II Part Management Architectures Internet Management
Chapter 6 Internet Management
Learning Objectives • Overview • Internet Information Model (SMI and MIB) • Internet Communication Model • Remote Monitoring MIBs • SNMP Version 3 and Other Developments • Chapter Summary
Overview • The Internet management architecture / SMTP forms the basis for the majority of multivendor management solutions in the data communications environment • IP based protocols are used as a result of the Internet • Internet standard are less complicated and more open to informal participation • Standards working and or developing bodies of the Internet • Internet Architecture Board (IAB) • Internet Research Task Force (IRTF) • Internet Engineering Task Force (IETF) • OSI management serves as the basis for TMN • Management protocols came in the late 1980S with the development of the host monitoring protocol (HMP), the high-load entity management systems (HEMS), the simple gateway monitoring protocol (SGMP), and CMOT (i.e. CMIP over TCP/IP) • SNMP is widely use today
Internet Informational Model (SMI and MIB) • IIM (structure of management information) is available in two versions • SNMPv1-SMI (original) is the most widely used one. • SNMPv2-SMI (recent) an extension of SNMPv1-SMI • SNMPv1-SMI – IM is based on the client-server principle where the client is usually designated as the management station (manager), and the server is the management agent (agent) • The manager is the carrier system for all management applications; it provides an interface to human operators. • Using the SNMP management protocol, a manager communicates with the monitored resources of the agent. • Through the agent – the manager has R/W access to the agent MIB (management information base) • The Internet MIBs describe the structure of the agent MIB
Internet Informational Model (SMI and MIB) • Syntax of Internet Objects • Network address – enables the selection of a protocol family • IP Address – used in the representation of the 32-bit-long Internet address • Time ticks – allows the specification of periods of time with each tick compromising 1/100 second • Gauge – defines a counting object that can assume a value between 0 and 232 – 1, it can be increased or decreased and it does not loop. • Counter defines - defines a counting object that can assume a value between 0 and 232 – 1, it can only be increased (cyclical counter). • SNMPv2-SMI - an enhancement to SNMPv1-SMI
Internet Informational Model (SMI and MIB) • Table as object types • Tables are the only combine objects that occur in an Internet MIB • Constructed on the basis of the following principles: • Object type – describes an entire table consists of a “SEQUENCE OF (table row)”. • Each row the table consisting of a “SEQUENCE (table column). • ANS.1 types (SEQUENCE OF and SEQUENCE) consider the fact that the entries in a table can be added or remove dynamically as table rows. • Columns that describes the MIB variables stored in the table must be established at the time the table is defined. • Example of table structure: (page 164).
Internet Informational Model (SMI and MIB) • Groups in MIB • Group systems - objects in this group supply general information about the managed node (sysDescr, sysObjectID, SysLocation, sysUptime) and (sysContact, sysName), (sysServices) • Interface group – consists of the number of network interfaces (ifNumber) provided by the managed node plus a table (ifTable) that contain the (ifType) • Address translation (at) group – formerly part of MIB I, now with MIB II for compatibility reasons only • Protocol groups (ip, icmp, tcp, udp, egp, snmp). Statistics counting for different types of in coming and outgoing protocol data units as well as error situations • Transmission group – contains management information for different transmission protocols and network interfaces (X.25, Ethernet, etc.) • OIM group – OSI Internet Management MIB. Contain MOs for CMOT, CMIP over TCP
Internet Informational Model (SMI and MIB) • SNMP (simple network management protocol) – is the core of the Internet communication model • SNMP Version 1 • Communication between manager and agent is over the SNMP. • Manager access the remote agent using SNMP operations. • SNMP agent receives the manager’s request, carries out the action s required, and generates appropriate response. • Manager can initiate request without having to wait for the agent to supply a response (asynchronously)
Internet Informational Model (SMI and MIB) • SNMP Operations: • Read access (get-request-operation) – manager’s task, operation is atomic (retrieve all values or none) • Browsing the agent MIB (get-next-operation) – to access the next instance of an object in the MIB • Write access (set-operation) –manager’s task generate SetRequest. (success or failure of write action) • Notification by agents (trap-operation) – agent generates a trap to notify the manager of certain events without having received a prior request from the manager to do so. • Structure of SNMP Protocol Data Units. • Request-id (unique identification of a request) • Error-status – to notify manager of possible error during execution • Error-index – use by agent to identify first variable causing error • Variable-binding – variable names and values
Internet Informational Model (SMI and MIB) • Elements of a trap PDU (protocol data unit) • Trap PDU is the only protocol data unit in SNMP that allows the transmission of information that has been initiated by an agent and therefore is not based on the polling principle. • A trap tells the manager to get object value (poll them) in the case of an event having occurred. • PDU Structure: • PDU-type for trap PDU is characterized by type = 4 • Enterprise – contains the object identifier of the object that has produced the trap • Agent-adder – describe the network address of the SNMP agent that sent the trap • Generic-trap – provides a rough identification of the trap • Specific-trap – allows for enterprise-specific classification of “enterpriseSpecific” • Time-stamp – contains time ticks that has passed since the last initialization of the network, when the event occurred at the agent • Variable-binding – additional information relating to the trap.
Internet Informational Model (SMI and MIB) • SNMP Version 2 (an improvement to SNMP Version 1) • It offers the most comprehensive security concept. • A data encryption standard (DES) encryption algorithm • Packet source and content authentication is implicit • A time stamp procedure using weakly synchronized clocks is offered • Remote Monitoring MIBs • (RMON) is a standard developed on the basis of experience gained with proprietary networks probes • Probes - are measurement logging components used to monitor LAN traffic in different LAN segments • RMON-MIB consists of ten MIB groups (Figure 6.11) page 185.
Internet Informational Model (SMI and MIB) • SNMP Version 3 and Other Developments • SNMP V3 as convergence of SNMP proposals • A working group to produce a uniform security and management framework for SNMP that will enable the implementation of a secure control management, using the simplest possible and incorporate modularity for adaptability to different areas of application • SNMPv3 Framework consists of: • Several nodes each with an SNMP entity containing a notification originator and a command responder application (agent) • At least one SNMP entity that contains a command generator or a notification receiver application (traditional manager) • A manager protocol for exchanging information between SNMP entities
SNMP SGMP SMI SNMPv1, SNMPv2, SNMPv3 MIB Network address IpAddress Time ticks Gauge Counter RMON Summary Key Terms:
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