 Service Provider Service Provider SP’s generate contractually repeating revenues for the services delivered to their customers over a network, typically the Internet. These services must be commercially available to the general population. The price for such services must include the actual delivery of the service including accommodations for the cost of the infrastructure to deliver the service (e.g. hardware, software, data center, labor, IP). 4 SP’s generate contractually repeating revenues for the services delivered to their customers over a network, typically the Internet. These services must be commercially available to the general population. The price for such services must include the actual delivery of the service including accommodations for the cost of the infrastructure to deliver the service (e.g. hardware, software, data center, labor, IP). 4

5. Revised Spring 2006 Chap 1 - Large Enterprise Networks5 Main Goals of the Enterprise Network Two Main Focus Areas Two Main Focus Areas Provide or improve business processes Save the organization money rather than act as a revenue source

6. Revised Spring 2006 Chap 1 - Large Enterprise Networks6 Enterprise Network Characteristics Large in Size (Equipment & Personnel) Large in Size (Equipment & Personnel) Can be Geographically Separated Can be Geographically Separated Can maintain Legacy Equipment Can maintain Legacy Equipment Generally Hard to Manage Generally Hard to Manage Network Scalability affects Network Manageability & Network Usability Network Scalability affects Network Manageability & Network Usability Generally owned by one organization Generally owned by one organization

7. Revised Spring 2006 Chap 1 - Large Enterprise Networks7 Enterprise Network Characteristics (Con’t) Many users simultaneously supported Many users simultaneously supported Wide Range of Multi-vendor devices Wide Range of Multi-vendor devices Network Elements can contain other intelligent devices Network Elements can contain other intelligent devices Individual N.Es can provide multiple services Individual N.Es can provide multiple services Specialized Servers provide advanced services (I.e., SAN servers) Specialized Servers provide advanced services (I.e., SAN servers) All network services are used as essential business process components by organizational personnel All network services are used as essential business process components by organizational personnel

8. Revised Spring 2006 Chap 1 - Large Enterprise Networks8 Enterprise Network Functional Components Network Management Challenges include: Complex apps & services Ever-changing apps & services Geographically-dispersed locations and Personnel All Bold text boxes provide some type of service

9. Revised Spring 2006 Chap 1 - Large Enterprise Networks9 Enterprise Networks: Advantages Centralized computing facilitates data sharing Centralized computing facilitates data sharing Centralized computing facilitates data backups Centralized computing facilitates data backups Centralized management of software & resources Centralized management of software & resources Network Authentication/Authorization can be enforced Network Authentication/Authorization can be enforced Network Administrators can perform remote software installations Network Administrators can perform remote software installations Expensive devices (laser printers, scanners, etc.,) can be shared Expensive devices (laser printers, scanners, etc.,) can be shared Users can access their files from any workstation Users can access their files from any workstation

10. Revised Spring 2006 Chap 1 - Large Enterprise Networks10 Enterprise Networks: Disadvantages Expensive to build, operate, maintain, and upgrade Expensive to build, operate, maintain, and upgrade Require skilled maintenance & support personnel Require skilled maintenance & support personnel Data & Voice traffic traditionally kept separate – now merging Data & Voice traffic traditionally kept separate – now merging

11. Revised Spring 2006 Chap 1 - Large Enterprise Networks11 What is Network Management? A set of activities (e.g. network monitoring, gathering and analyzing the statistics, adjusting network configuration) performed in order to increase the network performance and availability 5 A set of activities (e.g. network monitoring, gathering and analyzing the statistics, adjusting network configuration) performed in order to increase the network performance and availability 5 The process and techniques of remotely or locally monitoring and configuring networks. Under the OSI model network management takes account of five key areas: configuration management, fault management, performance management, accounting management, and security management 6 (FCAPS) The process and techniques of remotely or locally monitoring and configuring networks. Under the OSI model network management takes account of five key areas: configuration management, fault management, performance management, accounting management, and security management 6 (FCAPS)FCAPS

12. Revised Spring 2006 Chap 1 - Large Enterprise Networks12 What is Network Management? Network management provides the means to keep network up and running in as orderly a fashion as possible. Network management provides the means to keep network up and running in as orderly a fashion as possible. Functional areas required for effective network management include: FCAPS Functional areas required for effective network management include: FCAPS Fault – Detecting network errors/break downs Fault – Detecting network errors/break downs Configuration – The set up and fine tuning of s/w & h/w into an existing infrastructure Configuration – The set up and fine tuning of s/w & h/w into an existing infrastructure Accounting – Financial responsibilities such as paying SPs, verifying charges Accounting – Financial responsibilities such as paying SPs, verifying charges Performance – Ensuring the network is operating to standards/expectations; Performance – Ensuring the network is operating to standards/expectations; Evaluate current and future performance metrics Evaluate current and future performance metrics Security – Protect network vs. hackers, or malicious activity Security – Protect network vs. hackers, or malicious activity Figure: Taken from the Telecommunications Management Network architecture definition created by the International Telecommunications Union in 1988. Source: http://www.luteus.biz/ Download/LoriotPro_Doc/V4/LoriotProV4 Doc/N14Management_Goals/FCAPS_EN. htm#FaultManagement

13. Revised Spring 2006 Chap 1 - Large Enterprise Networks13 What is Network Management? BML - Business Management Layer BML - Business Management Layer Manage the overall business, gaining return on investment, market share, employee satisfaction, community and governmental goal. Manage the overall business, gaining return on investment, market share, employee satisfaction, community and governmental goal. SML - Service Management Layer SML - Service Management Layer Manage the service offered to customer or internal users, meeting customer service level, service quality, cost and time-to-market objectives Manage the service offered to customer or internal users, meeting customer service level, service quality, cost and time-to-market objectives NML - Network Management Layer NML - Network Management Layer Manage the network and systems that deliver those services, capacity, diversity, and congestion Manage the network and systems that deliver those services, capacity, diversity, and congestion

14. Revised Spring 2006 Chap 1 - Large Enterprise Networks14 What is Network Management? EML - Element Management Layer EML - Element Management Layer Mange the elements comprising the networks and systems Mange the elements comprising the networks and systems NEL - Network Element Layer NEL - Network Element Layer Switches, routers, transmission, distribution systems Switches, routers, transmission, distribution systems

15. Revised Spring 2006 Chap 1 - Large Enterprise Networks15 The Management System Pyramid OSS – Operations Support System OSS – Operations Support System System that handles workflows, management inventory details, capacity planning, and repair functions for SPs System that handles workflows, management inventory details, capacity planning, and repair functions for SPs OSS used by the business support system OSS used by the business support system OSS uses underlying NMS to communicate with lower level devices OSS uses underlying NMS to communicate with lower level devices Expensive to deploy and develop Expensive to deploy and develop Approx. Cost: $1M+ Approx. Cost: $1M+ Example: AceComm is an OSS vendor Example: AceComm is an OSS vendorAceComm is an OSS vendorAceComm is an OSS vendor

16. Revised Spring 2006 Chap 1 - Large Enterprise Networks16 The Management System Pyramid NMS – Network Management System NMS – Network Management System Computer based SW application suite that manages N.Es Computer based SW application suite that manages N.Es Provides abstractions (signaling links, virtual connections, etc), fault & network configuration, retrieve performance & billing data, execute provisioning, security, script management, audit trails Provides abstractions (signaling links, virtual connections, etc), fault & network configuration, retrieve performance & billing data, execute provisioning, security, script management, audit trails Network-wide oversight & usage Network-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.Es Uses EMS to communicate with N.Es Approx. Cost: $10K+ Approx. Cost: $10K+ Example: Altiris can be used as an NMS Example: Altiris can be used as an NMSAltiris can be used as an NMSAltiris can be used as an NMS

17. Revised Spring 2006 Chap 1 - Large Enterprise Networks17 The Management System Pyramid EMS – Element Management Systems EMS – 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 of each NE individually EMS allows the user to manage all the features of each NE individually Specific functions include: Specific functions include: S/W upload/download S/W upload/download Configuration DB backup/restore Configuration DB backup/restore Alarm processing & storage Alarm processing & storage Approx. Cost: $1K+ Approx. Cost: $1K+

18. Revised Spring 2006 Chap 1 - Large Enterprise Networks18 Key Difference (NMS vs EMS) Easy to confuse NMS and EMS roles/functions Easy to confuse NMS and EMS roles/functions Key general difference is: Key general difference is: NMS operations involve more than one NE simultaneously NMS operations involve more than one NE simultaneously EMS operations focus on a single NE EMS operations focus on a single NE The guiding principle is the same for any OSS/NMS/EMS: The guiding principle is the same for any OSS/NMS/EMS: Make using the object of attention easier to use Make using the object of attention easier to use

19. Revised Spring 2006 Chap 1 - Large Enterprise Networks19 Why is Network Management Important? Maintains Network Availability Maintains Network Availability Network keeps running Network keeps running Law of Five Nines: The definition of system uptime or availability as 99.999%, or an approx. downtime of 5 min/yr Law of Five Nines: The definition of system uptime or availability as 99.999%, or an approx. downtime of 5 min/yr Law of Five Nines Law of Five Nines Good Network Management facilities assist in all the lifecycle stages Good Network Management facilities assist in all the lifecycle stages Overall Operational Costs are reduced Overall Operational Costs are reduced Manage multiple incompatible management systems Manage multiple incompatible management systems SNMPv3 uses MIBs for network management of data objects SNMPv3 uses MIBs for network management of data objects

20. Revised Spring 2006 Chap 1 - Large Enterprise Networks20 Why Use Network Management? Comprehensive Network Oversight Comprehensive Network Oversight Management systems maintain entire network oversight - N.Es typically do not Management systems maintain entire network oversight - N.Es typically do not Record & Audit Trail Logging Record & Audit Trail Logging An NMS maintains useful records & audit trails of past configuration actions An NMS maintains useful records & audit trails of past configuration actions Unsupported Management Protocols Unsupported Management Protocols If N.Es don’t support SNMP, then a NMS can facilitate a superior CLI If N.Es don’t support SNMP, then a NMS can facilitate a superior CLI Network-wide service implementation Network-wide service implementation NMS can facilitate network wide service like (I.e., traffic engineering, QoS, planning, modeling, & backup/restore) NMS can facilitate network wide service like (I.e., traffic engineering, QoS, planning, modeling, & backup/restore)

21. Revised Spring 2006 Chap 1 - Large Enterprise Networks21 Why Use Network Management? Fast Fault Rectification Fast Fault Rectification NMS enable fast access to faults. NMS enable fast access to faults. Some network faults can only be handled by an NMS Some network faults can only be handled by an NMS Rebalancing Facilitation Rebalancing Facilitation NMS assist in rebalancing networks after new hardware is added NMS assist in rebalancing networks after new hardware is added Network-wide Object Support Network-wide Object Support Management system can provide network wide object support for service profile Management system can provide network wide object support for service profile

22. Revised Spring 2006 Chap 1 - Large Enterprise Networks22 Common Network Management Challenges Backward Compatibility Backward Compatibility Rare to experience “forklift” upgrades Rare to experience “forklift” upgrades General expectation: rich mixture of old & new N.Es General expectation: rich mixture of old & new N.Es Result: Complex set of MIBs deployed across network Result: Complex set of MIBs deployed across network Multiplicity of Management Systems Multiplicity of Management Systems Lack of Standards-based management system consolidation Lack of Standards-based management system consolidation Older N.Es

23. Revised Spring 2006 Chap 1 - Large Enterprise Networks23 Advantages of Standards-Based Consolidation Fewer & simpler user management interfaces Fewer & simpler user management interfaces Reduced IT staff training time Reduced IT staff training time Fast fault identification & problem resolution Fast fault identification & problem resolution Easier integration of new hardware/software to overall infrastructure Easier integration of new hardware/software to overall infrastructure Management system can provide network wide object support for service profile (lessons learned; case studies for future reference) Management system can provide network wide object support for service profile (lessons learned; case studies for future reference)

24. Revised Spring 2006 Chap 1 - Large Enterprise Networks24 The Manageability Factor For the number of reasons, not all NEs lend themselves to flexible, integrated, centralized management. For the number of reasons, not all NEs lend themselves to flexible, integrated, centralized management. This tends to add to the cost of ownership due to the following range of reasons: This tends to add to the cost of ownership due to the following range of reasons: The NE is a legacy device with proprietary management infrastructure The NE is a legacy device with proprietary management infrastructure The NE implements only SNMPv1 with support for set operations The NE implements only SNMPv1 with support for set operations The NE implements only SNMPv1 without support for set (a set operations is an update to a network-resident manage object operations) The NE implements only SNMPv1 without support for set (a set operations is an update to a network-resident manage object operations) The NE supports SNMPv3, but it has been poorly implemented The NE supports SNMPv3, but it has been poorly implemented The NE supports SNMP3 but has a number of low quality MIB modules The NE supports SNMP3 but has a number of low quality MIB modules An NE is considered to have good manageability if it supports a well implemented SNMPv3 agent and a high-quality MIB An NE is considered to have good manageability if it supports a well implemented SNMPv3 agent and a high-quality MIB

25. Revised Spring 2006 Chap 1 - Large Enterprise Networks25 Operating & Managing Large Networks Important Aspects of Network Management include: Important Aspects of Network Management include: Traffic-Management as # of services/apps increase Traffic-Management as # of services/apps increase Measuring traffic levels and checking for network congestion Measuring traffic levels and checking for network congestion Bandwidth Management Bandwidth Management Network & N.Es Availability Network & N.Es Availability Network & N.E Status Monitoring Network & N.E Status Monitoring Discovery and Asset Inventory management Discovery and Asset Inventory management Network Configuration – Network Configuration – VLAN setup, SAN volume setup,storage allocations, remote control software VLAN setup, SAN volume setup,storage allocations, remote control software Service level agreement (SLA) reporting, SLA verification between an enterprise and SP Service level agreement (SLA) reporting, SLA verification between an enterprise and SP Security control Security control Resistance to attacks from both sides of the firewall Resistance 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 recovery Disaster recovery

26. Revised Spring 2006 Chap 1 - Large Enterprise Networks 26 SNMP Layer 2, 3, and 2.5 Ports and Interfaces

27. Revised Spring 2006 Chap 1 - Large Enterprise Networks27 Understanding OSI Layer 2 & 3 To understand Network Management, one must have a thorough comprehension of OSI Layer 2 and Layer 3 To understand Network Management, one must have a thorough comprehension of OSI Layer 2 and Layer 3 Layer 2 – Data Link Layer Layer 2 – Data Link Layer Defines rules for sending/receiving data across a physical connection Defines rules for sending/receiving data across a physical connection Examples: ATM, Frame Relay, Ethernet Switch Examples: ATM, Frame Relay, Ethernet Switch Layer 3 – Network Layer Layer 3 – Network Layer Ensures packets of information reach destination across multiple point-to-point links Ensures packets of information reach destination across multiple point-to-point links Interconnected networks joined by routers Interconnected networks joined by routers Example Device: IP Router Example Device: IP Router

28. Revised Spring 2006 Chap 1 - Large Enterprise Networks28 Layers 2, 3, and 2.5 Layer 2 – Data Link Layer Layer 2 – Data Link Layer Layer 3 – Network Layer Layer 3 – Network Layer Layer 2.5 has been used to categorize some protocols that operate between layer 2 and layer 3. Layer 2.5 has been used to categorize some protocols that operate between layer 2 and layer 3.

29. Revised Spring 2006 Chap 1 - Large Enterprise Networks29 Layer 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 manufactureMAC address

30. Revised Spring 2006 Chap 1 - Large Enterprise Networks30 MPLS on Layer 2.5 Multiprotocol Label Switching Multiprotocol Label Switching Multiprotocol Label Switching Multiprotocol Label Switching A method used to increase the speed of network traffic flow by inserting information about a specific path the packet is taking en route to its destination. A method used to increase the speed of network traffic flow by inserting information about a specific path the packet is taking en route to its destination. Saves the time needed for a router to look up the address for the next receiving node Saves the time needed for a router to look up the address for the next receiving node MPLS is multiprotocol in that it works with IP, ATM, and Frame Relay communications methods MPLS is multiprotocol in that it works with IP, ATM, and Frame Relay communications methods MPLS has some Quality of Service features that make it an attractive communications technique. MPLS has some Quality of Service features that make it an attractive communications technique. Supplemental Link: Click here Supplemental Link: Click hereClick hereClick here

31. Revised Spring 2006 Chap 1 - Large Enterprise Networks31 How MPLS Works Click here for full article

32. Revised Spring 2006 Chap 1 - Large Enterprise Networks32 MPLS Advantages/Disadvantages Advantages Advantages Can be deployed on routers Can be deployed on routers Paths can be reserved before traffic arrives at the network Paths can be reserved before traffic arrives at the network Different QoS options can be applied Different QoS options can be applied Ex: Higher QoS can be reserved for VoIP; lower for e-mail Ex: Higher QoS can be reserved for VoIP; lower for e-mail Traditional IP routing protocols can be used Traditional IP routing protocols can be used Ex: OSPF, IS-IS, BGP4 Ex: OSPF, IS-IS, BGP4 Congested route problems can be reduced through dynamic traffic monitoring and engineering Congested route problems can be reduced through dynamic traffic monitoring and engineering Disadvantage Disadvantage All nodes in the path must run MPLS protocols – additional burden All nodes in the path must run MPLS protocols – additional burden

33. Revised Spring 2006 Chap 1 - Large Enterprise Networks33 Ports 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

34. Revised Spring 2006 Chap 1 - Large Enterprise Networks 34 SNMP Simple Network Management Protocol Providing Network Management Capability

35. Revised Spring 2006 Chap 1 - Large Enterprise Networks35 The Goal of a NMS The difference between the real- time network situation and the NMS picture of the network situation must be as small as possible The difference between the real- time network situation and the NMS picture of the network situation must be as small as possible Administrators constantly strive to know and/or be able to quickly find out what is going on with their network Administrators constantly strive to know and/or be able to quickly find out what is going on with their network The purpose of NMSs and SNMP: The purpose of NMSs and SNMP: Help administrators stay on top of network operations, events, and faults Help administrators stay on top of network operations, events, and faults

36. Revised Spring 2006 Chap 1 - Large Enterprise Networks36 What is SNMP? A protocol used by network hosts to: A protocol 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, performance, and security used in the management of networks. Manage configurations, statistics collection, performance, and security used in the management of networks. SNMP network management is based on the client and server model SNMP network management is based on the client and server model Used almost exclusively in TCP/IP networks, but not limited to them Used almost exclusively in TCP/IP networks, but not limited to them SNMP facilitates communication between network devices SNMP facilitates communication between network devices

37. Revised Spring 2006 Chap 1 - Large Enterprise Networks37 What is SNMP? An SNMP-Managed Network Consists of Managed Devices, Agents, and NMSs

38. Revised Spring 2006 Chap 1 - Large Enterprise Networks38 What does SNMP do? Notify network administrators about network status through “network notifications” Notify network administrators about network 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

39. Revised Spring 2006 Chap 1 - Large Enterprise Networks39 Main SNMP Components Principal Components of SNMP are: Principal Components of SNMP are: 1. Manager 1. Manager An application that performs the operational roles of generating requests to modify and retrieve management information, and receiving the requested information and trap-event reports that are generated by the SNMP agent An application that performs the operational roles of generating requests to modify and retrieve management information, and receiving the requested information and trap-event reports that are generated by the SNMP agent 2. Agent 2. Agent An application that performs the operational role of receiving and processing requests, sending responses to the manager, and sending traps when an event occurs An application that performs the operational role of receiving and processing requests, sending responses to the manager, and sending traps when an event occurs

40. Revised Spring 2006 Chap 1 - Large Enterprise Networks40 Main 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 management station can query or set in the SNMP agent of a networked device (e.g, router). The set of parameters (database) that an SNMP management station can query or set in the SNMP agent of a networked device (e.g, router). The unique identifier of each managed object includes the type (such as counter, string, gauge, or address), access level (such as read/write), size restrictions, and range information of the object. The unique identifier of each managed object includes the type (such as counter, string, gauge, or address), access level (such as read/write), size restrictions, and range information of the object. 4. Protocol Data Units (PDUs) 4. Protocol Data Units (PDUs) A data object exchanged by protocol machines (e.g. SNMP agents) & consisting of both protocol control information and user data A data object exchanged by protocol machines (e.g. SNMP agents) & consisting of both protocol control information and user data

41. Revised Spring 2006 Chap 1 - Large Enterprise Networks41 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

42. Revised Spring 2006 Chap 1 - Large Enterprise Networks42 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 500 Network Element Manager

43. Revised Spring 2006 Chap 1 - Large Enterprise Networks43 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

44. Revised Spring 2006 Chap 1 - Large Enterprise Networks44 SNMP Agent Role (Explained) The SNMP agent listens on UDP port 161

45. Revised Spring 2006 Chap 1 - Large Enterprise Networks45 SNMP MIBs (Explained) Each management station or agent in an SNMP- managed network maintains a local database of information relevant to network management, known as the management information base (MIB) Each management station or agent in an SNMP- managed network maintains a local database of information relevant to network management, known as the management information base (MIB) An SNMP-compliant MIB An SNMP-compliant MIB Contains definitions and information about the properties of managed resources and the services that the agents support. Contains definitions and information about the properties of managed resources and the services that the agents support. Managed objects/Management variables Managed objects/Management variables The manageable features of resources The manageable features of resources A management station gets and sets objects in the MIB, and an agent notifies the management station of significant but unsolicited events called traps A management station gets and sets objects in the MIB, and an agent notifies the management station of significant but unsolicited events called traps

46. Revised Spring 2006 Chap 1 - Large Enterprise Networks46 SNMP MIBs (Explained) MIBs MIBs The most crucial/important NMS component The most crucial/important NMS component MIBs contain data definitions for managed objects MIBs contain data definitions for managed objects SNMP managers & agents exchange object instances using SNMP protocol SNMP managers & agents exchange object instances using SNMP protocol Are Plain-text files Are Plain-text files MIBs are compiled into agent source code -> executable file MIBs are compiled into agent source code -> executable file Textual Conventions Textual Conventions MIB refinements (similar to programming language data types or classes in Java or C++) MIB refinements (similar to programming language data types or classes in Java or C++)

47. Revised Spring 2006 Chap 1 - Large Enterprise Networks47 SNMP MIB (Explained) The following keywords are used to define a MIB object: The following keywords are used to define a MIB object: Syntax Syntax Defines the abstract data structure corresponding to the object type Defines the abstract data structure corresponding to the object type Access Access Defines whether the object value may only be retrieved but not modified (read-only) or whether it may also be modified (read- write) Defines whether the object value may only be retrieved but not modified (read-only) or whether it may also be modified (read- write) Description Description Contains a textual definition of the object type. The definition provides all semantic definitions necessary for interpretation; it typically contains information of the sort that would be communicated in any ASN.1 commentary annotations associated with the object Contains a textual definition of the object type. The definition provides all semantic definitions necessary for interpretation; it typically contains information of the sort that would be communicated in any ASN.1 commentary annotations associated with the object

48. Revised Spring 2006 Chap 1 - Large Enterprise Networks48 SNMP MIB (Explained) Object Identifer (OID) – used by the management station to request the object's value from the agent Object Identifer (OID) – used by the management station to request the object's value from the agent OID - a sequence of integers that uniquely identifies a managed object by defining a path to that object through a tree-like structure called the OID tree or registration tree OID - a sequence of integers that uniquely identifies a managed object by defining a path to that object through a tree-like structure called the OID tree or registration tree When an SNMP agent needs to access a specific managed object, it traverses the OID tree to find the object. When an SNMP agent needs to access a specific managed object, it traverses the OID tree to find the object. Lexicographic Ordering

49. Revised Spring 2006 Chap 1 - Large Enterprise Networks49 SNMP MIB & Lexicographic Ordering The OID serves as a unique name that represents a node in the tree-based structure All objects can be traced from the root in a process called “walking the MIB.” During a walk, each branch of the MIB is traversed from left to right, starting at the root

50. Revised Spring 2006 Chap 1 - Large Enterprise Networks50 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

51. Revised Spring 2006 Chap 1 - Large Enterprise Networks51 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.

52. Revised Spring 2006 Chap 1 - Large Enterprise Networks52 SNMP “Get” PDU

53. Revised Spring 2006 Chap 1 - Large Enterprise Networks53 SNMP “Get-Next” PDU

54. Revised Spring 2006 Chap 1 - Large Enterprise Networks54 SNMP “Set” Protocol

55. Revised Spring 2006 Chap 1 - Large Enterprise Networks55 SNMP “Trap” PDU

56. Revised Spring 2006 Chap 1 - Large Enterprise Networks56 SNMPv1 SNMPv1 is probably best known for its relative simplicity SNMPv1 is probably best known for its relative simplicity Much more complicated than following versions Much more complicated than following versions SNMPv1 message format is simple & straight-forward SNMPv1 message format is simple & straight-forward

57. Revised Spring 2006 Chap 1 - Large Enterprise Networks57 SNMPv2 Certain issues with SNMPv1 were noticed & areas for improvement identified Certain issues with SNMPv1 were noticed & areas for improvement identified MIB object definitions MIB object definitions Protocol operations Protocol operations security security Several versions of SNMPv2 & several message formats Several versions of SNMPv2 & several message formats PDU format is the same for all the SNMPv2 types, PDU format is the same for all the SNMPv2 types, The overall message format differs for each variant. The overall message format differs for each variant. Click here to see SNMPv2 Message Format

58. Revised Spring 2006 Chap 1 - Large Enterprise Networks58 SNMPv3 Created in the late 1990s Created in the late 1990s SNMP version 3 resolved the problems that occurred with the many different variations of SNMPv2 SNMP version 3 resolved the problems that occurred with the many different variations of SNMPv2 Adopts many components created in SNMPv2 including: Adopts many components created in SNMPv2 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 parameters – allowing the coexistence of multiple security techniques more flexible way of defining security methods and parameters – allowing the coexistence of multiple security techniques Click here to see SNMPv3 Message Format

59. Revised Spring 2006 Chap 1 - Large Enterprise Networks59 SNMP Management Systems & Agents SNMP manager SNMP manager Any computer that sends queries for IP-related information to a managed computer Any computer that sends queries for IP-related information to a managed computer SNMP manager can send a request to an SNMP agent to change a configuration value SNMP manager can send a request to an SNMP agent to change a configuration value SNMP agent SNMP agent Any computer or other network device that monitors and responds to queries from SNMP managers Any computer or other network device that monitors and responds to queries from SNMP managers Can send a trap message to the manager when specified events (I.e., system reboots, illegal access notification) Can send a trap message to the manager when specified events (I.e., system reboots, illegal access notification)

60. Revised Spring 2006 Chap 1 - Large Enterprise Networks60 SNMP Manager/Agent Communication

61. Revised Spring 2006 Chap 1 - Large Enterprise Networks61 Chapter 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.”

62. Revised Spring 2006 Chap 1 - Large Enterprise Networks62 Chapter 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

63. Revised Spring 2006 Chap 1 - Large Enterprise Networks63 Supplemental Materials General Network Management General Network Management Article: “Network Management as Core Competency” Computerworld, 20 March 2006 Article: “Network Management as Core Competency” Computerworld, 20 March 2006Network Management as Core CompetencyNetwork Management as Core Competency Article: “Cisco Moves to Support Network Management” Computerworld, 12 December 2005 Article: “Cisco Moves to Support Network Management” Computerworld, 12 December 2005Cisco Moves to Support Network ManagementCisco Moves to Support Network Management MPLS MPLS Article: “Building Large Metro Ethernets requires MPLS” Converge! Network Digest, 24 October 2004 Article: “Building Large Metro Ethernets requires MPLS” Converge! Network Digest, 24 October 2004Building Large Metro Ethernets requires MPLSBuilding Large Metro Ethernets requires MPLS SNMP SNMP Article: “Is it time to re-engineer SNMP” Networkworld, 22 March 2004 Article: “Is it time to re-engineer SNMP” Networkworld, 22 March 2004Is it time to re-engineer SNMPIs it time to re-engineer SNMP