Prior art

Most Relevant Prior Art for US Patent 7061859

The following patents are identified as the most relevant prior art for US Patent 7061859, based on their titles, examiner citations (marked with * in the original document), and thematic relevance to fault protection in ring networks. For each, a full citation, key dates, a brief description, and a preliminary assessment of potential claim anticipation under 35 U.S.C. § 102 are provided. The filing date of US7061859 is August 30, 2001.

1. US6456587B2

• Full Citation: US6456587B2, "Ring transmission system and squelch method used for same", assigned to Fujitsu Limited, published September 24, 2002.
• Publication/Filing Date: Filing Date: September 26, 1995; Publication Date: September 24, 2002.
• Prior Art Status: This patent has a filing date (Sep 26, 1995) prior to US7061859's filing date (Aug 30, 2001), making it valid prior art.
• Brief Description: This patent describes a ring transmission system designed for fault recovery. It involves detecting a break in the ring and performing squelch control to suppress unnecessary signals, as well as a return function to restore communication using the surviving parts of the ring. It focuses on physical layer issues and preventing signal looping during recovery.
• Potential Claim(s) Anticipated (35 U.S.C. § 102):
  • Independent Claims 1 & 7: This patent broadly relates to fault recovery in ring networks. However, its description does not explicitly disclose the "general mask" and "specific mask" structure, nor the "superimposing" operation (specifically Boolean conjunction of two distinct masks for path determination) as defined in claims 1 and 7 of US7061859. It focuses on squelch control and signal return after a break, rather than a packet flow disposition based on bitmask comparison. Therefore, it is unlikely to directly anticipate these specific methodological and device claims.

2. US6366556B1

• Full Citation: US6366556B1, "Self-healing networks using virtual rings", assigned to Lucent Technologies Inc., published April 2, 2002.
• Publication/Filing Date: Filing Date: June 22, 1998; Publication Date: April 2, 2002.
• Prior Art Status: This patent has a filing date (Jun 22, 1998) prior to US7061859's filing date (Aug 30, 2001), making it valid prior art.
• Brief Description: This invention describes a method for creating self-healing networks using virtual rings (VRs) within a physical mesh network. It aims to provide fast, bandwidth-efficient protection, particularly in ATM and IP networks. Upon failure detection, traffic is re-routed onto a protection path, with emphasis on managing multiple VRs to minimize wasted bandwidth. While it discusses re-routing, it doesn't detail a mask-based decision mechanism.
• Potential Claim(s) Anticipated (35 U.S.C. § 102):
  • Independent Claims 1 & 7: Similar to US6456587B2, this patent describes a system for self-healing and rerouting in response to faults in ring-like (virtual ring) networks. However, the mechanism disclosed focuses on creating and managing virtual rings and switching traffic to a protection path. It does not explicitly teach the construction of a "general mask" indicating unreachable segments and a "specific mask" for a flow's desired path, nor the superimposing of these specific bitmask-based representations to determine the disposition of a data flow, as required by claims 1 and 7.

3. US6233073B1

• Full Citation: US6233073B1, "Diagnostic injection of transmission errors in fiber optic networks", assigned to International Business Machines Corporation, published May 15, 2001.
• Publication/Filing Date: Filing Date: July 30, 1998; Publication Date: May 15, 2001.
• Prior Art Status: This patent has a filing date (Jul 30, 1998) and publication date (May 15, 2001) prior to US7061859's filing date (Aug 30, 2001), making it valid prior art.
• Brief Description: This patent describes a method for diagnosing transmission errors in fiber optic networks by selectively injecting errors into a data stream at various points and observing the results. It's a diagnostic tool rather than a fault protection and recovery mechanism for live traffic.
• Potential Claim(s) Anticipated (35 U.S.C. § 102):
  • Independent Claims 1 & 7: This patent is directed towards diagnostic methods for network errors, not active fault protection and rerouting of data flows as described in US7061859. It does not disclose any form of general or specific masks, nor a method of superimposing them to determine data flow disposition. Therefore, it does not anticipate claims 1 or 7.

4. US5307353A

• Full Citation: US5307353A, "Fault recovery system of a ring network", assigned to Fujitsu Limited, published April 26, 1994.
• Publication/Filing Date: Filing Date: May 9, 1990; Publication Date: April 26, 1994.
• Prior Art Status: This patent has a filing date (May 9, 1990) and publication date (Apr 26, 1994) prior to US7061859's filing date (Aug 30, 2001), making it valid prior art.
• Brief Description: This patent describes a fault recovery system for a ring network that involves detecting a fault and using a loop-back switch to bypass the failed section. It describes using a control signal to perform the switching. While it addresses fault recovery in a ring network, the mechanism is based on loop-back switching triggered by fault detection, not on mask-based path determination.
• Potential Claim(s) Anticipated (35 U.S.C. § 102):
  • Independent Claims 1 & 7: This patent teaches a fault recovery system using loop-back switching in a ring network. It lacks the core elements of US7061859's independent claims, specifically the construction of distinct "general" and "specific" segment masks, their bitmap representation, and the superposition (e.g., Boolean operation) to determine data flow disposition (convey, steer, or stop).

5. US6820210B1

• Full Citation: US6820210B1, "System and method for fault recovery for a two line bi-directional ring network", assigned to Cisco Technology, Inc., published November 16, 2004.
• Publication/Filing Date: Filing Date: April 27, 1998; Publication Date: November 16, 2004.
• Prior Art Status: This patent has a filing date (Apr 27, 1998) prior to US7061859's filing date (Aug 30, 2001), making it valid prior art.
• Brief Description: This patent describes a fault recovery system for a bidirectional ring network where nodes maintain a routing table for primary and secondary paths. Upon detection of a fault, the node switches traffic from the failed path to a standby protection path (secondary path). It mentions a routing information field that can indicate status. While it addresses fault recovery in bidirectional rings and uses routing information, it doesn't describe the specific mask-based approach of US7061859.
• Potential Claim(s) Anticipated (35 U.S.C. § 102):
  • Independent Claims 1 & 7: This patent describes fault recovery using routing tables and switching to secondary paths in a bidirectional ring. While functionally similar in its goal of fault protection, its technical implementation does not align with the specific mask-based method claimed in US7061859. It does not disclose constructing a general mask of unreachable segments and a specific mask of the flow's desired path as bitmaps, nor the superimposing of these two masks to determine the three-fold disposition of the data flow.

Conclusion on Anticipation:

Based on the analysis of these selected prior art patents, none of them appear to directly anticipate the specific combination of features recited in independent claims 1 and 7 of US7061859. The novelty of US7061859 appears to reside in the specific mask-based approach where:

1. A "general mask" (preferably bitmap) is constructed to indicate unreachable segments due to a fault.
2. A "specific mask" (preferably bitmap) is constructed for each data flow to indicate its desired path.
3. These two distinct masks are "superimposed" (e.g., via a Boolean operation) to rapidly determine one of three specific dispositions for the data flow: convey over the desired path, steer over an alternative path, or stop conveying.

While the cited prior art generally addresses fault recovery or protection in ring networks, they do not disclose this particular mask-based methodology and device for making rapid, optimized decisions for individual data flows.