Document:

<PAGE>   1
                                                                   EXHIBIT 10.13

                             EMPLOYMENT AGREEMENT

THIS AGREEMENT (this "Agreement") is executed at 1215 Apollo Way, Sunnyvale,
CA  94086, Santa Clara County, California between INVERSE NETWORK TECHNOLOGY,
a California corporation and its affiliates (the "Company"), and Michael
Watters, whose address is Emilie Avenue, Atherton, CA 94025  ("Employee")
on this 15th day of September  1999, and shall be effective as of the Closing
Date (as defined in the Merger Agreement (as defined)).

WHEREAS, Employee has heretofore been employed by the Company, serving as
President and Chief Executive Officer;

WHEREAS, Employee is the holder of 3,924,000 shares of the common stock,
7,500 shares of Series A Preferred Stock and 6,066 shares of Series B
Preferred Stock, each of the Company (the "Employee Shares");

WHEREAS, the Company, Visual Networks, Inc. ("Visual"), and Visual
Acquisitions Two, Inc. have executed an Agreement and Plan of Merger (the
"Merger Agreement") which will result in the Employee Shares in the Company
being converted into shares of Visual (the "Merger");

WHEREAS, as a condition of the future employment of Employee by the Company,
the parties now wish to set forth their agreements relating to Employee's
employment with the Company in accordance with the terms and conditions
specified in this Agreement;

NOW, THEREFORE, in consideration of the premises, the future employment of
Employee by the Company, and the mutual covenants contained herein, the
parties agree as follows:

1.    EMPLOYMENT.  The Company hereby employees Employee, and Employee
      accepts such employment, as President and Chief Executive Office for
      the Company prior to the Merger, and as Chief Operating Officer of
      Visual after the Merger, to perform such duties as may be reasonably
      assigned by the Company's Board of Directors or, following the Merger,
      by Visual's Board of Directors or Chief Executive Officer.  Employee
      will also perform such additional duties as he may be assigned.
      Employee and the Company both recognize that the services to be
      rendered by Employee during the term of his employment are special,
      unique, and of extraordinary character.

2.    MANNER OF PERFORMANCE.  Employee shall devote his full business time,
      best efforts and ability, skill and attention exclusively to the duties
      assigned to him from time to time and to the furtherance of the best
      business objectives and interests of the Company, all to the exclusion
      of other employers or interests, or their products and service.
      Notwithstanding the foregoing, Employee may engage in activities in
      connection with any charitable or civic activities, personal
      investments, serving as a director or advisor to other companies or
      ventures or as an executor, trustee or in other similar fiduciary
      capacity; provided, however, that such activities do not interfere with
      his performance of his responsibilities

<PAGE>   2

      and obligations pursuant to this Agreement and are not competitive with
      the Company.

3.    COMPENSATION.

      (a)   For all of the service rendered by Employee to the Company,
      Employee shall receive an annual base salary of not less than One
      Hundred and Seventy Five Thousand dollars ($175,000), payable in
      reasonable periodic installments in accordance with the Company's
      regular payroll practices in effect from time to time.

      (b)   In addition to Employee's base salary, Employee shall be eligible
      for an annual bonus targeted at twenty-five percent (25%) of his then
      base salary.

      (c)   Throughout the term of this Agreement and as long as they are
      kept in force by the Company, Employee shall be entitled to participate
      in and receive such employee benefits and perquisites as are available
      to other similarly situated employees of the Company.

4.    SPECIALIZED TRAINING.  The Company has provided and shall continue to
      provide Employee with specialized and shall furnish him with all of the
      proprietary information of the Company.  All such information,
      equipment and materials shall remain the property of the Company and
      shall be returned upon demand.

5.    PROPRIETARY INFORMATION AGREEMENT.  Employee and the Company
      acknowledge and agree that the Proprietary Information Agreement dated
      as of ________, 199__, shall remain in full force and effect.

6.    PROTECTION OF THE COMPANY'S BUSINESS.  Employee agrees and covenants
      that, during the term of his employment with the Company and for a
      period of eighteen (18) months from the effective date of the Merger,
      the Employee will not directly or indirectly, in all locations where
      the Company carries on business, including Sunnyvale and Santa Clara
      County:

      (a)   recruit, solicit or induce, or attempt to induce, any employee or
      employees of the Company or its affiliates to terminate their
      employment with, or otherwise cease their relationship with, the
      Company or its affiliates; or

      (b)   make any competitive sales or service contracts with, or solicit,
      accept, or service any competitive business from, any client or
      customer of the Company for whom Employee had sales or service or other
      material responsibilities during Employee's employment with the
      Company; or

      (c)   in any other way carry on a business competitive to that of the
      Company.

7.    REMEDIES.  In the event of a breach or threatened breach by Employee of
      any obligation(s) or covenant(s) under Section 6 of this Agreement, the
      Company shall be

<PAGE>   3

      entitled to injunctive relief in addition to any and all other rights and
      remedies which it may have.

8.    TERMINATION OF EMPLOYMENT.

      (a)   With Cause:  Employee's employment may be terminated by the
      Company without advance notice to Employee for "cause." As used in this
      Agreement, "cause" shall be defined as:

            (i)   conviction of or plea of nolo contendre to a nonvehicular
      felony;

            (ii)  willful violation of specific and lawful directions from
      the Board of Directors of the Company or excessive absenteeism which
      shall continue for a period of thirty (30) days after written notice
      thereof is given of such violation or absenteeism;

            (iii) embezzlement or theft of Company assets, or other fraud or
      dishonesty as determined in a court of law; or

            (iv)  material breach by Employee of the provisions of this
      Agreement, which breach shall continue for a period of thirty (30) days
      after a written notice thereof is given to Employee.

      (b)   Without Cause:  The employment of Employee may be terminated
      without cause by either party upon two (2) weeks notice.  In the event
      Employee's employment is terminated without cause, or in the event
      Employee voluntarily resigns his employment for good reason, Employee
      shall be entitled to the following as severance:

            (i)   in a lump sum all unpaid salary, vacation and bonus accrued
      through the date of termination;

            (ii)  payable in the discretion of the Company either in a lump
      sum or over a period of twelve (12) months in accordance with the
      Company's normal payroll practices, an amount equal to the sum of (x)
      Employee's one year base salary then in effect and (y) the greater of
      the amount Employee would have received as a bonus in the year of
      termination assuming that all performance targets or other conditions
      for receipt of such bonus were met, or the amount of Employee's bonus
      in the year prior to termination;

            (iii) notwithstanding any provision to the contrary contained in
      any plan or agreement, Employee shall become 100% vested in all
      restricted stock owned by Employee as of the date hereof to the extent
      not previously vested.

      As used in this Agreement, "good reason" shall mean:

            (A)   the assignment to Employee of any duties materially
      inconsistent with his

<PAGE>   4

      authority, duties or responsibilities, or any other action by the Company
      which results in a material diminution or material adverse change in such
      authority, duties or responsibilities, other than such assignment or any
      other such action which is not related to any failure by Employee to
      satisfy mutually agreed upon performance goals, excluding for this purpose
      an isolated action not taken in bad faith by the Company and which is
      remedied prior to the expiration of the 30-day period after receipt of
      notice thereof given by Employee; or

            (B)   any material breach of this Agreement by the Company, other
      than an isolated failure not occurring in bad faith and which is
      remedied prior to the expiration of the 30-day period after receipt of
      written notice thereof given by Employee; or

            (C)   any material reduction in Employee's base salary or bonus
      opportunities which is not related to any failure by Employee to
      satisfy mutually agreed upon performance goals; or

            (D)   without Employee's consent, relocation of Employee's
      principal office location by more than 20 miles from Sunnyvale,
      California.

9.    SEVERABILITY.  If any clause or portion of this Agreement, or any
      covenant or restriction against competition set forth herein, is
      determined or declared to be void, unenforceable, excessive, or
      unreasonable, all remaining parts of the Agreement shall be enforceable
      to the full extent found valid and/or reasonable by any Court of
      competent jurisdiction.

10.   GENERAL CONDITIONS.  This Agreement is executed under and shall be
      construed in accordance with the laws of the State of California,
      irrespective of the legal residence of the Employee.  The rights and
      obligations hereunder shall be binding upon and inure to the benefit of
      the successors or assigns of the parties.  No waiver by the Company of
      any breach hereunder by Employee shall be deemed or construed as a
      waiver of any other breach or of any subsequent breach.  This Agreement
      constitutes the entire agreement between the parties and all prior or
      contemporaneous agreements or understandings, whether written or oral,
      are revoked and integrated herein.

<PAGE>   5

      IN WITNESS WHEREOF, the parties have each caused this Employment
Agreement to be executed on the day and in the year below written.

                        INVERSE NETWORK TECHNOLOGY

Dated:     /    /             By: /s/ MIKE GENNERO
                                 ----------------------------
                              Name:  Mike Gennero
                              Title: CFO

Dated:     /    /             /s/ MICHAEL WATTERS
                              -------------------------------
                              Employee<PAGE>   1

                                                                EXHIBIT 10.10(a)

                                HESKA CORPORATION

                              AMENDED AND RESTATED
                              EMPLOYMENT AGREEMENT
                                      WITH
                                ROBERT B. GRIEVE

     THIS AMENDED AND RESTATED EMPLOYMENT AGREEMENT ("Agreement") is entered
into effective as of February 23, 2000, by and between Heska Corporation,
formerly Paravax, Inc. ("Company") and Robert B. Grieve ("Employee"). Company
and Employee are collectively referred to herein as the "Parties."

     WHEREAS, effective as of January 1, 1994, Company and Employee entered into
an Employment Agreement, as amended by Amendment No. 1 to Employment Agreement
dated effective as of March 4, 1997 (together, the "Employment Agreement"); and

     WHEREAS, the Parties desire to restate the Employment Agreement for ease of
reference and to further amend said agreement for the purpose of making certain
provisions more consistent with current Company practice.

     NOW THEREFORE, in consideration of the foregoing, the Parties agree as
follows:

A.   The Employment Agreement is hereby restated and amended as set forth below:

     1. Employment. Company hereby employs Employee as its Vice Chairman of the
     Board of Directors and Chief Executive Officer, and Employee hereby accepts
     such employment.

     2. Duties and Responsibilities. Employee shall serve as Vice Chairman of
     the Board of Directors and Chief Executive Officer, with such duties and
     responsibilities as may be assigned to him from time to time by or under
     the direction of the Board of Directors of Company, and with such on-going
     daily duties and responsibilities as are typically entailed in such
     position. Employee shall devote his full time and energies to such duties.

     3. Compensation. Company shall pay Employee, as compensation for services
     rendered under this Agreement, a "base salary" per year, payable in
     accordance with the usual and customary payroll practices of Company. If
     for any reason during any given year, Employee does not work an entire
     year, other than normal vacations as provided hereunder, the compensation
     will be prorated to compensate only for the actual time worked.

<PAGE>   2

     4. Expenses. Company shall reimburse Employee for his reasonable
     out-of-pocket expenses incurred in connection with the business of Company,
     including travel away from the Company's facilities, upon presentation of
     appropriate written receipts and reports and subject to the customary
     practices of Company.

     5. Employee Benefits. During the term of his employment hereunder, Employee
     shall be entitled to receive the same benefits that the Board of Directors
     establishes generally for the officers and other employees of Company.
     These may include from time to time, medical insurance, life insurance,
     paid vacation time and medical disability insurance.

     6. Termination.

        (a) At-Will. This is an at-will employment agreement and does not bind
        either of the parties to any specific term or duration.

            (i) Employee is free to terminate employment with Company at any
            time, for any reason, or for no reason, and without any prior
            notice.

            (ii) Company is free to terminate the employment of Employee at any
            time, for any reason or for no reason, for cause or without cause,
            and without any prior notice.

        (b) Severance Pay.

            (i) Upon "Involuntary Termination" of his employment (as defined in
            subsections (ii) and (iii) below), Employee will be entitled to
            severance pay in the amount of one (1) year's "base salary" in not
            less than twelve equal monthly installments (subject to all
            applicable tax and other deductions), with the first installment
            being due 15 days after the date of termination and with the
            following installments due no later than monthly thereafter on
            Company's then regular payroll dates. Upon "Involuntary Termination"
            of his employment (as defined in subsections (ii) and (iii) below,
            Company also will pay (or reimburse Employee for) the health
            insurance premiums for the medical and dental insurance coverage
            maintained by Company at the time of termination for Employee and
            his eligible dependents for a period of one year after the date of
            termination, provided that, Company's obligations for such payments
            shall cease immediately if Employee becomes (and remains) covered
            under the medical and dental insurance plan of another employer with
            coverages and benefits comparable to those provided under Company's
            plans and the premiums for which are paid in full by such other
            employer. In

                                       2

<PAGE>   3

            the event such benefits provided by the other employer shall cease
            at any time during the one-year period following Employee's
            termination from Company, Company's obligations for payment or
            reimbursement of premiums under this subsection shall resume for the
            remainder of such one-year period. Upon request by the Company,
            Employee will sign a release of claims against Company and its
            affiliates as a condition of receiving severance pay, payment or
            reimbursement of insurance premiums, or any other benefits or
            payments provided in Section 6(b) of this Agreement. If Employee's
            employment shall end for any reason(s) other than those described in
            subsections (ii) and (iii), below, as "Involuntary Termination,"
            Employee shall only receive pay and benefits which Employee earned
            as of the date of termination.

            (ii) If the Employee is subjected to "Involuntary Termination" under
            this subsection (ii), Employee also shall be entitled to an
            additional twelve (12) months of vesting (calculated from the
            effective termination date, and not from the end of the severance
            pay period) under all stock option agreements, stock purchase
            agreements or other stock rights granted to Employee by Company
            prior to the effective termination date. "Involuntary termination"
            under this subsection (ii) shall mean any termination of Employee's
            employment by Company, other than a termination under one or more of
            the following circumstances:

                 (A) any termination by Company or Employee following Employee's
                 refusal to accept a reasonable transfer to a position with
                 comparable responsibility and salary with any affiliated
                 company that does not involve commuting more than fifty (50)
                 miles each way from his home in the Fort Collins, Colorado
                 area, unless such circumstances constitute a Change of Control
                 Event as defined in subsection (iii), below;

                 (B) Employee shall die, be adjudicated to be mentally
                 incompetent or become mentally or physically disabled to such
                 an extent that Employee is unable to perform his duties under
                 this Employment Agreement for a period of ninety (90)
                 consecutive days;

                 (C) Employee shall commit any material breach of his
                 obligations under this Agreement;

                 (D) Employee shall commit any material breach of any fiduciary
                 duty to Company;

                                       3

<PAGE>   4

                  (E) Employee shall be convicted of, or enter a plea of nolo
                  contendere to, any crime involving moral turpitude or
                  dishonesty, whether a felony or misdemeanor, or any crime
                  which reflects so negatively on Company to be detrimental to
                  Company's image or interests;

                  (F) Employee shall commit repeated insubordination or refusal
                  to comply with any reasonable request of the Board of
                  Directors of Company related to the scope or performance of
                  Employee's duties;

                  (G) Employee shall possess any illegal drug on Company
                  premises or Employee shall be under the influence of illegal
                  drugs or abusing prescription drugs or alcohol while on
                  Company business, attending Company-sponsored functions, or on
                  Company premises; or

                  (H) Employee shall conduct himself in a manner which, in the
                  good faith and reasonable determination of the Board of
                  Directors of Company demonstrates Employee's substantial
                  unfitness to serve.

            (iii) For purposes of this Section 6(b), "Involuntary Termination"
            also shall include a "Change of Control Event." If Employee's
            employment shall end as the result of such "Change of Control
            Event", Employee also shall be entitled to the immediate vesting as
            of the effective date of termination, under all stock option
            agreements, stock purchase agreements, or other stock rights granted
            to Employee by Company prior to the effective termination date. A
            "Change of Control Event" shall occur when, in connection with the
            merger, acquisition or sale of Company or substantially all of
            Company's assets with, into or to a previously unaffiliated third
            party,

                  (A) Employee declines to continue his employment with the
                  acquiring company within 30 days following the consummation of
                  such merger, acquisition, or sale;

                  (B) Employee is not offered or continued in a position of
                  employment with the acquiring entity with comparable pay,
                  benefits, title, and responsibility, for a period of at least
                  nine (9) months following the consummation of such merger,
                  acquisition, or sale, and Employee resigns as a result, with
                  such resignation being submitted no later than

                                       4

<PAGE>   5

                  ten (10) days after the date on which Employee is not offered
                  or continued in such position; or

                  (C) the acquiring company fails to assume or be bound by the
                  terms of this Agreement.

     7. Proprietary Information. Employee agrees that if he has not already done
     so, he will promptly execute Company's standard employee proprietary
     information and assignment of inventions agreement.

     8. Attorneys' Fees. If any legal action arises under this Agreement or by
     reason of any asserted breach of it, the prevailing party shall be entitled
     to recover all costs and expenses, including reasonable attorney's fees,
     incurred in enforcing or attempting to enforce any of the terms, covenants
     or conditions, including costs incurred prior to commencement of legal
     action, and all costs and expenses, including reasonable attorney's fees,
     incurred in any appeal from an action brought to enforce any of the terms,
     covenants or conditions. For purposes of this section, "prevailing party"
     includes without limitation, a party who agrees to dismiss a suit or
     proceeding upon the other's payment or performance of substantially the
     relief sought.

     9. Notices. Any notice to be given to Company under the terms of this
     Agreement shall be addressed to Company at the address of its principal
     place of business, and any notice to be given to Employee shall be
     addressed to him at his home address last shown on the records of Company,
     or to such other address as a party shall have given notice of hereunder.

     10. Miscellaneous. This Agreement shall be governed by the laws of the
     State of Colorado as applied to contracts between residents of that state
     to be performed wholly within that state. This Agreement is the entire
     agreement of the Parties with respect to the subject matter hereof and
     supersedes all prior understandings and agreements. This Agreement may be
     modified only by a writing signed by both Parties. This Agreement shall be
     binding upon and shall inure to the benefit of the successors and assigns
     of the Parties.

                                       5

<PAGE>   6

IN WITNESS WHEREOF, the Parties hereto have executed this Agreement the day and
year hereinabove written.

                                       HESKA CORPORATION

                                       By: /s/ Fred M. Schwarzer
                                           -------------------------------------

                                       Its: Chairman of the Board
                                            ------------------------------------

                                       EMPLOYEE

                                       Name: /s/ Robert B. Grieve
                                             -----------------------------------
                                             Robert B. Grieve

                                       6

Source: [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00004-of-00352.parquet"}, [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00004-of-00352.parquet"}]]