US 7697552

US Patent 7697552, titled "MAC address scalability in interconnected rings," was granted to Orckit Corrigent Ltd (Original Assignee) and is currently assigned to Quicker Connections LLC. The patent's sole inventor is Leon Bruckman. It was filed on June 18, 2007, and issued on April 13, 2010.

No active litigation regarding US Patent 7697552 was found in the CAFC 2026 dockets.

Abstract:
The patent describes a communication method within a network featuring multiple ring nodes arranged in at least two interconnected ring networks. A data packet from a source user node in the first ring network, destined for a user node in the second ring network, is accepted. An identifier is attached to the data packet in the first ring network, which specifies the interconnect node through which the packet should be forwarded to the second ring network. The data packet is then forwarded over the first ring network, accepted by the identified interconnect node, and subsequently forwarded from that interconnect node to the second ring network and ultimately to the destination user node.

Plain-language overview of independent claims:

• Independent Claim 1 (Method Claim):
  This claim describes a method for sending a data packet from a source user in a first ring network to a destination user in a second ring network. The core of the invention lies in how the forwarding path is determined: the first ring node (serving the source user) learns which interconnect node to use based on a previous data packet. This previous packet originated from a user in the second ring, was addressed to a user in the first ring, and was forwarded through that same interconnect node. When the first ring node receives the new packet for the second ring, it attaches an identifier for the learned interconnect node and sends the packet along its ring. The interconnect node then recognizes its identifier on the packet and forwards it to the second ring, which then delivers it to the destination user.

• Independent Claim 12 (System/Network Claim):
  This claim describes a communication network designed to perform the method of Claim 1. It comprises first and second sets of ring nodes forming respective ring networks. Within the first ring network, there is an interconnect node connected to the second ring network and a first ring node. This first ring node is configured to accept a data packet from a source user for a destination user in the second ring network. Crucially, the first ring node attaches an identifier to the packet, specifying the interconnect node in its own ring that should be used for forwarding. The interconnect node in the network is arranged to "learn" the forwarding path to the second ring network for data packets based on a previous packet (similar to Claim 1's learning mechanism). Upon receiving the new data packet, the interconnect node recognizes its identifier and forwards the packet to the second ring network, ensuring it reaches the destination user via the second ring node.

I have searched for litigation involving US patent 7697552 on various patent litigation tracking sites. As of today, April 26, 2026, no specific litigation cases directly involving US patent 7697552 have been found in the search results.

While some search results discuss general patent litigation, PACER system overcharges, and the activities of organizations like Unified Patents, none of them mention US7697552 specifically in the context of a lawsuit.

Therefore, based on the current search, no known litigation involving US patent 7697552 can be provided at this time.As of April 26, 2026, no specific litigation cases involving US patent 7697552 have been identified through the conducted searches. While searches were performed on platforms that cover patent litigation, including information about organizations like Unified Patents and the PACER system, no records directly linked to US7697552 in a litigation context were found.

The search results provide general information about PTAB trial types (IPR, PGR, CBM) and how to search for cases via P-TACTS. However, none of the snippets directly mention US7697552 or any specific PTAB proceeding involving it. This reinforces the initial information that the USPTO ODP API returns no AIA trial proceedings.

Therefore, I can conclude that there are no PTAB proceedings on file or readily discoverable via general web search for US7697552.

Proceedings overview

There are no AIA trial proceedings on file for US Patent 7,697,552 as of today, July 29, 2026. This means the patent has not been subjected to IPR, PGR, or CBM challenges, giving a defendant no immediate defensive leverage from canceled claims through these specific trial types.

Strategic summary

As of the current date, all claims of US Patent 7,697,552 remain untested by AIA trial proceedings. There have been no IPRs, PGRs, or CBMs filed against this patent, which means no claims have been canceled or sustained by the PTAB. Consequently, there is no estoppel landscape under 35 U.S.C. § 315(e)(2) for any potential petitioner, leaving all prior-art grounds available for future challenges. The absence of PTAB activity suggests that either the patent has not been extensively asserted, or previous assertions did not lead to defensive challenges in the PTAB.

Recommended next steps

Since no PTAB activity exists for US Patent 7,697,552, a defendant facing assertion of this patent would have all avenues open for a potential AIA trial challenge. The first step would be to conduct a thorough prior art search to identify strong invalidity grounds under 35 U.S.C. §§ 102 and 103 against the asserted claims. If such art is found, filing an Inter Partes Review (IPR) petition would be a viable defensive strategy, as no estoppel would apply. The absence of prior PTAB challenges also means there are no prior institution decisions or Final Written Decisions from which to glean the PTAB's stance on the patent's claims or the patent owner's typical litigation posture within the PTAB. The one-year statutory deadline for filing an IPR from the date of service of a complaint alleging infringement would be a critical consideration.## Proceedings overview
There are no AIA trial proceedings on file for US Patent 7,697,552 as of today, July 29, 2026. This means the patent has not been subjected to Inter Partes Review (IPR), Post-Grant Review (PGR), or Covered Business Method (CBM) challenges, offering a defendant no immediate defensive leverage from claims invalidated through these specific trial types.

Strategic summary

As of the current date, all claims of US Patent 7,697,552 remain untested by AIA trial proceedings. There have been no IPRs, PGRs, or CBMs filed against this patent, which means no claims have been canceled or sustained by the PTAB. Consequently, there is no estoppel landscape under 35 U.S.C. § 315(e)(2) for any potential petitioner, leaving all prior-art grounds available for future challenges. The absence of PTAB activity suggests that either the patent has not been extensively asserted, or previous assertions did not lead to defensive challenges in the PTAB.

Recommended next steps

Since no PTAB activity exists for US Patent 7,697,552, a defendant facing assertion of this patent would have all avenues open for a potential AIA trial challenge. The first step would be to conduct a thorough prior art search to identify strong invalidity grounds under 35 U.S.C. §§ 102 and 103 against the asserted claims. If such art is found, filing an Inter Partes Review (IPR) petition would be a viable defensive strategy, as no estoppel would apply. The absence of prior PTAB challenges also means there are no prior institution decisions or Final Written Decisions from which to glean the PTAB's stance on the patent's claims or the patent owner's typical litigation posture within the PTAB. The one-year statutory deadline for filing an IPR from the date of service of a complaint alleging infringement would be a critical consideration.

Inventors

• Leon Bruckman, employed by Corrigent Systems Ltd. (later Orckit-Corrigent Ltd.) at the time of filing.

Original assignee

The original assignee was Corrigent Systems Ltd., which later changed its name to Orckit-Corrigent Ltd. This Israel-based company was a supplier of telecommunications networking equipment and products, primarily focusing on Carrier Ethernet and TDM migration applications, including the development of Resilient Packet Ring (RPR) technology and the CM4000 Packet Transport Networking (PTN) product line. The company shipped products globally to various telecom providers, such as Deutsche Telekom and KDDI. However, Orckit-Corrigent Ltd. faced increasing debt, underwent a failed restructuring, and entered bankruptcy and liquidation proceedings in mid-2015, becoming defunct.

Assignment timeline

The following is a chronological list of recorded assignments for US Patent 7697552, ordered by execution date. Correspondent information was obtained via a USPTO Assignment Center search.

• 2007-06-11 (executed) / recorded 2007-06-18 — Reel 019459/0806

  • Conveyance: ASSIGNMENT OF ASSIGNORS INTEREST
  • Assignor: BRUCKMAN, LEON
  • Assignee: CORRIGENT SYSTEMS LTD.
  • Correspondent: G. E. EHRLICH, EHRLICH & FENER, P.O. BOX 19018, TEL AVIV, ISRAEL 61190.
  • Context: Inventor assigned patent rights to their employer.

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

  • Conveyance: CHANGE OF NAME
  • Assignor: CORRIGENT SYSTEMS LTD.
  • Assignee: ORCKIT-CORRIGENT LTD.
  • Correspondent: G. E. EHRLICH, EHRLICH & FENER, P.O. BOX 19018, TEL AVIV, ISRAEL 61190. This correspondent also handled the initial assignment.
  • Context: Internal corporate name change of the original assignee.

• 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: JOHN M. D'ANGELO, D'ANGELO & HINDS, LLC, 17 STATE STREET, SUITE 2100, NEW YORK, NY 10004.
  • Context: Original assignee granted a security interest in the patent portfolio to an investment fund.

• 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: JOHN M. D'ANGELO, D'ANGELO & HINDS, LLC, 17 STATE STREET, SUITE 2100, NEW YORK, NY 10004. This correspondent also handled the security agreement.
  • Context: Release of the security interest.

• 2016-04-25 (executed) / recorded 2016-05-09 — Reel 038507/0587

  • Conveyance: ASSIGNMENT OF ASSIGNORS INTEREST
  • Assignors: ORCKIT COMMUNICATION LTD.;ORCKIT-CORRIGENT LTD.;CORRIGENT SYSTEMS LTD.
  • Assignee: ORCKIT IP, LLC
  • Correspondent: KEVIN P. GRONHOLZ, D'ANGELO & HINDS, LLC, 17 STATE STREET, SUITE 2100, NEW YORK, NY 10004. This correspondent's firm also handled the Hudson Bay security agreement and release.
  • Context: Transfer of patent from the bankrupt operating company group to an IP holding company.

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

  • Conveyance: ASSIGNMENT OF ASSIGNORS INTEREST
  • Assignor: ORCKIT IP, LLC.
  • Assignee: SUCA LTD.
  • Correspondent: A. WILLIAM RICE, RICE AND RICE, 4770 BANISTER DR., SAN ANTONIO, TX 78228.
  • Context: Transfer from an IP holding company to another entity.

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

  • Conveyance: ASSIGNMENT OF ASSIGNORS INTEREST
  • Assignor: SUCA LTD
  • Assignee: QUICKER CONNECTIONS LLC
  • Correspondent: A. WILLIAM RICE, RICE AND RICE, 4770 BANISTER DR., SAN ANTONIO, TX 78228. This correspondent also handled the previous assignment.
  • Context: Transfer between two entities.

• 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: E. TIMOTHY COYNE, COYNE AND ASSOCIATES, PLLC, 3030 NORTH STEMMONS FREEWAY, SUITE 1000, DALLAS, TX 75247.
  • Context: Current owner granted a security interest to a litigation finance entity.

Timeline diagram

timeline
    title Ownership of US 7697552
    2007 : Inventor to Corrigent Systems Ltd
    2009 : Corrigent renamed Orckit-Corrigent
    2010 : Patent Issued
    2013 : Orckit-Corrigent secured by Hudson Bay
         : Hudson Bay releases security
    2015 : Orckit-Corrigent bankrupt (approx)
    2016 : Assigned to Orckit IP LLC
    2022 : Assigned to Suca Ltd
         : Assigned to Quicker Connections LLC
    2024 : Quicker Connections grants security

NPE / troll-pattern signals

1. Shell-entity transfer — Present.

   • Reel 038507/0587 (recorded 2016-05-09): Transfer to ORCKIT IP, LLC. The "IP" suffix in the name strongly indicates an IP holding or licensing entity, which is further supported by external evidence of patent assertion by Orckit IP LLC for its portfolio.
   • Reel 070953/0085 (recorded 2025-04-26): Transfer to SUCA LTD. Public information for "SUCA LTD" suggests a focus on food, industrial materials, and textiles, not telecommunications, indicating it's a shell for patent holding in this context.
   • Reel 071087/0641 (recorded 2025-05-12): Transfer to QUICKER CONNECTIONS LLC. While "Quicker Connections LLC" describes IT services and network installation, the specific technology of the patent (RPR/VPLS telecom infrastructure) makes it unlikely to be an operating company productizing the patented invention.

2. Known asserter in the chain — Present.

   • HUDSON BAY IP OPPORTUNITIES MASTER FUND, LP (assignee of security interest, Reel 030033/0774, recorded 2013-03-18) is a private equity fund that engages in "special opportunities" investments, which often include IP monetization.
   • ORCKIT IP, LLC (assignee, Reel 038507/0587, recorded 2016-05-09) is cited in court documents as a "prior owner of the Asserted Patents" that "initiated discussions with Defendant about its patent portfolio". RPX also reported on the assertion activity of patents from Orckit IP LLC.
   • IP LITFIN US 2024 LLC (assignee of security interest, Reel 069230/0593, recorded 2024-10-23) has "LITFIN" in its name, which strongly suggests it is a litigation finance entity, a common partner for NPEs.

3. Repeat correspondent across the chain — Present.

   • G. E. EHRLICH, EHRLICH & FENER appears on Reel 019459/0806 (recorded 2007-06-18) and Reel 032579/0201 (recorded 2014-04-01).
   • JOHN M. D'ANGELO, D'ANGELO & HINDS, LLC appears on Reel 030033/0774 (recorded 2013-03-18) and Reel 030887/0983 (recorded 2013-07-26).
   • A. WILLIAM RICE, RICE AND RICE appears on Reel 070953/0085 (recorded 2025-04-26) and Reel 071087/0641 (recorded 2025-05-12). The same correspondent handled consecutive assignments.

4. Cascading transfers — Present.

   • The transfer to SUCA LTD (Reel 070953/0085, executed 2022-08-10) and then to QUICKER CONNECTIONS LLC (Reel 071087/0641, executed 2022-10-25) occurred within 2.5 months. Both transfers were handled by the same correspondent, A. WILLIAM RICE.

5. Pre-litigation transfer — Unclear.

   • No specific litigation for US7697552 has been found. Therefore, it's not possible to establish a pre-litigation transfer for this specific patent. However, other patents from the Orckit IP LLC portfolio have shown a pattern of transfer to an asserting entity followed by litigation, as reported by RPX.

6. Bankruptcy fire-sale — Present.

   • The original operating assignee, Orckit-Corrigent Ltd., entered bankruptcy and liquidation proceedings in mid-2015. The subsequent assignment to ORCKIT IP, LLC (Reel 038507/0587, executed 2016-04-25) represents the transfer of assets, including this patent, out of the defunct company.

7. Privateering — Unclear.

   • While the patent originated from an operating company that went bankrupt and was subsequently transferred to NPE-like entities, there is no direct evidence to suggest an operating company is now directing assertion against its competitors.

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

   • The patent has not been assigned to a known defensive aggregator.

Verdict

NPE — high confidence

The patent shows multiple strong indicators of being held for assertion by an NPE. It originated from a bankrupt operating company (Orckit-Corrigent Ltd.) and was transferred in a bankruptcy fire-sale to ORCKIT IP, LLC (Reel 038507/0587, executed 2016-04-25), an entity explicitly linked to patent assertion activity. This was followed by cascading transfers to entities (SUCA LTD and QUICKER CONNECTIONS LLC) that appear to be shell companies for patent holding. The chain concludes with the current owner, QUICKER CONNECTIONS LLC, granting a security interest to IP LITFIN US 2024 LLC (Reel 069230/0593, executed 2024-10-08), a strong indicator of litigation finance involvement. The consistent use of the same correspondent attorneys for consecutive transfers also signals a deliberate and professional monetization strategy.

Verification: USPTO Patent Assignment Search for US7697552

Most Relevant Prior Art for US Patent 7697552

To identify the most relevant prior art for US Patent 7697552, we will examine the patent citations identified as "Cited by examiner" within the patent document itself. The following analysis focuses on these references and their potential to anticipate claims under 35 U.S.C. § 102.

Cited Patent References (Cited by Examiner)

The patent document lists the following patent citations, with an asterisk indicating they were "Cited by examiner":

1. US6091705A

   • Full Citation: US6091705A, Sebring Systems, Inc., "Method and apparatus for a fault tolerant, software transparent and high data integrity extension to a backplane bus or interconnect"
   • Priority Date: 1996-12-20
   • Publication Date: 2000-07-18
   • Brief Description: This patent describes a method and apparatus for a fault-tolerant, software-transparent, and high data integrity extension to a backplane bus or interconnect. It focuses on maintaining data integrity and fault tolerance in bus or interconnect extensions. While it broadly relates to network interconnects, its primary focus is on fault tolerance and data integrity in bus extensions rather than MAC address scalability in ring networks.
   • Potential Anticipation (35 U.S.C. § 102): Unlikely to anticipate Claims 1 or 12. Its focus on bus/backplane extensions for fault tolerance does not appear to teach or suggest the specific MAC learning and interconnect identifier (IID) forwarding mechanisms for interconnected RPR networks as described in US7697552. The specific problem of MAC address scalability in interconnected ring networks, particularly RPR and VPLS, and the solution involving IIDs for forwarding decisions and MAC table reduction, are not evidently addressed.

2. US7016979B2

   • Full Citation: US7016979B2, Huawei Technologies Co., Ltd., "System and method of accessing and transmitting different data frames in a digital transmission network"
   • Priority Date: 2003-01-28
   • Publication Date: 2006-03-21
   • Brief Description: This patent describes a system and method for accessing and transmitting different data frames in a digital transmission network. Without deeper analysis, the title suggests a general approach to data transmission.
   • Potential Anticipation (35 U.S.C. § 102): A more detailed examination of US7016979B2 would be needed to definitively assess anticipation. However, based on its generic title, it is not immediately apparent that it would teach the specific combination of interconnected RPR networks, VPLS, interconnect identifiers for MAC learning scalability, and the precise forwarding logic detailed in Claims 1 and 12 of US7697552. The US7697552 patent specifically addresses a scalability problem with MAC learning in interconnect nodes of RPR/VPLS networks by introducing IIDs. It's unclear if US7016979B2 addresses this particular problem or solution.

Analysis against Independent Claims 1 and 12

US Patent 7697552's independent claims (Claims 1 and 12) focus on a method and system for MAC address scalability in interconnected ring networks, particularly RPR, by using an interconnect identifier (IID) and a specialized MAC learning process. Key aspects include:

• Interconnected ring networks (RPR).
• Data packets associated with VPLS.
• Learning at a first ring node (serving the source user) that a packet is to be forwarded to a second ring network through a specific interconnect node, based on a previous data packet originating from the destination ring and passing through that interconnect node.
• Attaching an identifier (IID) to the data packet, identifying the interconnect node.
• The interconnect node forwarding the packet to the second ring network responsively to this identifier.
• Reduction of MAC table size at interconnect nodes by learning edge node MACs rather than user node MACs, and optionally doing so independently of VPLS instances.

Based on the brief descriptions:

• US6091705A appears to focus on hardware-level fault tolerance and data integrity for bus extensions. It does not seem to address the specific problems of MAC address scalability in interconnected ring networks or the proposed solution involving IIDs and specific MAC learning processes, especially in the context of RPR and VPLS. Therefore, it is unlikely to anticipate Claims 1 or 12.

• US7016979B2 has a very broad title related to "accessing and transmitting different data frames in a digital transmission network." Without delving into its detailed claims and specification, it's not possible to conclude if it teaches or suggests the specific combination of features central to US7697552's invention, such as the use of IIDs for directing traffic between interconnected RPR rings, the specific MAC learning process driven by prior packets with IIDs, and the resulting MAC table scalability. The novelty of US7697552 lies in its specific approach to managing MAC addresses for scalability in a particular network topology (interconnected RPR rings with VPLS). If US7016979B2 were to anticipate US7697552, it would need to disclose a mechanism that inherently includes or strongly suggests the IID-based forwarding and learning described.

Therefore, while these patents are cited as prior art, their high-level descriptions do not immediately reveal a direct anticipation of the specific MAC address scalability solution for interconnected RPR networks using IIDs as claimed in US7697552. A more thorough anticipation analysis would require a detailed claim-by-claim comparison with the full texts of the cited patents.

The obviousness of US Patent 7697552 under 35 U.S.C. § 103 can be argued by combining several pieces of prior art and general networking knowledge, motivated by the problem explicitly identified in the patent itself: the scalability limitations of MAC address learning in interconnect nodes within interconnected Resilient Packet Ring (RPR) networks, especially when attempting to use MAC-in-MAC methods while preserving spatial reuse.

The independent claims (Claim 1 and Claim 12) describe a system and method where:

1. Data packets are forwarded between first and second interconnected ring networks (conforming to RPR standards) via an interconnect node.
2. An identifier (IID) that uniquely identifies the interconnect node in the source ring is attached to the data packet.
3. A first ring node (serving the source user) learns which interconnect node (and thus its IID) to use for forwarding to a destination ring.
4. This learning is based on a previous data packet that originated from the destination ring, traversed the same interconnect node, and was addressed to a user in the first ring.
5. The interconnect node then uses this IID to responsively strip the packet from the source ring and forward it to the destination ring.

Prior Art References and General Knowledge:

1. IEEE Standard 802.17 (Resilient Packet Ring - RPR): This standard, explicitly cited in the patent, defines the architecture and operation of RPR networks, including ring nodes, packet structures, and fundamental copy/strip rules for forwarding within a ring. The patent's background also acknowledges that "some network configurations comprise interconnected rings," implying the concept of interconnected RPR rings was known.
2. IEEE 802.1ah/D2.20 (Provider Backbone Bridges - MAC-in-MAC): This draft amendment, also cited in the patent, describes a known method for reducing MAC address learning requirements in network nodes. It achieves this by encapsulating user packets with an outer header that uses the MAC addresses of edge nodes (where packets enter/leave the network), rather than individual user MAC addresses. This significantly reduces the size of MAC tables at intermediate nodes.
3. U.S. Patent Application Publication 2006/0109802 (US20060109802A1): This publication, incorporated by reference, describes a method for delivering Virtual Private LAN Service (VPLS) over ring networks. It specifically mentions that a data packet includes "an identification of the VPLS," and a node forwards the packet "responsively to reading the identification." This demonstrates a known concept of embedding service-specific identifiers in packets to influence forwarding decisions.
4. General Networking Principles: A person having ordinary skill in the art (PHOSITA) would be familiar with fundamental networking concepts such as:
   • MAC learning: Nodes build MAC tables by observing the source MAC addresses of incoming packets and associating them with the ingress port or path.
   • Flooding: When a destination MAC address is unknown, a packet is broadcast (flooded) to all ports (except the ingress port) to ensure it reaches its destination and to facilitate learning.
   • Packet identifiers: The use of various identifiers (e.g., VLAN tags, MPLS labels) within packet headers or as part of encapsulation to provide additional forwarding context, segregate traffic, or identify services. The patent itself lists VLAN tags, MPLS labels, and reserved bits in the RPR header as suitable places for the interconnect identifier.

Motivation to Combine the Prior Art References:

The patent clearly identifies a problem with existing approaches:

• While interconnected RPR rings using VPLS were known (IEEE 802.17, US20060109802A1), the interconnect nodes faced scalability issues due to needing to learn a vast number of user MAC addresses for each VPLS instance.
• MAC-in-MAC (IEEE 802.1ah) offered a solution to reduce MAC table sizes by learning only edge node MACs, not user MACs. However, the patent states that applying MAC-in-MAC directly in RPR for inter-ring traffic, by using the edge node's MAC as the RPR Destination Address (DA), would force the RPR network to flood the packet around the ring, resulting in a "losing spatial reuse" and reduced bandwidth efficiency.

A PHOSITA would be strongly motivated to combine these known techniques to overcome this specific technical challenge: achieving scalable MAC address learning at RPR interconnect nodes for inter-ring VPLS traffic while preserving RPR's spatial reuse.

The combination would proceed as follows:

1. Leveraging RPR (IEEE 802.17) for the network and MAC-in-MAC (IEEE 802.1ah) for MAC table reduction: The PHOSITA would start with an interconnected RPR network and employ MAC-in-MAC encapsulation, understanding its benefit in having intermediate nodes (including interconnect nodes) only learn edge node MAC addresses.
2. Addressing the RPR spatial reuse conflict: Recognizing that using the destination edge node's MAC as the RPR DA leads to flooding in RPR, the PHOSITA would look for an alternative mechanism to direct the packet to the correct interconnect node in the source ring.
3. Introducing an "Interconnect Identifier" (IID) inspired by existing identifiers (US20060109802A1, VLAN/MPLS): Building on the concept of embedding identifiers in packets for forwarding decisions (as seen in VPLS identification from US20060109802A1, or in VLAN/MPLS tags), the PHOSITA would introduce a small, unique identifier for each interconnect node within a ring. This IID would be placed in a suitable, perhaps reserved, field of the RPR header, or an associated tag (like VLAN or MPLS, as the patent mentions), to explicitly indicate which interconnect node should process and forward the packet. This allows the interconnect node to make a targeted "strip and forward" decision if the IID matches its own, thus avoiding flooding and preserving spatial reuse.
4. Implementing reverse-path learning for the IID (general MAC learning principles): For the first ring node (edge node serving the source user) to know which IID to attach, it would need to learn this information. This learning process is analogous to conventional MAC learning. When a "previous data packet" originates from the destination ring, travels through an interconnect node (which would attach its IID for learning purposes), and reaches the first ring node, the first ring node would observe the source MAC of the remote edge node (or the remote interconnect node) and the associated IID of the local interconnect node that forwarded it. This information would be stored in the first ring node's MAC table, linking the destination edge node's MAC address with the appropriate IID for inter-ring forwarding (Claim 5). Flooding for initial learning (Claim 8) and limiting its scope (Claim 9) are standard network optimizations for MAC learning.

The combination of RPR's ring architecture (IEEE 802.17), MAC-in-MAC's MAC table reduction (IEEE 802.1ah), the concept of packet identifiers for forwarding decisions (US20060109802A1, general knowledge), and standard MAC learning techniques, all driven by the clear motivation to solve the identified scalability and spatial reuse problem, would have rendered the claimed invention obvious to a PHOSITA. The invention represents a logical adaptation and integration of existing network protocols and concepts to address a recognized deficiency in a specific network configuration.