SYSTEM AND METHOD FOR OPTIMIZING WITHIN SUBNET COMMUNICATION IN A NETWORK ENVIRONMENT

• US 20140140244A1
• Filed: 11/20/2012
• Published: 05/22/2014
• Est. Priority Date: 11/20/2012
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Kapadia, Shyam, Ramesh, Chengelpet V., Zhang, Ming
• Granted Patent: US 9,253,140 B2
• Time in Patent Office: Days
• US Class Current: 370/255
• CPC Class Codes: H04L 49/3009 Header conversion, routing tables or routing tags
• CPC Class Codes: H04L 61/103 across network layers, e.g. resolution of network layer into physical layer addresses or address resolution protocol [ARP]
• CPC Class Codes: H04L 61/5046 Resolving address allocation conflicts; Testing of addresses testing when self-assigning an address H04L61/5092

Abstract

A method for optimizing within subnet communication in a network environment is provided and includes receiving, at a Top-Of-Rack (ToR) switch, an advertisement from an attached host belonging to a subnet of a network environment, seeking a Media Access Control (MAC) address of a remote host in the subnet, looking up a host information database in a control plane of the ToR switch, and responding to the advertisement with the MAC address of the remote host. If the MAC address is not found, the ToR switch may not respond to the advertisement. The method can further include receiving, at the ToR switch from a remote ToR switch in the subnet, a host information of the remote host in the subnet, including an IP address and the MAC address of the remote host, the Layer 2 broadcast domain it belongs to, and storing the host information in the host information database.

Claims

1. A method, comprising:

receiving an advertisement from an attached host belonging to a subnet of a network environment, wherein the advertisement seeks a Media Access Control (MAC) address of a remote host in the subnet;

looking up a host information database in a control plane of a Top-Of-Rack (ToR) switch; and

responding to the advertisement with the MAC address of the remote host.

2. The method of claim 1, further comprising:

electing not to respond to the advertisement if the MAC address is not found in the host information database.

3. The method of claim 1, wherein the advertisement comprises an Address Resolution Protocol (ARP)/Neighbor Discovery (ND) request.

4. The method of claim 1, further comprising:

receiving, from a remote ToR switch in the subnet, a host information of the remote host in the subnet, wherein the host information comprises an Internet Protocol (IP) address and the MAC address of the remote host; and

storing the host information in the host information database.

5. The method of claim 4, wherein the host information database is looked up based on at least the IP address of the remote host.

6. The method of claim 4, further comprising:

discovering another host information of the attached host, wherein the another host information comprises another IP address and another MAC address of the attached host;

storing the another host information in the host information database; and

distributing the another host information to the remote ToR switch.

7. The method of claim 6, wherein the another host information is discovered through at least one of the following mechanisms:

Dynamic Host Configuration Protocol (DHCP) snooping, ARP/ND snooping, and Layer 2 learning.

8. The method of claim 1, further comprising:

populating a Layer 2 table in a data plane of the ToR switch with an entry having the MAC address of the remote host;

receiving a data from the attached host destined to the remote host; and

forwarding the data on Layer 2 according to the Layer 2 table.

9. The method of claim 8, wherein the entry is populated in the Layer 2 table before the data is received at the ToR switch.

10. The method of claim 8, further comprising:

removing the entry from the Layer 2 table if the attached host does not converse with the remote host for a predetermined time duration.

11. Logic encoded in non-transitory media that includes instructions for execution and when executed by a processor, is operable to perform operations comprising:

receiving an advertisement from an attached host belonging to a subnet of a network environment, wherein the advertisement seeks a Media Access Control (MAC) address of a remote host in the subnet;

looking up a host information database in a control plane of a Top-Of-Rack (ToR) switch; and

responding to the advertisement with the MAC address of the remote host.

12. The logic of claim 11, the operations further comprising:

electing not to respond to the advertisement if the MAC address is not found in the host information database.

13. The logic of claim 11, the operations further comprising:

receiving, from a remote ToR switch in the subnet, a host information of the remote host in the subnet, wherein the host information comprises an IP address and the MAC address of the remote host; and

storing the host information in the host information database.

14. The logic of claim 13, the operations further comprising:

discovering another host information of the attached host, wherein the another host information comprises another IP address and another MAC address of the attached host;

storing the another host information in the host information database; and

distributing the another host information to the remote ToR switch.

15. The logic of claim 11, the operations further comprising:

populating a Layer 2 table in a data plane of the ToR switch with an entry having the MAC address of the remote host;

receiving a data from the attached host destined to the remote host; and

forwarding the data on Layer 2 according to the Layer 2 table.

16. An apparatus, comprising:

a subnet module;

a memory element for storing data; and

a processor operable to execute instructions associated with the data, wherein the subnet module, the processor and the memory element cooperate, such that the apparatus is configured for;

receiving an advertisement from an attached host belonging to a subnet of a network environment, wherein the advertisement seeks a Media Access Control (MAC) address of a remote host in the subnet;

looking up a host information database in a control plane of a Top-Of-Rack (ToR) switch; and

responding to the advertisement with the MAC address of the remote host.

17. The apparatus of claim 16, further configured for:

electing not to respond to the advertisement if the MAC address is not found in the host information database.

18. The apparatus of claim 16, further configured for:

receiving, from a remote ToR switch in the subnet, a host information of the remote host in the subnet, wherein the host information comprises an IP address and the MAC address of the remote host; and

storing the host information in the host information database.

19. The apparatus of claim 18, further configured for:

discovering another host information of the attached host, wherein the another host information comprises another IP address and another MAC address of the attached host;

storing the another host information in the host information database; and

distributing the another host information to the remote ToR switch.

20. The apparatus of claim 16, further configured for:

populating a Layer 2 table in a data plane of the ToR switch with an entry having the MAC address of the remote host;

receiving a data from the attached host destined to the remote host; and

forwarding the data on Layer 2 according to the Layer 2 table.