RFC1315

Network Working Group C. Brown Request for Comments: 1315 Wellfleet Communications, Inc.

                                                            F. Baker
                                    Advanced Computer Communications
                                                         C. Carvalho
                                    Advanced Computer Communications
                                                          April 1992

        Management Information Base for Frame Relay DTEs

Status of this Memo This RFC specifies an IAB standards track protocol for the Internet community, and requests discussion and suggestions for improvements. Please refer to the current edition of the "IAB Official Protocol Standards" for the standardization state and status of this protocol. Distribution of this memo is unlimited. 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 defines objects for managing Frame Relay. Table of Contents 1. The Network Management Framework ............................ 2 2. Objects ..................................................... 2 2.1 Format of Definitions ...................................... 3 3. Overview .................................................... 3 3.1 Frame Relay Operational Model .............................. 3 3.2 Textual Conventions ........................................ 3 3.3 Structure of MIB ........................................... 3 4. Definitions ................................................. 4 4.1 Data Link Connection Management Interface .................. 4 4.2 Circuit Table .............................................. 9 4.3 Error Table ................................................ 14 5. Acknowledgements ............................................ 17 6. References .................................................. 17 7. Security Considerations...................................... 18 8. Authors' Addresses........................................... 19

The Network Management Framework

The Internet-standard Network Management Framework consists of three components. They are: RFC 1155 which defines the SMI, the mechanisms used for describing and naming objects for the purpose of management. RFC 1212 defines a more concise description mechanism, which is wholly consistent with the SMI. RFC 1156 which defines MIB-I, the core set of managed objects for the Internet suite of protocols. RFC 1213 defines MIB-II, an evolution of MIB-I based on implementation experience and new operational requirements. RFC 1157 which defines the SNMP, the protocol used for network 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) [7] defined in the SMI. In particular, each object has a name, a syntax, and an encoding. The name is an object identifier, an administratively assigned name, which specifies an object type. 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 OBJECT DESCRIPTOR, to also refer to the object type. The syntax of an object type defines the abstract data structure corresponding to that object type. The ASN.1 language is used for this purpose. However, the SMI [3] purposely restricts the ASN.1 constructs which may be used. These restrictions are explicitly made for simplicity. The encoding of an object type is simply how that object type is represented using the object type's syntax. Implicitly tied to the notion of an object type's syntax and encoding is how the object type is represented when being transmitted on the network. The SMI specifies the use of the basic encoding rules of ASN.1 [8], subject to the additional requirements imposed by the SNMP.

Format of Definitions

Section 4 contains 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 [9,10].

Overview

Frame Relay Operational Model

For the purposes of understanding this document, Frame Relay is viewed as a multi-access media, not as a group of point-to-point connections. This model proposes that Frame Relay is a single interface to the network (physical connection) with many destinations or neighbors (virtual connections). This view enables a network manager the ability to group all virtual connections with their corresponding physical connection thereby allowing simpler diagnostics and trouble shooting.

Textual Conventions

Several new data types are introduced as a textual convention in this MIB document. These textual conventions enhance the readability of the specification and can ease comparison with other specifications if appropriate. It should be noted that the introduction of the these textual conventions has no effect on either the syntax nor the semantics of any managed objects. The use of these is merely an artifact of the explanatory method used. Objects defined in terms of one of these methods are always encoded by means of the rules that define the primitive type. Hence, no changes to the SMI or the SNMP are necessary to accommodate these textual conventions which are adopted merely for the convenience of readers and writers in pursuit of the elusive goal of clear, concise, and unambiguous MIB documents. The new data types are Index and DLCI. Index refers to the range 1..ifNumber, and is used to establish the correspondence between ifEntries and Frame Relay Interfaces. DLCI refers to the range 0..DLCINumber, and is used to refer to the valid Data Link Connection Indices. DLCINumber is, by definition, the largest possible DLCI value possible under the configured Q.922 Address Format.

Structure of MIB

The MIB is composed of three groups, one defining the Data Link Connection Management Interface (DLCMI), one describing the Circuits, and a third describing errors.

During normal operation, Frame Relay virtual circuits will be added, deleted and change availability. The occurrence of such changes is of interest to the network manager and therefore, one trap is defined, intended to be corollary to the SNMP "Link Up" and "Link Down" traps.

Definitions

 RFC1315-MIB DEFINITIONS ::= BEGIN
 IMPORTS
         OBJECT-TYPE
                 FROM RFC-1212
         transmission
                 FROM RFC1213-MIB
         TimeTicks
                 FROM RFC-1155
         TRAP-TYPE
                 FROM RFC-1215;
 --  Frame Relay DTE MIB
 frame-relay     OBJECT IDENTIFIER ::= { transmission 32 }
 --
 --      the range of ifIndex
 --
 Index ::= INTEGER       -- 1..ifNumber
 --
 --      the range of a Data Link Connection Identifier
 --
 DLCI ::= INTEGER        -- 0..DLCINumber

 --  Data Link Connection Management Interface
 --      The variables that configure the DLC Management Interface.
 frDlcmiTable OBJECT-TYPE
     SYNTAX   SEQUENCE OF FrDlcmiEntry
     ACCESS   not-accessible
     STATUS   mandatory
     DESCRIPTION
        "The Parameters for the Data Link Connection Management
        Interface for the frame relay service on this
        interface."
     REFERENCE

        "Draft American National Standard T1.617-1991, Annex D"
     ::= { frame-relay 1 }
     frDlcmiEntry OBJECT-TYPE
         SYNTAX   FrDlcmiEntry
         ACCESS   not-accessible
         STATUS   mandatory
         DESCRIPTION
            "The Parameters for a particular Data Link Con-
            nection Management Interface."
        INDEX { frDlcmiIfIndex }
        ::= { frDlcmiTable 1 }
     FrDlcmiEntry ::=
         SEQUENCE {
             frDlcmiIfIndex
                 Index,
             frDlcmiState
                 INTEGER,
             frDlcmiAddress
                 INTEGER,
             frDlcmiAddressLen
                 INTEGER,
             frDlcmiPollingInterval
                 INTEGER,
             frDlcmiFullEnquiryInterval
                 INTEGER,
             frDlcmiErrorThreshold
                 INTEGER,
             frDlcmiMonitoredEvents
                 INTEGER,
             frDlcmiMaxSupportedVCs
                 INTEGER,
             frDlcmiMulticast
                 INTEGER
     }

     frDlcmiIfIndex OBJECT-TYPE
         SYNTAX   Index
         ACCESS   read-only
         STATUS   mandatory
         DESCRIPTION
            "The ifIndex value of the  corresponding  ifEn-
            try."
        ::= { frDlcmiEntry 1 }

     frDlcmiState OBJECT-TYPE
         SYNTAX INTEGER {
             noLmiConfigured (1),
             lmiRev1         (2),
             ansiT1-617-D    (3),  -- ANSI T1.617 Annex D
             ansiT1-617-B    (4)   -- ANSI T1.617 Annex B
         }
         ACCESS   read-write
         STATUS   mandatory
         DESCRIPTION
            "This variable states which Data  Link  Connec-
            tion Management scheme is active (and by impli-
            cation, what DLCI it uses) on the  Frame  Relay
            interface."
        REFERENCE
           "Draft American National Standard T1.617-1991"
       ::= { frDlcmiEntry 2 }

     frDlcmiAddress OBJECT-TYPE
         SYNTAX      INTEGER {
                     q921           (1),  -- 13 bit DLCI
                     q922March90    (2),  -- 11 bit DLCI
                     q922November90 (3),  -- 10 bit DLCI
                     q922           (4)   -- Final Standard
         }
         ACCESS  read-write
         STATUS  mandatory
         DESCRIPTION
            "This variable states which address  format  is
            in use on the Frame Relay interface."
        ::= { frDlcmiEntry 3 }

     frDlcmiAddressLen OBJECT-TYPE
         SYNTAX  INTEGER {
                 two-octets (2),
                 three-octets (3),
                 four-octets (4)
         }
         ACCESS  read-write
         STATUS  mandatory
         DESCRIPTION
            "This variable states which address  length  in
            octets.  In the case of Q922 format, the length
            indicates the entire length of the address  in-
            cluding the control portion."

        ::= { frDlcmiEntry 4 }

     frDlcmiPollingInterval OBJECT-TYPE
         SYNTAX   INTEGER (5..30)
         ACCESS   read-write
         STATUS   mandatory
         DESCRIPTION
            "This is the number of seconds between  succes-
            sive status enquiry messages."
        REFERENCE
           "Draft American National  Standard  T1.617-1991,
           Section D.7 Timer T391."
       DEFVAL { 10 }
       ::= { frDlcmiEntry 5 }

     frDlcmiFullEnquiryInterval OBJECT-TYPE
         SYNTAX   INTEGER (1..255)
         ACCESS   read-write
         STATUS   mandatory
         DESCRIPTION
            "Number of status enquiry intervals  that  pass
            before  issuance  of a full status enquiry mes-
            sage."
        REFERENCE
           "Draft American National  Standard  T1.617-1991,
           Section D.7 Counter N391."
       DEFVAL { 6 }
       ::= { frDlcmiEntry 6 }

     frDlcmiErrorThreshold OBJECT-TYPE
         SYNTAX   INTEGER (1..10)
         ACCESS   read-write
         STATUS   mandatory
         DESCRIPTION
            "This  is  the  maximum  number  of  unanswered
            Status Enquiries the equipment shall accept be-
            fore declaring the interface down."
        REFERENCE
           "Draft American National  Standard  T1.617-1991,
           Section D.5.1 Counter N392."
       DEFVAL { 3 }
       ::= { frDlcmiEntry 7 }

     frDlcmiMonitoredEvents OBJECT-TYPE
         SYNTAX   INTEGER (1..10)
         ACCESS   read-write
         STATUS   mandatory
         DESCRIPTION
            "This is the number of status polling intervals
            over which the error threshold is counted.  For
            example, if within 'MonitoredEvents' number  of
            events  the  station  receives 'ErrorThreshold'
            number of errors, the interface  is  marked  as
            down."
        REFERENCE
           "Draft American National  Standard  T1.617-1991,
           Section D.5.2 Counter N393."
       DEFVAL { 4 }
       ::= { frDlcmiEntry 8 }

     frDlcmiMaxSupportedVCs OBJECT-TYPE
         SYNTAX   INTEGER
         ACCESS   read-write
         STATUS   mandatory
         DESCRIPTION
            "The maximum number of Virtual Circuits allowed
            for  this  interface.   Usually dictated by the
            Frame Relay network.
            In response to a SET, if a value less than zero
            or  higher  than the agent's maximal capability
            is configured, the agent  should  respond  bad-
            Value"
        ::= { frDlcmiEntry 9 }

     frDlcmiMulticast OBJECT-TYPE
         SYNTAX   INTEGER {
                     nonBroadcast (1),
                     broadcast (2)
                     }
         ACCESS   read-write
         STATUS   mandatory
         DESCRIPTION
            "This indicates whether the Frame Relay  inter-
            face is using a multicast service."
        ::= { frDlcmiEntry 10 }

 -- A Frame Relay service is a multiplexing service.  Data
 -- Link Connection Identifiers enumerate virtual circuits
 -- (permanent or dynamic) which are layered onto the underlying
 -- circuit, represented by ifEntry.  Therefore, each of the entries
 -- in the Standard MIB's Interface Table with an IfType of
 -- Frame Relay represents a Q.922 interface.  Zero or more
 -- virtual circuits are layered onto this interface and provide
 -- interconnection with various remote destinations.
 -- Each such virtual circuit is represented by an entry in the
 -- circuit table.
 --   Circuit Table
 -- The table describing the use of the DLCIs attached to
 -- each Frame Relay Interface.
 frCircuitTable OBJECT-TYPE
     SYNTAX   SEQUENCE OF FrCircuitEntry
     ACCESS   not-accessible
     STATUS   mandatory
     DESCRIPTION
        "A table containing information about specific Data
        Link Connection Identifiers and corresponding virtual
        circuits."
     ::= { frame-relay 2 }
     frCircuitEntry OBJECT-TYPE
         SYNTAX   FrCircuitEntry
         ACCESS   not-accessible
         STATUS   mandatory
         DESCRIPTION
            "The information regarding a single  Data  Link
            Connection Identifier."
        INDEX { frCircuitIfIndex, frCircuitDlci }
        ::= { frCircuitTable 1 }

     FrCircuitEntry ::=
         SEQUENCE {
             frCircuitIfIndex
                 Index,
             frCircuitDlci
                 DLCI,
             frCircuitState
                 INTEGER,
             frCircuitReceivedFECNs
                 Counter,
             frCircuitReceivedBECNs

                 Counter,
             frCircuitSentFrames
                 Counter,
             frCircuitSentOctets
                 Counter,
             frCircuitReceivedFrames
                 Counter,
             frCircuitReceivedOctets
                 Counter,
             frCircuitCreationTime
                 TimeTicks,
             frCircuitLastTimeChange
                 TimeTicks,
             frCircuitCommittedBurst
                 INTEGER,
             frCircuitExcessBurst
                 INTEGER,
             frCircuitThroughput
                 INTEGER
     }

     frCircuitIfIndex OBJECT-TYPE
         SYNTAX   Index
         ACCESS   read-only
         STATUS   mandatory
         DESCRIPTION
            "The ifIndex Value of the ifEntry this  virtual
            circuit is layered onto."
        ::= { frCircuitEntry 1 }

     frCircuitDlci OBJECT-TYPE
         SYNTAX   DLCI
         ACCESS   read-only
         STATUS   mandatory
         DESCRIPTION
            "The Data Link Connection Identifier  for  this
            virtual circuit."
        REFERENCE
           "Draft American National  Standard  T1.618-1991,
           Section 3.3.6"
       ::= { frCircuitEntry 2 }

     frCircuitState OBJECT-TYPE
         SYNTAX   INTEGER {
                     invalid (1),
                     active (2),
                     inactive (3)
                  }
         ACCESS   read-write
         STATUS   mandatory
         DESCRIPTION
            "Indicates whether the particular virtual  cir-
            cuit  is operational.  In the absence of a Data
            Link Connection Management  Interface,  virtual
            circuit  entries  (rows) may be created by set-
            ting virtual  circuit  state  to  'active',  or
            deleted by changing Circuit state to 'invalid'.
            Whether or not the row actually  disappears  is
            left  to the implementation, so this object may
            actually read as 'invalid' for  some  arbitrary
            length  of  time.   It is also legal to set the
            state of a virtual  circuit  to  'inactive'  to
            temporarily disable a given circuit."
        DEFVAL { active }
        ::= { frCircuitEntry 3 }

     frCircuitReceivedFECNs OBJECT-TYPE
         SYNTAX   Counter
         ACCESS   read-only
         STATUS   mandatory
         DESCRIPTION
            "Number of frames received from the network in-
            dicating  forward  congestion since the virtual
            circuit was created."
        REFERENCE
           "Draft American National  Standard  T1.618-1991,
           Section 3.3.3"
       ::= { frCircuitEntry 4 }

     frCircuitReceivedBECNs OBJECT-TYPE
         SYNTAX   Counter
         ACCESS   read-only
         STATUS   mandatory
         DESCRIPTION
            "Number of frames received from the network in-
            dicating  backward congestion since the virtual
            circuit was created."

        REFERENCE
           "Draft American National  Standard  T1.618-1991,
           Section 3.3.4"
       ::= { frCircuitEntry 5 }

     frCircuitSentFrames OBJECT-TYPE
         SYNTAX   Counter
         ACCESS   read-only
         STATUS   mandatory
         DESCRIPTION
            "The number of frames sent  from  this  virtual
            circuit since it was created."
        ::= { frCircuitEntry 6 }

     frCircuitSentOctets OBJECT-TYPE
         SYNTAX   Counter
         ACCESS   read-only
         STATUS   mandatory
         DESCRIPTION
            "The number of octets sent  from  this  virtual
            circuit since it was created."
        ::= { frCircuitEntry 7 }

     frCircuitReceivedFrames OBJECT-TYPE
         SYNTAX   Counter
         ACCESS   read-only
         STATUS   mandatory
         DESCRIPTION
            "Number of frames received  over  this  virtual
            circuit since it was created."
        ::= { frCircuitEntry 8 }

     frCircuitReceivedOctets OBJECT-TYPE
         SYNTAX   Counter
         ACCESS   read-only
         STATUS   mandatory
         DESCRIPTION
            "Number of octets received  over  this  virtual
            circuit since it was created."
        ::= { frCircuitEntry 9 }

     frCircuitCreationTime OBJECT-TYPE
         SYNTAX   TimeTicks
         ACCESS   read-only
         STATUS   mandatory
         DESCRIPTION
            "The value of sysUpTime when the  virtual  cir-
            cuit was created, whether by the Data Link Con-
            nection Management Interface  or  by  a  SetRe-
            quest."
        ::= { frCircuitEntry 10 }

     frCircuitLastTimeChange OBJECT-TYPE
         SYNTAX   TimeTicks
         ACCESS   read-only
         STATUS   mandatory
         DESCRIPTION
            "The value of sysUpTime when last there  was  a
            change in the virtual circuit state"
        ::= { frCircuitEntry 11 }

     frCircuitCommittedBurst OBJECT-TYPE
         SYNTAX   INTEGER
         ACCESS   read-write
         STATUS   mandatory
         DESCRIPTION
            "This variable indicates the maximum amount  of
            data,  in  bits,  that  the  network  agrees to
            transfer under normal  conditions,  during  the
            measurement interval."
        REFERENCE
           "Draft American National  Standard  T1.617-1991,
           Section 6.5.19"
       DEFVAL   { 0 }  -- the default indicates no commitment
       ::= { frCircuitEntry 12 }

     frCircuitExcessBurst OBJECT-TYPE
         SYNTAX   INTEGER
         ACCESS   read-write
         STATUS   mandatory
         DESCRIPTION
            "This variable indicates the maximum amount  of
            uncommitted data bits that the network will at-

            tempt to deliver over the measurement interval.
            By default, if not configured when creating the
            entry, the Excess Information Burst Size is set
            to the value of ifSpeed."
        REFERENCE
           "Draft American National  Standard  T1.617-1991,
           Section 6.5.19"
               ::= { frCircuitEntry 13 }

     frCircuitThroughput OBJECT-TYPE
         SYNTAX   INTEGER
         ACCESS   read-write
         STATUS   mandatory
         DESCRIPTION
            "Throughput is the average number of 'Frame Re-
            lay  Information  Field'  bits  transferred per
            second across a user network interface  in  one
            direction, measured over the measurement inter-
            val.
            If the  configured  committed  burst  rate  and
            throughput  are  both non-zero, the measurement
            interval
            T=frCircuitCommittedBurst/frCircuitThroughput.
            If the  configured  committed  burst  rate  and
            throughput  are  both zero, the measurement in-
            terval
                   T=frCircuitExcessBurst/ifSpeed."
        REFERENCE
           "Draft American National  Standard  T1.617-1991,
           Section 6.5.19"
       DEFVAL {0}  -- the default value of Throughput is
                   -- "no commitment".
       ::= { frCircuitEntry 14 }

 --  Error Table
 -- The table describing errors encountered on each Frame
 -- Relay Interface.
 frErrTable OBJECT-TYPE
     SYNTAX   SEQUENCE OF FrErrEntry
     ACCESS   not-accessible

     STATUS   mandatory
     DESCRIPTION
        "A table containing information about Errors on the
        Frame Relay interface."
     ::= { frame-relay 3 }
     frErrEntry OBJECT-TYPE
         SYNTAX   FrErrEntry
         ACCESS   not-accessible
         STATUS   mandatory
         DESCRIPTION
            "The error information for a single frame relay
            interface."
        INDEX { frErrIfIndex }
        ::= { frErrTable 1 }

     FrErrEntry ::=
         SEQUENCE {
             frErrIfIndex
                 Index,
             frErrType
                 INTEGER,
             frErrData
                 OCTET STRING,
             frErrTime
                 TimeTicks
     }

     frErrIfIndex OBJECT-TYPE
         SYNTAX   Index
         ACCESS   read-only
         STATUS   mandatory
         DESCRIPTION
            "The ifIndex Value of the  corresponding  ifEn-
            try."
        ::= { frErrEntry 1 }

     frErrType OBJECT-TYPE
         SYNTAX   INTEGER {
                     unknownError(1),
                     receiveShort(2),
                     receiveLong(3),

                     illegalDLCI(4),
                     unknownDLCI(5),
                     dlcmiProtoErr(6),
                     dlcmiUnknownIE(7),
                     dlcmiSequenceErr(8),
                     dlcmiUnknownRpt(9),
                     noErrorSinceReset(10)
                  }
         ACCESS   read-only
         STATUS   mandatory
         DESCRIPTION
            "The type of error that was last seen  on  this
            interface."
        ::= { frErrEntry 2 }

     frErrData OBJECT-TYPE
         SYNTAX   OCTET STRING
         ACCESS   read-only
         STATUS   mandatory
         DESCRIPTION
            "An octet string containing as much of the  er-
            ror  packet as possible.  As a minimum, it must
            contain the Q.922 Address or  as  much  as  was
            delivered.   It is desirable to include all in-
            formation up to the PDU."
        ::= { frErrEntry 3 }

     frErrTime OBJECT-TYPE
         SYNTAX   TimeTicks
         ACCESS   read-only
         STATUS   mandatory
         DESCRIPTION
            "The value of sysUpTime at which the error  was
            detected."
        ::= { frErrEntry 4 }

     -- Frame Relay Globals
     frame-relay-globals OBJECT IDENTIFIER ::= { frame-relay 4 }
     frTrapState OBJECT-TYPE
         SYNTAX  INTEGER { enabled(1), disabled(2) }
         ACCESS   read-write

         STATUS   mandatory
         DESCRIPTION
            "This variable  indicates  whether  the  system
            produces the frDLCIStatusChange trap."
        DEFVAL { disabled }
        ::= { frame-relay-globals 1 }

     --  Data Link Connection Management Interface Related Traps
     frDLCIStatusChange TRAP-TYPE
         ENTERPRISE frame-relay
         VARIABLES  { frCircuitIfIndex, frCircuitDlci, frCircuitState }
         DESCRIPTION
            "This trap indicates that the indicated Virtual
            Circuit  has changed state.  It has either been
            created or invalidated, or has toggled  between
            the active and inactive states."
         ::= 1
 END

Acknowledgements

This document was produced by the IP Over Large Public Data Networks (IPLPDN) Working Group. The following people provided additional comments and suggestions: Art Berggreen of Advanced Computer Communications, and Jim Philippou of Xyplex Communications.

References

[1] Cerf, V., "IAB Recommendations for the Development of Internet

   Network Management Standards", RFC 1052, NRI, April 1988.

[2] Cerf, V., "Report of the Second Ad Hoc Network Management Review

   Group", RFC 1109, NRI, August 1989.

[3] Rose M., and K. McCloghrie, "Structure and Identification of

   Management Information for TCP/IP-based internets", RFC 1155,
   Performance Systems International, Hughes LAN Systems, May 1990.

[4] McCloghrie K., and M. Rose, "Management Information Base for

   Network Management of TCP/IP-based internets", RFC 1156, Hughes
   LAN Systems, Performance Systems International, May 1990.

[5] Case, J., Fedor, M., Schoffstall, M., and J. Davin, "Simple

   Network Management Protocol", RFC 1157, SNMP Research,
   Performance Systems International, Performance Systems
   International, MIT Laboratory for Computer Science, May 1990.

[6] McCloghrie K., and M. Rose, Editors, "Management Information Base

   for Network Management of TCP/IP-based internets", RFC 1213,
   Performance Systems International, March 1991.

[7] Information processing systems - Open Systems Interconnection -

   Specification of Abstract Syntax Notation One (ASN.1),
   International Organization for Standardization, International
   Standard 8824, December 1987.

[8] 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.

[9] Rose, M., and K. McCloghrie, Editors, "Concise MIB Definitions",

   RFC 1212, Performance Systems International, Hughes LAN Systems,
   March 1991.
 [10] Rose, M., Editor, "A Convention for Defining Traps for use with
   the SNMP", RFC 1215, Performance Systems International, March
   1991.

Security Considerations

Security issues are not discussed in this memo.

Authors' Addresses

Caralyn Brown Wellfleet Communications, Inc. 15 Crosby Drive Bedford, Massachusetts 01730 Phone: (617) 275-2400 EMail: [email protected]

Fred Baker Advanced Computer Communications 315 Bollay Drive Sannta Barbara, California 93117 Phone: (805) 685-4455 EMail: [email protected]

Charles Carvalho Advanced Computer Communications 315 Bollay Drive Sannta Barbara, California 93117 Phone: (805) 685-4455 EMail: [email protected]