# US 2013/0279367 A1 · System and Apparatus for Router Advertisement Options for Configuring Networks to Support Multi-Homed Next Hop Routes > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2013/0279367 A1 - Document ID: US20130279367A1 - Status: Published application - Kind: A1 - Application number: 13/866,832 - Filed: 2013-04-19 - Published: 2013-10-24 - Earliest claimed: 2012-04-19 - Assignees: Futurewei Technologies, Inc. - Applicants: Futurewei Technologies, Inc. - Inventors: Behcet Sarikaya - Web page: https://patentgrep.com/patent/US20130279367A1 ## CPC - H04L 45/72: {Routing based on the source address} - H04L 45/741: Routing in networks with a plurality of addressing schemes, e.g. with both IPv4 and IPv6 - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract A network element (NE) comprising a processor configured to receive a Router Solicitation (RS) from a multi-homed host interested in obtaining routing information, and in response to the RS, send the route information to the multi-homed host in a Router Advertisement (RA) message, wherein the route information comprises source address information for the multi-homed host. Also disclosed is a NE comprising a processor configured to receive a RS from a multi-homed host interested in obtaining routing information, and in response to the RS, send the route information to the multi-homed host in a RA message, wherein the route information comprises next hop information for the multi-homed host. ## Claims ### Claim 1 A network element (NE) comprising: a memory; and a processor coupled to the memory and configured to: receive a Router Solicitation (RS) from a multi-homed host interested in obtaining routing information; and in response to the RS, send the route information to the multi-homed host in a Router Advertisement (RA) message, wherein the route information comprises source address information for the multi-homed host. ### Claim 2 (depends on 1) The NE of claim 1, wherein the source address information comprises an Internet Protocol version Six (IPv6) source address. ### Claim 3 (depends on 1) The NE of claim 1, wherein the source address information comprises an Internet Protocol version Six (IPv6) source prefix. ### Claim 4 (depends on 1) The NE of claim 1, wherein the source address information is encoded in the RA message in a Source Address option, and wherein the Source Address option comprises: a Type field that indicates the option is a Source Address option; a Length field that indicates the length of the Source Address option; and a Source Address field that indicates a source address for the multi-homed host. ### Claim 5 (depends on 1) The NE of claim 1, wherein the source address information is encoded in the RA message in a Source Prefix option, and wherein the Source Prefix option comprises: a Type field that indicates the option is a Source Prefix option; a Length field that indicates the length of the Source Prefix option; a Source Prefix field that indicates an IPv6 source prefix for the multi-homed host; and a Prefix Length field that indicates the length of the source prefix. ### Claim 6 (depends on 1) The NE of claim 1, wherein the route information is encoded in the RA message in a Next Hop Address with Source Address and Route Prefix option, and wherein the Next Hop Address with Source Address and Route Prefix option comprises: a Type field that indicates the option is a Next Hop Address with Route Prefix option; a Length field that indicates a length of the Next Hop Address with Route Prefix option; a Next Hop Address field that indicates an address of a next hop node; a Source Address field that indicates a source address for the multi-homed host; a Prf field that indicates whether the host should prefer the NE as a default router over other default routers; a Prefix field that indicates an Internet Protocol version Six (IPv6) destination prefix or IPv6 destination address reachable via the next hop node; a Metric field that indicates whether the host should prefer the next hop node associated with the IPv6 destination prefix or IPv6 destination address over other next hops when multiple identical prefixes for different next hops have been received; a Route Lifetime field that indicates a length of time in seconds that the IPv6 destination prefix or IPv6 destination address is valid for route determination; and a Prefix Length field that indicates a number of leading bits in the prefix field that comprise the prefix. ### Claim 7 A network element (NE) comprising: a memory; and a processor coupled to the memory and configured to: receive a Router Solicitation (RS) from a multi-homed host interested in obtaining routing information; and in response to the RS, send the route information to the multi-homed host in a Router Advertisement (RA) message, wherein the route information comprises next hop information for the multi-homed host. ### Claim 8 (depends on 7) The NE of claim 7, wherein the next hop information comprises an Internet Protocol version Six (IPv6) address of a next hop node. ### Claim 9 (depends on 8) The NE of claim 8, wherein the next hop information is encoded in the RA message in a Next Hop Address option. ### Claim 10 (depends on 9) The NE of claim 9, wherein the Next Hop Address option comprises: a Type field that indicates the option is a Next Hop Address option; a Length field that indicates a length of the Next Hop Address option; and a Next Hop Address field that indicates the next hop information. ### Claim 11 (depends on 9) The NE of claim 9, wherein the RA message further comprises at least one Route Prefix option that indicates an IPv6 destination prefix or IPv6 destination address reachable via a next hop node. ### Claim 12 (depends on 11) The NE of claim 11, wherein the Route Prefix option comprises a Metric field, and wherein the Metric field indicates whether the host should prefer the next hop associated with the IPv6 destination prefix over other next hops when multiple identical prefixes for different next hops have been received. ### Claim 13 (depends on 11) The NE of claim 11, wherein the RA message further comprises at least one Source Address option that represents a source address that is associated with the IPv6 destination prefix which is associated with the next hop node. ### Claim 14 (depends on 7) The NE of claim 7, wherein the route information is encoded in the RA message in a Next Hop Address with Route Prefix option. ### Claim 15 (depends on 14) The NE of claim 14, wherein the Next Hop Address with Route Prefix option comprises: a Type field that indicates the option is a Next Hop Address with Route Prefix option; a Length field that indicates a length of the Next Hop Address with Route Prefix option; a Next Hop Address field that indicates an address of a next hop node; a Prf field that indicates whether the host should prefer the NE as a default router over other default routers; a Prefix field that indicates an Internet Protocol version Six (IPv6) destination prefix or IPv6 destination address reachable via the next hop node; a Metric field that indicates whether the host should prefer the next hop associated with the IPv6 destination prefix or IPv6 destination address over other next hops when multiple identical prefixes for different next hops have been received; a Route Lifetime field that indicates a length of time in seconds that the IPv6 destination prefix or IPv6 destination address is valid for route determination; and a Prefix Length field that indicates a number of leading bits in the prefix field that comprise the prefix. ### Claim 16 (depends on 7) The NE of claim 7, wherein the route information is encoded in the RA message in a Next Hop Address with Source Address and Route Prefix option, and wherein the Next Hop Address with Source Address and Route Prefix option comprises: a Type field that indicates the option is a Next Hop Address with Source Address and Route Prefix option; a Length field that indicates a length of the Next Hop Address with Source Address and Route Prefix option; a Next Hop Address field that indicates an address of a next hop node; a Source Address field that indicates an IPv6 source address for the multi-homed host; a Prf field that indicates whether the host should prefer the NE as a default router over other default routers; a Prefix field that indicates an Internet Protocol version Six (IPv6) destination prefix or IPv6 destination address reachable via the next hop node; a Metric field that indicates whether the host should prefer the next hop associated with the IPv6 destination prefix or IPv6 destination address over other next hops when multiple identical prefixes for different next hops have been received; a Route Lifetime field that indicates a length of time in seconds that the IPv6 destination prefix or IPv6 destination address is valid for route determination; a Prefix Length field that indicates a number of leading bits in the prefix field that comprise the prefix. ### Claim 17 (depends on 7) The NE of claim 7, wherein the route information is encoded in the RA message in a Next Hop Address with Source Prefix and Route Prefix option, and wherein the Next Hop Address with Source Prefix and Route Prefix option comprises: a Type field that indicates the option is a Next Hop Address with Source Prefix and Route Prefix option; a Length field that indicates a length of the Next Hop Address with Source Prefix and Route Prefix option; a Next Hop Address field that indicates an address of a next hop node; a Source Prefix field that indicates an IPv6 source prefix for the multi-homed host; a Prf field that indicates whether the host should prefer the NE as a default router over other default routers; a Prefix field that indicates an Internet Protocol version Six (IPv6) destination prefix or IPv6 destination address reachable via the next hop node; a Metric field that indicates whether the host should prefer the next hop associated with the IPv6 destination prefix or IPv6 destination address over other next hops when multiple identical prefixes for different next hops have been received; a Route Lifetime field that indicates a length of time in seconds that the IPv6 destination prefix or IPv6 destination address is valid for route determination; a Prefix Length field that indicates a number of leading bits in the prefix field that comprise the prefix. ### Claim 18 A method comprising: configuring a multi-homed host with at least one source address derived from an Internet Protocol (IP) address prefix supported by a destination network by transmitting a Router Advertisement (RA) message comprising the source address to the multi-homed host; and performing ingress filtering on messages received from the multi-homed host, wherein ingress filtering comprises dropping messages received from the multi-homed host that do not comprise any source addresses derived from any prefixes supported by the destination network. ### Claim 19 (depends on 18) The method of claim 18, wherein the RA message further comprises an IP address of a next hop node positioned on a route between the multi-homed host and the destination network. ### Claim 20 (depends on 18) The method of claim 18, wherein the RA message further comprises a route prefix that represents an IP prefix of the destination network.