Lecture 5: Foundation of Network Management

Transcription

1 Lecture 5: Foundation of Network Management Prof. Shervin Shirmohammadi SITE, University of Ottawa Prof. Shervin Shirmohammadi CEG Network Management Standards OSI: Common Management Information Protocol (CMIP) International standard (ISO / OSI) Management of data comm. Network LAN and WAN Deals with all 7 layers Most complete Object oriented representation Well structured and layered Consumes large resources in implementation Internet: Simple Network Management Protocol (SNMP) Industry standard (IETF) Originally intended for management of Internet components, currently adopted for WAN and telecom systems. Easy to implement Most widely implemented NM standard. Lacks advanced functionality (compared to CMIP) Prof. Shervin Shirmohammadi CEG

2 Network Management Standards ( ) Telecommunication Management Network (TMN) International standard of the ITU-T Management of telecom networks Based on the OSI network management framework Addresses both network, administrative, and business aspects of management. IEEE Addresses LAN and MAN management. Deals with the first 2 layers. Web-based Management Web-based Enterprise Management (WBEM) Java Management Application Program Interface (JMAPI) Desktop Management Management of desktop PCs and applications Prof. Shervin Shirmohammadi CEG Management Architecture This architecture is used for both OSI and SNMP-based management Consists of a number of models Network Mangement Organization Model Information Model Communication Model Functional Model Figure 3.1 OSl Network Management Model Prof. Shervin Shirmohammadi CEG

3 Organization OSI Models Network management components Functions of components Relationships Information Structure of Management Information (SMI) Syntax and semantics Management Information Base (MIB) Organization of management information Communication Transfer syntax with bi-directional messages Transfer structure (PDU) Functions Application functions Configure components Monitor components Measure performance Secure information Usage accounting Object-oriented Prof. Shervin Shirmohammadi CEG SNMP Architecture and Models Organization Same as OSI model Information Same as OSI, but scalar Communication Messages less complex than OSI and unidirectional Transfer structure (PDU) Functions Application functions Operations Administration Security Prof. Shervin Shirmohammadi CEG

4 Organizational Model Sends requests to agents Monitors alarms Houses applications Provides user interface Agent Gathers information from objects Configures parameters of objects Responds to managers requests Generates alarms and sends them to mangers Managed object Network element that is managed Houses management agent All objects are not managed / manageable Implementation approaches: - Two-tier - Three-tier - MoM Prof. Shervin Shirmohammadi CEG Managed Object Managed objects can be Network elements (hardware, system) hubs, bridges, routers, transmission facilities Software (non-physical) programs, algorithms Administrative information contact person, name of group of objects (IP group) Prof. Shervin Shirmohammadi CEG

5 Two-tier Organizational Model Agent built into network element; e.g., Managed hub, managed router. An agent can handle multiple elements.; e.g., Switched hub, ATM switch is a physical database Unmanaged objects are network elements that are not managed - both physical (unmanaged hub) and logical (passive elements). Management Database Agent process Managed objects Unmanaged objects Figure 3.2 Two-Tier Network Mangement Organization Model Prof. Shervin Shirmohammadi CEG Three-tier Organization Model Middle layer plays the dual role Agent to the top-level manager to the managed objects Example of middle level: Remote monitoring agent (RMON) Management Database Agent process Agent / Managed objects Figure 3.3 Three-Tier Network Mangement Organization Model Prof. Shervin Shirmohammadi CEG

6 A of s (MoM) MoM presents integrated view of domains. Agent manages the domain Domain may be geographical, administrative, vendor-specific, etc. Web-based management project uses similar concept. Agent Agent NMS Managed objects MoM Agent NMS Agent Agent NMS Managed objects MoM of s Management Database Agent process Agent Figure 3.4 Network Mangement Organization Model with MoM Prof. Shervin Shirmohammadi CEG Information Model Analogy: A figure in a book is uniquely identified by ISBN, Chapter, and Figure number in that hierarchical order ID: {ISBN, chapter, figure number} The three elements above define the syntax Semantics is the meaning of the three entities; e.g., according to Webster s dictionary The information comprises syntax and semantics about an object. In network management, SMI and MIB are used for similar purposes: defining and identifying specific managed objects. Prof. Shervin Shirmohammadi CEG

7 Structure of Management Information (SMI) SMI defines a managed object Syntax and Semantics plus additional information such as access and status. Example sysdescr: { system 1 } Syntax: OCTET STRING Definition: "A textual description of the entity. " Access: read-only Status: mandatory Prof. Shervin Shirmohammadi CEG Management Information Base (MIB) MIB contains information about objects. Organized by grouping of related objects. Defines relationship between objects. It is not a physical database. It is a virtual database that is compiled into management module. Analogy: UofO library system has many branches. Each branch has a set of books. The books in each branch is a different set. The information base of UoO has the view (catalog) of all books. The information base of each branch has the catalog of books that belong to that branch. That is, each branch has its view (catalog) of the information base Prof. Shervin Shirmohammadi CEG

8 Management Data Base vs. Management Information Base Distinction between and MIB physical database; e.g.. Oracle, Sybase MIB virtual database; schema compiled into management software An NMS can automatically discover a managed object, such as a hub, when added to the network. The NMS can identify the new object as hub only after the MIB schema of the hub is compiled into NMS software. Managed objects MIB Prof. Shervin Shirmohammadi CEG Management Information Tree Managed objects are uniquely defined by a tree structure similar to the one shown below: Root Level 1 Level 2 Level 3 Figure 3.7 Generic Representation of Management Information Tree Prof. Shervin Shirmohammadi CEG

9 OSI Management Information Tree iso = International Standards Organization itu = International Telecommunications Union dod = Department of Defense All have come together to define the OSI Management Information Tree. Designation: iso 1 org 1.3 dod internet iso-itu 2 Prof. Shervin Shirmohammadi CEG itu 0 This tree is not complete!! iso 1 org 3 dod 6 internet 1 Figure 3.8 OSI Management Information Tree Object Type and Instance Internet perspective: Acquired from the IETF RFC 1155 (Managed Object in the Internet Model) Type: name (unique ID and name for the object type) syntax (used to model the object) access (access privileges to the object) status (implementation requirements) definition (textual description of the semantics) This is a scalar model that is easy to understand. OSI perspective: Object oriented model rather than scalar. Has the capability to do more. object class attributes operations behaviour notifications managed object attributes visible at its boundary operations which may be applied to it Behaviour exhibited by the object in response to operation notifications emitted by the object Prof. Shervin Shirmohammadi CEG

10 Internet Example Example of a circle: object ID = circle syntax = English syntax access = John Smith status = mandatory description = A plane figure bounded by a single curved line, every point of which is of equal distance from the center of the figure Access: Access privilege Syntax : model of object Object Type: Object ID and Descriptor circle Defintion: Semantics - textual description Figure 3.9(a) Internet Perspective Status: Implementaion requirements Prof. Shervin Shirmohammadi CEG OSI Example Notifications : Notify changes in attribute values Operations: Push Object Class: Circular object Behaviour Object Class: Elliptical object Attributes : circle, dimension Attributes: ellipse, dimension Figure 3.9(b) OSI Perspective Prof. Shervin Shirmohammadi CEG

11 Packet Counter Example: Internet vs. OSI Internet OSI Characteristics Example Characteristics Example Object type PktCounter Object class Packet Counter Syntax Counter Attributes Single-valued Access Read-only Operations get, set Status Mandatory Behavior Retrieves or resets values Description Counts number of packets Notifications Generates notifications on new value Prof. Shervin Shirmohammadi CEG Internet vs. OSI Managed Object Scalar object in Internet vs. Object-oriented approach in OSI. OSI characteristics of operations, behaviour, and notification are part of communication model in Internet: get, set, response, and alarm. Internet syntax is absorbed as part of OSI attributes. Internet access is part of OSI security model. Internet status is part of OSI conformance application. OSI permits creation and deletion of objects; Internet does not. Enhancement in SNMPv2 Prof. Shervin Shirmohammadi CEG

12 Communication Model Internet: requests/response OSI: operations Internet: traps and notifications (SNMPv2) OSI: notifications Operations / Requests Applications Responses Notifications / Traps Agent Network Elements / Managed Objects Figure 3.11 Management Message Communication Model Prof. Shervin Shirmohammadi CEG Applications Transfer Protocols Operations / Requests / Responses Traps / Notifications Agent Applications Communication Module SNMP (Internet) CMIP (OSI) Agent Communication Module Transport Layers UDP / IP (Internet) OSI Lower Layer Protocols (OSI) Transport Layers Physical Medium OSI uses CMISE (Common Management Information Service Element) application with CMIP (Common Management Information Protocol). OSI specifies both connection oriented and connectionless transport protocol. SNMPv2extended to connection oriented, but rarely used. Prof. Shervin Shirmohammadi CEG

13 Functional Model OSI Functional Model Configuration Management Fault Management Performance Management Security Management Accounting Management Configuration management Security management Set and change network Authentication configuration and component Authorization parameters Encryption Set up alarm thresholds Accounting management Fault management Functional accounting of network usage Detection and isolation of failures in network Trouble ticket administration Performance management Monitor performance of network Prof. Shervin Shirmohammadi CEG