Systems and method for using DCI-ESI to build highly scalable EVPN DCI networks

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.

2. The method of claim 1 , wherein the second gateway device does not locally install the MAC address.

3. 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.

4. 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.

5. 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.

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.

7. The method of claim 6 , wherein the second gateway device is configured not to install the received MAC address.

8. 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.

9. 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.

10. 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.

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.

12. The system of claim 11 , wherein the second gateway device is configured not to locally install the MAC address.

13. 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.

14. 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.

15. 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.

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.

17. The system of claim 16 , wherein the second gateway device is configured not to install the received MAC address.

18. 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.

19. 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.

20. 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.