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Versions: 00                                                            
Internet Draft                                             Stephen Bush
Expires in June 1997                                    Sunil Jagannath
<draft-bush-vnc-mib-00.txt>                                        ITTC
                                                       January 13, 1997


  The Definition of Managed Objects for Virtual Network Configuration

Status of this Memo


   This document is a submission by the Information and Telecommunica-
   tions Technologies Center (ITTC) at the University of Kansas. Com-
   ments should be submitted to sbush@tisl.ukans.edu.

   Distribution of this memo is unlimited.

   This document is an Internet-Draft.  Internet-Drafts are working doc-
   uments of the Internet Engineering Task Force (IETF), its areas, and
   its working groups.  Note that other groups may also distribute work-
   ing documents as Internet-Drafts.

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   ftp.isi.edu (US West Coast).

Abstract

   This memo defines a portion of the Management Information Base (MIB)
   for use with network management protocols in TCP/IP-based internets.
   In particular, it describes managed objects used for managing Virtual
   Network Configuration (VNC) of the Rapidly Deployable Radio Network
   (RDRN) Network Control Protocol (NCP).

The Network Management Framework


   The Internet-standard Network Management Framework consists of three
   components. They are:





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      STD 16/RFC 1155 which defines the SMI, the mechanisms used for
      describing and naming objects for the purpose of management.  STD
      16/RFC 1212 defines a more concise description mechanism, which is
      wholly consistent with the SMI.

      STD 17/RFC 1213 which defines MIB-II, the core set of managed
      objects for the Internet suite of protocols.

      STD 15/RFC 1157 which defines the SNMP, the protocol used for net-
      work access to managed objects.

      The Framework permits new objects to be defined for the purpose of
      experimentation and evaluation.


Objects


   Managed objects are accessed via a virtual information store, termed
   the Management Information Base or MIB.  Objects in the MIB are
   defined using the subset of Abstract Syntax Notation One (ASN.1) [3]
   defined in the SMI.  In particular, each object type is named by an
   OBJECT IDENTIFIER, an administratively assigned name.  The object
   type together with an object instance serves to uniquely identify a
   specific instantiation of the object.  For human convenience, we
   often use a textual string, termed the descriptor, to refer to the
   object type.

Format of Definitions


   Section 5 contains the specification of all object types contained in
   this MIB module.  The object types are defined using the conventions
   defined in the SMI, as amended by the extensions specified in [5,6].

Overview

 Network Control Protocol Terminology


   This section defines some of the terminology used in the Description
   of the Network Control Protocol [11] and [12] operation.









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     o   "AX.25"

         Asynchronous X.25 Protocol (See [1]).

     o   "Callsign"

         The packet radio callsign is assigned by the FCC and
         identifies the packet radio operator.

     o   "Edge Switch" (ES)

         A node which either resides within the wireless
         network or at the edge of the fixed and
         wireless network and which serves as a base station.

     o   "Global Positioning System" (GPS)

          Satellite system which provides location and time.

     o   "Remote Node" (RN)

         A host with the ability to connect via a beamforming
         antenna to an edge switch (ES).


 Virtual Network Configuration


   Virtual Network Configuration (VNC) allows future states of a system
   to be predicted and used efficiently. VNC is used for the configura-
   tion of a wireless mobile Asynchronous Transfer Mode (ATM) network
   known as the Rapidly Deployable Radio Network (RDRN).  Configuration
   in a mobile network must be a dynamic and continuous process.  Fac-
   tors such as load, distance, capacity and topology are all constantly
   changing in a mobile environment. The VNC algorithm anticipates con-
   figuration changes and speeds the reconfiguration process by pre-
   computing and caching results.  The Global Positioning System (GPS)
   is a key element in the implementation of this algorithm because it
   provides location information and accurate time for each node.  The
   effort required to enhance network configuration with Virtual Network
   Configuration is minimal. New fields are added to each existing mes-
   sage and additional structures are added to existing processes.  The
   benefit of prediction is gained at the cost of additional traffic and
   processing.

 Virtual Network Configuration Algorithm

   The Virtual Network Configuration (VNC) algorithm is an application



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   of a more general mechanism called Time Warp Emulation (TWE). Time
   Warp Emulation is a modification of Time Warp.  The motivation behind
   TWE is to allow the actual components of a real-time system to work
   ahead in time in order to predict future behavior and adjust them-
   selves when that behavior does not match reality. This is accom-
   plished by realizing that there are now two types of false messages,
   those which arrive in the past relative to the process's Local Vir-
   tual Time (LVT) and those messages which have been generated which
   are time-stamped with the current real time, but whose values exceed
   some tolerance from the component's current value.

   The basic Time Warp mechanism is modified by adding a verification
   query phase. This phase occurs when real time matches the receive
   time of a message in the output queue of a process. In this phase,
   the physical device being emulated in time is queried and the results
   compared with the value of the message. A value exceeding a prespeci-
   fied tolerance will cause a rollback of the process.

   The Virtual Network Configuration (VNC) algorithm can be explained by
   an example.  A remote node's direction, velocity, bandwidth used,
   number of connections, past history and other factors can be used to
   approximate a new configuration sometime into the future. All actual
   configuration processes can begin to work ahead in time to where the
   remote node is expected to be at some point in the future. If the
   prediction is incorrect, but not far off, only some processing will
   have to be rolled back in time. For example, the beamsteering process
   results may have to be adjusted, but the topology and many higher
   level requirements will still be correct. Working ahead and rolling
   back to adjust for error with reality is an on-going process, which
   depends on the tradeoff between allowable risk and amount of process-
   ing time allowed into the future.

 Virtual Network Configuration Implementation

   The effort required to enhance the network configuration algorithm to
   include Virtual Network Configuration is minimal. Three new fields
   are added to each existing message: antimessage toggle, send time,
   and receive time. Physical processes include beamforming, topology
   acquisition, table updates, and all processing required for configu-
   ration. Each physical process is assigned a tolerance. When the value
   of a real message exceeds the tolerance of a predicted message stored
   in the send queue, the process is rolled back.

   Also, an additional packet type was created for updating an approxi-
   mation of the Global Virtual Time (GVT). Because the system is com-
   posed of asynchronously executing logical processes, each working
   ahead as quickly as possible with its own local notion of time, it is
   necessary to calculate the time of the system as a whole.  This



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   system-wide time is the GVT. The difference between GVT and current
   time is the amount of lookahead, Lambda. Although GVT >= t where t is
   real time, Lambda is required because it is used to control the effi-
   ciency and accuracy of the system. Since the network configuration
   system uses a master node as described in the physical layer setup,
   this is a natural centralized location for a centralized GVT update
   method.  RNs transmit their LVT to the master, the master calculates
   an approximate GVT and returns the result.

   The Rapidly Deployable Radio Network (RDRN) consists of links formed
   by beamforming antennas. While beamforming allows improved spectrum
   usage through spatial reuse, it poses a challenge to configure. Each
   mobile node and base station contains a GPS receiver and is aware of
   its current location. This information is shared among nodes and an
   optimal topology for beamformed links is determined.  The protocol
   which carries this information is known as the network control proto-
   col (NCP). The NCP is carried over an omni-directional packet radio
   overlay network. See reference [8] and [9] for detailed information
   about the operation of NCP.

 Virtual Network Configuration MIB Overview


   A very brief overview of VNC components and operation will be pro-
   vided in this section.  The VNC algorithm is an extension of opti-
   mistic parallel simulation [10] and accomplishes configuration of a
   mobile wireless ATM network including handoff.  A driving process
   injects virtual messages into the VNC system.  Virtual messages are
   similar to real messages except that they exist in the future and are
   thus predictions of future events.

   VNC consists of Logical Processes (LP) which communicate via mes-
   sages. An LP is comprised of a State Queue, Receive Queue, and Send
   Queue. Each LP State has an associated tolerance. If messages arrive
   out of order or beyond the given tolerance, a rollback occurs.  Roll-
   backs produce anti-messages which cancel the effects of causality
   violations and inaccurate VNC predictions. The system may contain a
   global virtual time calculation (GVT) and global lookahead parameter
   (LA). The MIB objects described below manage each of these compo-
   nents.  The GvtUpdate MIB object manages the rate at which a simple
   polling algorithm for GVT calculation is performed. The StepSize
   object controls the rate of virtual messages generation from the
   driving process.

Definitions






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     RDRN-VNC-MIB DEFINITIONS ::= BEGIN

     IMPORTS
         MODULE-IDENTITY, OBJECT-TYPE,
         enterprises, Counter32, Integer32, TimeTicks, Unsigned32
          FROM SNMPv2-SMI
         DisplayString, RowStatus, DateAndTime, TruthValue, TimeStamp,
         TAddress
             FROM SNMPv2-TC;

     RdrnVncMIB MODULE-IDENTITY
          ORGANIZATION "KU TISL"
          CONTACT-INFO
                   "        Steve Bush
               sbush@tisl.ukans.edu"

          DESCRIPTION
                  "Experimental MIB modules for the Rapidly Deployable
                   Radio Networks (RDRN) Project Network Control
                   Protocol (NCP) enhanced with the Virtual Network
                   Configuration."
          ::= { 1 3 6 1 3 ncp(75) 2 }


     vnc OBJECT IDENTIFIER ::= { ncp(75) 2 }

     --
     -- Logical Process Table
     --

     logicalProcess OBJECT IDENTIFIER ::= { vnc 1 }

     logicalProcessTable OBJECT-TYPE
          SYNTAX SEQUENCE OF LogicalProcessEntry
          ACCESS read-only
          STATUS mandatory
          DESCRIPTION
               "Table of VNC LP information."
          ::= { logicalProcess 1 }

     logicalProcessEntry OBJECT-TYPE
          SYNTAX LogicalProcessEntry
          ACCESS read-only
          STATUS mandatory
          ::= { logicalProcessTable 1 }

     LogicalProcessEntry ::= SEQUENCE {
          logicalProcessID



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               DisplayString,
          logicalProcessLVT
               INTEGER,
             logicalProcessQRSize
               INTEGER,
             logicalProcessQSSize
               INTEGER,
             logicalProcessRollbacks
               INTEGER,
             logicalProcessSQSize
               INTEGER,
             logicalProcessTolerance
               INTEGER,
             logicalProcessGVT
               INTEGER,
             logicalProcessLookAhead
               INTEGER,
             logicalProcessGvtUpdate
               INTEGER,
             logicalProcessStepSize
               INTEGER
          }

     logicalProcessID OBJECT-TYPE
          SYNTAX DisplayString
          ACCESS read-only
          STATUS mandatory
          DESCRIPTION
               "The LP identifier."
          ::= { logicalProcessEntry 1 }

     logicalProcessLVT OBJECT-TYPE
          SYNTAX INTEGER
          ACCESS read-only
          STATUS mandatory
          DESCRIPTION
               "This is the LP Local Virtual Time."
          ::= { logicalProcessEntry 2 }

     logicalProcessQRSize OBJECT-TYPE
             SYNTAX INTEGER
             ACCESS read-only
             STATUS mandatory
             DESCRIPTION
                     "This is the LP Receive Queue Size."
             ::= { logicalProcessEntry 3 }

     logicalProcessQSSize OBJECT-TYPE



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             SYNTAX INTEGER
             ACCESS read-only
             STATUS mandatory
             DESCRIPTION
                     "This is the LP send queue size."
             ::= { logicalProcessEntry 4 }

     logicalProcessRollbacks OBJECT-TYPE
             SYNTAX INTEGER
             ACCESS read-only
             STATUS mandatory
             DESCRIPTION
                     "This is the number of rollbacks this LP has suffered."
             ::= { logicalProcessEntry 5 }

     logicalProcessSQSize OBJECT-TYPE
             SYNTAX INTEGER
             ACCESS read-only
             STATUS mandatory
             DESCRIPTION
                     "This is the LP state queue size."
             ::= { logicalProcessEntry 6 }

     logicalProcessTolerance OBJECT-TYPE
             SYNTAX INTEGER
             ACCESS read-only
             STATUS mandatory
             DESCRIPTION
                     "This is the allowable deviation between process's
                      predicted state and the actual state."
             ::= { logicalProcessEntry 7 }

     logicalProcessGVT  OBJECT-TYPE
             SYNTAX INTEGER
             ACCESS read-only
             STATUS mandatory
             DESCRIPTION
                     "This is this system's notion of Global Virtual Time."
             ::= { logicalProcessEntry 8 }

     logicalProcessLookAhead  OBJECT-TYPE
             SYNTAX INTEGER
             ACCESS read-only
             STATUS mandatory
             DESCRIPTION
                     "This is this system's maximum time into which it can
                      predict."
             ::= { logicalProcessEntry 9 }



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     logicalProcessGvtUpdate OBJECT-TYPE
             SYNTAX INTEGER
             ACCESS read-only
             STATUS mandatory
             DESCRIPTION
                     "This is the GVT update rate."
             ::= { logicalProcessEntry 10 }

     logicalProcessStepSize OBJECT-TYPE
             SYNTAX INTEGER
             ACCESS read-only
             STATUS mandatory
             DESCRIPTION
                     "This is the time until next virtual message."
             ::= { logicalProcessEntry 11 }
     END


Security Considerations


   None.

References

   [1] Rose M., and K. McCloghrie, "Structure and Identification of
       Management Information for TCP/IP-based internets", STD 16, RFC
       1155, Performance Systems International, Hughes LAN Systems, May
       1990.

   [2] McCloghrie K., and M. Rose, Editors, "Management Information Base
       for Network Management of TCP/IP-based internets", STD 17, RFC
       1213, Performance Systems International, March 1991.

   [3] Information processing systems - Open Systems Interconnection -
       Specification of Abstract Syntax Notation One (ASN.1),
       International Organization for Standardization, International

   [4] Information processing systems - Open Systems Interconnection -
       Specification of Basic Encoding Rules for Abstract Notation One
       (ASN.1), International Organization for Standardization,
       International Standard 8825, December 1987.

   [5] Rose, M., and K. McCloghrie, Editors, "Concise MIB Definitions",
       STD 16, RFC 1212, Performance Systems International, Hughes LAN
       Systems, March 1991.

   [6] Rose, M., Editor, "A Convention for Defining Traps for use with



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       the SNMP", RFC 1215, Performance Systems International, March
       1991.

   [7] McCloghrie, K., "Extensions to the Generic-Interface MIB", RFC
       1229, Hughes LAN Systems, Inc., May 1991.

   [8] Stephen F. Bush, Sunil Jagannath, Joseph B. Evans, and Victor
       Frost, "A Control and Management Network for Wireless ATM
       Systems" in Proceedings of the International Communications
       Conference '96, p. 459,463 (1996  June). Online version
       available at: http://www.tisl.ukans.edu/~sbush/pspapers/icc96.ps

   [9] Stephen F. Bush, Sunil Jagannath, Ricardo Sanchez, Joseph B.
       Evans, Victor Frost, and K. Sam Shanmugan, Rapidly Deployable
       Radio Networks (RDRN) Network Architecture, Telecommunications
       Information Sciences Laboratory (1995  July). Online version
       available at:
       http://www.tisl.ukans.edu/~sbush/pspapers/network_arch.ps

   [10] D. R. Jefferson and H. A. Sowizral, Fast Concurrent Simulation
        Using The Time Warp Mechanism, Part I: Local Control, pp. 27-53,
        The Rand Corporation (1982).

   [11] Network Control Protocol for the Configuration of Mobile
        Wireless Beamformed GPS-Based Networks,
        <draft-bush-ncp-config-00.txt>, Stephen F. Bush, Sunil Jagan-
   nath.

   [12] The Definition of Managed Objects for the Configuration of
        Mobile Wireless Beamformed GPS-Based Networks,
        <draft-bush-rdrn-mib-00.txt>, Stephen F. Bush, Sunil Jagannath.

Author's Address


   Stephen F. Bush
   Sunil Jagannath
   Information and Telecommunications Technologies Center (ITTC)
   University of Kansas
   Lawrence, Kansas 66045

   Phone: (913) 864-7761

   EMail: sbush@tisl.ukans.edu







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