PHYSICAL PATH DETERMINATION FOR VIRTUAL NETWORK PACKET FLOWS

• US 20130332602A1
• Filed: 03/15/2013
• Published: 12/12/2013
• Est. Priority Date: 06/06/2012
• Status: Active Grant

• Current Assignee: Juniper Networks Incorporated
• Original Assignee: Juniper Networks Incorporated
• Inventors: Nakil, Harshad Bhaskar, Singla, Ankur, Reddy, Rajashekar
• Granted Patent: US 8,750,288 B2
• Time in Patent Office: Days
• US Class Current: 709/224
• CPC Class Codes: G06F 11/008 Reliability or availability analysis
• CPC Class Codes: G06N 20/00 Machine learning
• CPC Class Codes: H04L 41/0631 using root cause analysis; using analysis of correlation between notifications, alarms or events based on decision criteria, e.g. hierarchy, tree or time analysis
• CPC Class Codes: H04L 41/122 of virtualised topologies, e.g. software-defined networks [SDN] or network function virtualisation [NFV]
• CPC Class Codes: H04L 41/147 for predicting network behaviour
• CPC Class Codes: H04L 41/40 using virtualisation of network functions or resources, e.g. SDN or NFV entities
• CPC Class Codes: H04L 43/04 Processing captured monitoring data, e.g. for logfile generation
• CPC Class Codes: H04L 43/0852 Delays
• CPC Class Codes: H04L 43/10 Active monitoring, e.g. heartbeat, ping or trace-route
• CPC Class Codes: H04L 43/20 the monitoring system or the monitored elements being virtualised, abstracted or software-defined entities, e.g. SDN or NFV
• CPC Class Codes: H04L 45/16 Multipoint routing
• CPC Class Codes: H04L 45/38 Flow based routing
• CPC Class Codes: H04L 45/42 Centralised routing
• CPC Class Codes: H04L 45/48 Routing tree calculation
• CPC Class Codes: H04L 45/586 of virtual routers
• 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 69/40 for recovering from a failure of a protocol instance or entity, e.g. service redundancy protocols, protocol state redundancy or protocol service redirection management of faults, events, alarms or notifications in data switching networks H04L41/06

Abstract

In general, techniques are described for determining a physical network path taken by packets of a network packet flow. The techniques may be applied to determine, or “trace,” a physical network path in the virtualized network domain. In some examples, a network device includes one or more processors and a switch executed by the processors to forward packets of a packet flow to a physical network path. The network device also includes a flow trace module to generate one or more flow trace packets having incrementally increasing respective time-to-live (TTL) values, wherein the switch module forwards the flow trace packets on an outbound interface of the network device for the physical network path, and wherein the flow trace module receives corresponding time exceeded messages for the flow trace packets, wherein each of the time exceeded message includes a source network address of a network element on the physical network path.

Claims

1. A method for determining a physical network path of a packet flow comprising:

generating, with a network device, one or more flow trace packets having incrementally increasing respective time-to-live (TTL) values;

sending, with the network device, the flow trace packets on an outbound interface of the network device for the physical network path; and

receiving, with the network device, corresponding time exceeded messages for the flow trace packets, wherein each of the time exceeded messages includes a source network address of a network element on the physical network path.

2. The method of claim 1, wherein each of the flow trace packets includes a tunnel header comprising an Internet Protocol (IP) field value that is equivalent to an IP field value of a tunnel header for a packet of the packet flow.

3. The method of claim 1, wherein each of the flow trace packets includes a flow trace packet indicator.

4. The method of claim 3, wherein the flow trace packet indicator is one of a Multiprotocol Label Switching (MPLS) label value or Virtual eXtensible Local Area Network (VxLAN) network identity value that identifies a packet as a flow trace packet.

5. The method of claim 1, further comprising:

receiving, with the network device, a packet;

determining whether the packet is a flow trace packet;

upon determining the packet is a flow trace packet, sending a confirmation message to a network address that is a source network address of the flow trace packet, wherein the confirmation message indicates that the network device is a tunnel endpoint for the packet and that the network device received the packet.

6. The method of claim 5, wherein determining whether the packet is a flow trace packet comprises determining whether the packet includes a flow trace packet indicator.

7. The method of claim 1, further comprising:

receiving, with the network device and from a requesting device, a request to determine the physical network path;

generating a list of the source network addresses received in the time exceeded messages; and

responsive to the request, sending the list to the requesting device.

8. The method of claim 7,

wherein the request includes a destination network address of the packet flow, and

wherein generating the flow trace packets comprises determining the tunnel header using the destination network address and adding the tunnel header as an outer header of each of the flow trace packets.

9. The method of claim 1, further comprising:

receiving, with the network device, a confirmation message that is associated with the flow trace packets and that indicates that a tunnel endpoint for a tunnel that transports the packet flow received one of the flow trace packets; and

responsive to receiving the confirmation message, refraining from generating additional flow trace packets for determining the physical network path of the packet flow.

10. The method of claim 9, wherein the confirmation message comprises an Internet Control Message Protocol (ICMP) Echo Reply message.

11. A network device comprising:

one or more processors;

a switch executed by the processors to forward packets of a packet flow to a physical network path; and

a flow trace module to generate one or more flow trace packets having incrementally increasing respective time-to-live (TTL) values,

wherein the switch module forwards the flow trace packets on an outbound interface of the network device for the physical network path, and

wherein the flow trace module receives corresponding time exceeded messages for the flow trace packets, wherein each of the time exceeded messages includes a source network address of a network element on the physical network path.

12. The network device of claim 11, wherein each of the flow trace packets includes a tunnel header comprising an Internet Protocol (IP) field value that is equivalent to an IP field value of a tunnel header for a packet of the packet flow.

13. The network device of claim 11, wherein each of the flow trace packets includes a flow trace packet indicator.

14. The network device of claim 13, wherein the flow trace packet indicator is one of a Multiprotocol Label Switching (MPLS) label value or Virtual eXtensible Local Area Network (VxLAN) network identity value that identifies a packet as a flow trace packet.

15. The network device of claim 11,

wherein the switch receives a packet,

wherein the switch determines whether the packet is a flow trace packet,

wherein the flow trace module, upon determining the packet is a flow trace packet, sends a confirmation message to network address that is a source network address of the flow trace packet, and

wherein the confirmation message indicates that the network device is a tunnel endpoint for the packet and that the network device received the packet.

16. The network device of claim 15, wherein determining whether the packet is a flow trace packet comprises determining whether the packet includes a flow trace packet indicator.

17. The network device of claim 11,

wherein the flow trace module receives, from a requesting device, a request to determine a physical network path, and

wherein the flow trace module generates a list of the source network addresses received in the time exceeded messages and, responsive to the request, sends the list to the requesting device.

18. The network device of claim 17,

wherein the request includes a destination network address of the packet flow, and

wherein the flow trace module generates the flow trace packets by determining the tunnel header using the destination network address and adding the tunnel header as an outer header of each of the flow trace packets.

19. The network device of claim 11,

wherein the switch receives a confirmation message that is associated with the flow trace packets and that indicates a tunnel endpoint for a tunnel that transports the packet flow received one of the flow trace packets and

wherein the flow trace module, responsive to the switch receiving the confirmation message, refrains from generating additional flow trace packets for determining the physical network path of the packet flow.

20. The network device of claim 19, wherein the confirmation message comprises an Internet Control Message Protocol (ICMP) Echo Reply message.

21. A non-transitory computer-readable medium comprising instructions for causing one or more programmable processors to:

generate, with a network device, one or more flow trace packets having incrementally increasing respective time-to-live (TTL) values;

send, with the network device, the flow trace packets on an outbound interface of the network device for the physical network path;

receive, with the network device, corresponding time exceeded messages for the flow trace packets, wherein each of the time exceeded message includes a source network address of a network element on a physical network path; and

determine, with the network device, the physical network path using the source network addresses of the time exceeded message.