Issue 117 | October 3, 2003
CAFC Clarifies Limiting Effect of Claim Preambles
 On May 13, in Storage Technology Corp. v. Cisco Systems, the Federal Circuit clarified when preamble terminology will limit the scope of a claim by reaching opposite conclusions on two sets of claims in the same patent. For the first set of claims, the use of "policy caching method" or "policy cache" was not limiting and did not require the claims to include caching policy identification information or an instance of a policy. In the second set of claims, the terms "forwarding device" and "method of operating a forwarding device" were limiting and required the recited elements to be in the same device.

With regard to the non-limiting preambles, claims 1 and 18 can be summarized as follows:
1. A policy caching method ..., comprising ...caching policy identification information.

18. A policy cache ..., comprising: ...cached instance classification means, ..., for caching policy identification information ...
Citing Catalina Mtkg. Int'l, Inc. v. Coolsavings.com, Inc., and IMS Tech. v. Haas Automation, Inc., the court held that these preambles did not limit the scope of claims because (a) the specification used similar terms to refer to the invention as a whole, and (b) dependent claims explicitly recited an "instance policy cache." On the first point, the court specifically stated "Given the lack of explicit language in claim 1 requiring the instance of network policy to be cached and the absence of any such step from Figure 2, the written description is not a basis for construing the claim as requiring the step of caching an instance of network policy." The court also went on to note that even though the applicant stated during prosecution that the instance of network policy and the policy identification information are both cached, this "inaccurate statement cannot override the claim language itself."

With regard to the limiting preambles, claims 14 and 23 can be summarized as follows:
14. A ... forwarding device ..., comprising:
(a) protocol data unit processor .......; and
(b) forwarding processor, ...

23. A method of operating a forwarding device ... comprising ...:
(a) in a first processor, performing the steps of ... ; and
(b) in a second processor, forwarding ....
The sole issue in interpreting the latter claims was whether the preamble was limited to a single "forwarding device" that would otherwise have otherwise allowed both processors to be located at different locations in the communications network. On this point, the court held that both processors must be part of the same forwarding device and therefore located at the same place in the network. To support its conclusion, the court noted that a key benefit of the invention, specifically identified in the Summary and drawings, was the use of next operation information within the forwarding device to reduce processing otherwise performed by the forwarding device.

It did not matter that the phrase "such that subsequent processing of the protocol data unit by the protocol data unit forwarding device is reduced" had been removed from the originally-filed claims. The remarks accompanying that amendment specifically stated that the deleted language was unnecessary "because the use of the added next operation information by the forwarding device is [still] recited as part of each claim." The remarks also went on to argue that the interface in a cited reference was not "part of a forwarding device in a communication network" and that this reference did not teach or suggest a preprocessor that "will modify header information by inserting next operation instructions so as to decrease the amount of processing that would otherwise be required to be performed by the processor in the forwarding device."

A copy of the decision is available on the Internet at http://www.fedcir.gov/opinions/02-1232.doc. For more information on "Recent Developments in Interpretation of Preamble Limitations in Patent Claims," sign up for the Georgia Bar's patent roundtable, October 16, 2003, 11:30 a.m.-1:00 p.m, in Atlanta at http://www.gabar.org/pdf/sections/IPL1016patent.pdf, or contact the authors, Sami Malas (sami.malas@tkhr.com) or Bill Heinze (bill.heinze@tkhr.com) at Thomas, Kayden, Horstemeyer & Risley in Atlanta, Georgia USA, to discuss the ramifications of this decision for your claim drafting technique.

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