Transcript SCADA (Supervisory Control And Data Acquisition)

CASE Diagrams &
SNMP Standard MIBs
Sukiswo
[email protected]
Manajemen Jaringan, Sukiswo ST, MT
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Table of Contents
 Case Diagrams
 MIB-II
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CASE Diagrams
 a useful tool for developing MIBs
 developed by Jeffrey Case in 1989
 for many MIB groups, it is necessary to record
the traffic pattern at a particular protocol layer
 must make sure that every PDU received at a
layer or issued from a layer is accounted for,
including valid PDUs and PDUs with various
types of errors
 Case Diagrams can be used to describe the flow
of packets within individual layers
Manajemen Jaringan, Sukiswo ST, MT
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CASE Diagram Elements
 a main path in each direction between the layer
below and a layer above
 a horizontal line cutting across a main path
corresponds to a counter that counts all passing
PDUs
 an arrow leaving the main path indicates a
counter for an error condition or flow that results
in PDUs not continuing on the main path
 an arrow into the main path indicates a counter
for a point where additional PDUs are injected into
the main path
Manajemen Jaringan, Sukiswo ST, MT
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Case Diagram - Example
Main path
Upper layer
InDelivers
OutRequests
ReasmOKs
Horizontal line
ReasmFails
FragOKs
ReasmReqds
InErrors
ForwPDUs
FragCreates
InReceives
OutSends
Lower layer
additive counters
subtractive counters
filter counters
An arrow into the main
path
An arrow leaving the
main path
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Case Diagram - Example
Counters
InReceives = InErrors + ReasmReqds
+ ForwPDUs - ReasmOKs
+ InDelivers
OutSends = OutRequests + ForwPDUs
- FragOKs + FragCreates
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MIB-II
 Internet Full Standard (RFC 1213)
 a superset of MIB-I (RFC 1156)
 the most important and basic MIB specification,
covering a broad range of managed objects
 consists of 10 groups of objects
 all objects in MIB-II are mandatory but only
groups applicable to managed devices need to be
implemented
– e.g., bridge or router need not implement the tcp group
– why not?
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MIB-II
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MIB-II Groups
Group
Description
system
overall information about the system
interfaces
information about the interfaces from the
system to a network
at
description of address translation table for
internet-to-subnet address mapping
ip
information related to IP on this system
icmp
information related to ICMP on this system
tcp
udp
information related to TCP on this system
information related to UDP on this system
egp
information related to EGP on this system
transmission information about the transmission schemes
and access protocols at each system interface
snmp
information related to SNMP on this system
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MIB-II System Group
system (mib-2 1)
sysDescr (1)
sysObjectID (2)
sysUpTime (3)
sysContact (4)
sysName (5)
sysLocation (6)
sysServices (7)
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System Group Objects
Object
Syntax
sysDescr
DisplayString
Access
RO
(SIZE (0 ... 255))
sysObjectID
OBJECT IDENTIFIER
Description
A description of the entity, such as
hardware, operating system, etc.
RO
The vendor’s authoritative identification
of the network management subsystem
contained in the entity.
sysUpTime
TimeTicks
RO
The time since the network management
portion of the system was last reinitalized.
sysContact
DisplayString
RW
(SIZE (0 ... 255))
The contact information
of the contact person for this
managed node.
sysName
DisplayString
RW
(SIZE (0 ... 255))
sysLocation
DisplayString
An administratively assigned name for
this managed node.
RW
The physical location of this node
RO
A value that indicates the set of services
(SIZE (0 ... 255))
sysServices
INTEGER (0 ... 127)
this entity primarily offers
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sysServices Meanings
Service
Layer
Application
Transport
Network
Data-link
Physical
7
4
3
2
1
Value
64
8
4
2
1
Examples: repeater (physical device) = 1
bridge (data-link device) = 2
router (network device) = 2 + 4 = 6
W/S host = 64 + 8 = 72
PC = 64 + 8 + 4 = 76
printer = 64
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Case Diagram for
MIB-II interfaces Group
Upper layer
ifInUcastPkts +
ifInNUcastPkts
ifInUcastPkts +
ifInNUcastPkts
ifInDiscards
ifOutErrors
ifInUnKnownProtos
ifOutDiscards
ifInErrors
Network
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READING
 Read Chapter 6 Standard MIBs
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