Transcript Lecture 22: Introduction of Network Management

CS 453
Computer Networks
Lecture 22
Network Management
Network Management
We have discussed a lot of network
examples that have a very small number
of hosts, routers, switches and links
…but in the real world networks can have
thousands of devices and links, and span
cities, countries, continents, and the globe
In many important ways, networks are the
life blood of many organizations and
critically important to individuals
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A network that does not run reliably, stably
and efficiently can have devastating
consequences…
Imagine a network failure for an airlines
operations system…
…or the Air Traffic control system…
…or the electric power grid
Network Management
This becomes more and more important
with network delivered services like
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VoIP
Streaming video
On-demand Hi-Res video/audio
Collaboration and video conferencing
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Bottom line
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We need to monitor,
manage,
Troubleshoot
Repair
Networks and do this very well
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Some network management activities
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Detecting an interface or component failure
Monitor hosts on the network
Traffic monitoring and resource deployment
Recognizing frequent changes in router tables
Setting standards for SLAs
Intrusion detection and other security threats
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International Standards Organization’s
Five Areas of Network Management
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Performance Management
Quantify, measure, track, analyze and control
network performance
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Fault management
Identify, log and respond to faults in a network
Like performance management, but short-term
specific problem focused
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International Standards Organization’s Five
Areas of Network Management
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Configuration management
How are network devices configured
…and keeping track of these configurations
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Accounting
Tracking resource utilization
Quota management, usage charges, resource access
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Security management
Monitoring and managing network (and related) access in
accordance with defined policies
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Network Management Architecture –very high
level
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Managing entity
Network administrator/network management workstation
NOC (most likely)
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Managed devices
Routers, switches, hosts, hubs, printers, etc.
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MIB – Management Information Base (more on
this…)
Network management protocol
A well defined protocol for communications and control
between managing entities and managed devices
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Network Management Architecture –very high
level
From:
http://www.cisco.com/univercd/cc/td/doc/cisintwk/ito_doc/snmp.htm
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Network management protocol
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There are several, notably…
OSI –Common Management Information
Services Element/Common Management
Information Protocol (CMISE/CMIP)
Simple Network Management Protocol –
SNMP
For IP networks
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MIB – Management Information Base
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Collections of discrete and organized pieces
of information about managed devices
Sort of a virtual database
…to be collected from managed devices by
managing entities…
…usually as needed
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MIB – made up of MIB objects
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MIB objects are the information elements
maintained by managed devices
MIB tables – MIB objects with recurrent or
multiple instances of data elements
MIB modules – groupings of related MIB
objects
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Each type of managed object has its own
set of MIB objects
MIB objects are defined by a data
definition language – Structure of
Management Information – SMI
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Subset of ANS.1 - abstract syntax notation 1
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Object descriptors
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1.3.6.1.4.1.9.3.3.1
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SMI has several constructs
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OBJECT-TYPE
Defines objects
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MODULE-IDENTITY
Defines modules of objects
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NOTIFICATION-TYPE
Defines the kinds of messages that agents generate
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MODULE-COMPLIANCE
Defines the set of objects that must be defined within a
module
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AGENT-CAPABILITIES
Defines agents cabilities regarding object and event
notifications
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SMI basic data types
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INTEGER – 32 bit integers or list of named constants
INTEGER32 – 32 bit integers
Unsigned32 – 32 bit unsigned integer
OCTET STRING – byte string up to 65K bytes long
OBJECT IDENTIFER – defined structure name
IPaddress – 32 bit IP address in network byte order
Counter32 – 32 bit modulo 232 counter
Counter64 – 64 bit modulo 264 counter
Gauge32 – counter with 0-232 limit
TimeTicks – Time in 1/100 seconds
Opaque – uninterrupted string
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SMI object definition
ipInDelievers OBJECT-TYPE
SYNTAX
Counter32
MAX-ACCESS
read-only
STATUS
current
Descriptions
“IP datagrams delivered”
::={ ip 9 }
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IETF – has developed many MIB object
definitions
Network vendors develop their own MIB
object definitions
There are 100s of MIB objects
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SNMPv1
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Simple objects, simple protocol, MIB tables
SNMPv2
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Modules
SNMPv3
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Message integrity
Source authenication
encryption
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SMI basic data types
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INTEGER – 32 bit integers or list of named constants
INTEGER32 – 32 bit integers
Unsigned32 – 32 bit unsigned integer
OCTET STRING – byte string up to 65K bytes long
OBJECT IDENTIFER – defined structure name
IPaddress – 32 bit IP address in network byte order
Counter32 – 32 bit modulo 232 counter
Counter64 – 64 bit modulo 264 counter
Gauge32 – counter with 0-232 limit
TimeTicks – Time in 1/100 seconds
Opaque – uninterrupted string
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Example – managed objects in MIB-2 system group
Name
Data type
Description (RFC 1213)
sysDescr
OCTET STRING
Name & version of system hw, OS,
Network software
sysObjectID
OBJECT
IDENTIFER
ID – kind of box it is
sysUpTime
TimeTicks
Time since last reboot
sysContact
OCTET STRING
Who manages this thing
sysName
OCTET STRING
Assigned name for this device
sysLocation
OCTET STRING
Physical location for this device
sysServices
Integer32
Code for services available
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Example – managed objects in MIB-2 udp module
Name
Data type
Description (RFC 1213)
udpInDatagrams
Counter32
UDP datagrams delivered
udpNoPorts
Counter32
Number of received datagram where
there was no app assigned to port
udpInErrors
Counter32
No. of received datagrams that could
not be delivered
udpOutDatagrams
udpTable
No. of datagrams sent from this device
Sequence Sequence of udpEntry objects – port
of udpEntry open by an application
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Two more PDUs in SNMPv2
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GET BULK REQUEST – iterative GET
REQUEST (from manager to agent)
INFORM – an acknowledged trap
NOTIFY – event notification – same as trap,
added in SNMPv2
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SNMPv2 PDU
PDU type—Identifies the type of PDU transmitted (Get, GetNext, Inform,
Response, Set, or Trap).
• Request ID—Associates SNMP requests with responses.
• Error status—Indicates one of a number of errors and error types. Only the
response operation sets this field. Other operations set this field to zero.
• Error index—Associates an error with a particular object instance. Only the
response operation sets this field. Other operations set this field to zero.
• Variable bindings—Serves as the data field of the SNMPv2 PDU. Each
variable binding associates a particular object instance with its current value
(with the exception of Get and GetNext requests, for which the value is
ignored).
From:
http://www.cisco.com/univercd/cc/td/doc/cisintwk/ito_doc/snmp.htm
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SNMPv1 Trap PDU
Enterprise—Identifies the type of managed object generating the trap.
• Agent address—Provides the address of the managed object generating the
trap.
• Generic trap type—Indicates one of a number of generic trap types.
• Specific trap code—Indicates one of a number of specific trap codes.
• Time stamp—Provides the amount of time that has elapsed between the last
network reinitialization and generation of the trap.
• Variable bindings—The data field of the SNMPv1 Trap PDU. Each variable
binding associates a particular object instance with its current value.
From:
http://www.cisco.com/univercd/cc/td/doc/cisintwk/ito_doc/snmp.htm
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More things to see
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http://www.cisco.com/univercd/cc/td/doc/cisintwk/ito_doc/snmp.htm
http://en.wikipedia.org/wiki/Network_performance_management
http://en.wikipedia.org/wiki/Snmp
http://www.cotse.com/tools/netman.htm
TCP/IP
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http://www.redbooks.ibm.com/Redbooks.nsf/RedbookAbstracts/gg243376.html?Open