Flow-Based Host Discovery In SDN Networks

• US 20170118128A1
• Filed: 08/10/2016
• Published: 04/27/2017
• Est. Priority Date: 10/27/2015
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Brocade Communications Systems, Inc. (Broadcom, Inc.)
• Inventors: Varadaraju, Balaji, Vishnoi, Anil, Srinivasan, Vasu
• Granted Patent: US 10,447,605 B2
• Time in Patent Office: Days
• CPC Class Codes: H04L 41/12 Discovery or management of network topologies
• CPC Class Codes: H04L 41/122 of virtualised topologies, e.g. software-defined networks [SDN] or network function virtualisation [NFV]
• CPC Class Codes: H04L 45/02 Topology update or discovery
• CPC Class Codes: H04L 47/2483 involving identification of individual flows

Abstract

Techniques for performing flow-based host discovery in an SDN network are provided. According to one embodiment, an SDN controller can select, based on network topology information that is stored on the controller, a leaf network device in the network, and can determine a traffic flow corresponding to a flow rule installed on the leaf network device. The determining of the traffic flow can be based on flow rule information that is stored on the SDN controller. The SDN controller can further determine a forward path for the traffic flow through the network, where the determining of the forward path is performed by associating the flow rule with other flow rules for the traffic flow that are included in the flow rule information, and where the other flow rules are installed on other network devices in the network. The SDN controller can then determine, based on at least the forward path, host information for the source and destination hosts of the traffic flow.

Claims

1. A method comprising:

selecting, by a software-defined networking (SDN) controller, a leaf network device in a network, the selecting being based on network topology information that is stored on the SDN controller;

determining, by the SDN controller, a traffic flow corresponding to a flow rule installed on the leaf network device, the traffic flow originating at a source host and ending at a destination host, the determining of the traffic flow being based on flow rule information that is stored on the SDN controller;

determining, by the SDN controller, a forward path for the traffic flow through the network, the determining of the forward path being performed by associating the flow rule with other flow rules for the traffic flow that are included in the flow rule information, the other flow rules being installed on other network devices in the network; and

determining, by the SDN controller, host information for the source host and the destination host based on at least the forward path.

2. The method of claim 1 wherein the network is proactively configured.

3. The method of claim 1 wherein the leaf network device is selected at random.

4. The method of claim 1 wherein the SDN controller selects the flow rule based on one or more criteria that are applied to one or more match parameters of the flow rule.

5. The method of claim 4 wherein the one or more criteria include a criterion that indicates the one or more match parameters should include:

a parameter for matching a source IP address of an incoming packet with an IP address of the source host; and

a parameter for matching a destination IP address of an incoming packet with an IP address of the destination host.

6. The method of claim 4 wherein the one or more criteria includes a criterion that indicates the one or more match parameters should include:

a parameter for matching a source MAC address of an incoming packet with a MAC address of the source host; and

a parameter for matching a destination MAC address of an incoming packet with a MAC address of the destination host.

7. The method of claim 4 wherein the one or more criteria includes a criterion that indicates the one or more match parameters should include a parameter for matching a destination IP address of an incoming packet with an IP address of the destination host.

8. The method of claim 4 wherein the one or more criteria includes a criterion that indicates the one or more match parameters should include a parameter for matching a destination MAC address of an incoming packet with a MAC address of the destination host.

9. The method of claim 4 wherein the SDN controller further selects the flow rule based on whether a flow counter for the flow rule that is locally stored on the SDN controller is determined to be increasing.

10. The method of claim 1 wherein the determining of the forward path allows the SDN controller to identify the last network device in the forward path and an output port of the last network device to which the destination host is connected.

11. The method of claim 1 further comprising:

determining a reverse path for the traffic flow through the network, the determining of the reverse path being performed by associating the flow rule with other flow rules included in the flow rule information that correspond to a reversed version of the traffic flow.

12. The method of claim 11 wherein the determining of the reverse path allows the SDN controller to identify the first network device in the forward path and an output port of the first network device to which the source host is connected.

13. The method of claim 1 wherein associating the flow rule with other flow rules for the traffic flow that are included in the flow rule information comprises:

determining, based on an action configured in the flow rule, an output port of the leaf network device through which the traffic flow should be forwarded; and

determining, based on the output port and the network topology information, whether a next hop for the traffic flow is another network device in the network.

14. The method of claim 13 wherein associating the flow rule with other flow rules for the traffic flow that are included in the flow rule information further comprises, if the next hop for the traffic flow is another network device:

selecting, based on the flow rule information, a flow rule installed on the another network device that corresponds to the traffic flow from the source host to the destination host; and

determining, based on an action configured in the flow rule installed on the another network device, an output port of the another network device through which the traffic flow should be forwarded; and

determining, based on the output port of the another network device and the network topology information, whether a next hop for the traffic flow is yet another network device in the network.

15. The method of claim 13 wherein associating the flow rule with other flow rules for the traffic flow that are included in the flow rule information further comprises, if the next hop for the traffic flow is not another network device:

concluding that the leaf network device is the last network device in the forward path; and

identifying the destination host as being connected to the output port.

16. The method of claim 1 further comprising, upon determining the host information for the source host and the destination host:

identifying, based on the flow rule information, a flow rule installed on a first network device of the traffic flow that includes a match parameter for matching a source IP address of an incoming packet with an IP address of the source host;

determining, based on flow counter information stored on the SDN controller, a flow counter for the flow rule; and

verifying that the flow counter is increasing.

17. The method of claim 1 further comprising, upon determining the host information for the source host and the destination host:

identifying, based on the flow rule information, a flow rule installed on a last network device of the traffic flow that includes a match parameter for matching a source IP address of an incoming packet with an IP address of the destination host;

determining, based on flow counter information stored on the SDN controller, a flow counter for the flow rule; and

verifying that the flow counter is increasing.

18. The method claim 1 further comprising:

monitoring a flow counter maintained on the SDN controller that identifies a match count for the traffic flow;

determining whether the flow counter has increased within a user-defined time interval; and

and if the flow counter has not increased within the user-defined time interval, determining that the source host has become inactive.

19. A computer system comprising:

a processor;

a storage component storing topology information for a network and flow rule information including flow rules that have been proactively configured in the network; and

a non-transitory computer readable storage medium having stored thereon program code that, when executed by the processor, cause the processor to;

select a leaf network device in the network, the selecting being based on network topology information that is stored on the SDN controller;

determine a traffic flow corresponding to a flow rule installed on the leaf network device, the traffic flow originating at a source host and ending at a destination host, the determining of the traffic flow being based on the flow rule information;

determine a forward path for the traffic flow through the network, the determining of the forward path being performed by associating the flow rule with other flow rules for the traffic flow that are included in the flow rule information, the other flow rules being installed on other network devices in the network; and

determine host information for the source host and the destination host based on at least the forward path.

20. A non-transitory computer readable medium having stored thereon program code executable by a software-defined networking (SDN) controller, the program code comprising:

code that causes the SDN controller to select a leaf network device in a network, the selecting being based on network topology information that is stored on the SDN controller;

code that causes the SDN controller to determine a traffic flow corresponding to a flow rule installed on the leaf network device, the traffic flow originating at a source host and ending at a destination host, the determining of the traffic flow being based on flow rule information that is stored on the SDN controller;

code that causes the SDN controller to determine a forward path for the traffic flow through the network, the determining of the forward path being performed by associating the flow rule with other flow rules for the traffic flow that are included in the flow rule information, the other flow rules being installed on other network devices in the network; and

code that causes the SDN controller to determine host information for the source host and the destination host based on at least the forward path.