# US 10,313,151 B2 · Enhanced loop-breaking protocol to support connectionless and connection-oriented ethernet > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,313,151 B2 - Document ID: US10313151B2 - Status: Granted - Kind: B2 - Application number: 14/596,896 - Filed: 2015-01-14 - Published: 2016-07-14 - Granted: 2019-06-04 - Earliest claimed: 2015-01-14 - Assignees: Fujitsu Limited - Applicants: Fujitsu Limited - Inventors: Maitreya Mukhopadhyay; Michael Colven; Wenao Hu - Web page: https://patentgrep.com/patent/US10313151B2 ## CPC - H04L 12/462: {LAN interconnection over a bridge based backbone} - H04L 45/18: Loop-free operations - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract A method and system for breaking loops in an Ethernet network that supports connectionless and connection-oriented Ethernet. A loop-breaking protocol may be used to detect a loop among a plurality of network elements and to identify a port to block in order to break the loop. The network elements may stop the flow of connectionless Ethernet traffic, while continuing to allow connection-oriented Ethernet traffic to pass. The loop-breaking protocol may be further configured to analyze and understand connection-oriented Ethernet within the network so that connection-oriented Ethernet paths are accounted for during loop detection and prevention. ## Claims ### Claim 1 A method for breaking loops in an Ethernet network, comprising: using a loop-breaking protocol to select a first port of a network element to block in order to break a network loop among a plurality of network elements that form a network; determining whether traffic egressing from the first port is connectionless Ethernet traffic or connection-oriented Ethernet traffic; blocking connectionless Ethernet traffic at the first port of the network element to break the network loop; while blocking the connectionless Ethernet traffic, permitting connection-oriented Ethernet traffic to pass through the first port of the network element; determining whether a second network loop exists among the plurality of network elements due to a connection-oriented Ethernet link within the plurality of network elements; using the loop-breaking protocol to select a second port to block in order to break the second network loop; blocking the connectionless Ethernet traffic at the second port to break the second network loop; and while blocking the connectionless Ethernet traffic, permitting connection-oriented Ethernet traffic to pass through the second port, wherein the loop-breaking protocol is a spanning tree protocol or an Ethernet Ring Protection Switching protocol. ### Claim 2 (depends on 1) The method of claim 1, wherein the loop-breaking protocol accounts for a connection-oriented Ethernet link within the network in determining whether the network loop exists. ### Claim 3 (depends on 2) The method of claim 2, wherein a starting port and an ending port of a connection-oriented Ethernet link within the network are considered separate ports of the network element by the loop-breaking protocol. ### Claim 4 (depends on 1) The method of claim 1, wherein at least one of a virtual local area network tag, a bit flag, and a protocol extension is used to determine whether Ethernet traffic is connectionless Ethernet traffic or connection-oriented Ethernet traffic. ### Claim 5 A network element in an Ethernet network, comprising: a processor; non-transitory computer readable memory media accessible to the processor, wherein the memory media store processor-executable instructions, the instructions, when executed by the processor, cause the processor to: execute a loop-breaking protocol to select a first port of the network element to block in order to break a network loop among a plurality of network elements that form a network; block the connectionless Ethernet traffic at the first port of the network element to break the network loop; while blocking the connectionless Ethernet traffic, permit a connection-oriented Ethernet traffic to pass through the first port of the network element; analyze a connection-oriented Ethernet link within a plurality of network elements to determine if a second network loop exists among the plurality of network elements; block the connectionless Ethernet traffic at a second port to break the network loop; and while blocking the connectionless Ethernet traffic, permit a connection-oriented Ethernet traffic to pass through the second port, wherein the loop-breaking protocol is a spanning tree protocol or an Ethernet Ring Protection Switching protocol. ### Claim 6 (depends on 5) The network element of claim 5, wherein the loop-breaking protocol accounts for a connection-oriented Ethernet link within the network in determining whether the network loop exists. ### Claim 7 (depends on 6) The network element of claim 6, wherein a starting port and an ending port of a connection-oriented Ethernet link within the network are considered separate ports of the network element by the loop-breaking protocol. ### Claim 8 (depends on 5) The network element of claim 5, wherein at least one of a virtual local area network tag, a bit flag, and a protocol extension is used to determine whether Ethernet traffic is connectionless Ethernet traffic or connection-oriented Ethernet traffic. ### Claim 9 A network system, comprising: a first customer sub-network; a second customer sub-network; a service provider network comprising a plurality of network elements, wherein the service provider network is configured to communicatively couple the first customer sub-network and the second customer sub-network through one or more connectionless Ethernet and connection-oriented Ethernet links across the plurality of network elements; and a network element, among the plurality of network elements, is configured to: execute a loop-breaking protocol to select a port of the network element to block in order to break a network loop among the plurality of network elements of the service provider network; block the connectionless Ethernet traffic at the port of the network element to break the network loop; while blocking the connectionless Ethernet traffic, permit a connection-oriented Ethernet traffic to pass through the port of the network element; analyze a connection-oriented Ethernet link within a plurality of network elements to determine if a second network loop exists among the plurality of network elements; block the connectionless Ethernet traffic at a second port to break the network loop; and while blocking the connectionless Ethernet traffic, permit a connection-oriented Ethernet traffic to pass through the second port, wherein the loop-breaking protocol is a spanning tree protocol or an Ethernet Ring Protection Switching protocol. ### Claim 10 (depends on 9) The network system of claim 9, wherein the loop-breaking protocol accounts for the connection-oriented Ethernet links between the plurality of network elements of the service provider network in determining whether the network loop exists. ### Claim 11 (depends on 9) The network element of claim 9, wherein at least one of a virtual local area network tag, a bit flag, and a protocol extension is used to determine whether Ethernet traffic is connectionless Ethernet traffic or connection-oriented Ethernet traffic.