module HCNUM-TC {

    yang-version 1;

    namespace
      "urn:ietf:params:xml:ns:yang:smiv2:HCNUM-TC";

    prefix hcnum-tc;

    import yang-smi {
      prefix smi;
    }
    import ietf-yang-types {
      prefix yang;
    }

    organization "IETF OPS Area";

    contact
      "        E-mail: mibs@ops.ietf.org
      Subscribe: majordomo@psg.com
        with msg body: subscribe mibs
      
      Andy Bierman
      Cisco Systems Inc.
      170 West Tasman Drive
      San Jose, CA 95134 USA
      +1 408-527-3711
      abierman@cisco.com
      
      Keith McCloghrie
      Cisco Systems Inc.
      170 West Tasman Drive
      San Jose, CA 95134 USA
      +1 408-526-5260
      kzm@cisco.com
      
      Randy Presuhn
      BMC Software, Inc.
      Office 1-3141
      2141 North First Street
      San Jose,  California 95131 USA
      +1 408 546-1006
      rpresuhn@bmc.com";

    description
      "A MIB module containing textual conventions
      for high capacity data types. This module
      addresses an immediate need for data types not directly
      supported in the SMIv2. This short-term solution
      is meant to be deprecated as a long-term solution
      is deployed.";

    revision "2000-06-08" {
      description
        "Initial Version of the High Capacity Numbers
         MIB module, published as RFC 2856.";
    }


    typedef CounterBasedGauge64 {
      type yang:counter64;
      description
        "The CounterBasedGauge64 type represents a non-negative
         integer, which may increase or decrease, but shall never
         exceed a maximum value, nor fall below a minimum value. The
         maximum value can not be greater than 2^64-1
         (18446744073709551615 decimal), and the minimum value can
         
         not be smaller than 0.  The value of a CounterBasedGauge64
         has its maximum value whenever the information being modeled
         is greater than or equal to its maximum value, and has its
         minimum value whenever the information being modeled is
         smaller than or equal to its minimum value.  If the
         information being modeled subsequently decreases below
         (increases above) the maximum (minimum) value, the
         CounterBasedGauge64 also decreases (increases).
         
         Note that this TC is not strictly supported in SMIv2,
         because the 'always increasing' and 'counter wrap' semantics
         associated with the Counter64 base type are not preserved.
         It is possible that management applications which rely
         solely upon the (Counter64) ASN.1 tag to determine object
         semantics will mistakenly operate upon objects of this type
         as they would for Counter64 objects.
         
         This textual convention represents a limited and short-term
         solution, and may be deprecated as a long term solution is
         defined and deployed to replace it.";
    }

    typedef ZeroBasedCounter64 {
      type yang:counter64;
      description
        "This TC describes an object which counts events with the
         following semantics: objects of this type will be set to
         zero(0) on creation and will thereafter count appropriate
         events, wrapping back to zero(0) when the value 2^64 is
         reached.
         
         Provided that an application discovers the new object within
         the minimum time to wrap it can use the initial value as a
         delta since it last polled the table of which this object is
         part.  It is important for a management station to be aware
         of this minimum time and the actual time between polls, and
         to discard data if the actual time is too long or there is
         no defined minimum time.
         
         Typically this TC is used in tables where the INDEX space is
         constantly changing and/or the TimeFilter mechanism is in
         use.
         
         Note that this textual convention does not retain all the
         semantics of the Counter64 base type. Specifically, a
         Counter64 has an arbitrary initial value, but objects
         defined with this TC are required to start at the value
         
         zero.  This behavior is not likely to have any adverse
         effects on management applications which are expecting
         Counter64 semantics.
         
         This textual convention represents a limited and short-term
         solution, and may be deprecated as a long term solution is
         defined and deployed to replace it.";
    }
  }  // module HCNUM-TC