SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                                  SCHEDULE 13G
                                 (Rule 13d-102)

            INFORMATION TO BE INCLUDED IN STATEMENTS FILED PURSUANT TO
                           RULES 13d-1(b)(c), AND (d)
                    AND AMENDMENTS THERETO FILED PURSUANT TO
                                  RULE 13d-2(b)
                               (AMENDMENT NO. )*

                          Internap Network Services Co.
- --------------------------------------------------------------------------------
                                (Name of Issuer)

                                  Common Stock
- --------------------------------------------------------------------------------
                         (Title of Class of Securities)

                                    45885A10
- --------------------------------------------------------------------------------
                                 (CUSIP Number)

                                 April 30, 2001
- --------------------------------------------------------------------------------
            (Date of Event which Requires Filing of this Statement)


Check the appropriate box to designate the rule pursuant to which this schedule
is filed:

/X/   Rule 13d-i(b)
/  /  Rule 13d-i(c)
/  /  Rule 13d-i(d)


- ------------------------
*The remainder of this cover page shall be filled out for a reporting person's
initial filing on this form with respect to the subject class of securities, and
for any subsequent amendment containing information which would alter the
disclosures provided in a prior cover page.

The information required in the remainder of this cover page shall not be deemed
to be "filed" for the purpose of Section 18 of the Securities Exchange Act of
1934 ("Act") or otherwise subject to the liabilities of that section of the Act
but shall be subject to all other provisions of the Act.

                        (Continued on following page(s))

                                Page 1 of 4 Pages




CUSIP NO. 45885A10 13G PAGE 2 OF 4 PAGES - -------------------------------------------------------------------------------- 1 NAME OF REPORTING PERSON I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS (ENTITIES ONLY) Massachusetts Financial Services Company ("MFS") I.R.S. Identification No.: 04-2747644 - -------------------------------------------------------------------------------- 2 CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP* (a) / / (b) / / - -------------------------------------------------------------------------------- 3 SEC USE ONLY - -------------------------------------------------------------------------------- 4 CITIZENSHIP OR PLACE OF ORGANIZATION Delaware - -------------------------------------------------------------------------------- NUMBER OF 5 SOLE VOTING POWER SHARES 14,130,141 shares of common stock BENEFICIALLY - -------------------------------------------------------------------------------- OWNED BY 6 SHARED VOTING POWER EACH - -------------------------------------------------------------------------------- REPORTING 7 SOLE DISPOSITIVE POWER PERSON 15,008,111 shares of common stock WITH - -------------------------------------------------------------------------------- 8 SHARED DISPOSITIVE POWER - -------------------------------------------------------------------------------- 9 AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 15,008,111 shares of common stock of which shares are also beneficially owned by certain other non-reporting entities as well as MFS. - -------------------------------------------------------------------------------- 10 CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES* - -------------------------------------------------------------------------------- 11 PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9 10.05% - -------------------------------------------------------------------------------- 12 TYPE OF REPORTING PERSON* IA - -------------------------------------------------------------------------------- *SEE INSTRUCTION BEFORE FILLING OUT!

SCHEDULE 13G PAGE 3 OF 4 PAGES ITEM 1: (a) NAME OF ISSUER: SEE COVER PAGE (b) ADDRESS OF ISSUER'S PRINCIPAL EXECUTIVE OFFICES: 601 Union Street Suite 1000 Seattle, WA 98101 ITEM 2: (a) NAME OF PERSON FILING: see item 1 on page 1 (b) ADDRESS OF PRINCIPAL BUSINESS OFFICE OR, IF NONE, RESIDENCE: 500 Boylston Street Boston, MA 02116 (c) CITIZENSHIP: See Item 4 on page 2 (d) TITLE OF CLASS OF SECURITIES: SEE COVER PAGE (e) CUSIP NUMBER: SEE COVER PAGE ITEM 3: See Item 12 on page 2 ITEM 4: (a) AMOUNT BENEFICIALLY OWNED: See Item 9 on page 2 (b) PERCENT OF CLASS: See Item 11 on page 2 (c) NUMBER OF SHARES AS TO WHICH SUCH PERSON HAS VOTING AND DISPOSITIVE POWERS: See Items 5 and 7 on page 2

SCHEDULE 13G PAGE 4 OF 4 PAGES ITEM 5: OWNERSHIP OF FIVE PERCENT OR LESS OF A CLASS: Inapplicable ITEM 6: OWNERSHIP OF MORE THAN FIVE PERCENT ON BEHALF OF ANOTHER PERSON: Inapplicable ITEM 7: IDENTIFICATION AND CLASSIFICATION OF THE SUBSIDIARY WHICH ACQUIRED THE SECURITY BEING REPORTED ON BY THE PARENT HOLDING COMPANY: Inapplicable ITEM 8: IDENTIFICATION AND CLASSIFICATION OF MEMBERS OF THE GROUP: Inapplicable ITEM 9: NOTICE OF DISSOLUTION OF GROUP: Inapplicable ITEM 10: CERTIFICATION: By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were acquired and are held in the ordinary course of business and were not acquired and are not held for the purpose of and do not have the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having such purpose or effect. After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct. Date: June 4, 2001 Massachusetts Financial Services Company By: STEPHEN E. CAVAN Stephen E. Cavan Senior Vice President, Secretary and General Counsel