# US 11,121,961 B2 · Systems and methods for determining secure network elements using flexible algorithm technology > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,121,961 B2 - Document ID: US11121961B2 - Status: Granted - Kind: B2 - Application number: 16/598,852 - Filed: 2019-10-10 - Published: 2020-10-08 - Granted: 2021-09-14 - Earliest claimed: 2019-04-04 - Assignees: Cisco Technology, Inc. - Applicants: Cisco Technology, Inc. - Inventors: Peter Psenak; Paul William Wells; Ketan Jivan Talaulikar; Clarence Filsfils - Web page: https://patentgrep.com/patent/US11121961B2 ## CPC - H04L 45/127: {based on intermediate node capabilities} - H04L 63/18: {using different networks or channels, e.g. using out of band channels (cryptographic mechanisms or cryptographic arrangements for key distribution involving distinctive intermediate devices or communication paths H04L9/0827; cryptographic mechanisms or cryptographic arrangements for authentication using a plurality of channels H04L9/3215)} - H04L 63/105: {Multiple levels of security} - H04L 63/205: {involving negotiation or determination of the one or more network security mechanisms to be used, e.g. by negotiation between the client and the server or between peers or by selection according to the capabilities of the entities involved (negotiation of communication capabilities H04L69/24)} - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract In one embodiment, an apparatus includes one or more processors and one or more computer-readable non-transitory storage media coupled to the one or more processors. The one or more computer-readable non-transitory storage media include instructions that, when executed by the one or more processors, cause the apparatus to perform operations including receiving a first type-length-value (TLV) associated with a winning flexible algorithm definition (FAD) from a first element of a network. The operations also include determining a security level for the winning FAD based on the TLV. The operations further include determining a data transmission route through a plurality of elements of the network based on the security level for the winning FAD. ## Claims ### Claim 1 An apparatus, comprising: one or more processors; and one or more computer-readable non-transitory storage media coupled to the one or more processors and comprising instructions that, when executed by the one or more processors, cause the apparatus to perform operations comprising: receiving a first type-length-value (TLV) associated with a winning flexible algorithm definition (FAD) from a first element of a network; determining a security level for the winning FAD based on the TLV; determining a data transmission route through a plurality of elements of the network based on the security level for the winning FAD; determining that a second element of the network did not advertise an attestation sub-TLV; and excluding the second element from the plurality of elements of the data transmission route. ### Claim 2 (depends on 1) The apparatus of claim 1, wherein the second element is a router. ### Claim 3 (depends on 1) The apparatus of claim 1, the operations further comprising: determining that a third element of the network was advertised without a security-level sub-TLV; and excluding the third element from the plurality of elements of the data transmission route, wherein the third element is a link between two nodes of the network. ### Claim 4 (depends on 1) The apparatus of claim 1, the operations further comprising: determining that a prefix of the network was advertised without a security-level sub-TLV; and excluding the prefix when determining the data transmission route through the plurality of elements of the network. ### Claim 5 (depends on 1) The apparatus of claim 1, the operations further comprising: receiving a second TLV associated with the winning FAD from a third element of the network; determining a security level for the third element of the network based on the second TLV; determining that the security level of the third element of the network is lower than the security level of the winning FAD; and excluding the third element when determining the data transmission route through the plurality of elements of the network, wherein the third element is one of the following: a link; or a prefix. ### Claim 6 (depends on 1) The apparatus of claim 1, wherein the TLV is an Intermediate System to Intermediate System (ISIS) FAD sub-TLV. ### Claim 7 (depends on 1) The apparatus of claim 1, wherein the TLV is an Open Shortest Path First (OSPF) FAD TLV. ### Claim 8 A method, comprising: receiving a first type-length-value (TLV) associated with a winning flexible algorithm definition (FAD) from a first element of a network; determining a security level for the winning FAD based on the TLV; determining a data transmission route through a plurality of elements of the network based on the security level for the winning FAD; determining that a second element of the network did not advertise an attestation sub-TLV; and excluding the second element from the plurality of elements of the data transmission route. ### Claim 9 (depends on 8) The method of claim 8, wherein the second element is a router. ### Claim 10 (depends on 8) The method of claim 8, further comprising: determining that a third element of the network was advertised without a security-level sub-TLV; and excluding the third element from the plurality of elements of the data transmission route, wherein the third element is a link between two nodes of the network. ### Claim 11 (depends on 8) The method of claim 8, further comprising: determining that a prefix of the network was advertised without a security-level sub-TLV; and excluding the prefix when determining the data transmission route through the plurality of elements of the network. ### Claim 12 (depends on 8) The method of claim 8, further comprising: receiving a second TLV associated with the winning FAD from a third element of the network; determining a security level for the third element of the network based on the second TLV; determining that the security level of the third element of the network is lower than the security level of the winning FAD; and excluding the third element when determining the data transmission route through the plurality of elements of the network, wherein the third element is one of the following: a link; or a prefix. ### Claim 13 (depends on 8) The method of claim 8, wherein the TLV is an Intermediate System to Intermediate System (ISIS) FAD Sub-TLV. ### Claim 14 (depends on 8) The method of claim 8, wherein the TLV is an Open Shortest Path First (OSPF) FAD TLV. ### Claim 15 One or more computer-readable non-transitory storage media embodying instructions that, when executed by a processor, cause the processor to perform operations comprising: receiving a first type-length-value (TLV) associated with a winning flexible algorithm definition (FAD) from a first element of a network; determining a security level for the winning FAD based on the TLV; determining a data transmission route through a plurality of elements of the network based on the security level for the winning FAD; determining that a second element of the network did not advertise an attestation sub-TLV; and excluding the second element from the plurality of elements of the data transmission route. ### Claim 16 (depends on 15) The one or more computer-readable non-transitory storage media of claim 15, wherein the second element is a router. ### Claim 17 (depends on 15) The one or more computer-readable non-transitory storage media of claim 15, the operations further comprising: determining that a third element of the network was advertised without a security-level sub-TLV; and excluding the third element from the plurality of elements of the data transmission route, wherein the third element is a link between two nodes of the network. ### Claim 18 (depends on 15) The one or more computer-readable non-transitory storage media of claim 15, the operations further comprising: determining that a prefix of the network was advertised without a security-level sub-TLV; and excluding the prefix when determining the data transmission route through the plurality of elements of the network. ### Claim 19 (depends on 15) The one or more computer-readable non-transitory storage media of claim 15, the operations further comprising: receiving a second TLV associated with the winning FAD from a third element of the network; determining a security level for the third element of the network based on the second TLV; determining that the security level of the third element of the network is lower than the security level of the winning FAD; and excluding the third element when determining the data transmission route through the plurality of elements of the network, wherein the third element is one of the following: a link; or a prefix. ### Claim 20 (depends on 15) The one or more computer-readable non-transitory storage media of claim 15, wherein the TLV is one of the following: an Intermediate System to Intermediate System (ISIS) FAD Sub-TLV; or an Open Shortest Path First (OSPF) FAD TLV.