DCT
1:19-cv-00939
Accelerated Memory Tech LLC v. Kemp Tech Inc
Key Events
Complaint
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: Accelerated Memory Tech, LLC (Georgia)
- Defendant: Kemp Technologies, Inc. (Delaware)
- Plaintiff’s Counsel: Bayard, P.A.; Hill, Kertscher & Wharton, LLP
- Case Identification: 1:19-cv-00939, D. Del., 05/20/2019
- Venue Allegations: Venue is asserted based on Defendant's incorporation and residence in the judicial district of Delaware.
- Core Dispute: Plaintiff alleges that Defendant’s LoadMaster load balancing products infringe a patent related to efficiently generating server responses by caching intermediate state information derived from initial resource requests.
- Technical Context: The technology addresses server-side performance bottlenecks by caching the results of repetitive computational tasks, such as mapping a requested URL to an internal resource, to avoid redundant processing in high-traffic environments.
- Key Procedural History: The complaint alleges Defendant had pre-suit knowledge of the patent and its alleged infringement via a notice letter dated December 18, 2018. The provided patent document includes a post-complaint disclaimer, recorded in the Official Gazette on May 25, 2021, disclaiming all claims (1-8) of the patent-in-suit.
Case Timeline
| Date | Event |
|---|---|
| 1999-05-25 | '062 Patent Priority Date (Application Filing) |
| 2003-01-28 | '062 Patent Issue Date |
| 2018-12-18 | Pre-suit notice letter sent from Plaintiff to Defendant |
| 2019-05-20 | Complaint Filing Date |
| 2021-05-25 | Disclaimer of all claims (1-8) of the '062 Patent recorded |
II. Technology and Patent(s)-in-Suit Analysis
U.S. Patent No. 6,513,062 - Method, Apparatus, and Computer Program Product for Efficient Server Response Generation Using Intermediate State Caching
The Invention Explained
- Problem Addressed: The patent’s background section describes the inefficiency of conventional web servers, which must "redundantly perform[] the mapping from an external name to an internal name for repeatedly-requested resources" (Compl. ¶9; ’062 Patent, col. 1:40-57). This repetitive processing consumes computational resources and can slow response times.
- The Patented Solution: The invention proposes a method to improve efficiency by caching "intermediate states" generated during the initial response to a resource request (’062 Patent, Abstract). Specifically, after a server performs a computationally expensive task like a "URI rewrite mapping" to find a resource, it caches the result of that mapping. When a subsequent request for the same resource arrives, the server can retrieve the cached result instead of re-computing the mapping, thereby generating the response more quickly (’062 Patent, col. 2:20-32, Fig. 2).
- Technical Importance: The technology aims to reduce server processing load, a critical factor for performance in high-traffic web environments, by targeting redundant computations at the application layer rather than just addressing network latency (’062 Patent, col. 1:58-67).
Key Claims at a Glance
- The complaint asserts infringement of at least Claim 1 (’062 Patent, Compl. ¶16).
- Independent Claim 1 recites the following essential elements:
- Receiving a first request for a first resource.
- Deriving intermediate state information, which comprises a result of mapping an external name of the request to an internal name for the resource.
- Caching the intermediate state information.
- Receiving a second request for the same resource.
- Retrieving the cached intermediate state information.
- Generating a second response using the retrieved intermediate state information.
- The complaint also alleges inducement and contributory infringement of "one or more claims of the ’062 Patent" (Compl. ¶26-27), but does not specify other claims.
III. The Accused Instrumentality
Product Identification
- The complaint identifies Kemp’s "LoadMaster" product line as the Accused Instrumentality, providing the "LM5305-FIPS" as an example (Compl. ¶14).
Functionality and Market Context
- The LoadMaster is a load balancing product that manages incoming network traffic across multiple backend "Real Servers" to optimize performance and availability (Compl. ¶12, ¶17).
- A key accused feature is "Active Cookie Persistence," which the complaint describes as a Layer 7 feature where the LoadMaster generates and inserts a cookie into the HTTP stream. This cookie allows the LoadMaster to identify subsequent requests from the same client and route them to the same Real Server that handled the initial request, maintaining session persistence (Compl. ¶18, quoting Exhibit B at 23). This functionality is supported by a "persistence table" stored in memory that associates the cookie with a specific user or session (Compl. ¶19, quoting Exhibit B at 23). The complaint includes a network diagram from Defendant's materials showing the LoadMaster positioned between the internet and a farm of "Real Servers" to manage client requests (Compl. ¶16, citing Exhibit B).
IV. Analysis of Infringement Allegations
'062 Patent Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| receiving a first request for a first resource | The LoadMaster receives a first request from a client over the internet and routes it to a real server. A diagram from Defendant's documentation illustrates this data flow (Compl. ¶16). | ¶16 | col. 8:67-col. 9:1 |
| deriving intermediate state information...said intermediate state information comprising a result of mapping an external name...to an internal name... | The complaint alleges this occurs when the LoadMaster's load balancing function maps an external name (e.g., a URL) to an internal name (e.g., a destination server's IP address) and also when its "Active Cookie Persistence" feature derives state information, such as an active cookie, to route subsequent requests efficiently (Compl. ¶17-18). | ¶17, ¶18 | col. 9:2-7 |
| caching said intermediate state information | After generating an active cookie, the Accused Instrumentality allegedly caches it by storing it as part of a "persistence table in memory" (Compl. ¶19). | ¶19 | col. 9:8 |
| receiving a second request for said first resource | A subsequent request from the same client includes the active cookie previously inserted into the HTTP stream by the LoadMaster (Compl. ¶20). | ¶20 | col. 9:9 |
| retrieving said intermediate state information | The LoadMaster performs a "lookup operation with respect to a persistence table" to determine where the request should be routed, based on the presence of the active cookie in the subsequent request (Compl. ¶21). | ¶21 | col. 9:10 |
| generating a second response to said second request using said intermediate state information | The LoadMaster generates subsequent responses using the active cookie, which involves inserting the cookie into the HTML stream and/or compressing responses from a real server. A diagram depicts this compression process (Compl. ¶22). | ¶22 | col. 9:11-13 |
- Identified Points of Contention:
- Scope Questions: The case may raise the question of whether the claimed "intermediate state information," described in the patent as the result of a "rewrite mapping" from a URI to an internal file path, can be read to cover the "active cookie" and "persistence table" used for session persistence in the accused load balancer. A court may need to decide if a session identifier created for routing is equivalent to a cached result of a resource-location mapping.
- Technical Questions: A potential point of dispute is whether the LoadMaster's "Active Cookie Persistence" feature actually performs the claimed step of "deriving" information from a "mapping [of] an external name... to an internal name." The complaint’s theory equates network routing with the patent's "rewrite mapping." The factual record would need to establish if creating a session cookie is technically the same as caching the result of a pre-existing mapping operation as described in the patent specification.
V. Key Claim Terms for Construction
The Term: "intermediate state information"
- Context and Importance: This term is central to the invention's scope. The infringement case depends on whether the accused "active cookie" and its associated data in the "persistence table" fall within this definition.
- Intrinsic Evidence for a Broader Interpretation: The patent summary states that such information can include "an internal name corresponding to the first resource and a type of the first resource... or a plurality of response header lines for the first resource" (’062 Patent, col. 2:28-32). This language could support an interpretation that covers various types of cached data used to facilitate a response.
- Intrinsic Evidence for a Narrower Interpretation: The detailed description repeatedly links the "intermediate state" to the output of a "URI rewrite mapping' process 2050" and a specific URI Descriptor data structure shown in Figure 1, which contains fields like "internalname" and "type" (’062 Patent, col. 4:5-15; col. 5:11-26). This could support a narrower construction limited to information about the location and type of a resource file, rather than a session identifier for routing.
The Term: "mapping an external name of the first request for the first resource to an internal name"
- Context and Importance: This phrase defines the specific action that generates the "intermediate state information." The viability of the infringement allegation hinges on whether the LoadMaster's routing decision constitutes this type of "mapping."
- Intrinsic Evidence for a Broader Interpretation: The plain language could be interpreted broadly to cover any process that correlates an external identifier (like a public URL) with an internal one (like a private server IP address), as the complaint alleges (Compl. ¶17).
- Intrinsic Evidence for a Narrower Interpretation: The patent's background describes this as a "rewrite mapping process that transforms an external name for the resource (in the URI) to an internal name used for locating the resource and generating the response" (’062 Patent, col. 1:44-48). This could be construed more narrowly to mean a file-system or content-location transformation, distinct from a network-level routing decision made by a load balancer.
VI. Other Allegations
- Indirect Infringement: The complaint alleges induced infringement based on Defendant’s alleged knowledge since December 2018, combined with the act of "disseminating user manuals, articles, and other documentations" that instruct customers on how to configure and use the accused features (Compl. ¶26). Contributory infringement is alleged on the basis that the LoadMaster is a material part of the invention, is especially adapted for infringement, and is not a staple article of commerce (Compl. ¶27).
- Willful Infringement: Willfulness is alleged based on Defendant’s continued infringement after receiving a notice letter on or about December 18, 2018, which allegedly described the patent and provided a claim chart demonstrating infringement (Compl. ¶25, ¶28).
VII. Analyst’s Conclusion: Key Questions for the Case
- A core issue will be one of definitional scope: can the term "intermediate state information", which is described in the patent in the context of caching the result of a URI-to-resource mapping, be construed to cover the "active cookie" and "persistence table" used for session persistence in the accused load balancing system?
- A key evidentiary question will be one of functional equivalence: does the accused product's function of creating a session cookie for routing purposes perform the same function, in the same way, to achieve the same result as the claimed method of "deriving" information from a "mapping an external name... to an internal name"? The case may turn on whether creating a session identifier is technically equivalent to caching the result of a resource-location mapping.
- Given the post-filing disclaimer of all patent claims included in the provided documents, a threshold question for the litigation is the procedural impact of this action, which may render the substantive infringement analysis moot and dispose of the case.