DCT
2:25-cv-01038
Enhanced Data Streaming LLC v. Cisco Systems Inc
Key Events
Complaint
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: Enhanced Data Streaming LLC (Delaware)
- Defendant: Cisco Systems, Inc. (Delaware)
- Plaintiff’s Counsel: Fabricant LLP
- Case Identification: 2:25-cv-01038, E.D. Tex., 10/10/2025
- Venue Allegations: Plaintiff alleges venue is proper in the Eastern District of Texas because Defendant Cisco maintains regular and established places of business in the district, including a data center in Allen and a corporate campus in Richardson, has transacted business and committed acts of infringement in the district, and has previously conceded to jurisdiction in the district for patent infringement litigation.
- Core Dispute: Plaintiff alleges that Defendant’s networking products, including its Aggregation Service Routers and its Catalyst and Nexus series switches, infringe five patents related to technologies for media packet distribution, dynamic packet fragmentation, bandwidth allocation for aggregated links, fault-tolerant MAC address assignment, and equipment protection architectures.
- Technical Context: The patents-in-suit relate to foundational technologies for managing efficiency, reliability, and Quality of Service (QoS) in high-performance computer networks, which are critical for enterprise and service-provider infrastructure.
- Key Procedural History: The complaint alleges that Cisco has had knowledge of the patents-in-suit since at least March 20, 2017, based on a notice letter from the prior owner, Orckit IP LLC, which allegedly identified the patents and the accused products. The complaint also notes that U.S. Patent No. 9,185,151, the predecessor to the asserted '398 Patent, was reissued on April 22, 2025.
Case Timeline
| Date | Event |
|---|---|
| 2000-07-27 | ’855 Patent Priority Date |
| 2002-08-02 | ’135 Patent Priority Date |
| 2003-05-13 | ’605 Patent Priority Date |
| 2005-05-10 | ’855 Patent Issue Date |
| 2006-04-18 | ’135 Patent Issue Date |
| 2006-09-22 | ’234 Patent Priority Date |
| 2007-10-16 | ’398 Patent Priority Date |
| 2008-02-26 | ’605 Patent Issue Date |
| 2010-02-09 | ’234 Patent Issue Date |
| 2015-11-10 | Original ’151 Patent (related to ’398) Issue Date |
| 2017-03-20 | Alleged Pre-Suit Notice Letter to Defendant |
| 2025-04-22 | ’398 Patent Reissue Date |
| 2025-10-10 | Complaint Filing Date |
II. Technology and Patent(s)-in-Suit Analysis
U.S. Reissued Patent No. RE50,398 - "Device, Method and System for Media Packet Distribution"
- Patent Identification: RE50,398, "Device, Method and System for Media Packet Distribution," issued April 22, 2025.
The Invention Explained
- Problem Addressed: In Internet Protocol Television (IPTV) networks, delivering a single multicast stream to all users is efficient but prevents customization, such as targeted advertising or optimizing streams for individual connections (Compl. ¶29). Creating separate unicast streams for every user from the source is highly inefficient and consumes significant network bandwidth ('398 Patent, col. 1:12-20).
- The Patented Solution: The patent describes a network distribution node that intercepts a primary multicast media stream. When a user's device requests a channel, this node can generate a new, "appliance specific" stream. This new stream can be a conversion from multicast to unicast for an individual user, or a new multicast stream for a smaller subgroup. A key feature is the ability to introduce a delay into this new stream, which can be used to reduce the channel-changing delay ("zap-time") perceived by the user by ensuring the new stream starts with a complete video frame ('398 Patent, Abstract; col. 9:5-20).
- Technical Importance: The technology aims to combine the bandwidth efficiency of multicast with the personalization capabilities of unicast, a key challenge for scaling IPTV services with advanced features.
Key Claims at a Glance
- The complaint asserts at least Claim 1 (Compl. ¶28).
- The essential elements of independent claim 1 include:
- A device for retransmitting a received IP media stream broadcast.
- A communication module adapted to receive a request for a given IP media stream from a media presentation appliance.
- A stream generator adapted to convert one single appliance specific version of the requested media stream from multicast to unicast.
- The stream generator is further adapted to retransmit with a delay the converted unicast version of the stream.
- A delay time for the delayed version is determined to reduce zap-time associated with presenting the stream, based at least partly on a timing parameter of the request.
U.S. Patent No. 6,891,855 - "Dynamic Packet Fragmentation"
- Patent Identification: 6,891,855, "Dynamic Packet Fragmentation," issued May 10, 2005.
The Invention Explained
- Problem Addressed: On variable-rate communication channels like Digital Subscriber Lines (DSL), a large, low-priority data packet (e.g., for email) can occupy the channel for a long time, delaying small, time-sensitive packets (e.g., for voice-over-IP) and causing poor quality of service. Using a fixed, small fragment size to solve this problem is inefficient on high-speed connections due to the high relative overhead of packet headers ('855 Patent, col. 1:17-46).
- The Patented Solution: The patent discloses a method to dynamically adjust the maximum fragment size for data packets based on the channel's current transmission rate. When the rate is high, fragment sizes are increased to improve efficiency. When the rate is low, fragment sizes are decreased to ensure that no single fragment monopolizes the channel for longer than a predetermined maximum time, thereby allowing high-priority packets to be transmitted with minimal delay ('855 Patent, Abstract; col. 2:32-49).
- Technical Importance: This approach allows a network to balance transmission efficiency with latency and jitter control, which is critical for delivering mixed data services with different QoS requirements over a single variable-rate link.
Key Claims at a Glance
- The complaint asserts at least Claim 1 (Compl. ¶46).
- The essential elements of independent method claim 1 include:
- A method for transmitting data over a channel having a variable transmission rate.
- Determining the rate of transmission of the data over the channel.
- Receiving a datagram for transmission over the channel.
- Dividing the datagram into fragments of a size no greater than a size limit that is set for the datagram responsive to the determined rate of transmission.
- Transmitting the fragments over the channel.
- Wherein the size limit is set such that the time to transmit each fragment is no greater than a predetermined maximum time, which is applicable to high-priority services transmitted over the same channel.
Multi-Patent Capsule: U.S. Patent No. 7,336,605 - "Bandwidth Allocation for Link Aggregation"
- Patent Identification: 7,336,605, "Bandwidth Allocation for Link Aggregation," issued February 26, 2008.
- Technology Synopsis: The patent addresses bandwidth management for aggregated links, where multiple physical links form a single logical channel. It describes allocating bandwidth to each physical link with a "predefined safety margin" based on factors like potential link failures or non-uniform traffic distribution. This ensures the logical link's guaranteed bandwidth is maintained even under adverse conditions ('605 Patent, Abstract).
- Asserted Claims: At least Claim 1 (Compl. ¶62).
- Accused Features: The complaint accuses Cisco ASR Routers, specifically their implementation of link bundling (IEEE 802.3ad) and adaptive Quality of Service (QoS) for Dynamic Multipoint VPN (DMVPN), which allegedly measure traffic fluctuation and allocate bandwidth to physical links to ensure an overall guaranteed bandwidth for the logical connection (Compl. ¶¶ 64-67).
Multi-Patent Capsule: U.S. Patent No. 7,660,234 - "Fault-Tolerant Medium Access Control (MAC) Address Assignment in Network Elements"
- Patent Identification: 7,660,234, "Fault-Tolerant Medium Access Control (MAC) Address Assignment in Network Elements," issued February 9, 2010.
- Technology Synopsis: The patent describes a fault-tolerant system for assigning MAC addresses within a network device. It provides for a primary set of MAC addresses stored in a backplane memory and a secondary set stored in a common function module (CFM). The CFM assigns addresses from the backplane memory during normal operation but switches to its local memory if the backplane becomes inaccessible, ensuring continuous operation ('234 Patent, Abstract).
- Asserted Claims: At least Claim 10 (Compl. ¶77).
- Accused Features: The complaint accuses Cisco Catalyst 9500 Series Switches and their StackWise Virtual technology. This feature allegedly assigns MAC addresses from an EEPROM on the backplane when accessible, but can assign addresses from the memory of an active switch (the CFM equivalent) if the backplane memory is unavailable, mirroring the claimed fault-tolerant method (Compl. ¶¶ 78-80).
Multi-Patent Capsule: U.S. Patent No. 7,032,135 - "Equipment Protection Using a Partial Star Architecture"
- Patent Identification: 7,032,135, "Equipment Protection Using a Partial Star Architecture," issued April 18, 2006.
- Technology Synopsis: The patent discloses a protection architecture for communication equipment using a "partial star" topology for its protection bus. This design connects a central card to multiple spoke cards, with some spokes connecting pairs of spoke cards. This architecture is described as enabling both 1:N (one-to-many) and 1:1 (one-to-one) protection schemes to be implemented on the same physical backplane traces, providing configuration flexibility ('135 Patent, Abstract).
- Asserted Claims: At least Claims 1 and 11 (Compl. ¶¶ 92, 95).
- Accused Features: The complaint accuses Cisco Nexus 7000 Series Switches. Their spine-and-leaf architecture, using technologies like FabricPath and virtual Port Channel (vPC), is alleged to create a protection bus with multiple spoke connections in a partial star configuration for fault protection and redundancy (Compl. ¶¶ 94-95).
III. The Accused Instrumentality
- Product Identification: The complaint names two categories of accused products: "Accused Cisco Routers" and "Accused Cisco Switches" (Compl. ¶22).
- Routers: All variants of Cisco’s Aggregation Service Routers (ASR), including the ASR 900, 1000, and 9000 series. These are accused of infringing the '398, '855, and '605 patents (Compl. ¶23).
- Switches: All variants of Cisco’s Catalyst Series Switches (e.g., 9200-9600 series) and Nexus Series Switches (e.g., 7000, 9200-9500 series). These are accused of infringing the '234 and '135 patents (Compl. ¶23).
- Functionality and Market Context: The accused products are high-performance networking hardware central to enterprise and service provider networks. The complaint alleges that specific features within these products perform the patented methods. For the ASR Routers, accused features include Multicast Service Reflection, Multilink Point-to-Point Protocol (MLP) with Link Fragmentation and Interleaving (LFI), and adaptive QoS (Compl. ¶¶ 32, 47, 65). For the Switches, accused features include StackWise Virtual MAC address management and spine-and-leaf fabric architectures (Compl. ¶¶ 78, 94).
IV. Analysis of Infringement Allegations
RE50,398 Patent Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| a device for retransmitting a received IP media stream broadcast... | The Cisco ASR 1000 Series Router is a network device that retransmits IP media streams for services like IPTV, quadruple-play, and video on demand. | ¶29 | col. 9:5-10 |
| a communication module adapted to receive from a media presentation appliance a request for a given IP media stream... | The ASR 1000 Series Router includes built-in Gigabit Ethernet ports and other adapters for receiving communications, such as requests for media streams. | ¶31 | col. 12:20-25 |
| a stream generator adapted to convert, in response to the request... one single appliance specific version of the requested media stream from multicast to unicast... | The Cisco Multicast Service Reflection feature provides the capability to translate externally received multicast destination addresses to unicast addresses. | ¶32 | col. 9:11-20 |
| and to retransmit with a delay the converted unicast, appliance specific, version of the requested media stream... | The Cisco ASR 1000 Series implements IEEE 1588v2 Precision Time Protocol (PTP), a two-way message exchange protocol used to determine and apply a delay. | ¶33 | col. 10:1-10 |
| wherein a delay time... is determined to reduce zap-time... based at least partly on a timing parameter of the request... | PTP synchronizes clocks between nodes in a network based on a timing parameter and is used to determine a delay time to reduce a requested IP media stream's zap-time. | ¶33 | col. 10:1-10 |
A network topology diagram titled "Figure 2: Multicast Service Reflection... in a Service Provider Network" illustrates the translation of a multicast source to a unicast destination through a router (R1) running the accused feature (Compl. p. 12).
6,891,855 Patent Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| A method for transmitting data over a channel having a variable transmission rate... | The Cisco ASR 1000 Series Routers are designed to handle data transmission over channels with variable transmission rates, such as in DSL-based networks. | ¶¶ 47, 49 | col. 3:1-5 |
| determining the rate of transmission of the data over the channel... | The router dynamically adjusts bandwidth using media-rate information received from a DSL Access Multiplexer (DSLAM). | ¶49 | col. 4:60-62 |
| receiving a datagram for transmission over the channel at the determined rate of transmission... | The routers receive datagrams for transmission, such as large data packets, over the channel. | ¶50 | col. 4:62-63 |
| dividing the datagram into fragments of a size no greater than a size limit that is set for the datagram responsive to the determined rate of transmission... | The Multilink PPP (MLP) feature breaks down large packets into smaller fragments, with the size calculated using parameters influenced by the link's bandwidth. | ¶51 | col. 2:38-44 |
| wherein dividing the datagram comprises setting the size limit such that a length of time required to transmit each of the fragments is no greater than a predetermined maximum time... | Link Fragmentation and Interleaving (LFI) and MLP set a size limit for each fragment to ensure fragments are transmitted on time without delaying important packets like voice or video. | ¶53 | col. 3:9-13 |
| wherein receiving the datagram comprises receiving a datagram associated with a low-priority service, and wherein the predetermined maximum time comprises a maximum delay applicable to other datagrams associated with a high-priority service... | LFI ensures that high-priority traffic (e.g., voice, video) is transmitted with minimal delay by interleaving it between fragments of lower-priority datagrams, thereby respecting the maximum delay for the high-priority service. | ¶54 | col. 3:13-21 |
A diagram titled "Figure 1: Multilink Fragmentation and Interleaving" shows a large datagram being fragmented while smaller IP voice packets bypass fragmentation and are interleaved with the fragments for transmission (Compl. p. 24).
- Identified Points of Contention:
- '398 Patent: The infringement theory connects Cisco's use of a general clock synchronization protocol (IEEE 1588v2 PTP) to the specific claimed function of creating a delay "to reduce zap-time." A potential point of contention is whether the PTP feature, as implemented, performs this specific function or serves a more general network timing purpose unrelated to the claimed zap-time reduction mechanism.
- '855 Patent: The analysis may raise the question of whether the accused routers' method of calculating fragment size based on configured parameters like "link weight" and "fragment delay" is sufficiently "responsive to the determined rate of transmission" as required by the claim. The dispute could focus on whether this constitutes the dynamic, real-time adjustment described in the patent or a more static, pre-configured approach.
V. Key Claim Terms for Construction
'398 Patent: "zap-time" (Claim 1)
- The Term: "zap-time"
- Context and Importance: This term is central to the infringement allegation, as it links the claimed "delay" to a specific purpose. The question of whether the accused product's delay functionality is intended to reduce "zap-time" will be critical.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The patent does not appear to provide a specific definition, which may support using the term's plain and ordinary meaning in the IPTV field, i.e., the perceived delay when a user changes channels.
- Evidence for a Narrower Interpretation: The specification discusses the delay in the context of ensuring a new stream begins with a complete reference frame (an I-Frame), which is necessary for the decoder to start rendering video ('398 Patent, col. 10:1-10). A party could argue the term is limited to this specific technical mechanism for reducing channel change delay.
'855 Patent: "responsive to the determined rate of transmission" (Claim 1)
- The Term: "responsive to the determined rate of transmission"
- Context and Importance: The patent's inventive concept centers on dynamically adjusting fragmentation based on the channel's current rate. The construction of this term will determine whether the accused product's method, which allegedly uses bandwidth as an input to a "link weight" calculation, meets the claim limitation.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The complaint alleges that link bandwidth influences the calculation of fragment size (Compl. ¶51). This may support an interpretation where any calculation that uses the transmission rate as an input, even indirectly, is "responsive."
- Evidence for a Narrower Interpretation: The specification describes determining the "optimal fragment size for efficient transmission, depending on the instantaneous channel speed" ('855 Patent, col. 2:49-52). This language may support a narrower construction requiring a more direct and immediate relationship between the measured rate and the resulting fragment size, rather than one mediated by other pre-configured parameters.
VI. Other Allegations
- Indirect Infringement: The complaint alleges induced infringement for all five patents. The factual basis is the allegation that Cisco provides the accused products to its customers along with instructions, user manuals, product literature, and other technical documentation that instruct end-users on how to operate the products in an infringing manner (e.g., by configuring MVPN, LFI, or StackWise Virtual features) (Compl. ¶¶ 38, 56, 69, 85, 100).
- Willful Infringement: The complaint alleges willful infringement based on pre-suit knowledge. It specifically pleads that a prior owner of the patents sent a notice letter to Cisco on March 20, 2017, identifying the patents-in-suit and the accused products. The complaint also alleges willful blindness based on a purported Cisco policy of not reviewing patents of others (Compl. ¶¶ 24-25, 39, 57, 70, 86, 101).
VII. Analyst’s Conclusion: Key Questions for the Case
This case presents several complex technical and legal questions. The litigation will likely focus on the following core issues:
- Pre-Suit Knowledge and Willfulness: A primary issue will be the legal effect of the March 20, 2017 notice letter. The determination of whether this letter provided Cisco with actual knowledge of infringement for the asserted patents will be central to the plaintiff's claim for enhanced damages.
- Functional Equivalence vs. Mismatch: A key technical question, particularly for the '398 patent, will be one of functional equivalence: does the accused router's use of a general-purpose time synchronization protocol (IEEE 1588v2 PTP) perform the specific, claimed function of creating a delay "to reduce zap-time," or is there a fundamental mismatch in the technical purpose and operation of the accused feature?
- Definitional Scope and Claim Construction: For the '855 patent, the case may turn on a matter of definitional scope: can the claim term "responsive to the determined rate of transmission" be construed to cover a system where fragment size is calculated based on pre-configured parameters that are themselves influenced by bandwidth, or does the patent require a more direct, dynamic link between the instantaneous channel rate and the fragment size?