# US 11,451,634 B2 · Systems and method for using DCI-ESI to build highly scalable EVPN DCI networks > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,451,634 B2 - Document ID: US11451634B2 - Status: Granted - Kind: B2 - Application number: 17/097,925 - Filed: 2020-11-13 - Published: 2022-05-12 - Granted: 2022-09-20 - Earliest claimed: 2020-11-13 - Assignees: Arista Networks, Inc. - Applicants: Arista Networks, Inc. - Inventors: Amit Ranpise; Rajesh Semwal; Isidoros Kouvelas - Web page: https://patentgrep.com/patent/US11451634B2 ## CPC - H04L 67/141: Setup of application sessions (admission control or resource allocation in data switching networks H04L47/70) - H04L 12/4641: {Virtual LANs, VLANs, e.g. virtual private networks [VPN] (LAN interconnection over a bridge based backbone H04L12/462; encapsulation techniques H04L12/4633; routing of packets H04L45/00; packet switches H04L49/00; virtual private networks for security H04L63/0272)} - H04L 12/66: Arrangements for connecting between networks having differing types of switching systems, e.g. gateways - H04L 45/74: Address processing for routing - H04L 61/103: across network layers, e.g. resolution of network layer into physical layer addresses or address resolution protocol [ARP] - H04L 61/50: Address allocation - H04L 67/10: in which an application is distributed across nodes in the network (software deployment G06F8/60; multiprogramming arrangements G06F9/46) - H04L 67/2876: Pairs of inter-processing entities at each side of the network, e.g. split proxies - H04L 67/56: Provisioning of proxy services (store-and-forward switching systems in data switching networks H04L12/54) - H04L 67/563: Data redirection of data network streams - H04L 2101/622: Layer-2 addresses, e.g. medium access control [MAC] addresses - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract Techniques disclosed herein provide a method for configuring a network in DCI environment. An EVPN session is established between a first gateway device of a first network, and a second gateway device of a second network that are linked by L2 DCI link. An ESI is allocated for that EVPN session. A label is created for every combination of the ESI and media access control virtual routing and forwarding table (MAC VRF) that is locally configured at the first gateway device. An EVPN path is received for a host in the first network that is associated with MAC VRF. The path in imported the first MAC VRF by the first gateway device and exported via the inter-DCI EVPN session. The second gateway device identifies a label for MAC and re-exports it in local EVPN session with the identified label. ## Claims ### Claim 1 A method for forwarding traffic, the method comprising: establishing an ethernet virtual private network (EVPN) session between a first gateway device of a first network in a first datacenter, and a second gateway device of a second network in a second datacenter, wherein the first gateway device and the second device are connected by a layer 2 datacenter interconnect link; allocating an ethernet segment identifier (ESI) for the EVPN session; generating a label for every combination of the ESI and media access control virtual routing and forwarding table (MAC VRF) that is locally configured at the first gateway device; receiving, at the first gateway device, an EVPN path for a host in the first network, wherein the host has a MAC address associated with a first MAC VRF; importing, at the first gateway device, the path in the first MAC VRF; exporting the MAC address via the EVPN session between the first gateway device of the first network and the second gateway device of the second network; importing, at the second gateway device, the exported MAC address; identifying a label that corresponds to the ESI of the EVPN session on which the MAC address was received and the MAC VRF of the MAC address; exporting, by the second gateway device, the MAC address into an EVPN session of the second network, with the identified label. ### Claim 2 (depends on 1) The method of claim 1, wherein the second gateway device does not locally install the MAC address. ### Claim 3 (depends on 1) The method of claim 1, wherein each label for combination of the ESI and MAC VRF is also associated with a corresponding combination of a layer 2 datacenter interconnect link and a VLAN identifier. ### Claim 4 (depends on 3) The method of claim 3, further comprising: receiving, at the second gateway device, a packet addressed to the MAC address of the host in the first network from a device in the second network; identifying, at the second gateway device, a destination layer 2 datacenter interconnect link and a destination VLAN identifier based on the label of the packet; and bridging the packet along the identified destination layer 2 datacenter interconnect link, wherein the bridged packet includes the VLAN identifier. ### Claim 5 (depends on 4) The method of claim 4, further comprising: receiving, at the first gateway device, a packet addressed to the MAC address of the host in the first network via the layer 2 datacenter interconnect link; and bridging the packet to the destination MAC address using a bridging table identified by the VLAN identifier. ### Claim 6 A method for forwarding traffic, the method comprising: receiving, at a first gateway device of a first network, an EVPN path for a host in the first network, wherein the host has a MAC address associated with a first MAC VRF; importing, at the first gateway device, the path in the first MAC VRF; exporting the MAC address via an EVPN session that was previously established between the first gateway device of the first network and a second gateway device of a second network, wherein: the MAC address is further configured to be exported into a local EVPN session of the second network, with a pre-configured label that corresponds to a combination of an ESI of the EVPN session and the MAC VRF of the MAC address; and the MAC address is configured to be imported by the second gateway device. ### Claim 7 (depends on 6) The method of claim 6, wherein the second gateway device is configured not to install the received MAC address. ### Claim 8 (depends on 6) The method of claim 6, wherein the second gateway device is configured to install in its hardware a local label associated with a combination of a layer 2 link and a VLAN identifier that is associated with the ESI of the EVPN session and the MAC VRF of the MAC address. ### Claim 9 (depends on 8) The method of claim 8, further comprising: receiving, via the layer 2 link, a packet addressed to the MAC address of the host in the first network; and bridging the packet to a destination MAC address using a bridging table identified by the VLAN identifier. ### Claim 10 (depends on 9) The method of claim 9, wherein the second gateway device is configured to bridge a packet received via the EVPN session that was previously established between the first gateway device of the first network and a second gateway device of a second network using the combination of a layer 2 link identifier and a VLAN identifier. ### Claim 11 A system for forwarding traffic, the system comprising: control circuitry of a first gateway device configured to: establishing an ethernet virtual private network (EVPN) session between the first gateway device of a first network in a first datacenter, and a second gateway device of a second network in a second datacenter, wherein the first gateway device and the second device are connected by a layer 2 datacenter interconnect link; allocate an ethernet segment identifier (ESI) for the EVPN session; generate a label for every combination of the ESI and media access control virtual routing and forwarding table (MAC VRF) that is locally configured at the first gateway device; input/output circuitry of the first gateway device configured to: receive an EVPN path for a host in the first network, wherein the host has a MAC address associated with a first MAC VRF; wherein the control circuitry of the first gateway device if further configured to: importing the path in the first MAC VRF on the first gateway device; and export the MAC address via the EVPN session between the first gateway device of the first network and the second gateway device of the second network; and control circuitry of the second gateway device configured to: import the exported MAC address; identify a label that corresponds to the ESI of the EVPN session on which the MAC address was received and the MAC VRF of the MAC address; and export the MAC address into an EVPN session of the second network, with the identified label. ### Claim 12 (depends on 11) The system of claim 11, wherein the second gateway device is configured not to locally install the MAC address. ### Claim 13 (depends on 11) The system of claim 11, wherein each label for combination of the ESI and MAC VRF is also associated with a corresponding combination of a layer 2 datacenter interconnect link and a VLAN identifier. ### Claim 14 (depends on 13) The system of claim 13, wherein the control circuitry of the second gateway device is further configured to: receive a packet addressed to the MAC address of the host in the first network from a device in the second network; identify a destination layer 2 datacenter interconnect link and a destination VLAN identifier based on the label of the packet; and bridge the packet along the identified destination layer 2 datacenter interconnect link, wherein the bridged packet includes the VLAN identifier. ### Claim 15 (depends on 14) The system of claim 14, wherein the control circuitry of the first gateway device is further configured to: receive a packet addressed to the MAC address of the host in the first network via the layer 2 datacenter interconnect link; and bridge the packet to the destination MAC address using a bridging table identified by the VLAN identifier. ### Claim 16 A system for forwarding traffic, the system comprising: an input/output circuitry of a first gateway device of a first network configured to: receive an EVPN path for a host in the first network, wherein the host has a MAC address associated with a first MAC VRF; and a control circuitry of the first gateway device configured to: importin the path in the first MAC VRF; export the MAC address via an EVPN session that was previously established between the first gateway device of the first network and a second gateway device of a second network, cause the MAC address to be exported into a local EVPN session of the second network, with a pre-configured label that corresponds to a combination of an ESI of the EVPN session and the MAC VRF of the MAC address; and cause the MAC address to be imported by the second gateway device. ### Claim 17 (depends on 16) The system of claim 16, wherein the second gateway device is configured not to install the received MAC address. ### Claim 18 (depends on 16) The system of claim 16, wherein the second gateway device is configured to install in its hardware a local label associated with a combination of a layer 2 link and a VLAN identifier that is associated with the ESI of the EVPN session and the MAC VRF of the MAC address. ### Claim 19 (depends on 18) The system of claim 18, wherein: the control circuitry of the first gateway device is configured to: receive, via the layer 2 link, a packet addressed to the MAC address of the host in the first network; and bridge the packet to a destination MAC address using a bridging table identified by the VLAN identifier. ### Claim 20 (depends on 19) The system of claim 19, wherein control circuitry of the second gateway device is configured to: bridge a packet received via the EVPN session that was previously established between the first gateway device of the first network and a second gateway device of a second network using the combination of a layer 2 link identifier and a VLAN identifier.