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with-defaultscapabilityin NETCONF

• Balazs Lengyel, Ericsson
• Andy Bierman
• draft-bierman-netconf-with-defaults-01
• IETF-73 Minneapolis 2008 November

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Problem

• Different network elements handle defaults
  differently
• We want predictable behavior
• Default data Data that is
• Set or used by the network element
• Not set by the manager

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Basic Use Cases

• Dont send defaults
• I know them from the YAMs (YANG modules)
• Why send a lot of unneeded data
• Defaults are there specifically not to burden the
  user with all the details

• Send all data
• I want to know exactly whats on the box
• Documentation (YAMs) are often unavailable or
  unreliable
• Some applications dont know the model
• Make it human readable
• The box itself doesnt know what is default

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Default Handling in the Real World

• Report all All default data is always reported.
• Trim Values are not reported if they match the
  default.
• Explicit Report values if they are explicitly
  set.
• One of the above based on user choice
• Etc.

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Manager Control

• The manager knows what it needs
• Let the manager control whether defaults are
  returned
• Caveat
• Some nodes dont know if a value is set
  explicitly to the default value or it is just a
  default

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With-defaults Capability

• Indicates
• Handling of defaults can be controlled
• What is the basic behavior of the box
• Impacts
• ltgetgt
• ltget-configgt
• ltcopy-configgt

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Example ltgetgt
ltrpc message-id"102" with-defaults"true"gt
ltgetgt ltfilter type"subtree"gt
ltinterfaces /gt lt/filtergt lt/getgt lt/rpcgt
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With-defaults ???

• True default data MUST be returned
• False default data SHOULD NOT be returned
• Must can not be used, as many nodes will not be
  able to implement it
• Changed compared to draft
• Missing the nodes basic behavior

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YANG

• Works nicely with YANG

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Questions

• Is this important?
• Should it be a WG item?
• Can this be solved?
• After !!! Answering the above
• Do you like the solution?