Address resolution using multiple designated instances of a logical router
A logical routing element (LRE) having multiple designated instances for routing packets from physical hosts (PH) to a logical network is provided. A PH in a network segment with multiple designated instances can choose among the multiple designated instances for sending network traffic to other network nodes in the logical network according to a load balancing algorithm. Each logical interface (LIF) of an LRE is defined to be addressable by multiple identifiers or addresses, and each LIF identifier or address is assigned to a different designated instance.
1. A non-transitory machine readable medium storing a program for operating a logical network in a network that comprises a plurality of host computers, the program for execution on a particular host computer, the program comprising sets of instructions for:
with a particular managed physical routing element (MPRE) executing on the particular host computer, implementing a logical routing element (LRE) along with a plurality of other MPREs executing on a plurality of other host computers; and
configuring the particular MPRE on the particular host (1) to respond to address resolution protocol (ARP) messages sent by a set of physical machines that are external to the particular host computer and (2) to perform logical L 3 routing on data packets from the set of physical machines for data compute machines executing on the particular host computer.
2. The non-transitory machine readable medium of claim 1 , wherein each MPRE of a plurality of MPREs on a plurality of host computers is assigned a different IP address for responding to the ARP messages querying for its assigned IP address.
3. The non-transitory machine readable medium of claim 2 , wherein each of the plurality of MPREs responds to an ARP message by resolving its assigned IP address to its own MAC address.
4. The non-transitory machine readable medium of claim 1 , wherein the different IP addresses assigned to the MPREs in the subset belong to a same network segment.
5. The non-transitory machine readable medium of claim 4 , wherein the network segment corresponds to an overlay encapsulation network.
6. The non-transitory machine readable medium of claim 4 , wherein the network segment comprises a plurality of IP subnets.
7. The non-transitory machine readable medium of claim 4 , wherein the different IP addresses belong to at least two different IP subnets.
8. The non-transitory machine readable medium of claim 1 , wherein the MPRE of each host computer performs logical L 3 routing on data packets for the data compute machines executing on its host computer to the set of physical machines.
9. A method of operating a logical network in a network that comprises a plurality of host computers, the method comprising:
with a particular managed physical routing element (MPRE) executing on a particular host computer, implementing a logical routing element (LRE) along with a plurality of other MPREs executing on a plurality of other host computers; and
configuring the particular MPRE on the particular host (1) to respond to address resolution protocol (ARP) messages sent by a set of physical machines that are external to the particular host computer and (2) to perform logical L 3 routing on data packets from the set of physical machines for data compute machines executing on the particular host computer.
10. The method of claim 9 , wherein each MPRE of a plurality of MPREs on a plurality of host computers is assigned a different IP address for responding to the ARP messages querying for its assigned IP address.
11. The method of claim 10 , wherein each of the plurality of MPREs responds to an ARP message by resolving its assigned IP address to its own MAC address.
12. The method of claim 9 , wherein the different IP addresses assigned to the MPREs in the subset belong to a same network segment.
13. The method of claim 12 , wherein the network segment corresponds to an overlay encapsulation network.
14. The method of claim 12 , wherein the network segment comprises a plurality of IP subnets.
15. The method of claim 12 , wherein the different IP addresses belong to at least two different IP subnets.
16. The method of claim 9 , wherein the MPRE of each host computer performs logical L 3 routing on data packets for the data compute machines executing on its host computer to the set of physical machines.