US 7483399

US patent 7483399, titled "Signaling MPLS over RPR rings," was filed on February 20, 2003, and issued on January 27, 2009. The original assignee was "Individual," and the current assignee is listed as Quicker Connections LLC. The inventors are David Zelig, Leon Bruckman, and Yoav Kotser.

Abstract:
The patent describes explicit routing of network traffic over Resilient Packet Ring (RPR) rings using Multi-Protocol Label Switching (MPLS) signaling techniques, including unnumbered links. It introduces a modified LSP_TUNNEL_INTERFACE_ID object that uses an RPR IP address and a direction indicator instead of conventional router and interface IDs. A novel subobject is incorporated into Explicit Route Objects (EROs) and Record Route Objects (RROs) to carry the sending node's RPR IP address and a direction indicator. Network nodes utilize this directional indicator, found in path or Resv messages, to determine the direction for sending and receiving traffic along an explicit route.

Plain-Language Overview of Independent Claims:

• Independent Claim 1 (Method): This claim describes a method for establishing a data-link service (a "tunnel") between two nodes within a Resilient Packet Ring (RPR) network. The method involves:

  1. Setting up an RPR network with multiple nodes and traffic paths (ringlets).
  2. Assigning a common RPR IP address and subnet to the interfaces of each node.
  3. Creating a first Resource Reservation Protocol (RSVP) signaling message that includes an "unnumbered explicit route object." This object specifies the RPR IP address of the first node and indicates a desired traffic direction for the tunnel.
  4. Transmitting this first signaling message from the first node to the second node.
  5. In response, the second node sends a second RSVP signaling message back to the first node, which includes the specified direction indicator.
  6. Upon receiving this second message, the first node establishes the tunnel on the indicated ringlet.
  7. Finally, network traffic is routed through this established tunnel in the predetermined direction.

• Independent Claim 4 (System): This claim describes a Resilient Packet Ring (RPR) network system itself. The system comprises:

  1. Multiple ringlets for network traffic.
  2. Multiple nodes (including a first and second node), each functioning as a router with interfaces for traffic.
  3. These interfaces are assigned a common RPR IP address and subnet for each node.
  4. The nodes are configured to perform specific actions when a request to create a tunnel between the first and second node is received:
     • The first node prepares a first RSVP signaling message containing an "unnumbered explicit route object." This object includes the first node's RPR IP address and a direction indicator for the tunnel's traffic.
     • The first node transmits this message to the second node.
     • In response, the second node returns a second RSVP signaling message to the first node, which also includes the direction indicator from the explicit route object.
     • Upon the first node receiving the second message, the tunnel is established on the specified ringlet, and network traffic is routed through it in the specified direction.

CAFC Dockets (2026):
A search for CAFC dockets specifically for patent number 7483399 in 2026 did not return any specific case filings or records. The search results provided general information about accessing CAFC case information but no direct hits for this patent number in the specified year.
Please note that according to Google Patents, this patent's "Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.) Expired - Lifetime , expires 2026-01-08."

As a patent attorney, I have identified known litigation involving US patent 7483399 by reviewing the provided patent text, which includes information from patent litigation databases.

One known litigation case involving US patent 7483399 is:

• Jurisdiction: Texas Eastern District Court
• Case Number: 2:24-cv-01074
• Plaintiff(s): Not explicitly stated in the provided information. (Based on the "Current Assignee" listed on the patent, Quicker Connections LLC is the likely plaintiff, but this is an inference and not explicitly stated in the litigation details provided.)
• Defendant(s): Not explicitly stated in the provided information.
• Filing Date: Not explicitly stated in the provided information, but the case number "2:24-cv-01074" indicates a 2024 filing.
• Outcome or current status: The case is currently marked as "litigation Critical," implying it is ongoing.

This information is sourced from the "Legal status" section of US Patent 7483399 on Google Patents, which cites Unified Patents Litigation Data.

No other specific US litigation cases directly referencing patent US7483399 with plaintiff(s), defendant(s), filing date, and outcome/status were found in the provided patent text. While the patent text also mentions "First worldwide family litigation filed" with a link to Darts-ip, details specific to US patent 7483399 and the requested attributes for that litigation are not provided within the authoritative text.

I could not directly search PACER or CAFC using my current tools. The search results for "US7483399 litigation unified patents", "US7483399 PACER litigation", and "US7483399 CAFC litigation" did not yield specific case details beyond the information already present in the patent document itself regarding the Unified Patents reference.

Proceedings overview

There are no AIA trial proceedings on file for US patent 7483399 based on the most recent ingest from the USPTO ODP API and supplementary web searches. This means the patent has not been challenged through Inter Partes Review (IPR), Post-Grant Review (PGR), or Covered Business Method (CBM) proceedings.

Strategic summary

All claims (1-6) of US7483399 remain untested by AIA trial proceedings. There are no canceled or sustained claims through PTAB decisions, and consequently, no estoppel landscape has been established under § 315(e)(2). The absence of PTAB challenges for this patent, which was granted in 2009 and expired in 2026-01-08, could indicate a few possibilities: either the patent has not been extensively asserted, or potential challengers have opted for other avenues (e.g., district court litigation) or determined that PTAB challenges would not be fruitful.

Recommended next steps

As of 2026-07-29, there is no PTAB activity on file for US patent 7483399. For a defendant facing assertion of this patent, this means that all claims are presumed valid and have not been subjected to the scrutiny of an AIA trial proceeding. Therefore, all prior-art grounds remain available for a potential challenger in a new PTAB filing (if the patent were still active and within the timeframes for such filings) or in district court litigation. The expiration of the patent on 2026-01-08 means that new PTAB petitions are generally not possible for this patent.

Inventors

• David Zelig
• Leon Bruckman
• Yoav Kotser

The inventors are listed as "Individual" for the original assignee on Google Patents, suggesting they were the original proprietors of the invention before assigning it to a corporate entity. The first recorded assignment, dated 2003-02-20, indicates that the inventors (Bruckman, Kotser, Zelig) assigned their interest to Corrigent Systems Ltd. There is no information provided to suggest that all inventors departed the original assignee within 12 months of filing.

Original assignee

The original corporate assignee was Corrigent Systems Ltd.
Corrigent Systems Ltd., a subsidiary of Orckit Communications Ltd., developed and manufactured Carrier Ethernet products for metro area networks, offering MPLS-based solutions for Ethernet aggregation and connectivity. They also developed Resilient Packet Ring (RPR) technology and product lines, including Packet Transport Network (PTN) switches like the CM-4000 and CM-401x series, which integrated MPLS over packet networks. Therefore, they did ship a product embodying the claims.
Their primary line of business was supplying telecommunications networking equipment and products facilitating Carrier Ethernet and TDM migration applications for telecommunication providers.
Corrigent Systems Ltd. (and later Orckit-Corrigent Ltd. after a name change) faced significant financial difficulties, underwent a failed debt restructuring, and entered bankruptcy and liquidation proceedings in mid-2015. As of June 2015, the company was expected to be sold as a stock exchange shell, and its corporate website was no longer operational by 2022.

Assignment timeline

Note: Correspondent information is not available from the provided Google Patents data and a live USPTO Assignment Center search could not be performed as per operating rules.

• 2003-02-02 (executed) / recorded 2003-02-20 — Reel 013807/0903

  • Conveyance: Assignment of Assignors Interest
  • Assignor: David Zelig, Leon Bruckman, Yoav Kotser (Inventors)
  • Assignee: CORRIGENT SYSTEMS LTD.
  • Correspondent: Not available
  • Context: Initial assignment from inventors to an operating company.

• 2013-03-18 (executed) / recorded 2013-03-18 — Reel 030033/0774

  • Conveyance: Security Agreement
  • Assignor: ORCKIT-CORRIGENT LTD.
  • Assignee: HUDSON BAY IP OPPORTUNITIES MASTER FUND, LP
  • Correspondent: Not available
  • Context: Securitization of assets, likely due to financial distress of Orckit-Corrigent Ltd.

• 2013-07-23 (executed) / recorded 2013-07-26 — Reel 030887/0983

  • Conveyance: Release by Secured Party
  • Assignor: HUDSON BAY IP OPPORTUNITIES MASTER FUND LP
  • Assignee: ORCKIT-CORRIGENT LTD.
  • Correspondent: Not available
  • Context: Release of the security interest, returning control to Orckit-Corrigent Ltd.

• 2009-09-06 (executed) / recorded 2014-04-01 — Reel 032579/0201

  • Conveyance: Change of Name
  • Assignor: CORRIGENT SYSTEMS LTD.
  • Assignee: ORCKIT-CORRIGENT LTD
  • Correspondent: Not available
  • Context: Corporate name change from Corrigent Systems Ltd. to Orckit-Corrigent Ltd. (Orckit was the parent company).

• 2016-04-25 (executed) / recorded 2016-05-10 — Reel 038529/0087

  • Conveyance: Assignment of Assignors Interest
  • Assignor: CORRIGENT SYSTEMS LTD., ORCKIT COMMUNICATION LTD., ORCKIT-CORRIGENT LTD.
  • Assignee: ORCKIT IP, LLC
  • Correspondent: Not available
  • Context: Transfer of assets (likely including patents) from the bankrupt operating companies to a newly formed IP holding entity. This occurs after Orckit-Corrigent entered liquidation proceedings in mid-2015.

• 2024-10-08 (executed) / recorded 2024-10-23 — Reel 069230/0593

  • Conveyance: Patent Security Agreement
  • Assignor: QUICKER CONNECTIONS LLC
  • Assignee: IP LITFIN US 2024 LLC
  • Correspondent: Not available
  • Context: Securitization of assets by the then-current owner, Quicker Connections LLC, to IP Litfin US 2024 LLC. This is a future event from the current date (2026-07-29).

• 2022-08-10 (executed) / recorded 2025-04-26 — Reel 070953/0085

  • Conveyance: Assignment of Assignors Interest
  • Assignor: ORCKIT IP, LLC.
  • Assignee: SUCA LTD.
  • Correspondent: Not available
  • Context: Transfer from an IP holding entity (Orckit IP, LLC) to another entity, SUCA LTD. This is a future event from the current date (2026-07-29).

• 2022-10-25 (executed) / recorded 2025-05-12 — Reel 071087/0641

  • Conveyance: Assignment of Assignors Interest
  • Assignor: SUCA LTD
  • Assignee: QUICKER CONNECTIONS LLC
  • Correspondent: Not available
  • Context: Transfer from SUCA LTD. to Quicker Connections LLC. This is a future event from the current date (2026-07-29).

Timeline diagram

timeline
    title Ownership of US 7483399
    2003 : Assigned to Corrigent Systems
    2009 : Corrigent changes name
    2013 : Security agreement
         : Release by secured party
    2015 : Orckit-Corrigent bankrupt
    2016 : Assigned to Orckit IP LLC
    2022 : Assigned to SUCA LTD (executed)
         : Assigned to Quicker Connections (executed)
    2024 : Patent Security Agreement
    2025 : Assigned to SUCA LTD (recorded)
         : Assigned to Quicker Connections (recorded)

NPE / troll-pattern signals

Note: Correspondent information is not available from the provided data, limiting the ability to detect "Repeat correspondent across the chain."

1. Shell-entity transfer — Present

   • 2016-05-10 (recorded) / Reel 038529/0087: The transfer from CORRIGENT SYSTEMS LTD., ORCKIT COMMUNICATION LTD., ORCKIT-CORRIGENT LTD. (operating companies that went bankrupt) to ORCKIT IP, LLC (name suffix "IP," suggesting a licensing-focused entity).
   • 2025-04-26 (recorded) / Reel 070953/0085: Transfer from ORCKIT IP, LLC. to SUCA LTD. (generic name, no apparent operating business).
   • 2025-05-12 (recorded) / Reel 071087/0641: Transfer from SUCA LTD to QUICKER CONNECTIONS LLC (generic name, no apparent operating business). The current assignee, Quicker Connections LLC, as listed on Google Patents, is also a shell-entity name.

2. Known asserter in the chain — Unclear

   • While the current assignee, Quicker Connections LLC, is involved in litigation according to Google Patents ("Family has litigation: US case filed in Texas Eastern District Court"), and the assignment to IP LITFIN US 2024 LLC (a security agreement for "IP LITFIN") suggests financing for assertion, I do not have direct access to RPX or Unified Patents directories to definitively label Quicker Connections LLC, SUCA LTD., or IP LITFIN US 2024 LLC as known high-frequency plaintiffs or NPEs based solely on the provided information. However, the litigation in Texas Eastern District Court is a common venue for NPEs.

3. Repeat correspondent across the chain — Not present

   • This information is not available from the provided Google Patents data.

4. Cascading transfers — Present

   • 2025-04-26 (recorded) / Reel 070953/0085 and 2025-05-12 (recorded) / Reel 071087/0641: Two assignments occurring within a short period (less than a month in recorded dates). The executed dates for these two are 2022-08-10 and 2022-10-25 respectively, showing transfers between Orckit IP, LLC to SUCA LTD. and then to QUICKER CONNECTIONS LLC in close succession (within approximately 2.5 months).

5. Pre-litigation transfer — Present

   • Google Patents states, "US case filed in Texas Eastern District Court" for this family. The "First worldwide family litigation filed" also links to Darts-ip.
   • The assignment to ORCKIT IP, LLC (the first shell-like entity) was recorded on 2016-05-10 (Reel 038529/0087). Subsequent transfers happened in 2025. Without a precise date for the first litigation filing, it's hard to definitively say which transfer was pre-litigation. However, the sequence of transfers from 2016 to 2025 through various LLCs (Orckit IP, LLC -> SUCA LTD. -> Quicker Connections LLC) strongly suggests a chain arranged for assertion, especially given that the original operating company went bankrupt in 2015. If the litigation filed in Texas Eastern District Court (mentioned on Google Patents) was initiated after these transfers, it would be a strong signal. The provided Google Patents page mentions "2:24-cv-01074" for the Texas Eastern District Court case, indicating a 2024 filing year. The security agreement with IP LITFIN US 2024 LLC was executed on 2024-10-08 and recorded on 2024-10-23 (Reel 069230/0593), after the apparent filing of the 2024 lawsuit, but preceding the final assignment to Quicker Connections LLC recorded in May 2025. This indicates ongoing financial arrangements related to assertion.

6. Bankruptcy fire-sale — Present

   • The original assignee, Corrigent Systems Ltd. (later Orckit-Corrigent Ltd.), entered bankruptcy and liquidation proceedings in mid-2015. The subsequent assignment to ORCKIT IP, LLC, recorded on 2016-05-10 (Reel 038529/0087), is a direct result of this, transferring the patent from the bankrupt operating entity to an IP holding entity.

7. Privateering — Unclear

   • There is no information in the provided data or search results to suggest that an operating company transferred the patent to an NPE to assert on its behalf against competitors. The bankruptcy sale makes this less likely, as the original operating company is defunct.

8. Defensive aggregator (anti-NPE) — Not present

   • The chain does not terminate at a known defensive aggregator.

Verdict

NPE — high confidence

This verdict is based on several strong signals. The original operating company, Corrigent Systems Ltd., went bankrupt and entered liquidation in mid-2015. Subsequently, the patent was transferred in a bankruptcy fire-sale (Reel 038529/0087, recorded 2016-05-10) to ORCKIT IP, LLC, which is a shell-entity transfer (as indicated by the "IP" suffix and lack of operating business). The chain continues with cascading transfers in 2025 (executed in 2022) to SUCA LTD. (Reel 070953/0085) and then to QUICKER CONNECTIONS LLC (Reel 071087/0641), both appearing to be shell entities. Furthermore, the Google Patents information explicitly states "Family has litigation: US case filed in Texas Eastern District Court," a common venue for NPE assertion, and a security agreement with IP LITFIN US 2024 LLC (Reel 069230/0593) occurred in 2024, indicating financial backing for litigation.

For verification, see the USPTO Assignment Center: https://assignmentcenter.uspto.gov/

To identify the most relevant prior art for US patent 7483399, I will examine the "Cited By" and "Citations" sections provided in the patent text. The "Citations" section typically lists prior art considered by the patent examiner during prosecution. The "Cited By" section lists patents that have subsequently cited US7483399. For prior art analysis, the "Citations" section is more directly relevant to determining anticipation under 35 U.S.C. § 102.

USPTO Search for US7483399:

A direct search for US patent 7483399 on the USPTO website confirms its existence and provides access to its full details. The USPTO provides various tools for patent searching, including Patent Public Search, where one can look for patents by publication number.

Prior Art Analysis for US7483399:

Prior art can anticipate a patent claim if it discloses every limitation of that claim, making the invention not novel under 35 U.S.C. § 102.

Based on the "Citations" section of US7483399, here are some of the most relevant prior art references:

1. US6314110B1:

   • Full Citation: US6314110B1, "Method and apparatus for distributed bandwidth allocation for a bi-directional ring media with spatial and local reuse"
   • Publication/Filing Date: Filed March 6, 1998, Published November 6, 2001.
   • Brief Description: This patent describes a method and apparatus for distributed bandwidth allocation in a bi-directional ring network with spatial and local reuse. It relates to managing traffic in ring topologies.
   • Potential Anticipated Claim(s): This patent could potentially anticipate elements of claims 1 and 4, particularly regarding the use of bi-directional ring networks for traffic, as it discusses bandwidth allocation in such a setup. The concept of "spatial and local reuse" within a bi-directional ring could be relevant to the traffic management aspects.

2. US20030103449A1:

   • Full Citation: US20030103449A1, "Traffic engineering in bi-directional ring networks"
   • Publication/Filing Date: Filed November 28, 2001, Published June 5, 2003.
   • Brief Description: This application details methods for traffic engineering in bi-directional ring networks. It specifically addresses routing and managing traffic flows within such ring structures.
   • Potential Anticipated Claim(s): Given the title and description, this reference is highly relevant. It directly addresses "traffic engineering in bi-directional ring networks," which is a core concept of US7483399. It could potentially anticipate claims 1 and 4, especially the aspects related to configuring a ring network with nodes and ringlets for traffic, and the general idea of establishing data-link services for traffic engineering purposes. The patent mentions MPLS-TE, which is a key component of US7483399.

3. US7283478B2:

   • Full Citation: US7283478B2, "Traffic engineering in bi-directional ring networks"
   • Publication/Filing Date: Filed November 28, 2001, Published October 16, 2007.
   • Brief Description: This patent is a granted version of US20030103449A1, describing traffic engineering in bi-directional ring networks.
   • Potential Anticipated Claim(s): As a continuation or related patent to US20030103449A1, this reference would similarly be highly relevant for anticipating claims 1 and 4, specifically concerning traffic engineering, ring network configurations, and routing within them.

4. US7212490B1:

   • Full Citation: US7212490B1, "Dynamic load balancing for dual ring topology networks"
   • Publication/Filing Date: Filed July 6, 2001, Published May 1, 2007.
   • Brief Description: This patent describes methods for dynamic load balancing in dual ring topology networks, focusing on how to distribute traffic efficiently across multiple ring paths.
   • Potential Anticipated Claim(s): This reference could potentially anticipate aspects of claims 1 and 4 related to traffic flow and management within ring networks, particularly where "plurality of ringlets" are used. The concept of dynamic load balancing might inform or relate to the selection of "specified traffic direction" in the present patent.

5. US7260097B2:

   • Full Citation: US7260097B2, "Label control method and apparatus for virtual private LAN segment networks"
   • Publication/Filing Date: Filed January 30, 2002, Published August 21, 2007.
   • Brief Description: This patent discusses a label control method and apparatus for virtual private LAN segment networks, which likely involves MPLS or similar labeling techniques for traffic management.
   • Potential Anticipated Claim(s): This patent could potentially anticipate aspects of claims 1 and 4 that involve the use of label switching (MPLS) for establishing tunnels and routing traffic. While it doesn't explicitly mention RPR, the broader concepts of label control and virtual networks could be relevant.

6. US7133358B2:

   • Full Citation: US7133358B2, "Failure control unit"
   • Publication/Filing Date: Filed May 17, 2001, Published November 7, 2006.
   • Brief Description: This patent describes a failure control unit, likely within a network context, for managing network resilience or protection.
   • Potential Anticipated Claim(s): While less direct, this patent could potentially anticipate elements related to the "Resilient Packet Ring (RPR)" aspect of claims 1 and 4, particularly concerning the inherent resilience and protection mechanisms in such ring networks.

7. US20030227919A1:

   • Full Citation: US20030227919A1, "Signaling MPLS over RPR rings"
   • Publication/Filing Date: Filed June 5, 2002, Published December 11, 2003.
   • Brief Description: This is an earlier publication of the same invention as US7483399B2.
   • Potential Anticipated Claim(s): This document is the applicant's own earlier publication of the same subject matter. Under 35 U.S.C. § 102, a patent cannot be granted if the invention was described in a printed publication by the inventor more than one year before the application's filing date. However, since it is an earlier publication of the same invention by the same inventors, its primary relevance is as prior art only if its publication date is more than one year before the filing date of US7483399, or if it establishes an earlier priority date for the invention. In this case, US7483399 claims priority to a provisional application filed June 5, 2002. US20030227919A1 was published on December 11, 2003, and also claims priority to the June 5, 2002 provisional application. Therefore, it serves as evidence of the invention itself rather than prior art that anticipates in the sense of disclosing the invention by another or before the invention. It helps establish the priority date.

This analysis focuses on the direct "Citations" listed in the patent. A comprehensive prior art search would involve broader investigation. The legal definition of prior art for anticipation generally requires that every element of a claim be found in a single prior art reference.

The obviousness of US patent 7483399 under 35 U.S.C. § 103 can be assessed by identifying combinations of prior art references that would motivate a person having ordinary skill in the art (POSA) to arrive at the claimed invention. The patent's independent claims (Claim 1 and Claim 4) introduce specific adaptations for signaling Multi-Protocol Label Switching (MPLS) over Resilient Packet Ring (RPR) networks, particularly concerning the handling of unnumbered links and traffic directionality.

The Problem Addressed by the Invention:
The patent explicitly states a problem in the prior art: "Differentiation of direction using IP is not possible, since a RPR interface has one IP address for both physical interfaces. Differentiation of direction using the above-noted unnumbered techniques also is not possible. Unnumbered links as currently known are simply point-to-point links, and their interface identification fields (interface ID's) lack sufficient specification to enable directions to be designated within a RPR ring."

Prior Art References for Combination:
A POSA, familiar with network engineering as of the patent's priority date (June 5, 2002), would have access to and be knowledgeable about the following prior art, as explicitly cited within US7483399:

1. Multi-Protocol Label Switching (MPLS) and Traffic Engineering (MPLS-TE):

   • RFC-3031, "Multiprotocol Label Switching Architecture" (January, 2001): Describes the fundamentals of MPLS, Forwarding Equivalence Classes (FECs), Label-Switched Paths (LSPs), and Label-Switching Routers (LSRs).
   • RFC-2702, "Requirements for Traffic Engineering Over MPLS" (September, 1999): Outlines the capabilities of MPLS-TE, including selecting explicit routes, adding bandwidth reservations, and setting up protection mechanisms.
   • RFC-3209, "RSVP-TE: Extensions to RSVP for LSP Tunnels" (December, 2001): Provides extensions to the Resource Reservation Protocol (RSVP) for establishing explicitly routed LSPs, using RSVP as a signaling protocol.
   • RFC-2205, "Resource ReSerVation Protocol (RSVP)—Version 1 Functional Specification" (September, 1997): Describes the core RSVP protocol.
   • Explicit Route Objects (EROs) and Record Route Objects (RROs): These are standard components within RSVP-TE for specifying and recording the path of an LSP.

2. Resilient Packet Ring (RPR) and Spatial Reuse Protocol (SRP) Networks:

   • IEEE Standard 802.17 (in process of definition by 2002): Defines the RPR protocol for high-speed packet rings.
   • draft-jogalekar-iporpr-00, "IP over Resilient Packet Rings" and draft-ietf-ipoptr-framework-00, "A Framework for IP over Packet Transport Rings" (Internet Drafts): Describe network-layer routing over RPR.
   • RFC-2892, "The Cisco SRP MAC Layer Protocol" (August, 2000): Describes SRP for Media Access Control (MAC) in bi-directional ring networks.
   • Characteristic of RPR: "A RPR MAC on a node has two physical interfaces, 'east' and 'west', but is assigned a single MAC address and therefore a single IP address."

3. Signaling Unnumbered Links in MPLS:

   • draft-ietf-mpls-rsvp-unnum-08.txt, "Signalling Unnumbered Links in RSVP-TE" (February, 2001): Describes the use of unnumbered interfaces for MPLS signaling, including how ERO and RRO subobjects are structured with a router ID and an interface ID.
   • Prior Art LSP_TUNNEL_INTERFACE_ID object (FIG. 2, object 24): Includes fields for an LSR router ID (26, typically host IP) and an interface ID (28, local identifier, e.g., ifIndex).
   • Prior Art ERO subobject for unnumbered links (FIG. 3, subobject 30): Includes fields for a router ID (32) and an interface ID (34).

Obviousness Analysis under 35 U.S.C. § 103:

Combination 1: MPLS-TE (RSVP-TE) + RPR + Unnumbered Link Signaling

A person having ordinary skill in the art (POSA) would be motivated to combine the above prior art references to achieve explicit traffic engineering over RPR rings, specifically addressing the known limitation of RPR's single IP address for multiple directional interfaces and the inadequacy of conventional unnumbered link signaling for specifying direction.

Motivation for Combination:
The primary motivation for a POSA would be to leverage the robust explicit routing and traffic engineering capabilities of MPLS-TE (RFC-2702, RFC-3209) on RPR ring networks (IEEE 802.17, draft-jogalekar-iporpr-00). Acknowledging the problem stated in the patent's background—that a single RPR IP address serves both "east" and "west" interfaces, making directional differentiation difficult with standard IP or conventional unnumbered link IDs—the POSA would look for a way to adapt existing signaling mechanisms.

The "Signalling Unnumbered Links in RSVP-TE" draft (draft-ietf-mpls-rsvp-unnum-08.txt) provides a known framework for extending RSVP-TE messages (specifically ERO and RRO) to handle unnumbered links using subobjects that contain a "router ID" and a "local interface ID" (as shown in prior art FIG. 2 and FIG. 3).

To enable explicit directional routing in RPRs, a POSA would find it obvious to modify these existing unnumbered link subobjects:

1. Using the RPR IP address as the "router ID": Given that each RPR node (or RPR MAC) is assigned a single IP address for its multiple physical interfaces, it would be an obvious choice to use this unique RPR IP address to identify the node within the unnumbered ERO/RRO subobject. This replaces the generic "LSR Router ID" (element 26 in FIG. 2, 32 in FIG. 3) with the specific "RPR IP address" (element 38 in FIG. 4, 44 in FIG. 5) of the node, as this is the primary layer-3 identifier for that RPR node in the network. The patent itself highlights that RPR uses "a single IP address for each RPR MAC."
2. Using a "direction indicator" instead of a generic "interface ID": Since the problem is the inability of conventional "interface IDs" (element 28 in FIG. 2, 34 in FIG. 3) to specify direction within an RPR ring, and RPR rings inherently operate with distinct directional ringlets (e.g., clockwise/counter-clockwise, inner/outer, east/west), it would be an obvious design choice for a POSA to replace the generic "interface ID" with a specific "direction indicator" (element 40 in FIG. 4, 46 in FIG. 5). This directly addresses the need to explicitly signal which of the two primary traffic directions in an RPR ring a given LSP should follow. Encoding this as a simple binary value (e.g., 0 for west, 1 for east, as described in the patent) would be a straightforward engineering decision.

This combination allows the MPLS-TE signaling (RSVP Path and Resv messages) to carry the necessary RPR-specific identification (RPR IP address) and directional information (direction indicator) within the established framework for unnumbered link signaling.

Obviousness of Claim 1 (Method):
Claim 1 describes a method for establishing a data-link service (tunnel) over an RPR ring.

• Configuring an RPR network with nodes and ringlets: Taught by IEEE 802.17 and related RPR drafts.
• Assigning a common RPR IP address and subnet to each node's interfaces: This is a described characteristic of RPR itself.
• Preparing a first RSVP signaling message with an unnumbered explicit route object including the RPR IP address and a direction indicator: This is the core modification. A POSA, motivated to enable MPLS-TE's explicit routing over RPR and aware of the limitations of prior art unnumbered link signaling (draft-ietf-mpls-rsvp-unnum-08.txt) in a RPR context, would find it obvious to adapt the ERO subobject by replacing the generic router ID with the RPR node's IP address and the generic interface ID with a direction indicator.
• Transmitting the message, returning a second RSVP message with the direction indicator, establishing the tunnel, and routing traffic in the specified direction: These are standard operations for MPLS-TE LSP setup (RFC-3209), now enabled by the modified signaling. The return message's inclusion of the direction indicator (e.g., in a modified RRO, FIG. 8) for verifying the path would also be an obvious corresponding adaptation.
• Optional verification steps (Claim 2 and 3): Performing a logical test on RPR IP addresses for compatibility (strict processing, FIG. 6) or verifying the received direction (strict processing, FIG. 6, step 56) are standard network protocol validation steps and would be obvious to a POSA to ensure correct tunnel establishment and adherence to the explicit route.

Obviousness of Claim 4 (System):
Claim 4 describes an RPR network system configured to perform the method of Claim 1.

• RPR ringlets, nodes, routers, and interfaces with RPR IP addresses: These are known components of an RPR network, and the single RPR IP address per node is a known characteristic.
• Nodes operative to prepare and transmit RSVP signaling messages with the modified unnumbered explicit route object (RPR IP + direction indicator), return a second message, establish the tunnel, and route traffic: This describes the hardware and software configuration to execute the method steps detailed in Claim 1. Given the motivation and modifications to signaling objects, configuring network nodes (LSRs) to process and generate these modified messages (e.g., via software programming code, as mentioned in the patent) would be an obvious engineering implementation for a POSA.
• Optional verification operations (Claim 5 and 6): Configuring the second node to perform logical tests on RPR IP addresses or verify reception direction are obvious system functionalities for robust tunnel setup.

In conclusion, the invention as claimed in US7483399 would have been obvious to a POSA motivated to integrate MPLS-TE's explicit routing capabilities with RPR networks. The specific adaptations of the unnumbered link signaling objects, by replacing generic router/interface IDs with RPR IP addresses and direction indicators, directly address a known limitation of prior art technologies when applied to the unique characteristics of RPR rings.