2:22-cv-00237
Parity Networks LLC v. Ciena Corp
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: Parity Networks LLC (Texas)
- Defendant: Ciena Corporation (Delaware)
- Plaintiff’s Counsel: DINOVO PRICE LLP
- Case Identification: 2:22-cv-00237, E.D. Tex., 06/28/2022
- Venue Allegations: Venue is alleged to be proper based on Defendant’s residence, commission of infringing acts, and maintenance of one or more regularly established places of business within the Eastern District of Texas.
- Core Dispute: Plaintiff alleges that Defendant’s Service Delivery Switch products infringe four patents related to data packet handling, including queue management, load balancing, prioritized packet sorting, and congestion control.
- Technical Context: The technology concerns methods for managing data traffic within high-speed network routers and switches to optimize performance, ensure reliability, and prevent congestion-related failures.
- Key Procedural History: The complaint discloses that certain claims of U.S. Patent No. 7,103,046 were subject to conflicting district court rulings on the issue of indefiniteness; the Central District of California found them indefinite in one case, while the Western District of Texas found them not indefinite in a subsequent case.
Case Timeline
| Date | Event |
|---|---|
| 1999-03-22 | U.S. Patent No. 6,252,848 Priority Date |
| 2000-07-26 | U.S. Patent No. 6,553,005 Priority Date |
| 2001-03-06 | U.S. Patent No. 7,719,963 Priority Date |
| 2001-06-26 | U.S. Patent No. 6,252,848 Issued |
| 2001-08-22 | U.S. Patent No. 7,103,046 Priority Date |
| 2003-04-22 | U.S. Patent No. 6,553,005 Issued |
| 2006-09-05 | U.S. Patent No. 7,103,046 Issued |
| 2010-05-18 | U.S. Patent No. 7,719,963 Issued |
| 2020-12-22 | ’046 Patent claims ruled indefinite by C.D. Cal. |
| 2021-01-13 | ’046 Patent claims ruled not indefinite by W.D. Tex. |
| 2022-06-28 | Complaint Filed |
II. Technology and Patent(s)-in-Suit Analysis
U.S. Patent No. 6,252,848 - "System Performance in a Data Network through Queue Management Based on Ingress Rate Monitoring," issued June 26, 2001
The Invention Explained
- Problem Addressed: The patent describes that prior art congestion control methods, like the Random Early Detection (RED) algorithm, drop packets to signal congestion without regard to the characteristics of the data flow, which can penalize well-behaved, critical traffic as much as the traffic actually causing the congestion (’848 Patent, col. 2:63-67).
- The Patented Solution: The invention proposes monitoring the ingress rate of individual data flows and comparing these rates against a pre-defined "flow profile." Based on this comparison, each packet is "marked." This marking is then used at the congested output queue to select a specific drop probability function, allowing the system to more aggressively drop packets from misbehaving flows while protecting compliant ones (’848 Patent, Abstract; col. 4:9-29).
- Technical Importance: This approach introduced a more granular and intelligent method for managing network congestion by differentiating traffic flows, aiming to improve overall system performance rather than treating all traffic indiscriminately (’848 Patent, col. 2:3-8).
Key Claims at a Glance
- The complaint asserts independent claim 1 and reserves the right to assert others (Compl. ¶20, ¶22-23).
- Independent Claim 1 requires:
- Monitoring ingress rates of a plurality of flows, where each flow has a profile.
- Marking each packet with one of a plurality of flow markings based on criteria including the ingress rate and the flow profile.
- Adjusting a packet's drop probability at an output queue based on a drop function that is a function of queue size.
- Selecting the drop function from a plurality of available drop functions based on the packet's marking.
- The drop functions are zero below a lower threshold and positive above it.
U.S. Patent No. 6,553,005 - "Method and Apparatus for Load Apportionment Among Physical Interfaces in Data Routers," issued April 22, 2003
The Invention Explained
- Problem Addressed: In high-speed routers, a single logical egress interface may consist of several physical ports (a "link aggregation group"). The router must select a specific physical port for each packet. Performing a second, software-based table lookup to make this choice is inefficient and can create a bottleneck, and failing to send all packets from the same source-destination "flow" down the same physical path can cause packets to arrive out of order (’005 Patent, col. 2:7-19, col. 2:40-51).
- The Patented Solution: The invention uses a "common function," such as a hashing algorithm, that processes packet header information (e.g., the source and destination addresses). The numerical result of this function is used to deterministically select one of the available physical ports. Because the same input (e.g., same source/destination pair) always produces the same output, all packets in a given flow are routed to the same physical port, ensuring order while efficiently balancing the load (’005 Patent, Abstract; col. 5:31-40).
- Technical Importance: The invention provides a fast, hardware-implementable method for load balancing across multiple physical links that preserves the critical in-order delivery of packets for individual data flows (’005 Patent, col. 2:20-25).
Key Claims at a Glance
- The complaint asserts independent claim 1 and reserves the right to assert others (Compl. ¶30, ¶32-33).
- Independent Claim 1 requires:
- Using a packet's common characteristic to choose a set of candidate egress ports.
- Processing the source/destination address pair of the packet using a hashing function to produce a binary string result.
- Using a subset of that binary string to select a single egress port from the chosen set.
- This process ensures packets with common source/destination address pairs egress via a common port.
U.S. Patent No. 7,103,046 - "Method and Apparatus for Intelligent Sorting and Process Determination of Data Packets Destined to a Central Processing Unit of a Router or Server on a Data Packet Network," issued September 5, 2006
Technology Synopsis
The patent addresses the problem of a router's central processing unit (CPU) being overwhelmed by low-priority or malicious data packets (e.g., during a denial-of-service attack), which prevents it from processing critical network control traffic (’046 Patent, col. 2:3-16). The proposed solution is a system that intercepts CPU-destined packets and sorts them into multiple queues based on priority (e.g., trusted, suspect, unknown), allowing the CPU to service the highest-priority queues first and maintain essential functions even under attack (’046 Patent, Abstract).
Asserted Claims
At least independent claim 1 (Compl. ¶40).
Accused Features
The complaint alleges that Ciena's switches use packet processors to categorize packets based on source, place them into queues, and have a CPU process them based on the priority of those categories (Compl. ¶41-42).
U.S. Patent No. 7,719,963 - "System for Fabric Packet Control," issued May 18, 2010
Technology Synopsis
The patent identifies a problem with conventional "Flow Control" in switch fabrics, where congestion at one node triggers upstream notifications that can halt traffic across a wide area, even on paths not affected by the original congestion (’963 Patent, col. 2:5-15). The invention proposes a localized congestion management system where each switch port monitors its own output queues and begins discarding incoming packets if a queue exceeds a certain threshold, avoiding the network-wide disruption caused by propagating flow control messages (’963 Patent, Abstract; col. 4:1-12).
Asserted Claims
At least independent claim 1 (Compl. ¶50).
Accused Features
The complaint accuses Ciena switches that implement congestion avoidance algorithms, such as Weighted Random Early Detection (WRED), to manage queue-based traffic by dropping packets as a function of queue size (Compl. ¶51).
III. The Accused Instrumentality
Product Identification
The accused instrumentalities are a range of Ciena’s Service Delivery Switches, including the 3916, 3930, 3931, 3932, 3938, 3942, 5142, 5150, and 5160 models, as well as all products operating in a substantially similar manner (Compl. ¶21, ¶31, ¶41, ¶51).
Functionality and Market Context
The complaint alleges these are data networking switches that provide customers with sophisticated traffic management capabilities (Compl. ¶15). The accused functionality includes:
- Traffic profiling and policing, which classifies traffic based on configured rates (e.g., Committed Information Rate) and applies a color marking (Green, Yellow, Red) to frames (Compl. ¶24). A screenshot from a Ciena configuration guide describes this "Traffic Profiling" feature (Compl. ¶24).
- Congestion avoidance mechanisms such as Simple/Weighted Random Early Discard (sRED/sWRED), which drop packets based on queue thresholds to manage congestion (Compl. ¶25).
- Link Aggregation (LAG) and Link Aggregation Control Protocol (LACP), which bundle multiple physical ports into a single logical port and distribute traffic among them (Compl. ¶34). A Ciena guide screenshot explains that "Traffic destined to egress on an aggregated port is distributed among all the links in the group" (Compl. ¶34).
- Quality of Service (QoS) and Class of Service (CoS) features that map packets to different hardware queues based on priority rules, which are then processed by a CPU (Compl. ¶44). A table from a Ciena guide shows a default mapping of internal "R-CoS" values to one of eight physical port queues (Compl. ¶44).
IV. Analysis of Infringement Allegations
’848 Patent Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| monitoring ingress rates of a plurality of flows... each flow having a profile related to flow characteristics | The accused products perform "traffic profiling" which "compares the traffic flow to a configured Committed Information Rate (CIR) and Peak Information Rate (PIR)." | ¶24 | col. 4:16-20 |
| marking each packet with one of a plurality of flow markings based on criteria including the ingress rate and the flow profile | Based on the comparison to CIR/PIR rates, "the R-COLOR of each frame is set to a specific value upon ingress." Packets are marked "Green," "Yellow," or "Red." | ¶24 | col. 4:16-29 |
| adjusting a drop probability of each packet at an output queue, according to a value of a drop function taken as a function of a queue size | The accused products use sWRED profiles for congestion avoidance, which feature a "configurable start threshold (1-100 percent), upper threshold (1-100 percent), and a maximum drop probability" that are dependent on queue fullness. | ¶25, ¶7 | col. 4:26-29 |
| the drop function being selected from a plurality of drop functions, each drop function being associated with one of the plurality of markings | The sWRED profiles handle different types of traffic distinctly, such as "TCP green traffic" and "TCP yellow traffic (has been metered to yellow from traffic profiling)," suggesting different drop functions are applied based on the packet's color marking from the profiling step. | ¶25, ¶7 | col. 4:21-29 |
| the drop functions are zero for queue sizes less than a lower threshold range | The sWRED profiles use a "configurable start threshold." Below this threshold, the drop probability is effectively zero. | ¶25, ¶7 | col. 5:32-36 |
Identified Points of Contention (’848 Patent)
- Scope Questions: A central question will be whether Ciena's "traffic profiling" system, which assigns a "color" based on CIR/PIR compliance, constitutes "marking" a packet based on a "flow profile" as those terms are understood in the patent.
- Technical Questions: The complaint suggests that different sWRED curves are used for green and yellow traffic, which would support the "selecting a drop function" limitation. A key factual question is whether the accused products actually implement distinct, selectable drop probability curves corresponding to the green/yellow/red markings, or if it is a single curve with different entry points.
’005 Patent Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| using a common characteristic of each packet, choosing a set of egress ports from a table of sets of ports associated with said characteristic | The accused products configure "link aggregation groups (LAG)," which combine "two or more full-duplex Ethernet ports... into a single logical port." This logical port represents the set of candidate egress ports. | ¶34 | col. 8:20-23 |
| processing a source/destination address pair of each packet using a hashing function, producing thereby a binary string result... | The accused products "use hashing functions to determine the route and egress port used by particular packets such that packets with common source/destination address pairs use a common egress port." | ¶31-32 | col. 8:23-28 |
| using a default subset of the binary string result to select a single egress port for each packet from among the egress ports of the set chosen... | Traffic destined for a LAG is "distributed among all the links in the group," which necessitates a selection of a single physical port. The complaint alleges this selection is determined by the hashing function. | ¶31, ¶34 | col. 8:29-31 |
Identified Points of Contention (’005 Patent)
- Technical Questions: The complaint alleges the use of a hashing function based on source/destination address pairs, but provides no specific evidence of the inputs to Ciena's LAG distribution algorithm. The critical question will be an evidentiary one: what specific algorithm and what specific packet data does Ciena's LAG feature use to distribute traffic, and does it align with the claim requirement of hashing a "source/destination address pair"?
V. Key Claim Terms for Construction
’848 Patent, Claim 1: "flow profile"
- Context and Importance: The infringement theory relies on Ciena’s use of Committed Information Rate (CIR) and Peak Information Rate (PIR) satisfying this term. Its construction is therefore central to determining if the accused traffic profiling meets the claim.
- Intrinsic Evidence for a Broader Interpretation: The claim requires a "profile related to flow characteristics" (’848 Patent, col. 6:43-44), and the specification states a profile can include thresholds for "bandwidth (i.e., average data rate)" (’848 Patent, col. 4:21-22). This language may support an argument that any set of rate-based parameters like CIR/PIR constitutes a "flow profile."
- Intrinsic Evidence for a Narrower Interpretation: The specification’s primary example describes a profile with a "lower threshold and an upper threshold for the bandwidth" (’848 Patent, col. 4:20-22). A party could argue the term should be limited to this specific two-threshold structure for average data rate.
’005 Patent, Claim 1: "processing a source/destination address pair... using a hashing function"
- Context and Importance: Infringement hinges on whether Ciena’s method for distributing traffic in a Link Aggregation Group (LAG) meets this specific functional requirement. If the accused system uses a different algorithm (e.g., round-robin) or hashes different inputs (e.g., only MAC addresses), there may be no literal infringement.
- Intrinsic Evidence for a Broader Interpretation: The patent describes the goal is to ensure "packets of common flow egress by a common egress port" (’005 Patent, col. 8:49-51). A party might argue that any function that achieves this goal by processing flow-identifying information should be considered. The specification also refers to the function more generally as a "common function" that "may be a hashing function" (’005 Patent, col. 7:51-52).
- Intrinsic Evidence for a Narrower Interpretation: The claim language is highly specific: it requires processing the "source/destination address pair" with a "hashing function." The body of the claim repeats the requirement that this ensures "packets having common source/destination address pairs egress by a common egress port" (’005 Patent, col. 8:26-31). This specificity may support a narrow construction limited to hashing this exact data pair.
VI. Other Allegations
Indirect Infringement
The complaint alleges both induced and contributory infringement for all four patents-in-suit. Inducement is primarily based on allegations that Ciena instructs and encourages its customers to configure and use the accused features (e.g., QoS, LAG, WRED) through its product documentation, datasheets, and configuration guides (Compl. ¶22, ¶32, ¶42, ¶52).
Willful Infringement
The complaint does not contain an explicit allegation of willful infringement. It pleads that Defendant had knowledge of the patents and infringement only "as early as the date when Parity Networks effected service of the Original Complaint," which would only support a claim for post-filing willfulness (Compl. ¶17).
VII. Analyst’s Conclusion: Key Questions for the Case
Technical Mapping: A primary front of the dispute will likely be the technical comparison between the accused products and the claims. For the ’848 patent, the key question is whether Ciena’s system of assigning a "color" based on CIR/PIR compliance and using that color in a WRED context is functionally equivalent to the patent’s claimed method of "marking" a packet based on a "flow profile" to select one of a "plurality of drop functions."
Algorithmic Proof: For the ’005 patent, the case may turn on a key evidentiary question: does Ciena’s Link Aggregation load-balancing mechanism actually employ a "hashing function" that operates on the "source/destination address pair," as strictly required by Claim 1? The complaint’s general allegations will need to be substantiated with specific evidence of the accused algorithm's internal workings.
Claim Scope and Litigation History: For the ’046 patent, the court will first need to navigate the patent’s history of conflicting indefiniteness rulings from other districts (Compl. ¶39). The court’s construction of the claims, particularly in light of this history, will be a critical threshold issue that could determine the viability of the infringement allegations for that patent.