Residence time measurement for optimizing network services

1. A method of packet communication, comprising:

determining, for a packet, a service function path comprising a set of one or more service functions (SFs) mapped to a service function forwarder (SFF);

encapsulating the packet in a header;

including a value in a mark field included in the header due to receiving information indicative of a requested residence time measurement for the packet, wherein the residence time provides information about time spend by the packet in each SF, and wherein the mark field indicates that the residence time measurement is requested;

inspecting, by the SFF, the mark field corresponding to the packet;

reading, based on the inspecting and for each SF associated with the SFF, a first clock value as the packet is passed thereto;

reading, based on the inspecting and for each SF associated with the SFF, a second clock value as the packet is received therefrom; and

calculating, by the SFF, the residence time measurement of the packet in each SF as a function of the first clock value and the second clock value.

2. The method of claim 1 , wherein the SFF calculates for each of the one or more SFs the residence time measurement of the packet by subtracting the first clock value from the second clock value.

3. The method of claim 1 , wherein the SFF sends to a pre-defined data collector the calculated residence time measurement of the packet, a description of each of the one or more SFs, a sequence number, and a timestamp.

4. The method of claim 1 , wherein the first clock value and the second clock value are read by the SFF from a wall clock.

5. The method of claim 1 , wherein the header is a network service header (NSH).

6. The method of claim 5 , wherein the mark field is located in the NSH.

7. The method of claim 1 , further comprising:

marking the packet;

sending the packet with the marking from a Classifier to the SFF.

8. The method of claim 1 , wherein

the service function path comprising a second set of one or more service functions (SFs) mapped to a second service function forwarder (SFF), and

the residence time measurement of the packet for each of the second set of one or more service functions (SFs) is calculated by:

inspecting, by the second SFF, the mark field corresponding to the packet;

reading, for each SF associated with the second SFF, the first clock value as the packet is passed thereto;

reading, for each SF associated with the second SFF, the second clock value as the packet is received therefrom; and

calculating, by the second SFF, the residence time measurement of the packet in each SF as a function of the first clock value and the second clock value.

9. The method of claim 8 , wherein the second SFF calculates for each of the second set of the one or more SFs the residence time measurement of the packet by subtracting the first clock value from the second clock value.

10. The method of claim 8 , wherein the first clock value and the second clock value are read by the second SFF from a wall clock.

11. The method of claim 8 , wherein the mark field is located in a network service header (NSH).

12. A method of packet communication, comprising:

determining, for a packet, a service function path comprising a set of one or more service functions (SFs) mapped to a service function forwarder (SFF), wherein each SF is associated with a corresponding Virtual Network Function (VNF);

encapsulating the packet in a header;

including a value in a mark field included in the header due to receiving information indicative of a requested residence time measurement for the packet, wherein the residence time provides information about time spend by the packet in each VNF, and wherein the mark field indicates that the residence time measurement is requested;

inspecting, by the SFF, the mark field corresponding to the packet;

reading, based on the inspecting and by each SF, a first clock value as the packet is passed to the VNF;

reading, based on the inspecting and by each SF, a second clock value as the packet is received from the VNF; and

calculating, by each SF, the residence time measurement of the packet in the VNF corresponding to each SF as a function of the first clock value and the second clock value.

13. The method of claim 12 , wherein the SF calculates the residence time measurement of the packet in the VNF corresponding to the SF by subtracting the first clock value from the second clock value.

14. The method of claim 12 , further comprising:

sending, from the SF to the SFF associated with the SF, the residence time measurement of the packet in the VNF corresponding to each SF; and

sending, from the SFF to a pre-defined data collector, the calculated residence time measurement of the packet, a description of the SF, a sequence number, and a timestamp.

15. The method of claim 12 , wherein the first clock value and the second clock value are read by the SF from a wall clock.

16. The method of claim 12 , wherein the header is a network service header (NSH).

17. The method of claim 16 , wherein the mark field located in the network service header (NSH).

18. The method of claim 12 , further comprising:

marking the packet; and

sending the packet with the marking from a Classifier to the SFF.

19. A packet communication system, comprising:

one or more computing devices comprising one or more processors configured to perform the operations of:

including a value in a mark field included in a header of a packet due to receiving information indicative of a requested residence time measurement for the packet, wherein the residence time provides information about time spend by the packet in a first network function, and wherein the mark field indicates that the residence time measurement is requested;

inspecting, by a service function forwarder (SFF), the mark field corresponding to the packet;

reading, based on the inspecting and by a second network function, a first clock value as the packet is passed to the first network function;

reading, based on the inspecting and by the second network function, a second clock value as the packet is received from the first network function; and

calculating, by the second network function, the residence time measurement of the packet in the first network function as a function of the first clock value and the second clock value.

20. The system of claim 19 , wherein the first network function is a service function (SF) and the second network function is the SFF.

21. The system of claim 20 , wherein the SFF calculates for each of the one or more SFs the residence time measurement of the packet by subtracting the first clock value from the second clock value.

22. The system of claim 19 , wherein the first network function is a virtual network function (VNF) and the second network function is a service function (SF).

23. The system of claim 22 , wherein the SF calculates the residence time measurement of the packet in the VNF corresponding to the SF by subtracting the first clock value from the second clock value.

24. The system of claim 19 , wherein the mark field is located in a network service header (NSH).

25. The system of claim 19 , wherein the first clock value and the second clock value are wall clock values.