Network Management

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Network Management

• 2110472 Computer Networks
• Natawut Nupairoj, Ph.D.
• Department of Computer Engineering
• Chulalongkorn University

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Outline

• Introduction to Network Management.
• Overview.
• Sample Applications.
• Simple Network Management Protocol.
• History of SNMP.
• Basic SNMP Concepts.
• MIB Standards.
• SNMPv3.
• ASN.1.

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Overview

• Typical System Administrators Life
• Manage many hosts and network devices.
• Detect and response to the PROBLEMS.
• Administrators should know the problems BEFORE
  the users.
• Must promise for some Service Level Agreement
  (SLA) levels
• System availability.
• Response time.
• Throughput.

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Overview

• What is the scope of network management ?
• Monitor for problems
• Hosts and services.
• Levels of status up, minor, major, critical.
• To reach SLA.
• Monitor for tune-up
• Should we add more network bandwidth ? For how
  much ?
• Detect the intrusion
• Intrusion detection against the hackers.

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Overview

• Why is it so hard ?
• SLA is usually difficult to achieve without good
  planning and tools
• Availability (uptime) Five Nines 99.999
• Thus, each host can be down only for
• 1 Year 365 24 60 525,600 minutes.
• 0.001 (acceptable downtime) of 1 Year 5.256
  minutes.
• This includes maintenance period !!!
• How about Six Nines ???
• There are MANYMANY devices.

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System Reliability

• Cause of downtime (by Gartner Group)

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Sample Network Monitoring Applications

• There are several network management applications
• OS Tools
• Ping, tracerout, netstat, etc.
• Freewares
• Netsaint, MRTG, snort, etc.
• Commercial
• CA Unicenter, HP Openview, IBM Trivoli,
  CiscoWorks.

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SNMP

• Simple Network Management Protocol.

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Basic SNMP Concepts
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Operational Modes
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SNMP Structure
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SNMP Frameworks MIB

• Management Information Base
• MIB Objects
• Variables that represent the resources of the
  system.
• Can have several types of values.

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SNMP Frameworks - MIB

• Structure of Management Information (SMI)
• Define a standard way to reference the
  information.
• Describe what includes / what not for each device.

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SMI - Example

• address
• Object ID 1.1
• Value of Instance 130.89.16.2
• info
• Object ID 1.2
• name
• Object ID 1.2.1
• Value of Instance printer-1
• uptime
• Object ID 1.2.2
• Value of Instance 123456
• ALTERNATIVE
• Object ID NEW-MIB info uptime

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Standard SMI
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MIB-II Internet MIB
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MIB ExampleHost Resources MIB
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SNMP Operations
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PDU Structure
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SNMPv3 Security Enhancements
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ASN.1

• Abstract Syntax Notation 1
• Similar to BNF notation for programming language.
• Define how data should be sent, in what order.
• The protocol designer must write ASN.1 to define
  the protocol
• Programming language designer uses BNF to define
  the grammar of the language.
• Encode in binary format.

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ASN.1 - Example

• How can I send an integer 65534 ?
• 2 bytes 1111 1111 1111 1110
• Big-endian or little-endian ?
• Sender uses little-endian, receiver uses
  big-endian.
• 1111 1110 1111 1111 65279
• What if I want to send a whole structure ?
• struct
• char code
• int x

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ASN.1 Syntax Definition

• Define a data type
• Define based on built-in types and other data
  types defined in the file.
• Built-in types INTEGER, OCTET STRING, REAL,
  BOOLEAN, etc.
• Newly-defined data type can be complicated
• SEQUENCE, SEQUENCE OF, CHOICE, etc.
• Format
• ltnamegt ltdescription -- componentsgt

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ASN.1 Examples

• --
• -- The currency codes from ISO 4217
• -- are used to identify a currency
• --
• Currency OCTET STRING
• ObjectId INTEGER
• DateTime SEQUENCE
• timeOffsetCode TimeOffsetCode,
• localTimeStamp LocalTimeStamp

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ASN.1 Encoding Rules

• Syntax definition defines the components of the
  data.
• Encoding defines how to actually store the data.
• Data can be encoded in several ways.
• Basic Encoding Rule (BER).
• Distinguished Encoding Rule (DER).
• Packed Encoding Rule (PER).

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BER Encoding

• Basic Encoding Rule (BER)
• Tag Length Value (TLV).
• TAG LENGTH VALUE
• MyId APPLICATION 12 INTEGER
• 12 4 1234
• (this is not the actual encoded data.)

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BER Encoding

• Constructed Encoded Form
• T L T L T L V T L V
• DateTime APPLICATION 83 SEQUENCE
• timeOffsetCode TimeOffsetCode,
• localTimeStamp LocalTimeStamp
• TimeOffsetCode APPLICATION 232 Code
• LocalTimeStamp APPLICATION 16 NumberString
• Code APPLICATION 243 INTEGER

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References

• J. Kurose and K. Ross, Computer Networking A
  Top-Down Approach Featuring the Internet, Addison
  Wesley, 2001.
• Netsaint, http//www.netsaint.org.
• The SimpleWeb Tutorials, http//www.simpleweb.org/
  tutorials/.
• Electronic and telecommunication Institute,
  Lessons about SNMP, http//www.et.put.poznan.pl/sn
  mp/main/mainmenu.html.
• Yoram Cohen, SNMP Simple Network Management
  Protocol, http//www.rad.com/networks/1995/snmp/sn
  mp.htm.