<PAGE>

                                                                    Exhibit 10.9

THIS NOTE HAS NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED.
NEITHER THIS NOTE NOR ANY SECURITIES ISSUABLE UPON CONVERSION HEREOF MAY BE
SOLD, TRANSFERRED, ASSIGNED OR HYPOTHECATED UNLESS THERE IS AN EFFECTIVE
REGISTRATION STATEMENT UNDER SUCH ACT COVERING SUCH SECURITIES, THE SALE IS MADE
IN ACCORDANCE WITH RULE 144 UNDER THE ACT, OR THE COMPANY RECEIVES AN OPINION OF
COUNSEL FOR THE HOLDER OF SUCH SECURITIES REASONABLY SATISFACTORY TO THE COMPANY
STATING THAT SUCH SALE, TRANSFER, ASSIGNMENT OR HYPOTHECATION IS EXEMPT FROM THE
REGISTRATION AND PROSPECTUS DELIVERY REQUIREMENTS OF SUCH ACT.

THE SECURITIES ISSUABLE UPON EXERCISE OF THIS CONVERTIBLE PROMISSORY NOTE ARE
ALSO SUBJECT TO CERTAIN RESTRICTIONS CONTAINED IN A SHAREHOLDERS AGREEMENT, AS
AMENDED, A COPY OF WHICH IS ON FILE AT THE OFFICE OF THE SECRETARY OF THE
COMPANY.

PAYMENTS ON ACCOUNT OF THE INDEBTEDNESS EVIDENCED BY THIS CONVERTIBLE PROMISSORY
NOTE ARE SUBORDINATED AS PROVIDED HEREIN.

                     $4,416,150 CONVERTIBLE PROMISSORY NOTE

$4,416,150                                                     December 21, 1999


                  Total Network Solutions, Inc., a New York corporation (the
"COMPANY"), for value received, promises to pay to Cisco Systems, Inc., a
California corporation (the "HOLDER"), the principal sum of Four Million Four
Hundred Sixteen Thousand One Hundred Fifty Dollars ($4,416,150), plus interest
on the unpaid balance hereof (the "NOTE"). Interest shall be computed on the
basis of a 360-day year and actual number of days elapsed and shall accrue from
and including the date funds are advanced hereunder at the rate of six point
forty seven percent (6.47%) per annum to but excluding the date of repayment.

                  1.       DEFINITIONS. As used in this Note, the following
terms shall have the definitions ascribed to them below:

                           a.       "Conversion Share Price" shall be equal to
the quotient obtained by dividing (A) the sum of accrued interest and the
principal amount of $4,416,150 by (B) 4,500,000 (and as appropriately adjusted
for any dilution, stock split, stock dividend, combination, reclassification or
similar event with respect to the Company's common stock).

                           b.       "Conversion Stock" shall mean shares of the
Company's common stock issuable upon conversion of this Note. The total number
of shares of Conversion Stock shall be determined by dividing (A) the amount of
the outstanding principal and accrued interest under this Note which the Holder
elects to convert at the time of conversion by (B) the Conversion Share Price.



<PAGE>

                           c.       "First Convertible Note" shall mean the
$3,172,872.24 Convertible Promissory Note to be issued by the Company to the
Holder pursuant to the Purchase Agreement.

                           d.       "Highest Lawful Rate" shall mean the maximum
non-usurious rate of interest, as in effect from time to time, which may be
charged, contracted for, reserved, received or collected by the Holder in
connection with this Note under applicable law.

                           e.       "Holder" shall mean the person specified in
the introductory paragraph together with its successors and permitted assigns.

                           f.       "Initial Public Offering" shall mean the
Company's first firm commitment underwritten offering pursuant to a registration
statement under the Securities and Exchange Act of 1933, as amended, covering
the sale of the Company's common stock with net proceeds to the Company of at
least Twenty Million Dollars ($20,000,000).

                           g.       "Letter Agreement" shall mean the Letter
Agreement, dated as of December 21, 1999, by and between the Company and the
Holder.

                           h.       "Note" shall mean this $4,416,150
Convertible Promissory Note.

                           i.       "Purchase Agreement" shall mean the
Convertible Note Purchase Agreement, dated as of December 21, 1999, by and
between the Company and the Holder.

                           j.       "Registration Rights Agreement" shall mean
the Second Amended and Restated Registration Rights Agreement, dated as of
December 21, 1999, by and among the Company, Morgan Stanley Venture Investors
III, L.P., Morgan Stanley Venture Partners III, L.P., The Morgan Stanley Venture
Partners Entrepreneur Fund, L.P., Merritt Lutz and the Holder.

                           k.       "Second Convertible Note" shall mean the
$9,000,004.68 Convertible Promissory Note to be issued by the Company to the
Holder pursuant to the Purchase Agreement.

                           l.       "Series B Preferred" shall mean shares of
the Company's Series B Preferred Stock.

                           m.       "Shareholders Agreement" shall mean the
shall mean the Second Amended and Restated Shareholders Agreement, dated as of
December 21, 1999, by and among the Company, Morgan Stanley Venture Investors
III, L.P., Morgan Stanley Venture Partners III, L.P., The Morgan Stanley Venture
Partners Entrepreneur Fund, L.P., Merritt Lutz, the Holder and each of the
stockholders listed on the signature pages thereof.

                  2.       MATURITY. The principal of this Note shall mature and
be due and payable on December 21, 2009 (the "MATURITY DATE"). All accrued and
unpaid interest shall be due and payable on the earlier of (i) the Maturity Date
or (ii) the maturity of the principal of this Note (whether at scheduled
maturity or upon acceleration of maturity following an Event of Default


                                       2
<PAGE>

(as defined below)), provided that in no event shall any interest be payable
prior to June 30, 2003.

                  3.       CONVERSION.

                           a.       HOLDER'S OPTION. The unpaid principal and
interest outstanding under this Note shall be convertible at any time or from
time to time, in whole or in part, at the option of the Holder, into Conversion
Stock at the Conversion Share Price. The Holder will give the Company thirty
(30) days' prior written notice of its intention to effectuate such conversion.
No fractional shares shall be issued and the value of any fractional share shall
be paid by the Company to the Holder in cash. Commencing ninety (90) days prior
to the Maturity Date, if the Note has not been converted by the Holder in
accordance with the terms hereof and the Company wishes to pay the Note, the
Company shall give thirty (30) days' prior written notice to the Holder (the
"NOTICE PERIOD"). After the commencement of the Notice Period, the Holder shall
have thirty (30) days thereof to advise the Company whether it will exercise its
right to convert the Note, in whole or in part, into shares of Conversion Stock
or whether it will accept payment or prepayment of the Note, in whole, from the
Company. The Company may not voluntarily pay prior to the Maturity Date any
portion of the Note if the conversion of such portion would result in the Holder
acquiring 19.9% or more of the equity ownership of the Company or if the Holder
advises the Company during the Notice Period that such conversion would require
the Holder to undertake the equity method of accounting in connection with its
ownership of the Conversion Stock (the "EQUITY LIMITATION") (it being understood
that the Equity Limitation shall be inapplicable to any payment on this Note on
or after the Maturity Date). Any portion of the Note at any time outstanding
because of the Equity Limitation set forth in the preceding sentence may be
voluntarily paid prior to the Maturity Date only at the option of the Holder.

                           b.       CONDITION TO AN ACQUISITION TRANSACTION. If
neither prepayment nor conversion has occurred prior to (i) any reorganization,
merger or consolidation in which the Company is not the surviving entity or (ii)
the sale or transfer by the Company of all or substantially all of its assets
otherwise than to a wholly owned affiliate of the Company, (any such transaction
being an "ACQUISITION TRANSACTION"), unless this Note is paid or converted as
provided in Section 5, as a condition to the consummation of the Acquisition
Transaction, the Note shall be cancelled and the surviving entity or transferee
shall enter into a successor note agreement with the Holder (the "SUCCESSOR
NOTE"). The Successor Note shall provide (i) that the Holder may convert it for
the kind and amount of capital stock or other securities or property which the
Holder would have received immediately after the Acquisition Transaction if the
Holder had converted the Note immediately before the effective date of the
Acquisition Transaction and (ii) that the surviving entity in the Acquisition
Transaction shall succeed to and be substituted to every right and obligation of
the Company in respect of this Note. The Successor Note shall provide for
adjustment which shall be as nearly equivalent as may be practicable to the
adjustments provided for in this Section 3. Notwithstanding the foregoing, if
the Company enters into an Acquisition Transaction and consideration payable to
holders of shares of the Company's common stock issuable or, deliverable upon
conversion of the Note in connection with such Acquisition Transaction consists
solely of cash, then the Holder shall be entitled to receive distributions on
the date of such event on an equal basis with holders of shares of the Company's
common stock issuable upon conversion of the Note as if the Note had been


                                       3
<PAGE>

converted immediately prior to such event and upon such distribution, the Note
shall be cancelled and the Company's obligations under the Note shall be
terminated.

                           c.       CONDITIONAL CONVERSION. Subject to Section
3(a), the Holder may specify that the conversion of the Note, in whole or in
part, is contingent upon and shall occur simultaneously with the consummation of
(i) the acquisition of the Company by another entity by means of any transaction
or series of related transactions (including, without limitation, any
reorganization, merger or consolidation), or (ii) a sale of all or substantially
all of the assets of the Company (including, for purposes of this paragraph,
intellectual property rights which, in the aggregate, constitute substantially
all of the Company's assets).

                  4.       MECHANICS AND EFFECT OF CONVERSION. Upon the
conversion of this Note pursuant to Section 3 above, the Holder shall surrender
this Note, duly endorsed, at the principal office of the Company. At its
expense, the Company shall, as soon as practicable thereafter, issue and deliver
to such Holder at such principal office a certificate or certificates for the
number of shares of such Conversion Stock to which the Holder shall be entitled
upon such conversion (bearing such legends as are required by applicable state
and federal securities laws in the opinion of counsel to the Company), together
with any other securities and property to which the Holder is entitled upon such
conversion under the terms of this Note, including a check payable to the Holder
for any cash amounts payable as described above. Upon conversion of this Note,
the Company shall be forever released from all its obligations and liabilities
under this Note.

                  5.       PREPAYMENTS. In addition to the Company's right to
prepay the Note pursuant to Section 3, if on or prior to the Maturity Date, the
Company notifies the Holder that it intends to consummate a merger,
consolidation, reorganization or sale of all or substantially all of its assets
following which the holders of the Company's voting securities outstanding prior
to such transaction will not hold more than 50% of the voting securities of the
surviving entity or transferee in such transaction (or an entity controlling
such surviving entity or transferee), the Company may prepay the Note in whole;
PROVIDED, HOWEVER, that the Company shall give the Holder at least thirty (30)
days prior written notice (or such other time as may be remaining if there are
less than 30 days remaining prior to the consummation of such transaction) of
its intent to consummate such transaction and; PROVIDED, FURTHER, that such
prepayment is subject to the Holder's right to convert the Note pursuant to
Section 3(a), and that such prepayment shall occur only upon the consummation of
such transaction. Upon the consummation of such transaction, the Holder shall
surrender the Note, duly endorsed, at the principal office of the Company, and
the Company shall pay the Holder in immediately available Funds the unpaid
principal and interest of the Note.

                  6.       USURY. Any scheduled principal payments hereunder, or
any other amounts payable hereunder, not paid within five (5) days from the date
due shall bear interest at a rate of 10% per annum, or the maximum rate
permitted by law, whichever is less. Overdue interest shall be payable on
demand. All computations of interest shall be made on the basis of a year of 360
days for the actual number of days (including the first day but excluding the
last day) occurring in the period for which such interest is payable. Anything
herein to the contrary notwithstanding, if during any period for which interest
is computed hereunder, the amount of interest computed on the basis provided for
in this Note, together with all fees, charges and other


                                       4
<PAGE>

payments which are treated as interest under applicable law, as provided for
herein or in any other document executed in connection herewith, would exceed
the amount of such interest computed on the basis of the Highest Lawful Rate,
the Company shall not be obligated to pay, and the Holder shall not be entitled
to charge, collect, receive, reserve or take, interest in excess of the Highest
Lawful Rate, and during any such period the interest payable hereunder shall be
computed on the basis of the Highest Lawful Rate.

                  7.       EVENTS OF DEFAULT. The entire unpaid principal
balance and accrued interest of this Note shall immediately be due and payable
at the option of the Holder upon the occurrence of any Event of Default. For
purposes of this Note, the Company shall be in default under this Note upon the
happening of any condition or event set forth below (herein called an "EVENT OF
DEFAULT"):

                           a.       The Company's failure to pay any principal
or accrued interest evidenced hereby within five (5) days after such payment of
principal or interest becomes due in accordance with the terms of this Note;

                           b.       The Company's failure to perform, keep or
observe any of its covenants, conditions, promises, agreements or obligations
under this Note, if such failure would have a material adverse effect on the
Company's assets, operations or condition, financial or otherwise and such
failure is not cured by the Company within thirty (30) days (or such longer
period as shall be reasonably necessary to effect such cure if efforts to cure
are commenced within such 30-day period and are pursued with reasonable
diligence until completion) of the date that written notice of such failure is
delivered to the Company.

                           c.       The institution of proceedings against the
Company, or the Company's filing of a petition or answer or consent seeking
reorganization or release, under the Federal Bankruptcy Code, or the
commencement of any proceeding under any bankruptcy or insolvency laws by or
against the Company which results in the entry of an order for relief or which
remains undismissed, undischarged or unbonded for a period of sixty (60) days or
more, or the Company's consent to the filing of any such petition or the
appointment of a receiver, liquidator, assignee, trustee or other similar
official of the Company or of any substantial part of its property, or the
Company's making of an assignment for the benefit of creditors, or the taking of
corporate action in furtherance of such action;

                           d.       Any warranty or representation contained in
this Note, the Letter Agreement, the First Convertible Note, the Second
Convertible Note, the Registration Rights Agreement, the Shareholders Agreement
or the Purchase Agreement proves to have been false in any material respect when
made or furnished and such falsity would have a material adverse effect on the
Company's assets, operations or condition, financial or otherwise.

                  8.       RESERVATION OF STOCK ISSUABLE UPON CONVERSION. The
Company shall reserve and keep available out of its authorized but unissued
shares of preferred or common stock such number of shares as shall from time to
time be sufficient to effect the conversion of this Note; and, if at any time
the number of authorized but unissued shares of the Company's preferred or
common stock shall not be sufficient to effect the conversion of the entire
outstanding principal amount of this Note, without limitation of such other
remedies as shall be


                                       5
<PAGE>

available to the Holder of this Note, the Company will use its best efforts to
take such corporate action as, in the opinion of counsel, may be necessary to
increase its authorized but unissued shares of preferred or common stock to such
number of shares as shall be sufficient for such purposes.

                  9.       NOTICES. Any notice required by any provision of this
Note to be given to the Holder shall be in writing or by telegram or facsimile
confirmed answer back, and shall be deemed to have been duly made when delivered
in person or sent by telegram or facsimile confirmed answer back , same day or
overnight courier, or 72 hours after having been deposited in the United States
first class or registered or certified mail return receipt requested, postage
prepaid. All such communications shall be addressed to the Holder of record at
its address appearing on the books of the Company.

                  10.      NO RIGHTS AS STOCKHOLDER. This Note, as such, shall
not entitle the Holder to any rights as a stockholder of the Company, except as
otherwise specified herein.

                  11.      LEGAL FEES. The Company agrees to pay on demand all
the losses, costs, and expenses (including, without limitation, attorneys' fees
and disbursements) which the Holder incurs in connection with enforcement or
attempted enforcement of this Note, or the protection or preservation of the
Holder's rights under this Note, whether by judicial proceedings or otherwise.
Such costs and expenses include, without limitation, those incurred in
connection with any workout or refinancing, or any bankruptcy, insolvency,
liquidation or similar proceedings.

                  12.      HEADINGS. The headings in this Note are inserted for
convenience only and do not constitute a part of this Note.

                  13.      GOVERNING LAW. This Note shall be governed by the
laws of the State of New York, without giving effect to conflicts of law
principles.

                  14.      ASSIGNMENT. This Note shall be binding on the Company
and its successors and permitted assigns, and shall be binding upon and inure to
the benefit of the Holder, any future holder of this Note and their respective
successors and permitted assigns. Neither the Company nor the Holder may assign
or transfer this Note or any of its rights or obligations hereunder (other than
by operation of law) without the other party's prior written consent; PROVIDED,
HOWEVER, that the Holder may transfer this Note and any of its rights and
obligations hereunder to a majority-owned affiliate thereof. Any transferee of
this Note shall become a party to the Shareholders Agreement in accordance with
the terms thereof.

                  15.      WAIVER. The Company hereby waives notice of default,
presentment or demand for payment, protest or notice of nonpayment or dishonor
and all other notices or demands relative to this Note. No single or partial
exercise of any power under this Note shall preclude any other or further
exercise of such power or exercise of any other power. No delay or omission on
the part of the Holder in exercising any right under this Note shall operate as
a waiver of such right or any other right hereunder.

                  16.      SEVERABILITY. In the event any one or more of the
provisions contained in this Note shall for any reason be held to be invalid,
illegal or unenforceable in any respect, such


                                       6
<PAGE>

invalidity, illegality or unenforceability shall not affect any other provision
hereof, and this Note shall be construed as if such invalid, illegal or
unenforceable provision had never been contained herein.

                  17.      SUBORDINATION. By accepting this Note, the Holder
agrees that all payments on account of the indebtedness, liabilities and other
obligations of the Company to the Holder of this Note, including, without
limitation, all amounts of principal, all interest accrued hereon, and all other
amounts payable by the Company to the Holder under this Note or in connection
herewith (the "Subordinated Indebtedness") shall be subordinate and subject in
right of payment, to the extent and in the manner set forth herein, to the prior
payment in full in cash or cash equivalents of the Senior Indebtedness. As used
herein, "Senior Indebtedness" shall mean (i) any indebtedness, liabilities and
other obligations of the Company (whether as primary obligor or as guarantor) to
any person (each a "Senior Lender") with respect to (a) any working capital,
revolving credit or other line of credit facility, any term loan facility, or
any other extension of credit by any individual or entity (whether or not
secured), including reimbursement obligations under letters of credit or
guaranties and (b) obligations in respect of bankers' acceptances purchased by,
and interest rate protection agreements and currency exchange and purchase
agreements entered into with, any individual or entity, (ii) any such types of
indebtedness which are incurred by any affiliate of the Company, (iii) all other
amounts due on or in connection with such Senior Indebtedness, including all
charges, fees, indemnities and expenses (including reasonable fees and expenses
of counsel), (iv) all interest accruing with respect to such Senior Indebtedness
during the pendency of a bankruptcy or insolvency proceeding, whether or not
allowable thereunder, and (v) all extensions, renewals, refinancings and
deferrals of the amounts referred to in clauses (i) through (iv) above. The
terms "indebtedness," "liabilities" and "obligations" are used herein in their
most comprehensive sense and include any and all advances, debts, obligations
and liabilities, now existing or hereafter arising, whether voluntary or
involuntary and whether due or not due, absolute or contingent, liquidated or
unliquidated, determined or undetermined.

                  As long as any of the Senior Indebtedness shall remain
outstanding and unpaid, the Holder shall not accept or receive, directly or
indirectly, and the Company shall not make, any Subordinated Debt Payment (as
defined below), except that prior to the occurrence of any Senior Lender Default
(as defined below) and receipt of the notice from the Senior Lender described
below, the Holder shall be entitled to accept and receive payments of principal
and interest under this Note, in accordance with the terms of this Note. Upon
the occurrence of any Senior Lender Default (or if any Senior Lender Default
would exist immediately after the making of a Subordinated Debt Payment), and
upon receipt by the Company and the Holder of notice in writing of such Senior
Lender Default, and until such Senior Lender Default is cured or waived, the
Company shall not make, and the Holder shall not accept or receive, any
Subordinated Debt Payment. In the event that, notwithstanding the foregoing
provisions, any Subordinated Debt Payments shall be received in contravention
hereof by the Holder before all Senior Indebtedness shall be paid, such
Subordinated Debt Payments shall be held in trust for the benefit of the Senior
Lenders and shall be paid over or delivered to the Senior Lenders for
application to the payment in full in cash or cash equivalents of all Senior
Indebtedness remaining unpaid to the extent necessary to give effect hereto,
after giving effect to any concurrent payments or distributions to any Senior
Lender in respect of the Senior Indebtedness. As used herein, "Senior Lender
Default" means any default in respect of any Senior


                                       7
<PAGE>

Indebtedness, or any other default specified in the agreement or instrument
under which any Senior Indebtedness is issued, continuing beyond the grace
period, if any, specified in any such agreement or instrument; and "Subordinated
Debt Payment" means any payment or distribution by or on behalf of the Company,
directly or indirectly, of assets of the Company or any person or entity with a
right of reimbursement against the Company of any kind or character, whether in
cash, property or securities, including on account of the purchase, redemption
or other acquisition of Subordinated Indebtedness, or by setoff, exchange or in
any other manner, for or on account of the Subordinated Indebtedness.

                  If, while any Subordinated Indebtedness is outstanding, any
bankruptcy, insolvency, reorganization, receivership, arrangement, marshalling
of assets and liabilities or similar proceeding is commenced by or against the
Company or its property, the Holder shall promptly take such action as any
Senior Lender may reasonably request (A) to collect the Subordinated
Indebtedness for the account of the Senior Lenders and to file appropriate
claims or proofs of claim in respect of the Subordinated Indebtedness, (B) to
execute and deliver to the Senior Lenders, such powers of attorney, assignments
and other instruments as they may request to enable them to enforce any and all
claims with respect to the Subordinated Indebtedness (to the extent and in the
manner provided herein), and (C) to collect and receive any and all payments or
distributions which may be payable or deliverable upon or with respect to the
Subordinated Indebtedness for the account of the Senior Lenders.

                  In the event of any payment or distribution of assets of the
Company of any kind or character, whether in cash, property or securities, upon
the dissolution, winding up or total or partial liquidation or reorganization,
readjustment, arrangement or similar proceeding relating to the Company or its
property, whether voluntary or involuntary or in bankruptcy, insolvency,
receivership, arrangement or similar proceedings or upon an assignment for the
benefit of creditors, or upon any other marshalling or composition of the assets
and liabilities of the Company, or otherwise: (i) all amounts owing on account
of the Senior Indebtedness shall first be paid in full in cash, or payment
provided for in cash or in cash equivalents, before any Subordinated Debt
Payment is made; and (ii) to the extent permitted by applicable law, any
Subordinated Debt Payment to which the Holder would be entitled except for the
provisions hereof, shall be paid or delivered by the trustee in bankruptcy,
receiver, assignee for the benefit of creditors or other liquidating agent
making such payment or distribution directly to the Senior Lenders for
application to the payment of the Senior Indebtedness in accordance with clause
(i) above, after giving effect to any concurrent payment or distribution or
provision therefor to the Senior Lenders in respect of such Senior Indebtedness.

                  If an Event of Default under Section 7 shall occur and be
continuing, the Holder shall, at least twenty (20) days prior to accelerating,
and as a condition to the effectiveness of any acceleration of, this Note, send
a written notice of such acceleration designated as a "Notice of Intent to
Accelerate" to all holders of Senior Indebtedness that have been identified as
such by the Company (or by any such holder of Senior Indebtedness).

                  The subordination provisions of this Note are intended solely
for the purpose of defining the relative rights against the Company of the
Holder, on the one hand, and the Senior Lenders, on the other hand. Nothing
contained herein shall (i) impair, as between the Company and the Holder, the
obligation of the Company to pay the principal of or interest on this Note and


                                       8
<PAGE>

its other obligations with respect to the Subordinated Indebtedness as and when
the same shall become due and payable in accordance with the terms thereof, or
(ii) otherwise affect the relative rights against the Company of the Holder, on
the one hand, and the creditors of the Company (other than the Senior Lenders),
on the other hand.

                  Until the payment and performance in full of all Senior
Indebtedness, the Holder shall not have, and shall not directly or indirectly
exercise, any rights that it may acquire by way of subrogation under this Note,
by any payment or distribution to the Senior Lenders hereunder or otherwise.
Upon the payment and performance in full of all Senior Indebtedness, the Holder
shall be subrogated to the rights of the Senior Lenders to receive payments or
distributions applicable to the Senior Indebtedness until the Subordinated
Indebtedness shall be paid in full. For the purposes of the foregoing
subrogation, no payments or distributions to the Senior Lenders of any cash,
property or securities to which the Holder would be entitled except for the
provisions of this Note shall, as among the Company, its creditors (other than
the Senior Lenders and the Holder), be deemed to be a payment by the Company to
or on account of the Senior Indebtedness.

                  Each Holder of this Note shall, upon request by the Company,
enter into an intercreditor agreement reflecting the foregoing provisions of
this Section 17 and other customary provisions reasonably acceptable to such
Holder implementing the foregoing provisions of this Section 17.

                            [signature page follows]


                                      9

<PAGE>

                  IN WITNESS WHEREOF, the Company has duly caused this
$4,416,150 Convertible Promissory Note to be signed in its names and on its
behalf by its duly authorized officers as of the date first above written.

                                         TOTAL NETWORK SOLUTIONS, INC.

                                         By:____________________________________
                                            Name:_______________________________
                                            Title:______________________________

                                         ACCEPTED AND AGREED:

                                         CISCO SYSTEMS, INC.

                                         By:____________________________________
                                            Name:_______________________________
                                            Title:______________________________





            [signature page - $4,416,150 Convertible Promissory Note]