IP-based forwarding of bridged and routed IP packets and unicast ARP

Patent metadata

Field	Value
Publication number	US-10951522-B2
Application number	US-201414301239-A
Country	US
Kind code	B2
Filing date	Jun 10, 2014
Priority date	Nov 5, 2013
Publication date	Mar 16, 2021
Grant date	Mar 16, 2021

Abstract

Disclosed herein are methods of forwarding data over an IP network. The methods may include receiving a packet from a source host connected to the IP network, identifying the IP address of a destination host designated in the packet, determining the location on the IP network where the destination host designated by the packet is connected, without reference to the MAC address specified in the packet, by using location-identification information stored on the IP network, and forwarding the packet to the location on the IP network where the destination host is connected without reference to the MAC address specified in the packet. Also disclosed herein are related network devices implementing such techniques and operations, as well as IP networks which include such network devices.

First claim

The invention claimed is:

1. A method of forwarding data over an internet-protocol (IP) network, the method comprising:
receiving, at a network device, an address resolution protocol (ARP) request packet from a source host connected to the IP network;
identifying an IP address of a destination host designated in the ARP request packet; determining, at the network device, a location on the IP network where the destination host designated by the ARP request packet is connected, without reference to a media access control (MAC) address of the destination host specified in the ARP request packet received from the source host, by using location-identification information locally stored in a database on the network device; and
forwarding the ARP request packet to the location on the IP network, without broadcasting the ARP request packet on the IP network and without referencing the MAC address of the destination host specified in the ARP request packet received from the source host,
wherein,
the database is distributed across multiple network devices including the network device and another network device,
the location on the network is determined from the database after forwarding the ARP request packet to the another network device,
the IP network comprises a leaf-spine network fabric,
the network device is a leaf network device in the leaf-spine network fabric which is an initial network device encountered by the ARP request packet when it reaches the IP network after it issues from the source host,
the location-identification information comprises a list matching one or more host IP addresses with one or more locations on the IP network where the hosts are connected, and
the location on the IP network is determined from the list.

2. The method of claim 1 , wherein the source host is connected to one or more switches and/or routers of the IP network.

3. The method of claim 1 , further comprising:
applying an encapsulation to the ARP request packet; and
removing the encapsulation from the ARP request packet before it reaches the destination host.

4. The method of claim 3 , wherein the encapsulation is virtual extensible local-area network (VXLAN) encapsulation.

5. The method of claim 1 , wherein the network device is a virtual switch device which operates within a virtualization layer running on a physical host, and wherein the source host issuing the ARP request packet operates as a virtual machine within said virtualization layer.

6. The method of claim 1 , wherein the network device is a leaf network device in the leaf-spine network fabric.

7. The method of claim 1 , wherein the database includes the list.

8. The method of claim 1 , wherein:
the location on the IP network is determined from the database before the ARP request packet is forwarded from the network device.

9. The method of claim 1 , wherein:
the location on the IP network is determined from the list before the ARP request packet is forwarded from the initial network device.

10. The method of claim 1 , wherein:
the network device is a leaf network device,
the list is distributed across multiple network devices including the leaf network device and a spine network device; and
the location on the IP network is determined from the list after forwarding the ARP request packet from the leaf network device to the spine network device.

11. The method of claim 10 , wherein the leaf-spine network fabric is deployed in a data center.

12. The method of claim 10 , further comprising:
applying an encapsulation to the ARP request packet; and

removing the encapsulation from the ARP request packet before it reaches the destination host.

13. The method of claim 12 ,
wherein the encapsulation is applied by the initial network device; and
wherein the encapsulation carries a proxy IP address associated with a proxy-function network device.

14. The method of claim 13 , wherein the encapsulation is VXLAN encapsulation.

15. The method of claim 13 , wherein the ARP request packet is forwarded to a third network device which is said location on the IP network where the destination host is connected.

16. The method of claim 15 , wherein the third network device is another leaf network device.

17. The method of claim 15 , wherein the third network device is a virtual switch device which operates within a virtualization layer running on a physical host, and wherein the destination host operates as virtual machine within said virtualization layer.

18. The method of claim 15 ,
wherein the encapsulation is removed from the ARP request packet at the third network device; and
wherein the method further comprises:
labeling the ARP request packet with the MAC address of the destination host, wherein the third network device labels the ARP request packet using a locally stored MAC address; and
forwarding the ARP request packet from the third network device to the destination host.

19. The method of claim 1 , further comprising:
preparing an ARP response packet in reply to the ARP request packet using a locally stored MAC address for the destination host; and
forwarding the ARP response packet to the initial network device encountered by the ARP request packet when it reached the IP network after it issued from the source host.

20. The method of claim 3 , further comprising:
removing the encapsulation from the ARP request packet at a network device which is said location on the IP network where the destination host is connected; and
broadcasting the ARP request packet from the network device which is said location on the IP network where the destination host is connected to the destination host.

21. The method of claim 3 , further comprising:
removing the encapsulation from the ARP request packet which is said location on the IP network where the destination host is connected; and
labeling the ARP request packet with the MAC address of the destination host, wherein the network device which is said location on the IP network where the destination host is connected labels the ARP request packet using a locally stored MAC address; and
forwarding the ARP request packet from the network device to the destination host.

22. The method of claim 19 , wherein the ARP response packet is prepared by a leaf network device connected to the IP network and the destination host.

23. The method of claim 22 , wherein the ARP response packet is prepared in reply to the ARP request packet without notifying a target device.

24. A network device for receiving an address resolution protocol (ARP) request packet from a source host connected to an IP network and forwarding the ARP request packet to a destination host connected to the IP network, said network device comprising:
machine-readable instructions for:
receiving the ARP request packet from the source host connected to said network device;
identifying an IP address of the destination host designated the ARP request packet;
determining a location on the IP network where the destination host designated by the ARP request packet is connected, without reference to a media access control (MAC) address of the destination host specified in the ARP request packet received from the source host, via look-up of a destination IP address in a list of location-identification information locally stored in a database on the network device; and
forwarding the ARP request packet to another network device without broadcasting the AR

Assignees

• Cisco Tech Inc

Inventors

• Merchant Sameer
• Edsall Thomas James
• Yadav Navindra

Classifications

• H04L61/103

  across network layers, e.g. resolution of network layer into physical layer addresses or address resolution protocol [ARP] · CPC title

• H04L45/74 Primary

  Address processing for routing · CPC title