DCT

1:25-cv-01254

Morris Routing Tech LLC v. Microsoft Corp

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I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 1:25-cv-01254, W.D. Tex., 08/07/2025
  • Venue Allegations: Plaintiff alleges venue is proper because Microsoft has regular and established places of business within the Western District of Texas, including in Austin and San Antonio.
  • Core Dispute: Plaintiff alleges that Defendant's global cloud network and related network solutions, including Microsoft Azure, infringe a portfolio of seven patents related to segment-based routing technology.
  • Technical Context: The technology at issue is Segment Routing (SR), a network routing technique that directs data packets through a network by including a list of path segments in the packet's header, which is critical for modern traffic engineering and Software-Defined Wide-Area Networking (SD-WAN).
  • Key Procedural History: The complaint alleges that Defendant Microsoft has been involved for over a decade in the Internet Engineering Task Force (IETF) working group (SPRING) responsible for standardizing the accused SR technology, and that Microsoft co-authored RFC 9256, a key standard for SR Policy.

Case Timeline

Date Event
2012-12-27 Priority Date for '133, '562, '134, '010, '204, '756, '914 Patents
2016-06-23 Microsoft presentation on SWAN (Segment-Routing MPLS) architecture
2019-08-20 U.S. Patent No. 10,757,010 Issues
2020-02-25 U.S. Patent No. 10,574,562 Issues
2020-05-12 U.S. Patent No. 10,652,133 Issues
2020-05-12 U.S. Patent No. 10,652,134 Issues
2020-10-13 U.S. Patent No. 10,805,204 Issues
2023-04-01 USENIX paper on Microsoft's OneWAN architecture published
2023-09-12 U.S. Patent No. 11,757,756 Issues
2023-10-10 U.S. Patent No. 11,784,914 Issues
2025-05-10 Microsoft presentation on SRv6 for AI backend networks
2025-08-07 Complaint Filing Date

II. Technology and Patent(s)-in-Suit Analysis

U.S. Patent No. 10,652,133

  • Patent Identification: U.S. Patent No. 10,652,133, entitled "ROUTING METHODS, SYSTEMS, AND COMPUTER PROGRAM PRODUCTS," issued May 12, 2020 (the "'133 Patent"). Compl. ¶53

The Invention Explained

  • Problem Addressed: The patent addresses the complexity and scalability problems in traditional network traffic engineering Compl. ¶27 In traditional IP/MPLS networks, every router on a path must maintain state information, and complex control protocols are required to establish and manage traffic-engineered paths, creating scalability issues. Compl. ¶¶14-15 '133 Patent, col. 2:7-59
  • The Patented Solution: The invention uses source routing, where the source node encodes the entire network path into the packet header as a sequence of "segment identifiers" (SIDs) Compl. ¶17 This allows intermediate routers to simply follow the instructions in the packet without needing to maintain per-flow state, dramatically simplifying the network control plane Compl. ¶17 Compl. ¶22 '133 Patent, col. 18:55-20:45 The patent describes implementing this with both MPLS labels and IPv6 addresses. Compl. ¶¶18-19
  • Technical Importance: This source-routing approach reduces the amount of state information required in network nodes, simplifies network architecture, and provides more granular control over traffic engineering. (Compl. ¶17; Compl. ¶18).

Key Claims at a Glance

  • The complaint asserts infringement of at least independent claim 12 of the '133 patent. Compl. ¶56
  • The essential elements of Claim 12 are:
    • A non-transitory computer readable medium comprising executable instructions for a method comprising:
    • receiving a packet, wherein the packet comprises an internet protocol (IP) header, which comprises a destination IP address field;
    • adding a first extension header to the packet, wherein the first extension header comprises a list of elements, wherein each of the elements comprises a respective segment identifier (SID);
    • updating the packet, wherein the updating comprises writing information to the destination IP address field of the IP header, and the information comprises one of the SIDs of the list.
  • The complaint does not explicitly reserve the right to assert dependent claims for this patent.

U.S. Patent No. 10,574,562

  • Patent Identification: U.S. Patent No. 10,574,562, entitled "ROUTING METHODS, SYSTEMS, AND COMPUTER PROGRAM PRODUCTS," issued February 25, 2020 (the "'562 Patent"). Compl. ¶61

The Invention Explained

  • Problem Addressed: The patent family addresses the scalability and complexity of traditional network routing. Compl. ¶¶14-15 This specific patent appears to target the problem of how to systematically assign and calculate segment identifiers within a large network domain. '562 Patent, abstract
  • The Patented Solution: The patent describes a system where a node receives a "globally unique" index value and a "base value." It uses these two inputs to calculate a segment identifier (segment ID). It can also use the index value and a second base value (from a next-hop node) to calculate a next-hop segment ID, facilitating routing across different network segments. '562 Patent, abstract '562 Patent, col. 2:5-13
  • Technical Importance: This invention provides a structured mathematical framework for generating segment identifiers, which may enhance scalability and interoperability in segment routing networks. '562 Patent, abstract

Key Claims at a Glance

  • The complaint asserts infringement of at least independent claim 1 of the '562 patent. Compl. ¶64
  • The essential elements of Claim 1 are:
    • A system comprising: a first node comprising a memory and one or more processors, the first node configured to
    • receive an index value, wherein the index value is globally unique within a network domain,
    • receive a base value, wherein the base value comprises one of a plurality of segment routing values, and the plurality of segment routing values comprises a set of segment routing values configured to identify nodal segments,
    • calculate a segment identifier (segment ID) based on the index value and the base value,
    • calculate, based on the index value and a second base value, a next hop segment ID associated with a packet, wherein the second base value comprises one of a second plurality of segment routing values reserved by a next-hop node, and
    • forwarding the packet based on the next hop segment ID.
  • The complaint does not explicitly reserve the right to assert dependent claims for this patent.

Multi-Patent Capsule: U.S. Patent No. 10,652,134

  • Patent Identification: U.S. Patent No. 10,652,134, entitled "ROUTING METHODS, SYSTEMS, AND COMPUTER PROGRAM PRODUCTS," issued May 12, 2020. Compl. ¶69
  • Technology Synopsis: The patent describes a system for generating a set of segment identifiers that encode a path. The segment identifiers are stored in tables at each enabled node along the path, and a first node adds the set of identifiers to a packet header to direct it through the network. Compl. Exhibit J This focuses on the generation and storage of the path information used for source routing.
  • Asserted Claims: At least independent claim 1. Compl. ¶72
  • Accused Features: Microsoft's networks and solutions, such as Azure and SONiC, are alleged to generate and use sets of segment identifiers to encode paths for network traffic. Compl. ¶51 Compl. Exhibit J

Multi-Patent Capsule: U.S. Patent No. 10,757,010

  • Patent Identification: U.S. Patent No. 10,757,010, entitled "ROUTING METHODS, SYSTEMS, AND COMPUTER PROGRAM PRODUCTS," issued August 20, 2019. Compl. ¶77
  • Technology Synopsis: The patent describes a monitoring system that identifies a plurality of segment identifiers by accessing a data structure where advertisements are used to communicate them. It then assembles these identifiers into a stack for routing a message and inserts the stack into the message's header. Compl. Exhibit K This invention focuses on the assembly and use of segment identifier stacks for routing messages.
  • Asserted Claims: At least independent claim 2. Compl. ¶80
  • Accused Features: Microsoft's networks are alleged to use monitoring systems that assemble segment identifiers into a stack (e.g., an SRH or MPLS label stack) to route messages through its network. Compl. ¶51 Compl. Exhibit K

Multi-Patent Capsule: U.S. Patent No. 10,805,204

  • Patent Identification: U.S. Patent No. 10,805,204, entitled "ROUTING METHODS, SYSTEMS, AND COMPUTER PROGRAM PRODUCTS," issued October 13, 2020. Compl. ¶85
  • Technology Synopsis: The patent describes a method for routing a data packet from a first access network through a subdivided segment routing network to a second access network. A centralized controller provides a "remote segment identifier stack" that encodes the path, which is then encapsulated with the data packet for forwarding. Compl. Exhibit L This focuses on routing between different network areas using a centralized controller.
  • Asserted Claims: At least independent claim 15. Compl. ¶88
  • Accused Features: Microsoft's network architecture is alleged to use centralized controllers (e.g., a Traffic Engineering engine) to define and manage paths for data packets traversing its subdivided global network. Compl. ¶49 Compl. p. 12 Compl. Exhibit L

Multi-Patent Capsule: U.S. Patent No. 11,757,756

  • Patent Identification: U.S. Patent No. 11,757,756, entitled "ROUTING METHODS, SYSTEMS, AND COMPUTER PROGRAM PRODUCTS," issued September 12, 2023. Compl. ¶93
  • Technology Synopsis: The patent describes an apparatus that receives path information and generates a set of segment identifiers. A key aspect is that at least one identifier is in an address space with a span in the current region, is used to identify a next region, and includes a value identical to another segment identifier for a different path segment. Compl. Exhibit M This appears to relate to creating and using segment identifiers that have values with dual meanings for different path segments.
  • Asserted Claims: At least independent claim 10. Compl. ¶96
  • Accused Features: Microsoft's networks are alleged to generate and use segment identifiers to define network paths, which Plaintiff alleges involves using identifiers with values that are re-used or have meanings dependent on their position in the path. Compl. ¶51 Compl. Exhibit M

Multi-Patent Capsule: U.S. Patent No. 11,784,914

  • Patent Identification: U.S. Patent No. 11,784,914, entitled "ROUTING METHODS, SYSTEMS, AND COMPUTER PROGRAM PRODUCTS," issued October 10, 2023. Compl. ¶101
  • Technology Synopsis: The patent describes a method where a transmitting node selects a sequence of segment identifiers based on a policy, identifies a network interface based on a subsequence of those identifiers, stores another subsequence in a packet header, and transmits the packet. This invention focuses on the process of selecting and using subsequences of segment identifiers to forward a packet. Compl. Exhibit N
  • Asserted Claims: At least independent claim 1. Compl. ¶104
  • Accused Features: Microsoft's networks are alleged to implement policies that select sequences of segment identifiers and use subsequences of those identifiers to make forwarding decisions at each node in the path. Compl. ¶51 Compl. Exhibit N

III. The Accused Instrumentality

  • Product Identification: The complaint identifies the "Accused Instrumentalities" as "Microsoft's networks and network solutions, including Azure and related products and services" that utilize Segment Routing (SR) functionality as specified in the IETF SR RFCs (Request for Comments) Compl. ¶51 Specific examples include Microsoft's SWAN and CORE networks and its open-source SONiC (Software for Open Networking in the Cloud) network operating system. Compl. ¶49 Compl. ¶50
  • Functionality and Market Context:
    • The complaint alleges Microsoft operates a global cloud network that uses SR for both SR-MPLS and SRv6 data planes Compl. ¶49 Compl. ¶50 A diagram in the complaint, taken from a 2016 Microsoft presentation, depicts the "SWAN Architecture" used for Microsoft's inter-datacenter WAN, showing a centralized Traffic Engineering (TE) Engine that programs the network, consistent with SR-MPLS principles. Compl. p. 12
    • Another diagram from a 2025 presentation shows Microsoft's use of SRv6 with uSID (micro-segment ID) for its "AI backend network," where a network interface card (NIC) encodes a multi-hop SRv6 path into the packet's destination IP address. Compl. p. 13
    • The complaint positions SR as a "key enabling technology for traffic engineering and and SD-WAN" and alleges Microsoft uses it to overcome the shortcomings of traditional routing technologies. Compl. ¶26 Compl. ¶32

IV. Analysis of Infringement Allegations

10,652,133 Infringement Allegations

The complaint references claim chart Exhibit H, but the exhibit provided is only a cover page. The infringement theory is summarized from the complaint narrative and the asserted claim language.

The complaint alleges that Microsoft's SR-capable networks infringe claim 12 of the '133 patent. The infringement theory appears to be that when a Microsoft router receives a data packet, it adds an SR extension header (e.g., an SRv6 Segment Routing Header) containing a list of segment identifiers that define the packet's path. As the packet traverses the network, the destination IP address field of the packet's IP header is updated with the next segment identifier from the list. (Compl. ¶17; Compl. ¶18; Compl. ¶19).

10,574,562 Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
A system comprising: a first node comprising a memory and one or more processors, the first node configured to Microsoft's accused networks and network solutions (e.g., Azure, SONiC) comprise nodes (routers, switches) with processors and memory that execute instructions to perform segment routing. Ex. I, p. 4 col. 7:60-65
receive an index value, wherein the index value is globally unique within a network domain, The Accused Instrumentalities are alleged to use globally unique index values (e.g., as defined in RFC 8402 for IGP-Prefix segments) within an SR domain. Ex. I, p. 6 col. 1:51-53
receive a base value, wherein the base value comprises one of a plurality of segment routing values, and the plurality of segment routing values comprises a set of segment routing values configured to identify nodal segments, The Accused Instrumentalities are alleged to use a base value, such as the start of a Segment Routing Global Block (SRGB), which comprises a set of segment routing values for identifying nodes in the domain. Ex. I, p. 9 col. 1:54-58
calculate a segment identifier (segment ID) based on the index value and the base value, The Accused Instrumentalities are alleged to calculate an MPLS label (the segment ID) by applying the index value as an offset to the base value (the SRGB start label), as specified in RFC 8660. Ex. I, p. 12 col. 1:59-62
calculate, based on the index value and a second base value, a next hop segment ID associated with a packet... The Accused Instrumentalities are alleged to be capable of calculating a next-hop segment ID based on the index and a different base value, such as the SRGB of a different network domain or next-hop node. Ex. I, p. 14 col. 1:63-66
forwarding the packet based on the next hop segment ID. The Accused Instrumentalities forward packets based on the calculated next hop segment ID (e.g., the resulting MPLS label). Ex. I, p. 15 col. 2:10-13
  • Identified Points of Contention:
    • Scope Questions: A central question for the '562 patent will be whether Microsoft's implementation of IETF standards, such as the use of a Segment Routing Global Block (SRGB), meets the specific claim limitations of a "base value" and a "globally unique index value" as defined and used within the patent's specification. The court may need to determine if the term "network domain" in the claim corresponds to an "SR domain" as used in the IETF standards.
    • Technical Questions: For the '133 patent, a key question will be whether adding an SRv6 Segment Routing Header (SRH) to an IPv6 packet constitutes "adding a first extension header" as claimed, and whether decrementing the "Segments Left" pointer and copying the next SID to the destination address constitutes "updating the packet" by "writing information to the destination IP address field" in the manner required by claim 12. For the '562 patent, the dispute may focus on whether the accused system performs the specific two-part calculation: first, calculating a local segment ID, and second, calculating a "next hop segment ID" using a "second base value."

V. Key Claim Terms for Construction

  • The Term: "index value" (from Claim 1 of the '562 Patent)
  • Context and Importance: This term is critical because the claim requires it to be "globally unique within a network domain." The viability of the infringement allegation will depend on whether the identifiers used in Microsoft's SR implementation (e.g., prefix-SIDs) can be shown to be "globally unique" index values as understood by the patent, and what constitutes the relevant "network domain."
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The specification states that "a first node configured to receive an index value, wherein the index value is globally unique within a network domain." '562 Patent, col. 1:50-53 The use of general terms like "network domain" without further express limitation may support a broader construction covering various types of administrative or routing domains.
    • Evidence for a Narrower Interpretation: The abstract and detailed description link the index value to a "base value" for calculating a segment ID. '562 Patent, abstract Specific embodiments might show the "network domain" is limited to a particular context, such as a single IGP area or an MPLS domain where a specific SRGB is used, which could support a narrower definition than, for example, the entire internet.
  • The Term: "calculating ... a next hop segment ID" (from Claim 1 of the '562 Patent)
  • Context and Importance: Practitioners may focus on this term because it requires a specific two-step calculation involving two different "base values." The infringement case depends on whether Microsoft's system is merely forwarding packets based on a pre-computed list of SIDs, or if it actually performs the claimed calculation to determine a "next hop segment ID" using a "second base value" from a next-hop node.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The claim language is functional, reciting "calculate...a next hop segment ID." This could be argued to cover any process that determines the next segment in the path, even if it's a simple lookup from a list provided by a controller.
    • Evidence for a Narrower Interpretation: The patent explicitly requires the calculation to be "based on the index value and a second base value." '562 Patent, claim 1 The specification clarifies that this is to "calculate a next hop segment ID based on the index value and a second base value." ('562 Patent, col. 2:10-13). This explicit two-part calculation based on a second base value suggests a more limited, specific mathematical operation rather than a generic path determination.

VI. Other Allegations

  • Indirect Infringement: The complaint does not plead specific facts to support a claim for indirect infringement, such as providing instructions or manuals that encourage infringement. The allegations focus on Microsoft's direct infringement through its own "making, using, selling, [or] importing" of the Accused Instrumentalities. (e.g.,Compl. ¶56).
  • Willful Infringement: The complaint does not contain an explicit count for willful infringement. However, it lays a potential foundation for such a claim, or at least an exceptional case finding, by alleging that Microsoft has been involved with the IETF's SR standards-setting process for over a decade, has co-authored a relevant RFC standard (RFC 9256), and uses SR in its products. Compl. ¶¶34-42 This suggests Plaintiff may argue that Microsoft had pre-suit knowledge of the technology and potentially the patents-in-suit. The prayer for relief requests a declaration that the case is exceptional under 35 U.S.C. § 285. Compl. p. 22, Prayer C

VII. Analyst's Conclusion: Key Questions for the Case

  • A core issue will be one of claim scope versus industry standards: Can Plaintiff demonstrate that Microsoft's implementation of standardized Segment Routing protocols (SR-MPLS and SRv6) meets the specific and potentially distinct limitations of the asserted claims, particularly the "globally unique index value" and "base value" calculation steps required by the '562 patent family?
  • A second central question will be evidentiary and technical: What evidence will emerge from discovery to show the precise inner workings of Microsoft's accused network infrastructure (e.g., Azure, SONiC)? The case will likely turn on whether the source code and technical specifications of these complex systems reveal the specific packet processing and calculation methods recited in the patent claims, as opposed to merely achieving a similar high-level routing outcome.
  • A third key issue will be the implication of Microsoft's standards-setting involvement: How will the court and a jury interpret Microsoft's alleged decade-long participation in the IETF's SR standards development? This could be a focal point for arguments regarding knowledge and potential willfulness, but may also give rise to defenses from Microsoft concerning the patentability of standardized technology or issues of estoppel.
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