Network Management

• fault detection, isolation, reporting
• device configuration
• network/device access (security) configuration
• performance management: tuning, detecting problems
• accounting
• challenges:
  • distributed system
  • heterogeneous system
  • asynchronous events
  • lots of data
  • how do you talk to a system that is disconnected?

SNMP

• Simple Network Management Protocol
• UDP-IP or LLC (some data might get through)
• ASN.1 encoding of data
• get a value
• get-next value
• set a configuration parameter
• signal a device event to a management tool

MIB

• Management Information Base
• database of values available from device
• each value is identified by a unique string of numbers (encoded in ASN.1, so numbers are arbitrarily large)
• unique string of numbers describes a tree
• get-next value gets next value in the tree
• MIB is description of subtree rooted at one device (file)
• corresponds to values for the device (loaded by SNMP or CMOT)

Network Management Software

• reads MIB, other configuration information
• loads network values
• displays GUI for network, devices
• allows user to set properties on device (e.g. address)
• sends changes to device
• OpenView

Performance Tuning

• when do I upgrade my ethernet? (e.g. split into two with a switch)
  • when users complain
  • when I have the money to do so
  • when peak utilization reaches 30%
• ethernet monitors, sniffers (hardware or software)
• who are the heavy users of my network? (maybe I can get them to contribute to my switch budget)
• do I need a new, or faster connection to the internet?

Security

• firewalls (need configuration)
• audit trails:
  • who broke in?
  • when?
  • what did they do?
• access rights (could enable X to access the web server for today while I'm debugging his browser installation)

Accounting

• big ISPs might want to charge by usage
• ultimately, everyone might want to charge by usage (better service for less price for most people...)
• budget justification
• money for next switch might come from heavy users...
• explanation of problems

Network Failures

• special equipment (expensive but fast)
• who is still talking to whom?
  • does not work if we have redundant paths
  • does not work if everyone is down (e.g. short circuit)
• alarms:
  • hardware
  • SNMP
• types of failures:
  • hardware (disconnect, malfunction)
  • software/algorithms (routing)
  • configuration (interface addresses, netmasks, server addresses)