Exhibit 5.1

        [Ballard Spahr Andrews & Ingersoll, LLP Letterhead appears here]

                                                               February 13, 2002


C-COR.net Corp.
60 Decibel Road
State College, Pennsylvania  16801

                  Re:      C-COR.net Corp. Common Stock Offering
                           -------------------------------------
Ladies and Gentlemen:

                  We have acted as special counsel to C-COR.net Corp., a
Pennsylvania corporation (the "Company") in connection with the registration
under the Securities Act of 1933, as amended, of 3,000,000 of common stock
(with up to 450,000 additional shares of common stock subject to an
over-allotment option granted by the Company to the underwriters) of the
Company, par value $0.05 per share (the "Shares"), to be sold by the Company
pursuant to the Registration Statement, as amended to the date hereof, filed on
Form S-3 (File No. 333-75888)(the "Registration Statement").

                  In our capacity as counsel, we have examined originals or
copies, certified or otherwise identified to our satisfaction, of the
Registration Statement and all exhibits thereto. We have also examined and
relied upon such corporate records of the Company, and other documents and
instruments, and such certificates or comparable documents of representatives of
the Company, and have made such inquiries of such officers, representatives and
other persons and have considered such matters of law as we have deemed
appropriate as the basis for the opinions hereinafter set forth. In all cases,
we have assumed the legal capacity and competence of all natural persons, the
genuineness of all signatures, the authenticity of all documents submitted to us
as originals and the conformity to original documents of documents submitted to
us as certified, conformed, photostatic or facsimile copies and the accuracy and
completeness of all corporate records and other information made available to us
by the Company.

                  Based upon the foregoing and subject to the assumptions set
forth herein, we are of the opinion that the Shares have been duly and properly
authorized for issuance and, when duly executed, delivered, issued and paid for,
will be legally issued, fully paid and non-assessable.

                  We hereby consent to the sole use of this opinion as an
exhibit to the Registration Statement and to the use of our name under the
heading "Legal Matters" in the prospectus included therein. This opinion is not
to be used, circulated, quoted, referred to or relied upon by any other person
or for any other purpose without our prior written consent.


                               Very truly yours,

                               /s/ Ballard Spahr Andrews & Ingersoll, LLP