<PAGE>

                                                                    EXHIBIT 10.3
 
                           RELOCATION LOAN AGREEMENT


     THIS RELOCATION LOAN AGREEMENT ("Agreement") is entered into as of the
14th day of April, 1998, by and between OBJECTIVE SYSTEMS INTEGRATORS, INC., a
Delaware corporation (the "Company"), and JAMES K.R. SOUDERS, an unmarried man
("Employee").


                                    RECITALS
                                    --------

     A.   Employee is employed by the Company as its Executive Vice President of
Sales and Marketing.

     B.   In connection with his employment with the Company, Employee has found
it necessary to relocate his principal place of residence.

     C.   To aid Employee in such relocation, the Company and Employee desire
that the Company loan to Employee the sum of Four Hundred Thousand Dollars
($400,000.00) to assist Employee in purchasing a new principal residence in the
vicinity of the offices of the Company.

     NOW, THEREFORE, the Company and Employee agree as follows:

                                   AGREEMENT
                                   ---------
                                        
     1.   LOAN:  The Company shall lend to Employee the amount of Four Hundred
          ----                                                                
Thousand Dollars ($400,000.00), which amount shall be used by Employee for the
sole purpose of purchasing a new residence located in the Folsom, California
area, pursuant to the terms and conditions set forth herein (the "Loan").

     2.   PROMISSORY NOTE:  Concurrently upon execution of this Agreement,
          ---------------                                                 
Employee shall execute and deliver to the Company the following: (i) one (1)
original promissory note in the amount of Four Hundred Thousand Dollars
($400,000.00) in substantially the same form as Exhibit A attached hereto (the
                                                ---------                     
"Note"); and (ii) Employee shall execute a Certificate of Employee in
substantially the same form as Exhibit B attached hereto.
                               ---------                 

     3.   DEED OF TRUST:   Concurrently upon execution of this Agreement,
          -------------                                                  
Employee shall duly execute and deliver to the Company one (1) original, validly
acknowledged deed of trust on Lot 39 of Sammamish 95, as per plat recorded in
volume 141 of plats, pages 21 through 25, Records of King County, Washington
State (the "Washington Property"), in substantially the same form as Exhibit C
                                                                     ---------
attached hereto, with all uncompleted information fully completed (the "Deed of
Trust").
<PAGE>
 
     4.   EMPLOYEE'S REPRESENTATIONS AND WARRANTIES:  Employee hereby makes the
          -----------------------------------------                            
following representations and warranties to the Company and acknowledges that
the Company is relying on such representations in making the Loan:
 
          A.     Employee has good and marketable title to the Washington
Property free and clear of any security interests, liens or encumbrances
securing monetary obligations other than a first deed of trust dated on or about
February 28, 1997, constituting a first lien against the Washington Property in
favor of Norwest Mortgage, Inc., securing a loan with a principal balance not in
excess of Two Hundred Fourteen Thousand Dollars ($214,000) ("First Deed of
Trust").

          B.   The consent of no other person or entity is required to grant the
security interest in the Washington Property to the Company evidenced by the
Deed of Trust.

          C.   There are no actions, proceedings, claims or disputes pending or,
to Employee's knowledge, threatened against or affecting Employee, or the
Washington Property.

     5.   CERTIFICATION BY EMPLOYEE:  Employee hereby certifies to the Company
          -------------------------                                           
as follows:

          A.   Employee understands that the Loan provided by this Agreement
between the Company and Employee is not transferable by the Employee and is
conditioned on the future performance of substantial services by the Employee.
Employee further agrees that the Loan proceeds will be used only to purchase a
principal residence for Employee being acquired in connection with the
commencement of employment at a "new principal place of work" within the meaning
of Section 217 of the Internal Revenue Code of 1986, as amended.

          B.   Employee reasonably expects to be entitled to and will itemize
deductions each year that the loan is outstanding.

          C.   The loan proceeds will be used only to purchase a new residence
for Employee.

     6.    EMPLOYEE'S ADDITIONAL OBLIGATIONS:  Employee shall take any and all
           ---------------------------------                                  
further actions that may from time to time be required to ensure that the Deed
of Trust creates a valid lien on the Washington Property in favor of the
Company, which shall secure the Note and be junior in priority only to the First
Deed of Trust.  Employee shall furnish evidence reasonably satisfactory to the
Company that:  (i) Employee has good and marketable title to the Washington
Property; (ii) the consent of no other person or entity is required to grant a
security interest in the Washington Property to the Company; and (iii) there is
no other deed of trust, mortgage or encumbrance against the Washington Property
other than the First Deed of Trust.  If it should be hereafter determined that
there are defects against title or matters which could result in defects against
title to the Washington Property or that the consent of another person or entity
is required to grant to and perfect in the Company a valid second-priority lien
on the Washington Property, Employee shall promptly take all action necessary to
remove such defects and to obtain such consent and grant (or 
<PAGE>
 
cause to be granted) and perfect such lien on the Washington Property. Failure
of Employee to comply with the provisions of this paragraph 6 shall be deemed a
default under the Note and the Deed of Trust.

     7.   MATURITY EVENT:  The outstanding balance of the Note secured by the
          --------------                                                     
Deed of Trust shall be due and payable, to the extent permitted by law, upon the
Maturity Event which is defined in this Agreement and will be identified in the
Note and Deed of Trust as the earlier of any of the following events: (a) the
termination or cessation of Employee's employment with the Company for any
reason, whether voluntary or involuntary, and whether with cause or without
cause, (b) any default in the performance of any obligation of Employee
contained in the Deed of Trust, the First Deed of Trust, or any other deed of
trust, security agreement or other agreement (including any amendment,
modification or extension thereof) which may hereafter be executed by Employee
for the purpose of securing the Note; (c) Employee voluntarily or by operation
of law sells, conveys, assigns, or otherwise transfers or agrees to sell, convey
or otherwise transfer, all or any portion of, or any interest in, the Washington
Property without the prior written consent of the Company; (d) Employee (i)
admits in writing his inability to pay debts, (ii) makes an assignment for the
benefit of creditors, (iii) files a voluntary petition in bankruptcy, effects a
plan or other arrangement with creditors, liquidates his assets under an
arrangement with creditors, or liquidates his assets under court supervision,
(iv) has an involuntary petition in bankruptcy filed against him that is not
discharged within sixty (60) days after such petition is filed, or (v) applies
for or permits the appointment of a receiver or trustee or custodian for any of
his property or assets who is not discharged within sixty (60) days after the
date of appointment; (e) the passing of sixty (60) days after the date of this
Agreement, or if later, the date of the Note; (f) Employee breaches any
representation or warranty contained herein, in the Note or the Deed of Trust,
or any agreement or instrument executed in connection with this Loan proves to
have been false or misleading in any material respect; (g) the Deed of Trust (as
defined herein) encumbering the Washington Property is not duly executed,
validly acknowledged, and delivered by Employee concurrently with the Note; (h)
the death of Employee; or (i) Employee conveys to any person or entity title to
the Washington Property.

     8.   REPAYMENT OF LOAN:  Notwithstanding anything to the contrary herein,
          -----------------                                                   
if a Maturity Event (as defined herein and in the Note), occurs at any time
within fifteen (15) days after the date of this Agreement, or if later, the date
of the Note, Employee shall pay to the Company the entire principal amount of
the Loan plus all accrued interest, and any other sums due under the Note or
this Agreement.

     9.   ENTIRE AGREEMENT:  This Agreement, the Note and the Deed of Trust,
          ----------------                                                  
constitute the full and entire understanding and agreement between the parties
hereto with regard to the subject hereof.  Neither this Agreement nor any term
hereof may be amended, waived, discharged or terminated other than by a written
instrument signed by the party against whom enforcement of any such amendment,
waiver, discharge or termination is sought.  No waiver of any provision of this
Agreement, the Note or the Deed of Trust shall be effective unless in writing
and the waiver of any one provision shall not be deemed a waiver of any other
provision unless expressly stated in writing.
<PAGE>
 
     10.  NO COVENANT FOR EMPLOYMENT OR ADVANCES:  Employee understands and
          --------------------------------------                           
acknowledges that this Agreement does not constitute an employment agreement or
a promise by the Company to continue Employee's employment.

     11.  NOTICES:  All notices and other communications required or permitted
          -------                                                             
hereunder shall be in writing and may be given by (a) personal delivery, (b)
certified mail, postage prepaid, return-receipt requested, (c) courier service,
fully prepaid, or (d) facsimile. Any such notice shall be properly addressed to
the address of the parties set forth on the signature page hereto and shall be
deemed to have been given (i) if personally delivered, when delivered, (ii) if
by certified mail, return-receipt requested, when delivered or refused, (iii) if
by courier service, on the next business day following deposit, cost prepaid,
with Federal Express or similar private carrier, or (iv) if by facsimile,
instantaneously upon confirmation of receipt of facsimile. Company or Employee
may change its address by giving notice of the same in accordance with this
Paragraph. The term "business day" shall mean a day on which the carrier used
(Federal Express or other private carrier, or the U.S. Postal Service, as
applicable) delivers, whether by special request or in the ordinary course of
operations.

     12.  ASSIGNMENT:  Employee may not assign its rights and/or duties under
          ----------                                                         
this Agreement to any other person or entity without the prior written consent
of the Company, which consent may be withheld at the Company's sole discretion.
The Company may assign the Note and the Deed of Trust at any time in its sole
discretion.

     13.  INCOME TAX CONSEQUENCES:  Employee hereby acknowledges that the
          -----------------------                                        
Company has made no representation or warranty to Employee concerning the income
tax consequences of the Loan to Employee and Employee agrees that Employee shall
be solely responsible for ascertaining and bearing such tax consequences and any
potential tax liabilities that may arise in connection herewith.

     14.  EXHIBITS:  All Exhibits attached hereto are incorporated herein by
          --------                                                          
this reference.

     15.  GOVERNING LAW:  This Agreement shall be governed in all respects by
          -------------                                                      
the laws of the State of California.

     16.  HEADINGS:  The titles and headings of the various paragraphs hereof
          --------                                                           
are intended for means of reference and are not intended to place any
construction on the provisions hereof.

     17.  INVALIDITY:  If any provision of this Agreement shall be invalid or
          ----------                                                         
unenforceable the remaining provisions shall not be affected thereby and every
provision hereof shall be valid and enforceable to the fullest extent permitted
by law.

     18.  COUNTERPARTS:  This Agreement may be executed in one (1) or more
          ------------                                                    
separate counterparts, each of which, when so executed, shall be deemed to be an
original.  Such counterparts, together, shall constitute one and the same
instrument.
<PAGE>
 
     19.  ACKNOWLEDGMENT:  THIS AGREEMENT, THE NOTE, THE DEED OF TRUST AND ALL
          --------------                                                      
RELATED DOCUMENTATION ARE EXECUTED VOLUNTARILY AND WITHOUT ANY DURESS OR UNDUE
INFLUENCE ON THE PART OF OR ON BEHALF OF THE PARTIES HERETO, WITH THE FULL
INTENT OF CREATING THE OBLIGATIONS AND SECURITY INTERESTS DESCRIBED HEREIN AND
THEREIN. THE PARTIES ACKNOWLEDGE THAT: (a) THEY HAVE READ SUCH DOCUMENTATION;
(b) THEY HAVE BEEN REPRESENTED IN THE PREPARATION, NEGOTIATION AND EXECUTION OF
SUCH DOCUMENTATION BY LEGAL COUNSEL OF THEIR OWN CHOICE OR THAT THEY HAVE
VOLUNTARILY DECLINED TO SEEK SUCH COUNSEL; (c) THEY UNDERSTAND THE TERMS AND
CONSEQUENCES OF THIS AGREEMENT, THE NOTE, THE DEED OF TRUST AND ALL RELATED
DOCUMENTATION AND THE OBLIGATIONS THEY CREATE; AND (d) THEY ARE FULLY AWARE OF
THE LEGAL AND BINDING EFFECT OF THIS AGREEMENT, THE NOTE, THE DEED OF TRUST AND
THE OTHER DOCUMENTS CONTEMPLATED BY THIS AGREEMENT.
<PAGE>
 
     IN WITNESS WHEREOF, the undersigned have executed this Agreement as of the
date first written above.

EMPLOYEE:                           EMPLOYER:

JAMES K.R. SOUDERS,                 OBJECTIVE SYSTEMS
an unmarried man                    INTEGRATORS, INC.,
                                    a Delaware corporation

                                          
  /s/ James K.R. Souders            By:    /s/ Philip N. Cardman        
______________________________         _________________________________
Date:  April 14, 1998               Its:   V.P. General Counsel         
     _________________________          ________________________________
                                           April 14, 1998               
                                    Date: ______________________________


                                    By:    /s/ David M. Allen
                                       _________________________________
                                    Its:   V.P. Finance & Admin. and CEO
                                        ________________________________

                                    Date: ______________________________ 


                                    By:    /s/ Tom L. Johnson
                                       _________________________________
                                    Its:   Co-CEO                       
                                        ________________________________
                                           
                                    Date: ______________________________ 

<TABLE> 
<CAPTION> 

<S>                                              <C> 
Address: Objective Systems Integrators Inc.      Address: Objective Systems Integrators Inc. 
         __________________________________               __________________________________
         100 Blue Ravine Rd.                              100 Blue Ravine Rd. 
         __________________________________               __________________________________
         Folsom, CA  95630                                Folsom, CA  95630 
         __________________________________               __________________________________
         __________________________________               __________________________________
                                                                  Legal Dept.
         ATTN: ____________________________               ATTN: ____________________________

Facsimile                                        Facsimile      (916) 353-0647
Number:  __________________________________      Number:____________________________________
</TABLE> 
<PAGE>
 
                                   EXHIBIT B
                                   ---------


                            CERTIFICATE OF EMPLOYEE
                            -----------------------
                                        

     The undersigned Employee hereby certifies to Objective Systems Integrators,
Inc. (the "Company") as follows:

     1.   He understands that the interest-free loan (the "Loan") provided for
by the Relocation Loan Agreement dated the date hereof between the Company and
Employee is not transferable by Employee and is conditioned on the future
performance of substantial services by Employee.

     2.   The Loan proceeds will be used only to purchase a principal residence
of Employee being acquired in connection with the commencement of employment at
a "new principal place of work" within the meaning of Section 217 of the
Internal Revenue Code of 1986, as amended.

     3.   Employee reasonably expects to be entitled to and will itemize
deductions each year the Loan is outstanding.

     4.   Employee's immediately former principal residence shall not be
converted to business or investment use.



April 14, 1998

                                        /s/ James K.R. Souders 
                                    ________________________________
                                            James K.R. Souders