Document:

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                                                                    EXHIBIT 10.7

                   AMENDED AND RESTATED TAX SHARING AGREEMENT

                                    BETWEEN

                                EMC CORPORATION

                                      AND

                               McDATA CORPORATION

                          EFFECTIVE AS OF MAY 31, 2000

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                                                                    EXHIBIT 10.7

                   AMENDED AND RESTATED TAX SHARING AGREEMENT

                  THIS AMENDED AND RESTATED TAX SHARING AGREEMENT (this
"Agreement"), dated as of May 31, 2000, by and among EMC Corporation, a
Massachusetts corporation ("Parent" or "EMC"), on behalf of itself and the EMC
Affiliates (as defined below), and McDATA Corporation, a Delaware corporation
and currently an indirect, controlled subsidiary of Parent ("McDATA"), on behalf
of itself and the McDATA Affiliates (as defined below), is entered into in
connection with the Distribution (as defined below).

                                    RECITALS

                  WHEREAS, the board of directors of Parent has determined that
it is appropriate and desirable to distribute, subject to certain conditions, to
its common shareholders all of Parent's interest in McDATA's common stock on the
Distribution Date (as defined below);

                  WHEREAS, the Distribution (as defined below) is intended to
qualify as a tax free distribution under Section 355 of the Code (as defined
below);

                  WHEREAS, Parent and the Affiliated Companies are part of an
affiliated group filing consolidated Federal income tax returns and certain
consolidated, combined, or unitary state or local income tax returns;

                  WHEREAS, it is appropriate and desirable to set forth the
principles and responsibilities of the parties to this Agreement regarding the
allocation of tax and other related liabilities and adjustments with respect to
taxes, tax contests and other related tax matters; and

                  WHEREAS, to that end, the parties to this Agreement wish to
amend and restate the Tax Sharing Agreement, dated January 1, 1997, by and among
Parent and each of the Affiliated Companies, as supplemented by that certain
Addendum to Section 6(a) of the Tax Sharing Agreement by and between Parent,
McDATA Holdings Corporation and McDATA effective as of January 1, 1997, and as
supplemented by that certain Letter Agreement by and between Parent and McDATA
dated as of April 27, 1999;

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                                    AGREEMENT

                  NOW, THEREFORE, in consideration of the mutual covenants and
promises contained herein, the parties hereto agree to amend and restate said
Tax Sharing Agreement, as so supplemented, as follows:

Section 1.        DEFINITIONS

                  (a)      As used in this Agreement:

                  "AFFILIATED COMPANIES" shall mean, for each taxable year, all
Members of the EMC Consolidated Group other than the common parent corporation.

                  "AFFILIATED GROUP" shall mean an affiliated group of
corporations within the meaning of Code section 1504(a) for the taxable year in
question.

                  "CODE" shall mean the Internal Revenue Code of 1986, as
amended and in effect for the taxable year in question.

                  "EMC AFFILIATE" shall mean each subsidiary of EMC other than
McDATA or any McDATA Affiliate.

                  "EMC CONSOLIDATED GROUP" shall mean, for each taxable year,
the Affiliated Group of which EMC is the common parent.

                  "IRS" means the United States Internal Revenue Service or any
successor thereto, including, but not limited to, its agents, representatives
and attorneys.

                  "MCDATA AFFILIATE" shall mean each subsidiary of McDATA.

                  "MEMBERS" shall mean, for each taxable year, each includible
member of the EMC Consolidated Group.

                  "SEPARATE RETURN TAX LIABILITY" shall have the meaning set
forth in Section 2(c) below.

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                  "SEPARATE RETURN YEAR" shall mean any taxable year for which a
former or future Member is not included in the EMC Consolidated Group's
consolidated Federal income tax return.

                  "TAX ATTRIBUTES" shall mean income, gain, loss, deduction and
credit, and all items entering into the computation thereof, for Federal income
tax purposes.

                  "TREASURY REGULATIONS" shall mean the income tax regulations
promulgated under the Code applicable to the taxable year in question.

                  (b) Any term used in this Agreement that is not defined in
this Agreement shall, unless the context otherwise requires, have the meaning
assigned in the Code or in the Treasury Regulations thereunder.

Section 2.        FILING OF CONSOLIDATED FEDERAL INCOME TAX RETURNS AND PAYMENT
                  OF TAXES

                  (a) FILING BY EMC.

                           (i) EMC will file consolidated federal income tax
returns on behalf of the EMC Consolidated Group for each taxable year ending
after the date hereof during which EMC and any one or more Affiliated Companies
are members of the EMC Consolidated Group.

                           (ii) Parent shall prepare the return and shall have
the right to exercise all the powers and shall have all the duties of a common
parent as are conferred upon it by the Code and Treasury Regulations. Parent and
its Affiliated Companies shall execute and file such consents, elections and
other documents that may be required or appropriate for the proper filing and
defense of such returns.

                  (b) OBLIGATIONS TO MAKE TAX SHARING PAYMENTS. For each taxable
year or period during which EMC and any one or more of the Affiliated Companies
are members of the EMC Consolidated Group, each Member will pay to EMC its
respective allocable share of the EMC Consolidated Group's consolidated federal
income tax liability for that taxable year or period. For these purposes, a
Member's allocable share of such tax liability equals the portion thereof that
is allocable to that Member in accordance with Treasury Regulation Section
1.1552-1(a)(2), in conjunction with the supplemental method set forth in
Treasury Regulation Section 1.1502- 33(d)(3), as provided in Section 2(c) of
this Agreement.

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                  (c) CALCULATION OF TAX SHARING PAYMENT. In order to compensate
Members of the EMC Consolidated Group for the use of net operating losses or tax
credits in arriving at the consolidated federal income tax liability of the EMC
Consolidated Group, the Members of the EMC Consolidated Group agree to determine
and allocate the tax liability of the EMC Consolidated Group among them selves
in the following manner:

Step 1.           The income of the Parent shall be adjusted, if so elected,
                  to allocate to the Parent the tax deduction allowed in
                  accordance with the EMC Corporation & Subsidiaries' Stock
                  Option and Stock Purchase Plan Agreement, effective January 1,
                  1997. The Member who would have been entitled to the tax
                  deduction under Section 421(b) of the Code, but for the
                  allocation allowed to the Parent under the EMC Corporation
                  and Subsidiaries' Stock Option and Stock Purchase Plan
                  Agreement, shall increase their income by the amount of the
                  deduction allowed to the Parent. The consolidated federal
                  income tax liability, as determined under Treasury Regulation
                  Section 1.1502-2, shall then be allocated to the Members in
                  accordance with Treasury Regulation Section 1.1552-1(a)(2).

Step 2.           An additional amount shall be allocated to each Member
                  equal to 100 percent of the excess, if any, of (1) the
                  Separate Return Tax Liability (as defined below) of such
                  Member for the taxable year over (2) the tax liability
                  allocated to such Member in accordance with Step 1 of
                  paragraph c of this section. For purposes of the preceding
                  sentence, the Separate Return Tax Liability of each Member for
                  the taxable year shall be determined as if such Member were
                  filing a separate tax return under the Code, and shall not
                  have the same meaning as Treasury Regulation Section
                  1.1502-12. For purposes hereof, the term "tax" shall include
                  regular corporate income tax or alternative minimum tax.

                  For purposes of determining the Separate Return Tax Liability
                  of a Member:

                  (1)      Any dividends received by one Member from another
                           Member will be assumed to qualify for the 100 percent
                           dividends-received deduction of Section 243 of the
                           Code, or excluded

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                           from income to the extent permitted by Treasury
                           Regulation Section 1.1502-13(f)(2)(ii).

                  (2)      Gain or loss on intercompany transactions, whether
                           deferred or not, shall be treated by each Member in
                           the manner required by Treasury Regulation Section
                           1.1502-13.

                  (3)      Limitations on utilization of Tax Attributes, such as
                           the calculation of a deduction or the utilization of
                           tax credits or the calculation of a tax liability,
                           shall be made on a consolidated basis. Accordingly,
                           the limitations provided in Section 38(c) (relating
                           to general business credit); 170(b)(2) (relating to
                           charitable contribution deduction), and 172(b)(2)
                           (relating to net operating loss deduction) of the
                           Code and similar limitations shall be applied on a
                           consolidated basis. Under the principles of Revenue
                           Ruling 66-374, 1966-2 C.B. 427, the "net operating
                           loss" of a Member is the deduction which such Member
                           would have had available if it actually filed a
                           separate return for the year and thus would not
                           include any portion of a Member's net operating loss
                           sustained in a prior or subsequent year which had
                           been absorbed by the EMC Consolidated Group or by the
                           Member in computing actual liabilities for prior or
                           subsequent years. Notwithstanding the preceding
                           sentence, no benefit shall be granted a Member unless
                           the net operating loss is availed of in reducing the
                           consolidated Federal income tax liability. The rules
                           stated in the previous sentences regarding carryover
                           net operating losses will also apply in the
                           computation of other Tax Attribute carryover items
                           such as general business credits, foreign tax
                           credits, and charitable contribution deductions.

                  (4)      Elections as to tax credits and tax computations
                           which may have been different from the consolidated
                           treatment if separate returns were filed shall be
                           made on an annual basis by Parent.

                  (5)      In calculating any benefit from a carryback or
                           carryover of net operating losses, adjustments shall
                           be made to each prior or subsequent year's Separate
                           Return Tax Liability as required under Section
                           172(b)(2) and 172(d) of the Code. For purposes

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                           of this calculation, the election under Section
                           172(b)(3) of the Code shall be made on a separate
                           company basis.

                  (6)      The sharing of the consolidated alternative minimum
                           tax shall be in accordance with Proposed Treasury
                           Regulation 1.1552-1(g), Allocation of Consolidated
                           AMT and Allowable MTC to Members.

                  (7)      Each Members' separate research and experimentation
                           tax credit for purposes of Step 2 shall be calculated
                           in accordance with Section 41(f)(1)(A)(ii) of the
                           Code.

Step 3.           The total of any additional amounts allocated to
                  Members pursuant to Step 2 of paragraph (c) of this Section
                  (including amounts allocated as a result of a carryback) shall
                  be paid (as provided in paragraph (b) of this Section) by such
                  members to those other Members which had items of income,
                  deductions, net operating losses, or tax credits to which the
                  Step 2 amount is attributable, pursuant to a consistent method
                  which reasonably reflects such items of income, deductions,
                  net operating losses, or tax credits (such consistency and
                  reasonableness to be determined by parent). However, for this
                  purpose, the amounts paid to Members will be deemed consistent
                  and reasonable if paid on a basis equal to 35 percent (or the
                  current federal tax rate on corporations) of net operating
                  losses utilized and 100 percent of tax credits utilized and
                  which is substantiated by specific records maintained by the
                  group for such purposes.

(Examples 1 and 2 attached to this Agreement illustrate the allocation of the
federal tax liability among the group members.)

Section 3.        TAX SHARING PAYMENTS

                  (a) Each Member shall pay Parent, or otherwise account to
Parent for, its Separate Return Tax Liability (if greater than zero) determined
under Section 2(c) of this Agreement. Parent shall pay to each Member with Tax
Attributes used by the EMC Consolidated Group during the taxable year, or
otherwise account to such Member for, such Member's allocable share of the tax
benefit to the EMC Consolidated Group of the utilization of such Tax Attributes.
Such tax benefit shall be determined on a marginal tax basis (calculating
consolidated tax liability with and

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without use of such Tax Attributes), and allocated to each Member whose Tax
Attributes are used by the EMC Consolidated Group during the taxable year
pursuant to a consistent method which reasonably reflects the utilization of
such Tax Attributes (such consistency and allocation to be determined by
Parent). Payments for these allocable shares are to be made no later than ten
days after the date of filing of the consolidated Federal income tax return for
such taxable year, except as may otherwise be agreed to by Parent and the
appropriate Member.

                  (b) Parent shall have the right to assess Members their share
of estimated tax payments to be made on the projected consolidated Federal
income tax liability for each year. Payment to Parent shall be made ten days
after such assessment, except as may otherwise be agreed to by Parent and the
appropriate Member. Such Member will receive credit for such prepayments in the
year-end computation under Paragraph (a) of this Section 3.

                  (c) If part or all of an unused consolidated Tax Attribute is
allocated to a Member of the EMC Consolidated Group pursuant to Treasury
Regulation Section 1.1502-79 or otherwise, and it is carried back or forward to
a year in which such Member filed or files a separate income tax return or a
consolidated Federal income tax return with another Affiliated Group, any refund
or reduction in tax liability arising from the carryback or carryover shall be
retained by such Member. (If such refund or reduction goes to some entity other
than the Member, then such entity shall pay over such amount to the Member.)
Notwithstanding the above, Parent shall determine whether an election shall be
made not to carry back any consolidated net operating loss or other Tax
Attribute arising in a consolidated return year (including any portion allocated
to a Member under Treasury Regulation Section 1.1502-79) in accordance with
Section 172(b)(3)(C) of the Code or other applicable provision.

Section 4.        TAX INDEMNITY

                  Except as otherwise agreed, Parent shall be liable for, and
shall indemnify and hold each Affiliated Company harmless (subject to setoff for
any unpaid amount under Section 2, paragraph (b) of this Agreement) against any
and all Federal income tax for periods in which it is included in the EMC
Consolidated Group's consolidated Federal income tax return. Each Affiliated
Company shall be liable for, and shall indemnify and hold each other Member
harmless against any and all Federal income tax for periods in which it is not
included in the EMC Consolidated Group's consolidated Federal income tax
return.

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Section 5.        ADJUSTMENT TO FEDERAL INCOME TAX LIABILITY

                  Parent shall control all decisions as to tax audits and
proceedings as exclusive agent of each of the Affiliated Companies. If the
consolidated Federal income tax liability is adjusted for any taxable year,
whether by means of an amended return, claim for refund, or after-tax audit by
the IRS, the liability of each Member shall be recomputed under this Agreement
to give effect to such adjustments. In the case of a refund, Parent shall make
payment to each Member for its share of the refund, determined in the same
manner as in Section 2 of this Agreement, within ten days after the refund is
received by Parent, and in the case of an increase in tax liability, each Member
shall pay to Parent its allocable share of such increased tax liability within
ten days after receiving notice of such liability from Parent. If any interest
is to be paid or received as a result of a consolidated Federal income tax
deficiency or refund, such interest shall be allocated to the Members in the
ratio each Member's change in consolidated Federal income tax liability bears to
the total change in tax liability. Any penalty shall be allocated upon such a
basis as Parent deems just and proper in view of all applicable circumstances.

Section 6.        CERTAIN STATE AND LOCAL INCOME TAX LIABILITIES

                  (a) Parent shall include certain Affiliated Companies in
certain consolidated, combined, or unitary state or local income tax returns.
Unless otherwise agreed, the allocation of each state's tax liability shall be
based upon the percentage of each member's post-apportionment separate company
state tax over the sum of each member's post-apportionment separate company
state tax. This allocation methodology shall be applied to the filing of
returns, assessments and claims for refund and reimbursements with respect to
state and local franchise or income tax liabilities to which any Member of the
EMC Consolidated Group is subject and which are required to be determined on a
unitary, combined or consolidated basis.

                  (b) If the parties are, after negotiation in good faith,
unable to agree upon the appropriate application of such rules with respect to
such franchise or income tax liabilities, the controversy shall be settled by
Parent's regular independent outside accounting firm.

                  (c) This section shall not apply to separate return filing
states. In those states, each member will bear its separate return liability.

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                  (d) For purposes of all state tax liabilities incurred in
Arizona, California, Connecticut and Florida:

                           (i) McDATA Holdings Corporation, an EMC Affiliate, or
any successor thereto, will absorb the additional state tax liability resulting
from its inclusion in a combined or unitary return in the event that McDATA's
activities have created a unitary or combined filing requirement;

                           (ii) The determination of the state tax allocation
for the jurisdictions to which this paragraph (d) applies shall be based upon
the percentage of each Member's separate federal taxable income (as shown on
line 30 of the EMC Consolidated Group's consolidated federal income tax return)
over the sum of each Member's separate federal taxable income; and

                           (iii) The allocation methodology set forth in this
paragraph (d) shall be applied to the filing of returns, assessments and claims
for refund and reimbursements with respect to state and local franchise or
income tax liabilities to which any Member of the EMC Consolidated Group are
subject and which are required to be determined on a unitary, combined or
consolidated basis.

Section 7.        MUTUAL COOPERATION - AUDIT BY TAXING AUTHORITY

                  (a) Each Member shall be notified by the Parent of an audit by
a taxing authority which includes any year in which a Member was included in the
consolidated return. The Parent shall provide to each Member the changes
proposed by the taxing authority.

                  (b) Parent and the Affiliated Companies shall provide each
other with such assistance as may be reasonably requested by either of them in
connection with the preparation and execution of any tax return, any audit or
other examination by any taxing authority, or any judicial or administrative
proceedings relating to any tax liability, and each will retain and, upon the
request of the other, provide the other with any records or information which
may be relevant to such return, audit or examination proceedings. Parent and the
Affiliated Companies agree to take whatever reasonable action is necessary to
minimize the aggregate tax liabilities of each of the Members, including filing
tax returns on a consolidated, combined or unitary basis, or not filing on such
basis.

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Section 8.        DECONSOLIDATION OF MCDATA

                  (a) PRIVATE LETTER RULING. Parent will provide to McDATA
copies of any material, information, covenant, representation or other documents
to be submitted to the IRS in connection with its request for any ruling with
respect to the Distribution reasonably in advance of the submission of any such
documents, will incorporate any reasonable suggestions or comments on such
documents made by McDATA, and will provide to McDATA copies of the final
documents submitted to the IRS. Promptly upon the receipt of any ruling from the
IRS, Parent will provide a copy of such ruling to McDATA.

                  (b) INDEMNIFICATION FOR DISTRIBUTION TAXES.

                           (i) INDEMNIFICATION BY MCDATA.  McDATA shall, for
itself and as agent for each member of the McDATA Group, indemnify, defend and
hold harmless the EMC Group from and against any and all Distribution Taxes that
are primarily attributable to:

                           (A)   any act, failure to act or omission of or by
                                 McDATA (or any member of the McDATA Group) that
                                 is inconsistent with any material, information,
                                 covenant or representation in (1) any ruling
                                 obtained from the IRS with respect to the
                                 Distribution or (2) any documents submitted to
                                 the IRS in connection with a request for any
                                 such ruling;

                           (B)   any act, failure to act or omission of or by
                                 McDATA (or any member of the McDATA Group)
                                 after the Distribution Date, including,
                                 without limitation, a cessation, transfer to
                                 affiliates, or disposition of its active
                                 trades or businesses, or an issuance of
                                 stock, stock buyback or payment of an
                                 extraordinary dividend by McDATA (or any
                                 member of the McDATA Group) following the
                                 Distribution;

                           (C)   any acquisition of any stock or assets of
                                 McDATA (or any member of the McDATA Group) by
                                 one or more other persons prior to or following
                                 the Distribution; or

                           (D)   any issuance of stock by McDATA (or any member
                                 of

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                                 the McDATA Group), or change in ownership of
                                 stock in McDATA (or any member of the McDATA
                                 Group), that causes Section 355(d) or Section
                                 355(e) of the Code to apply to the
                                 Distribution.

                           (ii)  INDEMNIFICATION BY EMC.  EMC shall, for itself
and as agent for each member of the EMC Group, indemnify, defend and hold
harmless the McDATA Group from and against any and all Distribution Taxes that
are primarily attributable to:

                           (A)   any act, failure to act or omission of or by
                                 EMC (or any member of the EMC Group) that is
                                 inconsistent with any material, information,
                                 covenant or representation in (1) any ruling
                                 obtained from the IRS with respect to the
                                 Distribution or (2) any documents submitted to
                                 the IRS in connection with a request for any
                                 such ruling;

                           (B)   any act, failure to act or omission of or by
                                 EMC (or any member of the EMC Group) after the
                                 Distribution Date, including, without
                                 limitation, a cessation, transfer to
                                 affiliates, or disposition of its active trades
                                 or businesses, or an issuance of stock, stock
                                 buyback or payment of an extraordinary dividend
                                 by EMC (or any member of the EMC Group)
                                 following the Distribution;

                           (C)   any acquisition of any stock or assets of EMC
                                 (or any member of the EMC Group) by one or more
                                 other persons prior to or following the
                                 Distribution; or

                           (D)   any issuance of stock by EMC (or any member of
                                 the EMC Group), or change in ownership of stock
                                 in EMC (or any member of the EMC Group), that
                                 causes Section 355(d) or Section 355(e) of the
                                 Code to apply to the Distribution.

                  (c) CERTAIN ACTIONS DURING RESTRICTION PERIOD.  During the
Restriction Period, unless (1) McDATA obtains the advance written consent of
Parent, which consent shall not be unreasonably withheld if McDATA provides
Parent with a written opinion of nationally recognized counsel or "Big 5"
accounting

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firm, in form and substance satisfactory to Parent, to the effect that such
transaction or transactions will not adversely affect the tax treatment of the
Distribution, or (2) Parent obtains, at McDATA's request (and expense), a
private letter ruling from the IRS that such transaction or series of
transactions will not adversely affect the tax treatment of the Distribution,
McDATA will not, directly or indirectly:

                           (i) enter into, or otherwise be a party to, any
transaction or arrangement (including, without limitation, stock issuances,
stock acquisitions, and transactions involving the stock or substantially all of
the assets of McDATA) pursuant to which one or more persons acquire stock of
McDATA representing a "50-percent or greater interest" within the meaning of
Section 355(d)(4) of the Code that would cause Section 355(e) of the Code to
apply to the Distribution;

                           (ii) take or fail to take any other action
(including, without limitation, any cessation, transfer to affiliates or
disposition of its active trade or business, and certain reacquisitions of its
stock and payments of extraordinary dividends to its shareholders) that would
cause the Distribution to fail to qualify for nonrecognition of gain or loss
under the Code;

                           (iii) issue stock or other equity interests of McDATA
(including, without limitation, options, rights, warrants or securities
exercisable for, or convertible into stock of McDATA, or any similar
arrangement), or redeem, purchase or otherwise reacquire any of its capital
stock (other than through stock purchases meeting the requirements of section
4.05(1)(b) of Rev. Proc. 96-30, 1996-1 C.B. 696); which, when aggregated with
all other such specified transactions undertaken during the Restriction Period,
would involve the acquisition (determined under the principles of Section 355 of
the Code) by one or more persons of more than thirty-five percent (35%) of the
stock of McDATA (including stock issued by McDATA in the IPO); or

                           (iv) undertake any transaction that is treated as a
liquidation or reorganization under the Code.

                  (d) NOTICE OF SPECIFIED TRANSACTIONS. Not later than fifteen
(15) days prior to entering into any oral or written contract or agreement
regarding any of the transactions described in paragraph (b), McDATA shall
provide written notice of its intent to consummate such transaction to Parent.

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                  (e) CARRYBACKS.

                           (i) IN GENERAL. Parent agrees to pay to McDATA the
United States federal income Tax Benefit from the use in any period prior to the
Deconsolidation Date of a carryback of any Tax Asset of the McDATA Group from
any period after the Deconsolidation Date. If subsequent to the payment by
Parent to McDATA of the United States federal income Tax Benefit of a carryback
of a Tax Asset of the McDATA Group, there is an adjustment (whether by means of
an amended return, claim for refund or after-tax audit by the IRS) which results
in a (1) change to the amount of the Tax Asset so carried back or (2) change to
the amount of such United States federal income Tax Benefit, McDATA shall repay
to Parent, or Parent shall repay to McDATA, as the case may be, the difference
between the amount of the Tax Benefit actually paid and the amount that would
have been paid if such amount had been determined in light of these events.

                           (ii) NET OPERATING LOSSES.  Notwithstanding any other
provision of this Agreement, McDATA hereby expressly agrees to elect (under
Section 172(b)(3) of the Code and, to the extent feasible, any similar provision
of any state, local or foreign tax law) to relinquish any right to carryback net
operating losses for any tax year with respect to which such net operating loss
could otherwise be carried back into a consolidated return or a combined return
of the EMC Consolidated Group (in which event no payment shall be due from
Parent to McDATA in respect of such net operating losses).

                  (f) ALLOCATION OF TAX ITEMS. All tax computations for (1) any
periods ending on the Deconsolidation Date and (2) the immediately following
taxable period of McDATA or any member of the McDATA Group, shall be made
pursuant to the principles of section 1.1502-76(b) of the Treasury Regulations,
as determined by Parent, taking into account all reasonable suggestions made by
McDATA with respect thereto.

                  (g) OPTIONS.

                          (i) Notwithstanding any other provision of this
Agreement, but without duplication of any other adjustment provided in this
Agreement, (A) Parent shall be entitled to any Tax Benefit arising by reason of
(1) exercises of options to acquire shares of Parent stock and (2) any
disqualifying disposition of shares of Parent stock within the meaning of
Section 421(b) of the Code, and (B) McDATA shall be entitled to any Tax Benefit
arising by reason of exercises of

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options to acquire shares of McDATA stock. Parent and McDATA agree to report all
tax deductions with respect to stock options consistently with this paragraph to
the extent permitted by the Code, to withhold any applicable taxes and satisfy
any applicable tax reporting obligations with respect to exercises of options to
acquire shares of Parent or McDATA stock by their respective employees, and to
timely provide to each other such information as may be necessary to satisfy
such withhold ing and reporting obligations. If McDATA receives any Tax Benefit
to which Parent is entitled under this paragraph, McDATA shall pay the amount of
such Tax Benefit to Parent, and if Parent receives any Tax Benefit to which
McDATA is entitled under this paragraph, Parent shall pay the amount of such Tax
Benefit to McDATA. For purposes of this paragraph, any Tax Benefit attributable
to any disqualifying disposition during a McDATA Separate Return Year of shares
of Parent stock or McDATA stock, as the case may be, within the meaning of
Section 421(b) of the Code shall be an amount equal to thirty-seven (37) percent
of any deduction attributable thereto, and McDATA or Parent, as the case may be,
shall be required to pay such amount to Parent or McDATA, as the case may be,
when McDATA or Parent, as the case may be, actually obtains and utilizes such
deduction on its United States federal income tax returns.

                           (ii) Parent agrees that in conjunction with the
contemplated initial public offering of McDATA stock and the Distribution,
McDATA's liability under the Stock Option Agreement with respect to any issuance
of Parent shares from the exercise of Parent stock options, will be limited to
the payment of the option price by the employees. Parent will not cross charge
McDATA the difference between the option price and fair market value on the date
of exercise. Parent will not require the issuance of additional shares from
McDATA, as a result of its capital contribution to McDATA resulting from the
exercise and issuance of Parent stock. The Tax Benefit that accrues as a result
of the exercise of a non-qualified option or the disqualifying disposition of an
incentive stock option with respect to Parent stock or McDATA stock, as the case
may be, will be due and payable within thirty (30) days of filing the federal
income tax return on which the Tax Benefit was utilized, to Parent or McDATA, as
the case may be, in cash.

                  (h) CONTINUING COVENANTS. Parent (for itself and each member
of the EMC Group) and McDATA (for itself and each member of the McDATA Group)
agree (1) not to take any action reasonably expected to result in an increased
tax liability to the other, a reduction in a Tax Asset of the other or an
increased liability to the other under this Agreement and (2) to take any action
reasonably requested by the other that would reasonably be expected to result in
a Tax Benefit or avoid a Tax

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Detriment to the other, provided that such action does not result in any
additional direct or indirect cost not fully compensated for by the requesting
party. The parties hereby acknowledge that the preceding sentence is a statement
of general principle and is not intended to limit, and therefore shall not apply
to, the rights of the parties with respect to matters otherwise covered by this
Agreement.

                  (i) ADDITIONAL DEFINITIONS.  For  purposes of this Section 8:

                  "DECONSOLIDATION DATE" shall mean the date on which McDATA
ceases to be a Member of the EMC Consolidated Group.

                  "DISTRIBUTION" shall have the meaning ascribed to such term in
that certain Master Transaction Agreement between EMC Corporation and McDATA
Corporation.

                  "DISTRIBUTION DATE" shall have the meaning ascribed to such
term in that certain Master Transaction Agreement between EMC Corporation and
McDATA Corporation.

                  "DISTRIBUTION TAXES" shall mean any and all taxes imposed on
Parent or any Member resulting from, or arising in connection with, the failure
of the Distribution to be tax-free to such party under the Code (including,
without limitation, any tax resulting from the failure of the Distribution to
qualify under Section 355 of the Code or the application of Section 355(d) or
Section 355(e) of the Code to the Distribution) or corresponding provisions of
the laws of any other jurisdictions.

                  "EMC GROUP" shall have the meaning ascribed to such term in
that certain Master Transaction Agreement between EMC Corporation and McDATA
Corporation.

                  "MCDATA GROUP" shall have the meaning ascribed to such term in
that certain Master Transaction Agreement between EMC Corporation and McDATA
Corporation.

                  "RESTRICTION PERIOD" shall mean the period beginning on
January 1, 1999 and ending twenty-seven (27) months after the Distribution Date.

                  "TAX ASSET" shall mean any item that has accrued for United
States federal income tax purposes, but has not been used during a taxable
period, and that

                                       15

<PAGE>   17

could reduce a United States federal income tax in another taxable period,
including a net operating loss, net capital loss, investment tax credit, foreign
tax credit, research and experimentation credit, charitable deduction or credit
related to alternative minimum tax or any other United States federal income
tax credit.

                  "TAX BENEFIT" shall mean a reduction in the tax liability of a
taxpayer (or of the affiliated group of which it is a member) for any taxable
period. Except as otherwise provided in this Agreement, a Tax Benefit shall be
deemed to have been realized or received from a tax item in a taxable period
only if and to the extent that the tax liability of the taxpayer (or of the
affiliated group of which it is a member) for such period, after taking into
account the effect of the tax item on the tax liability of such taxpayer in the
current period and all prior periods, is less than it would have been if such
tax liability were determined without regard to such tax item.

                  "TAX DETRIMENT" shall mean an increase in the tax liability of
a taxpayer (or of the affiliated group of which it is a member) for any taxable
period. Except as otherwise provided in this Agreement, a Tax Detriment shall be
deemed to have been realized or received from a tax item in a taxable period
only if and to the extent that the tax liability of the taxpayer (or of the
affiliated group of which it is a member) for such period, after taking into
account the effect of the tax item on the tax liability of such taxpayer in the
current period and all prior periods, is more than it would have been if such
tax liability were determined without regard to such tax item.

Section 9.        MISCELLANEOUS

                  (a) INJUNCTIONS. The parties acknowledge that irreparable
damage would occur in the event that any of the provisions of this Agreement
were not performed in accordance with its specific terms or were otherwise
breached. The parties hereto shall be entitled to an injunction or injunctions
to prevent breaches of the provisions of this Agreement and to enforce
specifically the terms and provisions hereof in any court having jurisdiction,
such remedy being in addition to any other remedy to which they may be entitled
at law or equity.

                  (b) ASSIGNMENT. Except by operation of law or in connection
with the sale of all or substantially all the assets of a party hereto, this
Agreement shall not be assignable, in whole or in part, directly or indirectly,
by any party hereto without the written consent of the other parties; and any
attempt to assign any rights or obligations arising under this Agreement without
such consent shall be void;

                                       16

<PAGE>   18

PROVIDED, HOWEVER, that the provisions of this Agreement shall be binding upon,
inure to the benefit of and be enforceable by the parties hereto and their
respective successors and permitted assigns, but no assignment shall relieve any
party's obligations hereunder without the written consent of the other parties.

                  (c) FURTHER ASSURANCES. Subject to the provisions hereof, the
parties hereto shall make, execute, acknowledge and deliver such other
instruments and documents, and take all such other actions, as may be reasonably
required in order to effectuate the purposes of this Agreement and to consummate
the transactions contemplated hereby. Subject to the provisions hereof, each of
the parties shall, in connection with entering into this Agreement, performing
its obligations thereunder and taking any and all actions relating hereto,
comply with all applicable laws, regulations, orders and decrees, obtain all
required consents and approvals and make all required filings with any
governmental agency, other regulatory or administrative agency, commission or
similar authority and promptly provide the other parties with all such
information as they may reasonably request in order to be able to comply with
the provisions of this paragraph.

                  (d) PARTIES IN INTEREST. Except as herein otherwise
specifically provided, nothing in this Agreement expressed or implied is
intended to confer any right or benefit upon any person, firm or corporation
other than the parties and their respective successors and permitted assigns.

                  (e) WAIVERS, ETC.. No failure or delay on the part of the
parties in exercising any power or right hereunder shall operate as a waiver
thereof, nor shall any single or partial exercise of any such right or power, or
any abandonment or discontinuance of steps to enforce such a right or power,
preclude any other or further exercise thereof or the exercise of any other
right or power. No modification or waiver of any provision of this Agreement nor
consent to any departure by the parties therefrom shall in any event be
effective unless the same shall be in writing, and then such waiver or consent
shall be effective only in the specific instance and for the purpose for which
given.

                  (f) SETOFF. All payments to be made by any party under this
Agreement shall, except to the extent otherwise specifically provided herein, be
made without setoff, counterclaim or withholding, all of which are expressly
waived.

                  (g) CHANGE OF LAW.   If due to any change in applicable law or
regulations interpretation thereof by any court of law or other governing body
having

                                       17

<PAGE>   19

jurisdiction subsequent to the date of this Agreement, performance of any
provision of this Agreement or any transaction contemplated thereby shall become
impracticable or impossible, the parties hereto shall use their best efforts to
find and employ an alternative means to achieve the same or substantially the
same result as that contemplated by such provision.

                  (h) Any Member corporation which leaves the EMC Consolidated
Group shall be bound by this Agreement.

                  (i) The Members hereto specifically recognize that from time
to time other companies may become Members of the EMC Consolidated Group and
hereby agree that such new Members may become parties to this Agreement by
executing the master copy of the Agreement which shall be maintained at Parent's
headquarters. It will not be necessary for all the other Members to re-sign the
Agreement, but the new Member may simply sign the existing Agreement and it will
be effective as if the old Members had re-signed.

                  (j) Any alteration, modification, addition, deletion, or other
change in the consolidated income tax return provisions of the Code or the
Treasury Regulations shall automatically be applicable to this Agreement mutatis
mutandis.

                  (k) Failure of one or more parties hereto to qualify by
meeting the definition of Member of the EMC Consolidated Group shall not operate
to terminate this Agreement with respect to the other parties as long as two or
more parties hereto continue so to qualify.

                  (l) CONFIDENTIALITY. Subject to any contrary requirement of
law or regulation and the right of each party to enforce its rights hereunder in
any legal action, each party agrees that it shall keep strictly confidential,
and shall cause its employees and agents to keep strictly confidential, any
information which it or any of its agents or employees may acquire pursuant to,
or in the course of performing its obligations under, any provision of this
Agreement; PROVIDED, HOWEVER, that such obligation to maintain confidentiality
shall not apply to information which (1) at the time of disclosure was in the
public domain not as a result of acts by the receiving party or (2) was in the
possession of the receiving party at the time of disclosure.

                  (m) HEADINGS.  Descriptive headings are for convenience only
and shall not control or affect the meaning or construction of any provision of
this Agreement.

                                       18

<PAGE>   20

                  (n) COUNTERPARTS. For the convenience of the parties, any
number of counterparts of this Agreement may be executed by the parties hereto,
and each such executed counterpart shall be, and shall be deemed to be, an
original instrument.

                  (o) GOVERNING LAW.  This Agreement shall be governed by and
construed and enforced in accordance with the laws of the State of Delaware
applicable to contracts made and to be performed therein.

                  (p) ENTIRE AGREEMENT. This Agreement contains the entire
agreement among the parties hereto with respect to the subject matter hereof and
supersedes any prior tax sharing agreements between Parent and McDATA and any of
their respective affiliates or subsidiaries and such prior tax sharing
agreements shall have no further force and effect.

                                       19

<PAGE>   21

                  IN WITNESS WHEREOF, the parties hereto have caused this
Agreement to be duly executed by their respective officers, each of whom is duly
authorized, all as of the day and year first above written.

                                  EMC CORPORATION
                                  on behalf of itself and the EMC Affiliates

                                  By: /s/ William J. Teuber, Jr.
                                      -----------------------------------------
                                      Name: William J. Teuber, Jr.
                                      Title:

                                  McDATA CORPORATION
                                  on behalf of itself and the McDATA Affiliates

                                  By: /s/ Dee J. Perry
                                      -----------------------------------------
                                      Name: Dee J. Perry
                                      Title: Chief Financial Officer

                                       20<PAGE>   1
                                                                   EXHIBIT 10.10

              MASTER CONFIDENTIAL DISCLOSURE AND LICENSE AGREEMENT

                                     BETWEEN

                                EMC CORPORATION,

                           MCDATA HOLDINGS CORPORATION

                                       AND

                               MCDATA CORPORATION

                          Effective as of May 31, 2000

<PAGE>   2

              MASTER CONFIDENTIAL DISCLOSURE AND LICENSE AGREEMENT

         This Master Confidential Disclosure and License Agreement (this
"Agreement") effective as of May 31, 2000, is between EMC Corporation, a
Massachusetts corporation ("EMC"), having an office at 171 South Street,
Hopkinton, MA 01748-9103; McDATA Holdings Corporation, a Delaware Corporation
("Holdings"), having an office at 171 South Street, Hopkinton, MA 01748-9103;
and McDATA Corporation, a Delaware corporation ("McDATA"), having an office at
310 Interlocken Parkway, Broomfield, CO 80021.

         WHEREAS, in connection with a corporate restructuring of McDATA, EMC
and McDATA entered into various agreements (the "1997 Agreements") as of October
1, 1997, relating to the allocation of various assets and liabilities between
EMC and McDATA and as to certain continuing rights and obligations of EMC and
McDATA; and

         WHEREAS, McDATA and EMC currently propose that McDATA sell shares of
its Class B common stock, $.01 par value, to the public in an underwritten
public offering (the "IPO"); and

         WHEREAS, EMC currently proposes to distribute to the stockholders of
EMC, approximately six to twelve months after the closing of the IPO, the Class
A common stock, $.01 par value, that EMC currently beneficially owns; and

         WHEREAS, EMC and McDATA have entered into a Master Transaction
Agreement as of the date hereof (the "Master Transaction Agreement"), to further
delineate the relationship between EMC and McDATA following the IPO, set forth
certain rights and obligations of EMC and McDATA following the IPO, address
certain matters relating to the Distribution and provide for the execution and
delivery of certain additional agreements in order to facilitate and provide for
the foregoing; and

         WHEREAS, as part of the foregoing, the parties desire to set forth
certain agreements regarding intellectual property; and

         WHEREAS, also as part of the foregoing, the parties further desire to
enter into this Agreement to provide for the protection of their Confidential
Information (as defined below);

         NOW, THEREFORE, in consideration of the mutual promises of the parties,
and of good and valuable consideration, it is agreed by and between the parties
as follows:

                                    ARTICLE I

                                   DEFINITIONS

         For the purpose of this Agreement the following capitalized terms are
defined in this

                                       1
<PAGE>   3

Article I and shall have the meaning specified herein:

         Section 1.1 AFFILIATED COMPANY. "Affiliated Company" of any Person
means any entity that controls, is controlled by, or is under common control
with such Person. As used herein, "control" means the possession, directly or
indirectly, of the power to direct or cause the direction of the management and
policies of such entity, whether through ownership of voting securities or other
interests, by contract or otherwise.

         Section 1.2 ANCILLARY AGREEMENTS. "Ancillary Agreements" has the
meaning set forth in Section 2.1 of the Master Transaction Agreement.

         Section 1.3 CONFIDENTIAL INFORMATION.

                  (a) "Confidential Information" means information, technical
data and know-how which is not otherwise in the public domain and which is (i)
disclosed to the Receiving Party by the Disclosing Party or which the Receiving
Party had access to on or before the Effective Date or (ii) the subject of any
Transaction Agreement or Ancillary Agreement and known to or in the possession
of the Receiving Party as of the Effective Date. Confidential Information may
include information relating to, by way of example, research, products,
services, customers, markets, software, developments, inventions, processes,
designs, drawings, engineering, marketing or finances, and may be in writing,
disclosed orally or learned by inspection of computer programming code,
equipment or facilities.

                  (b) Confidential Information of Third Parties that is known
to, in the possession of or acquired by a Receiving Party pursuant to a
relationship with the Disclosing Party shall be deemed the Disclosing Party's
Confidential Information for purposes hereof.

                  (c) Notwithstanding the foregoing provisions of this Section
1.3, Confidential Information shall exclude information that: (i) was in the
Receiving Party's possession before receipt from the Disclosing Party and
obtained from a source other than the Disclosing Party and other than through
the prior relationship of the Disclosing Party and the Receiving Party before
the Effective Date; (ii) is or becomes a matter of public knowledge through no
fault of the Receiving Party; (iii) is rightfully received by the Receiving
Party from a Third Party without a duty of confidentiality; (iv) is disclosed by
the Disclosing Party to a Third Party without a duty of confidentiality on the
Third Party; (v) is independently developed by the Receiving Party or (vi) is
disclosed by the Receiving Party with the Disclosing Party's prior written
approval.

         Section 1.4 CONFIDENTIALITY PERIOD. "Confidentiality Period" means, (i)
with respect to Confidential Information that is not Highly Confidential
Information, three (3) years, and (ii) with respect to Highly Confidential
Information, ten (10) years, after either (A) the Effective Date with respect to
Confidential Information of the Disclosing Party that is known to or in the
possession of the Receiving Party as of the Effective Date or (B) the date of
disclosure with respect to Confidential Information that is disclosed by the
Disclosing Party to the Receiving Party after the Effective Date.

                                       2
<PAGE>   4

         Section 1.5 DISCLOSING PARTY. "Disclosing Party" means the party owning
or disclosing the relevant Confidential Information.

         Section 1.6 EFFECTIVE DATE. "Effective Date" means the date of the
closing of the IPO.

         Section 1.7 EMC PATENTS. "EMC Patents" means all patents throughout the
world owned by EMC: (i) issued or issuing on a patent or patent application
entitled to an effective filing date prior to the Effective Date; and (ii) under
which EMC or any company which is an Affiliated Company of EMC as of the
Effective Date ("EMC Affiliated Company") has, as of the Effective Date, the
right to grant licenses, covenants or releases to McDATA or any company which is
an Affiliated Company of McDATA as of the Effective Date ("McDATA Affiliated
Company") without such grant or exercise of such license, covenant or release to
McDATA or such McDATA Affiliated Company resulting in the payment of royalties
or other consideration by EMC or such EMC Affiliated Company. EMC Patents shall
also include any patent issuing on a patent application which is a division,
continuation, continuation-in-part (but, only as to those claims that have a
priority date on or before the Effective Date), or reissue of any of the
aforesaid patents or patent applications.

         Section 1.8 EMC PRODUCTS. "EMC Products" means any products which are
sold or otherwise distributed by EMC at any time prior to the Effective Date.

         Section 1.9 HIGHLY CONFIDENTIAL INFORMATION. "Highly Confidential
Information" means Confidential Information that is (i) source code for products
that are commercially released or for which substantial steps have been taken to
commercialization; or (ii) which has been reasonably designated by either party
as Highly Confidential Information.

         Section 1.10 MCDATA PATENTS. "McDATA Patents" means all patents
throughout the world owned by McDATA: (i) issued or issuing on a patent or
patent application entitled to an effective filing date prior to the Effective
Date; and (ii) under which McDATA or a McDATA Affiliated Company has, as of the
Effective Date, the right to grant licenses, covenants or releases to EMC or an
EMC Affiliated Company without such grant or exercise of such license, covenant
or release to EMC or an EMC Affiliated Company resulting in the payment of
royalties or other consideration by McDATA or a McDATA Affiliated Company.
McDATA Patents shall also include any patent issuing on a patent application
which is a division, continuation, continuation-in-part (only as to those claims
that have a priority date on or before the Effective Date), or reissue of any of
the aforesaid patents or patent applications.

         Section 1.11 MCDATA PRODUCTS. "McDATA Products" means any products
which are sold or otherwise distributed by McDATA at any time prior to the
Effective Date.

                                       3
<PAGE>   5

         Section 1.12 PERSON. "Person" means an individual, a partnership, a
corporation, a limited liability company, an association, a joint stock company,
a trust, a joint venture, an unincorporated organization, and a governmental
entity or any department, agency or political subdivision thereof.

         Section 1.13 RECEIVING PARTY. "Receiving Party" means the non-owning
party or recipient of the relevant Confidential Information.

         Section 1.14 SOFTWARE PRODUCT. "Software Product" means any software
product which constitutes an EMC Product.

         Section 1.15 SUBSIDIARY. "Subsidiary" means with respect to any
specified Person, any corporation, any limited liability company, any
partnership or other legal entity of which such Person owns, directly or
indirectly, more than 50% of the stock or other equity interest entitled to vote
on the election of the members of the board of directors or similar governing
body.

         Section 1.16 THIRD PARTY. "Third Party" means a Person other than EMC
and its Subsidiaries and Affiliated Companies and McDATA and its Subsidiaries
and Affiliated Companies.

         Section 1.17 TECHNOLOGY RIGHTS AGREEMENT. "Technology Rights Agreement"
or "TRA" means the Technology Rights Agreement entered into October 1, 1997 by
and among EMC, McDATA Holdings Corporation and McDATA.

         Section 1.18 TRANSACTION AGREEMENTS. "Transaction Agreements" means the
Master Transaction Agreement and the Asset Transfer Agreement ("Asset Transfer
Agreement") among EMC, McDATA and McDATA Holdings Corporation, dated as of
October 1, 1997.

                                   ARTICLE II

                                 CONFIDENTIALITY

         Section 2.1 CONFIDENTIALITY AND NON-USE OBLIGATIONS. During the
Confidentiality Period, the Receiving Party shall (i) protect the Confidential
Information of the Disclosing Party by using the same degree of care, but no
less than a reasonable degree of care, to prevent the unauthorized use,
dissemination, or publication of the Confidential Information as Receiving Party
uses to protect its own confidential information of a like nature, (ii) not use
such Confidential Information in violation of any use restriction in any
Transaction Agreement or Ancillary Agreement, and (iii) not disclose such
Confidential Information to any Third Party, except as expressly permitted under
this Agreement, in the Transaction Agreements, the Ancillary Agreements or in
any other agreements entered into between the parties in writing, without prior
written consent of the Disclosing Party.

                                       4
<PAGE>   6

         Section 2.2 DISCLOSURE TO SUBLICENSEES. The Receiving Party has the
right to disclose to its sublicensees permitted under this Agreement portions of
Confidential Information as reasonably necessary in the exercise of the
Receiving Party's sublicense rights under this Agreement, subject to the
sublicensee's agreement in writing to confidentiality and non-use terms at least
as protective of the Disclosing Party as the provisions of this Agreement.

         Section 2.3 CONTRACT MANUFACTURERS. The Receiving Party has the right
to disclose to its contract manufacturers permitted under any Transaction
Agreement or Ancillary Agreement portions of the Confidential Information as
reasonably necessary in the exercise of the Receiving Party's "have made" rights
under any Transaction Agreement or Ancillary Agreement, subject to the contract
manufacturer's agreement in writing to confidentiality and non-use terms at
least as protective of the Disclosing Party as the provisions of this Agreement.

         Section 2.4 RESIDUALS. Notwithstanding any other provision of this
Agreement, the Receiving Party shall be free, and the Disclosing Party hereby
grants to the Receiving Party the right, to use for any purpose the Residuals
resulting from access to or work with the Confidential Information of the
Disclosing Party. "Residuals" means information retained in the unaided memory
of an individual who has had access to Confidential Information without
conscious attempt by such individual to memorize such information. The Receiving
Party shall have no obligation to pay royalties for any use of Residuals.
However, this Section 2.4 does not grant the Receiving Party any rights under
any patents or copyrights of the Disclosing Party.

         Section 2.5 COMPELLED DISCLOSURE. If the Receiving Party or any of its
respective Subsidiaries or Affiliated Companies believes that it will be
compelled by a court or other authority to disclose Confidential Information of
the Disclosing Party, it shall (i) give the Disclosing Party prompt written
notice so that the Disclosing Party may take steps to oppose such disclosure,
and (ii) cooperate with the Disclosing Party in its attempts to oppose such
disclosure. If the Receiving Party complies with the above, it shall not be
prohibited from complying with such requirement to disclose, but shall take all
reasonable steps to make such disclosure subject to a suitable protective order
or otherwise prevent unrestricted or public disclosure.

         Section 2.6 NO RESTRICTION ON DISCLOSING PARTY. Nothing in this
Agreement shall restrict the Disclosing Party from using, disclosing, or
disseminating its own Confidential Information in any way.

         Section 2.7 NO RESTRICTION ON REASSIGNMENT. This Agreement shall not
restrict reassignment of the Receiving Party's employees.

         Section 2.8 THIRD PARTY RESTRICTIONS. Nothing in the Agreement
supersedes any restriction imposed by Third Parties on their Confidential
Information, and there is no obligation on the Disclosing Party to conform Third
Party agreements to the terms of this Agreement except as expressly set forth
therein.

                                       5
<PAGE>   7

                                   ARTICLE III

                               WARRANTY DISCLAIMER

         EACH PARTY ACKNOWLEDGES AND AGREES THAT ALL CONFIDENTIAL INFORMATION IS
PROVIDED ON AN "AS IS, WHERE IS" BASIS AND THAT NEITHER PARTY NOR ANY OF ITS
SUBSIDIARIES OR AFFILIATED COMPANIES HAS MADE OR WILL MAKE ANY WARRANTY
WHATSOEVER, EXPRESS, IMPLIED OR STATUTORY, INCLUDING, WITHOUT LIMITATION, ANY
IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, TITLE,
ENFORCEABILITY OR NON-INFRINGEMENT.

                                   ARTICLE IV

                          INTELLECTUAL PROPERTY RIGHTS

         Section 4.1 INTELLECTUAL PROPERTY RIGHTS.

                  (a) McDATA shall retain all right, title, and interest in its
copyright, trade secret, patent, trademark and other intellectual property
rights.

                  (b) EMC shall retain all right, title and interest in its
copyright, trade secret, patent, trademark and other intellectual property
rights.

         Section 4.2 GRANT OF LICENSES.

                  (a) EMC grants to McDATA, effective as of the Effective Date,
a fully paid-up, unrestricted, non-exclusive, non-assignable (including by
operation by law or otherwise except as provided in subsection (e) of this
Section 4.2), non-transferable, non-sublicenseable (except as provided in
Section 4.7), irrevocable, world-wide right and license under EMC Patents, to
make, have made, manufacture, use, lease and sell or otherwise dispose of McDATA
Products, including products under development as of the Effective Date that are
first sold or otherwise distributed by McDATA within one year of the Effective
Date.

                  (b) McDATA grants to EMC, effective as of the Effective Date,
a fully paid-up, unrestricted, non-exclusive, non-assignable (including by
operation of law or otherwise except as provided in subsection (e) of this
Section 4.2), non-transferable, non-sublicenseable (except as provided in
Sections 4.3 and 4.7), irrevocable, world-wide right and license under McDATA
Patents, to make, have made, manufacture, use, lease and sell or otherwise
dispose of EMC Products, including products under development as of the
Effective Date that are first sold or otherwise distributed by EMC within one
year of the Effective Date.

                                       6
<PAGE>   8

                  (c) EMC grants to McDATA, effective as of the Effective Date,
a fully paid-up, unrestricted, non-exclusive, non-assignable (by operation of
law or otherwise), non-transferable (except as provided in Section 9.8),
irrevocable, world-wide right and license to use (including, without limitation,
the right to copy, reproduce, distribute copies of, modify and create derivative
works of) (i) EMC code that is specifically designed to provide interoperability
between a McDATA Product and an EMC Product and is in the possession of McDATA
as of the Effective Date; and (ii) documentation related to such EMC code in the
possession of McDATA as of the Effective Date.

                  (d) McDATA grants to EMC, effective as of the Closing Date, a
fully paid-up, unrestricted, non-exclusive, non-assignable (by operation of law
or otherwise), non-transferable (except as provided in Section 9.8),
irrevocable, world-wide right and license to use (including, without limitation,
the right to copy, reproduce, distribute copies of, modify and create derivative
works of) (i) McDATA code that is specifically designed to provide
interoperability between a McDATA Product and a EMC Product and is in the
possession of EMC as of the Effective Date; and (ii) documentation related to
such McDATA code in the possession of EMC as of the Effective Date.

                  (e) In the event of a change of control of either party which
would otherwise cause an assignment pursuant to Section 9.8, or in the event
this Agreement is assigned by either party by operation of law, such assignment
shall be effective (notwithstanding the provisions of Section 9.8) and the
assignee shall have a license under the same terms as the license granted in
Section 4.2(a) or 4.2(b), as the case may be (other than any right to sublicense
granted thereunder, which shall in any case be non-transferable and
non-assignable, including by operation of law or in connection with any change
of control), by the other party to the assignor and solely for the products
licensed herein to the assignor only if the assignee shall grant to such other
party a royalty-free license under the same terms as the license granted herein
by the assignor to such other party under all assignee patents for all products
licensed in Section 4.2(a) or 4.2(b), as the case may be, to such other party.

         Section 4.3 SUBLICENSE TO TECHNOLOGY

                  (a) Section 2.3 of the Technology Rights Agreement, as
currently written, is hereby stricken in its entirety, and the following new
Section 2.3 is hereby substituted in its place, and deemed incorporated within
and made a part of the TRA (terms used and not otherwise defined shall have the
meanings set forth in the TRA):

                  "2.3 Holdings retains and reserves for its and its parent's
(EMC) own benefit, the nonexclusive, irrevocable, royalty-free, nonassignable
right and license to make, use and sell all OldCo Technology, except that
Holdings and EMC shall have no license to any of the trademarks and service
marks rights assigned to New McDATA which exclusively shall belong to New
McDATA, and further provided that, except for ESCON Products, Holdings and EMC
may only embed OldCo Technology as additional functionality into EMC Products.
Neither Holdings nor EMC shall have the right to sublicense OldCo Technology,
except, in the event that

                                       7
<PAGE>   9

OldCo Technology is incorporated within a EMC Product, to the extent necessary
to enable EMC to license and distribute such EMC Product, directly or
indirectly, to its end-user customers."

         Section 4.4 NONCOMPETITION CLAUSE.

                  (a) Effective as of the Effective Date, Section 5.1 of the
Technology Rights Agreement, as currently written, shall be stricken in its
entirety, and the following new Section 5.1 substituted in its place, and deemed
incorporated within and made a part of the TRA:

                  "5.1 For a period of two (2) years from the Effective Date,
EMC and Holdings agree that they will not develop or manufacture products
competitive to McDATA Products. For the same period, McDATA agrees that it will
not develop or manufacture products competitive to EMC Products. Notwithstanding
the foregoing, the provisions of this section shall not restrict (i) a party
from developing or manufacturing products which it is developing or
manufacturing as of the Effective Date; (ii) the conduct of a business acquired
by a party where, in the case of an acquisition by EMC, not more than 20% of the
revenues of the acquired entity for its most recently completed fiscal period
are derived from products competitive to McDATA Products, and in the case of an
acquisition by McDATA, not more than 20% of the revenues of the acquired entity
for its most recently completed fiscal period are derived from products
competitive to EMC Products; (iii) an investment by EMC in any entity, provided
that such investment does not exceed 20% of the capital stock of such entity; or
(iv) an investment by McDATA in any entity, provided that such investment does
not exceed 20% of the capital stock of such entity."

         Section 4.5 TECHNOLOGY RIGHTS AGREEMENT.

                  (a) The TRA, as modified by Sections 4.3 and 4.4 hereof, shall
remain in full force and effect.

         Section 4.6 MUTUAL RELEASES.

                  (a) BY EMC. EMC hereby releases, acquits, and forever
discharges, and shall cause its Subsidiaries, which are Subsidiaries as of the
Effective Date, to release, acquit and forever discharge McDATA, its
Subsidiaries which are Subsidiaries as of the Effective Date, and its customers
for such customers' use of McDATA Products, from any and all claims or liability
for infringement of any EMC Patents based upon acts which occur prior to the
Effective Date, to the extent such infringement would have been licensed under
the license granted to McDATA under Section 4.2(a) if such license had been in
existence at the time of such infringing activity.

                  (b) BY MCDATA. McDATA hereby releases, acquits, and forever
discharges, and shall cause its Subsidiaries which are Subsidiaries as of the
Effective Date, to release, acquit and forever discharge EMC, its Subsidiaries,
which are Subsidiaries as of the Effective Date, and its customers for such
customers' use of EMC Products, from any and all claims or liability for

                                       8
<PAGE>   10

infringement of any McDATA Patents based upon acts which occur prior to the
Effective Date, to the extent such infringement would have been licensed under
the license granted to EMC under Section 4.2(b) if such license had been in
existence at the time of such infringing activity.

         Section 4.7 EXTENSION OF LICENSES TO SUBSIDIARIES. The licenses granted
herein shall include the non-assignable right of each party to grant sublicenses
to its Subsidiaries existing on or after the Effective Date, which sublicenses
may include the non-assignable right of sublicensed Subsidiaries to sublicense
other Subsidiaries of said party. No sublicense shall be broader in any respect
at any time during the life of this Agreement than the license held at that time
by the party that granted the sublicense. A sublicense granted to a Subsidiary
shall terminate on the earlier of: (a) the date such Subsidiary ceases to be a
Subsidiary except where the same results from a recapitalization, reorganization
or acquisition of more than 50% of the voting stock of such Subsidiary by a
third party and the resulting or surviving corporation in the case of any
recapitalization or reorganization, or the acquiring party, in any acquisition
of voting stock provides to the licensor a royalty-free license on the same
terms as the sublicense granted to such Subsidiary under all patents held by the
resulting or surviving corporation or acquiring party, as the case may be, for
all products licensed under this Section 4.7 to the Subsidiary; and (b) the date
of termination or expiration of the license of the party or Subsidiary that
granted the sublicense. Each licensed or sublicensed Subsidiary shall be bound
by the terms and conditions of this Agreement as if it were named herein in the
place of the party of which it is a Subsidiary. If a Subsidiary ceases to be a
Subsidiary and holds any patents under which a party hereto is licensed, such
license shall continue for the term defined herein.

         Section 4.8 EFFECT OF TRANSFER OF SUBSIDIARY. In the event of a
transfer of a Subsidiary after the Effective Date (i) which includes the
transfer of products licensed to the transferring party pursuant to Section
4.2(a) or 4.2(b), as the case may be, and (ii) revenues from such products as of
the Effective Date equal or exceed 35% of transferring party's product revenues
as of the Effective Date and (iii) there are patents relating to the such
products licensed hereunder, then after written request given within sixty (60)
days following the transfer by the transferring party, the other party hereto
shall grant a license under the same terms as the license granted to the
transferring party in Section 4.2(a) or 4.2(b) (excluding any right to grant
sublicenses), as the case may be, to the former Subsidiary (the "Recipient");
provided that:

         (a)      the applicable licensed field shall be defined as being
                  limited to the particular product lines being marketed and
                  sold by the Subsidiary as of the date of transfer, including
                  products under development as of the date of such transfer,
                  provided that such product lines and such products under
                  development would have been covered by the license to the
                  transferring party under Section 4.2(a) or 4.2(b) as the case
                  may be;

         (b)      the license granted shall be limited in the twelve (12) months
                  immediately following such transfer to a volume of licensed
                  products having an aggregate selling price equal to no more
                  than the aggregate selling prices of such products by the
                  transferring party in the twelve (12) months preceding such
                  transfer plus thirty percent (30%); and shall be limited, in
                  each of the successive twelve-month

                                       9
<PAGE>   11

                  periods following such transfer, to a volume of licensed
                  products having an aggregate selling price equal to no more
                  than the limit for the immediately preceding twelve-month
                  period plus thirty percent (30%);

         (c)      the Recipient shall grant to such other party a royalty-free
                  license (under the same terms as the license granted to such
                  other party herein) under all recipient patents for all
                  products licensed herein to such other party on the date of
                  the transfer; and

         (d)      the license granted to the Recipient shall terminate three
                  years from the date of the transfer, unless terminated earlier
                  (i) automatically, upon any termination of the license granted
                  to the transferring party or (ii) for any reason.

                                    ARTICLE V

                     ASSET TRANSFER AND SUBLICENSE OF RIGHTS

         Section 5.1 ASSET TRANSFER. EMC and Holdings hereby represent and
warrant that all of the tangible and intangible assets and related rights and
interests of Holdings, including all intellectual property rights, have been
conveyed, transferred, assigned and delivered to McDATA, with the sole exception
of the Excluded Assets (as such term is defined in the Asset Transfer
Agreement).

         Section 5.2 SUBLICENSE OF RIGHTS UNDER CROSS LICENSE. EMC hereby
confirms that it has sublicensed and, for the avoidance of doubt, does hereby
sublicense to McDATA, pursuant to Section 2.4 of the License Agreement between
EMC and IBM entered into March 19, 1999 ("License Agreement") EMC's rights and
licenses under such Agreement to the extent permitted under Section 2.4 and
subject to the terms and conditions of such Agreement.

         Section 5.3 SUBMISSION OF JOINT REQUEST. Upon request of McDATA to EMC,
EMC will submit jointly with McDATA, as provided in Section 2.8 of the License
Agreement, and within the time frame therein stipulated, a written request to
IBM for the grant from IBM to McDATA of a royalty-free license under IBM
Licensed Patents, upon the terms and conditions set forth in such Section.

                                   ARTICLE VI

                              TERM AND TERMINATION

         Section 6.1 TERM. This Agreement shall remain in full force and effect
unless and until terminated by the mutual written agreement of the parties.

                                       10
<PAGE>   12

         Section 6.2 SURVIVAL. Articles II (with respect to Confidential
Information acquired or disclosed prior to the date of termination), III, IV,
VII, VIII and IX shall survive any termination of this Agreement.

                                   ARTICLE VII

                               DISPUTE RESOLUTION

         Section 7.1 ARBITRATION. If a dispute, controversy or claim ("Dispute")
arises between the parties relating to the interpretation or performance of this
Agreement or the grounds for the termination hereof, unless otherwise mutually
agreed, it shall be submitted to final and binding arbitration under the then
current Commercial Arbitration Rules of the American Arbitration Association
("AAA"), by three (3) arbitrators in New York, New York. Such arbitrators shall
be selected by the mutual agreement of the parties or, failing such agreement,
shall be selected according to the aforesaid AAA rules. The arbitrators will be
instructed to prepare and deliver a written, reasoned opinion stating their
decision within thirty (30) days of the completion of the arbitration. The
arbitrators shall have the authority to allocate expenses in their sole
discretion, including costs and reasonable attorneys' and other professional
fees, incurred in connection with the arbitration (but excluding any costs and
fees associated with prior negotiation or mediation). The decision of the
arbitrator shall be final and non-appealable and may be enforced in any court of
competent jurisdiction. The use of any alternate dispute resolutions procedures
will not be construed under the doctrine of laches, waiver or estoppel to
adversely affect the rights of either party.

         Section 7.2 COURT ACTION. Any Dispute regarding any of the following is
not required to be arbitrated prior to seeking relief from a court of competent
jurisdiction: breach of any obligation of confidentiality; infringement,
misappropriation, or misuse of any intellectual property right; any other claim
where interim relief from the court is sought to prevent serious and irreparable
injury to one of the parties or to others.

                                  ARTICLE VIII

                             LIMITATION OF LIABILITY

         IN NO EVENT SHALL EITHER PARTY OR ITS SUBSIDIARIES OR AFFILIATED
COMPANIES BE LIABLE TO THE OTHER PARTY OR ITS SUBSIDIARIES OR AFFILIATED
COMPANIES FOR ANY SPECIAL, CONSEQUENTIAL, INDIRECT, INCIDENTAL OR PUNITIVE
DAMAGES, HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY (INCLUDING NEGLIGENCE)
ARISING IN ANY WAY OUT OF THIS AGREEMENT, WHETHER OR NOT SUCH PARTY HAS BEEN
ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.

                                       11
<PAGE>   13

                                   ARTICLE IX

                            MISCELLANEOUS PROVISIONS

         Section 9.1 EXPORT RESTRICTIONS. Both parties shall adhere to all
applicable laws, regulations and rules relating to the export of technical data,
and shall not export or reexport any technical data, any products received from
Disclosing Party, or the direct product of such technical data, to any
proscribed country listed in such applicable laws, regulations and rules unless
properly authorized.

         Section 9.2 NO IMPLIED LICENSES. Nothing contained in this Agreement
shall be construed as conferring any rights by implication, estoppel or
otherwise, under any intellectual property right, other than the rights
expressly granted in this Agreement with respect to Confidential Information.
Neither party is required hereunder to furnish or disclose to the other any
technical or other information.

         Section 9.3 INFRINGEMENT SUITS. Neither party shall have any obligation
hereunder to institute any action or suit against Third Parties for
misappropriation of any of its Confidential Information or to defend any action
or suit brought by a Third Party that alleges infringement of any intellectual
property rights by the Receiving Party's authorized use of the Disclosing
Party's Confidential Information.

         Section 9.4 NO OTHER OBLIGATIONS. NEITHER PARTY ASSUMES ANY
RESPONSIBILITIES OR OBLIGATIONS WHATSOEVER, OTHER THAN THE RESPONSIBILITIES AND
OBLIGATIONS EXPRESSLY SET FORTH IN THIS AGREEMENT OR IN A SEPARATE WRITTEN
AGREEMENT BETWEEN THE PARTIES.

         Section 9.5 ENTIRE AGREEMENT. This Agreement constitutes the entire
agreement between the parties with respect to the subject matter hereof and
shall supersede all prior written and oral and all contemporaneous oral
agreements and understandings with respect to the subject matter hereof,
provided, however, that the Transaction Agreements and the Ancillary Agreements
shall remain in full force and effect in accordance with their terms.

         Section 9.6 GOVERNING LAW. This Agreement shall be governed by and
construed and enforced in accordance with the laws of the State of New York as
to all matters regardless of the laws that might otherwise govern under
principles of conflicts of laws applicable thereto.

         Section 9.6 DESCRIPTIVE HEADINGS. The descriptive headings herein are
inserted for convenience of reference only and are not intended to be part of or
to affect the meaning or interpretation of this Agreement.

         Section 9.7 NOTICES. All notices and other communications hereunder
shall be in writing and shall be deemed to have been duly given when delivered
in person, by telecopy with

                                       12
<PAGE>   14

answer back, by express or overnight mail delivered by a nationally recognized
air courier (delivery charges prepaid), by registered or certified mail (postage
prepaid, return receipt requested) to the respective parties as follows:

                  if to EMC:

                           c/o EMC Corporation
                           171 South Street
                           Hopkinton, MA  01748-9103
                           Attention: Vice President of Corporate Development
                           cc:              Office of the General Counsel
                           Telecopy:  508-497-6915

                  if to McDATA:

                           c/o McDATA Corporation
                           310 Interlocken Parkway
                           Broomfield, CO  80021
                           Attention:  Chief Financial Officer
                           cc:              Corporate Counsel
                           Telecopy: (303) 465-4996

or to such other address as the party to whom notice is given may have
previously furnished to the other in writing in the manner set forth above. Any
notice or communication delivered in person shall be deemed effective on
delivery. Any notice or communication sent by telecopy or by air courier shall
be deemed effective on the first day following the day on which such notice or
communication was sent. Any notice or communication sent by registered or
certified mail shall be deemed effective on the third day following the day on
which such notice or communication was mailed.

         Section 9.8 NONASSIGNABILITY. Neither party may, directly or
indirectly, in whole or in part, assign or transfer this Agreement, without the
other party's prior written consent, and any attempted assignment, transfer or
delegation without such prior written consent shall be voidable at the sole
option of such other party. Subject to the provisions of Section 4.2(e), a
change of control of a party shall constitute an assignment of this Agreement by
such party. The provisions of this Section 9.8 notwithstanding, (i) the licenses
granted in Sections 4.2(a) and 4.2(b) hereof may be assigned only in accordance
with the provisions of Section 4.2(e) hereof and (ii) Sections 4.6 and 4.8
hereof shall be non-transferable and non-assignable in any event, including by
operation of law or in connection with any change of control. Without limiting
the foregoing, this Agreement will be binding upon and inure to the benefit of
the parties and their permitted successors and assigns.

         Section 9.9 SEVERABILITY. If any term or other provision of this
Agreement is determined by a nonappealable decision of a court, administrative
agency or binding arbitrator by

                                       13
<PAGE>   15

any court or in any binding arbitration to be invalid, illegal or incapable of
being enforced by any rule of law or public policy, all other conditions and
provisions of this Agreement shall nevertheless remain in full force and effect
so long as the economic or legal substance of the transactions contemplated
hereby is not affected in any manner materially adverse to either party. Upon
such determination that any term or other provision is invalid, illegal or
incapable of being enforced, the parties hereto shall negotiate in good faith to
modify this Agreement so as to effect the original intent of the parties as
closely as possible in an acceptable manner to the end that the transactions
contemplated hereby are fulfilled to the fullest extent possible.

         Section 9.10 FAILURE OR INDULGENCE NOT WAIVER; REMEDIES CUMULATIVE. No
failure or delay on the part of either party hereto in the exercise of any right
hereunder shall impair such right or be construed to be a waiver of, or
acquiescence in, any breach of any representation, warranty or agreement herein,
nor shall any single or partial exercise of any such right preclude other or
further exercise thereof or of any other right. All rights and remedies existing
under this Agreement are cumulative to, and not exclusive of, any rights or
remedies otherwise available.

         Section 9.11 AMENDMENT. No change or amendment will be made to this
Agreement except by an instrument in writing signed on behalf of each of the
parties to such agreement.

         Section 9.12 COUNTERPARTS. This Agreement may be executed in two or
more counterparts, all of which, taken together, shall be considered to be one
and the same instrument.

                                       14
<PAGE>   16

         WHEREFORE, the parties have signed this Master Confidential Disclosure
and License Agreement effective as of the date first set forth above.

EMC CORPORATION                         MCDATA CORPORATION

By: /s/ Michael J. Cody                       By: /s/ Dee J. Perry
   -------------------------------------         -------------------------------

Name: Michael J. Cody                         Name: Dee J. Perry
     -----------------------------------           -----------------------------

Title: Vice President,                        TITLE: Chief Financial Officer
       Corporate Development                        ----------------------------
      ----------------------------------

MCDATA HOLDINGS CORPORATION

By: /s/ Paul T. Dacier
   -------------------------------------

Name: Paul T. Dacier
     -----------------------------------

Title:
      ----------------------------------

                                       15

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