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. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet- Drafts as reference mate- rial or to cite them other than as ``work in progress.'' To learn the current status of any Internet-Draft, please check the ``1id-abstracts.txt'' listing contained in the Internet- Drafts Shadow Directories on ftp.is.co.za (Africa), nic.nordu.net (Europe), munnari.oz.au (Pacific Rim), ds.internic.net (US East Coast), or 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: Bush & Jagannath Expires in June 1997 [Page 1]
Internet-Draft Virtual Network Configuration 13 January 1997 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. Bush & Jagannath Expires in June 1997 [Page 2]
Internet-Draft Virtual Network Configuration 13 January 1997 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 Bush & Jagannath Expires in June 1997 [Page 3]
Internet-Draft Virtual Network Configuration 13 January 1997 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 Bush & Jagannath Expires in June 1997 [Page 4]
Internet-Draft Virtual Network Configuration 13 January 1997 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 Bush & Jagannath Expires in June 1997 [Page 5]
Internet-Draft Virtual Network Configuration 13 January 1997 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 Bush & Jagannath Expires in June 1997 [Page 6]
Internet-Draft Virtual Network Configuration 13 January 1997 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 Bush & Jagannath Expires in June 1997 [Page 7]
Internet-Draft Virtual Network Configuration 13 January 1997 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 } Bush & Jagannath Expires in June 1997 [Page 8]
Internet-Draft Virtual Network Configuration 13 January 1997 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 Bush & Jagannath Expires in June 1997 [Page 9]
Internet-Draft Virtual Network Configuration 13 January 1997 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 Bush & Jagannath Expires in June 1997 [Page 10]