COMM3D Network Administration and Management

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COMM3DNetwork Administration and Management

• Managed Objects and Management Information Bases
• http//osiris.sunderland.ac.uk/cs0cst/

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Objectives
In todays lecture A detailed description of
Managed Objects and Management Information
Basis. Further discussion about ASN.1 and
MIBs An examination of how these are integrated
into an SNMP system Learning outcomes Students
should understand the role of a MIB within an
SNMP system Students should understand Management
Trees and Naming Schemes (OIDs)
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SNMP Agents

Device Internal data structures hold its
configuration Agent Responds to requests for
that information OID Unique Object Identifier
for each variable on the device MIB Describes
the OIDs and what datatypes they contain
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Management Information Base
MIB-II This standard is used to define the data
maintained by a device in the network and what
operations are allowed on it. The data can be
structured in a tree form, and the unique path to
reach each variable is its OID. Naming Tree
-----------------? .1.3.6.1.4.1
.iso.org.dod.internet.private.enterprises
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Example Definition
IfEntry SEQUENCE ifIndex InterfaceIndex,
ifPhysAddress PhysAddress, ifOperStatus
INTEGER,
ifPhysAddress OBJECT-TYPE SYNTAX PhysAddress
MAX-ACCESS read-only STATUS current
DESCRIPTION "The interface's address at its
protocol sub- layer. For example, for an 802.x
interface, this object normally contains a MAC
address." ifEntry 6
http//tools.cisco.com/Support/SNMP/do/BrowseOID.d
o?localentranslateTranslateobjectInputifPhysA
ddress
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Integrating the MIB
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Example
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MIB Groups
RFC1213 Defines a set of 11 standard MIB types
or groups that are commonly used as the basis for
claiming that a device has SNMP support.
Extensible Companies can apply to the ISO to
have a unique OID tree assigned to their device
so that they can design extensions to the base
SNMP protocol in order to add support for new
types of device. Ive seen. SNMP Temperature
Monitors for Server Rooms SNMP Voltage Regulators
SNMP Power Supplies or Active PDUs

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SNMP Groups
System This MIB tree defines data about the
system the agent is running on. Examples
include sysUptime The System
Manufacturer sysDescr Description of the
System sysName Unique ID Useful for fault and
configuration management Interfaces The
interfaces group contains data about each
specific network interface on the device
inclusive of ifPhysAddress, ifType and usage
statistics. Allows us to check the status of the
interface (fault) Allows us to remotely start and
stop the interface (config) Allows us to measure
throughput (performance accounting)
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SNMP Groups
The IP Group Allows us to access the logical
address of any interface as well as query the
routing table of a device. ipAddrTable Logical
Addressing ipNettoMediaTable Mapping from
physical to logical ipRouteTable The Routing
Table Useful for fault, configuration,
performance, and accounting management The ICMP
Group The TCP/IP Group The UDP Group Contain
usage statistics for the relative protocols which
can be used to for fault , configuration ,
accounting management
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SNMP Groups
The EGP Group allows us to store information
about the nearest neighbours to a given managed
device. This information can be used to indicate
if a new route appears on the network or if a
device that used to appear on EGP table
disappears it can be an indication of problems.
Within the management system EGP data can be used
to identify alternative routes across the
network. The TRANSMISSION Group Provides
information about the underlying transport
mechanism utilised by each interface. So if you
think about the VMs youve been usiong in the
lab that would be ethernet. On a router it could
be an ADSL modem, an FDDI link, ATM card etc etc
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SNMP Groups
The SNMP Group Provides statistics about how the
SNMP agent is operating. This is an effective
management tool for managing SNMPIt can record
information about malformed SNMP requests SNMP
errors Attempts to update OIDs with invalid
information Ultimately it provides data to allow
you to debug when your management system goes
wrong.
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Summary
MIB Management information Base describes
features of the data on a managed device. RFC
1213 Defines MIBs for the common elements of
devices covered under the SNMP protocol. OID
Naming trees allow us to generate a unique ID
for each managed object (variable) on a
device. Required Reading (Handouts) RFC1213
MIB-2 Specification Chapter 10 from Network
Management A Practical Perspective Tutorial 5
Introduction to SNMP