Large Enterprise Networks Chapter 1

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

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

3. 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). Chap 1 - Large Enterprise Networks

4. Enterprise Networks: Defined • Two Main Categories • 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 • Service Provider • SP’sgenerate 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 Chap 1 - Large Enterprise Networks

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

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

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

8. Enterprise Network Functional 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 Chap 1 - Large Enterprise Networks

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

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

11. 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 availability5 • 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 management6 (FCAPS) Chap 1 - Large Enterprise Networks

12. What is Network Management? • 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 • Fault – Detecting network errors/break downs • 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 • Performance – Ensuring the network is operating to standards/expectations; • Evaluate current and future performance metrics • Security – Protect network vs. hackers, or malicious 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 Chap 1 - Large Enterprise Networks

13. What is Network Management? • BML - Business Management Layer • Manage the overall business, gaining return on investment, market share, employee satisfaction, community and governmental goal. • 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 • NML - Network Management Layer • Manage the network and systems that deliver those services, capacity, diversity, and congestion Chap 1 - Large Enterprise Networks

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

15. OSS NMS EMS The Management System Pyramid • OSS – Operations Support System • System that handles workflows, managementinventory details, capacity planning,and repair functions for SPs • OSS used by the business support system • OSS uses underlying NMS to communicatewith lower level devices • Expensive to deploy and develop • Approx. Cost: $1M+ • Example: AceComm is an OSS vendor Chap 1 - Large Enterprise Networks

16. OSS NMS EMS The Management System Pyramid • NMS – Network Management System • Computer based SW application suite thatmanages N.Es • Provides abstractions (signaling links, virtual connections, etc), fault & networkconfiguration, retrieve performance & billing data, execute provisioning,security, script management, audit trails • Network-wide oversight & usage • Oversight over many N.Es (not just one) • Uses EMS to communicate with N.Es • Approx. Cost: $10K+ • Example: Altiris can be used as an NMS Chap 1 - Large Enterprise Networks

17. OSS NMS EMS The Management System Pyramid • EMS – Element Management Systems • Manages one or more of a specific type of NEs • EMS allows the user to manage all the features of each NE individually • Specific functions include: • S/W upload/download • Configuration DB backup/restore • Alarm processing & storage • Approx. Cost: $1K+ Chap 1 - Large Enterprise Networks

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

19. Why is Network Management Important? • Maintains Network Availability • 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 • Good Network Management facilities assist in all the lifecycle stages • Overall Operational Costs are reduced • Manage multiple incompatible management systems • SNMPv3 uses MIBs for network management of data objects Chap 1 - Large Enterprise Networks

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

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

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

23. Advantages of Standards-Based Consolidation • Fewer & simpler user management interfaces • Reduced IT staff training time • Fast fault identification & problem resolution • 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) Chap 1 - Large Enterprise Networks

24. The Manageability Factor • 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: • 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 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 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 Chap 1 - Large Enterprise Networks

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

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

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

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

29. 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 manufacture Chap 1 - Large Enterprise Networks

30. MPLS on Layer 2.5 • 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. • 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 has some Quality of Service features that make it an attractive communications technique. • Supplemental Link: Click here Chap 1 - Large Enterprise Networks

31. How MPLS Works Click here for full article Chap 1 - Large Enterprise Networks

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

33. 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 Chap 1 - Large Enterprise Networks

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

35. 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 • 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: • Help administrators stay on top of network operations, events, and faults Chap 1 - Large Enterprise Networks

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

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

38. What does SNMP do? • 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 Chap 1 - Large Enterprise Networks

39. Main SNMP Components • Principal Components of SNMP are: • 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 • 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 Chap 1 - Large Enterprise Networks

40. Main SNMP Components • Four Principal Components of SNMP are: • 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 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) • A data object exchanged by protocol machines (e.g. SNMP agents) & consisting of both protocol control information and user data Chap 1 - Large Enterprise Networks

41. 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 Chap 1 - Large Enterprise Networks

42. 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 Chap 1 - Large Enterprise Networks

43. 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 Chap 1 - Large Enterprise Networks

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

45. 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) • An SNMP-compliant MIB • Contains definitions and information about the properties of managed resources and the services that the agents support. • Managed objects/Management variables • 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 Chap 1 - Large Enterprise Networks

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

47. SNMP MIB (Explained) • The following keywords are used to define a MIB object: • Syntax • Defines the abstract data structure corresponding to the object type • Access • Defines whether the object value may only be retrieved but not modified (read-only) or whether it may also be modified (read-write) • 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 Chap 1 - Large Enterprise Networks

48. SNMP MIB (Explained) • 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 theOID tree or registration tree • When an SNMP agent needs to access a specific managed object, it traverses the OID tree to find the object. Lexicographic Ordering Chap 1 - Large Enterprise Networks

49. SNMP MIB & Lexicographic Ordering 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 Chap 1 - Large Enterprise Networks

50. 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 Chap 1 - Large Enterprise Networks