Device, system, and method for determining a forwarding delay through a networking device
A device, system, and method determines a forwarding delay through a networking device. The method is performed at the networking device including a transceiver and an always running timer (ART). The method includes generating a first timestamp using a first clock of the transceiver when a packet to be forwarded has been received. The method includes capturing a first ART time corresponding to the first timestamp. The method includes generating a second timestamp using a second clock of the transceiver when the packet to be forwarded has been transmitted. The method includes capturing a second ART time corresponding to the second timestamp. The method includes determining a forwarding delay based on the first and second timestamps and the first and second ART times.
1. A method, comprising:
at a networking device including a transceiver and an always running timer (ART):
generating a first timestamp using a first clock of the transceiver when a packet to be forwarded has been received;
capturing a first ART time corresponding to the first timestamp;
generating a second timestamp using a second clock of the transceiver when the packet to be forwarded has been transmitted;
capturing a second ART time corresponding to the second timestamp; and
determining a forwarding delay based on the first and second timestamps and the first and second ART times.
2. The method of claim 1 , further comprising:
determining a first difference between the first and second ART times.
3. The method of claim 2 , further comprising:
determining a second difference between a first clock time of the first clock corresponding to the first timestamp and a second clock time of the second clock corresponding to the second timestamp; and
determining a third difference between the second difference and the first difference.
4. The method of claim 3 , further comprising:
determining a fourth difference between the first timestamp and the second timestamp; and
determining the forwarding delay as a fifth difference between the fourth difference and the third difference.
5. The method of claim 1 , further comprising:
after receiving the packet, placing the packet in an ingress queue.
6. The method of claim 5 , further comprising:
removing the packet from the ingress queue; and
processing the packet for preparation to be transmitted.
7. The method of claim 6 , further comprising:
after processing the packet, placing the packet in an egress queue.
8. The method of claim 5 , wherein the first timestamp and the first ART time correspond to when the packet is placed in the ingress queue.
9. The method of claim 7 , wherein the second timestamp and the second ART time correspond to when the packet leaves the egress queue.
10. The method of claim 1 , wherein the networking device includes a commercial off the shelf network interface card.
11. A networking device, comprising:
a transceiver configured to forward a packet;
a first clock generating a first timestamp when the packet to be forwarded has been received;
a second clock generating a second timestamp when the packet to be forwarded has been transmitted;
an always running timer (ART) capturing a first ART time corresponding to the first timestamp and capturing a second ART time corresponding to the second timestamp; and
a processor determining a forwarding delay based on the first and second timestamps and the first and second ART times.
12. The networking device of claim 11 , wherein the processor further determines a first difference between the first and second ART times.
13. The networking device of claim 12 , wherein the processor further determines a second difference between a first clock time of the first clock corresponding to the first timestamp and a second clock time of the second clock corresponding to the second timestamp, wherein the processor further determines a third difference between the second difference and the first difference.
14. The networking device of claim 13 , wherein the processor further determines a fourth difference between the first timestamp and the second timestamp, wherein the processor further determines the forwarding delay as a fifth difference between the fourth difference and the third difference.
15. The networking device of claim 11 , wherein, after receiving the packet, the processor places the packet in an ingress queue.
16. The networking device of claim 15 , wherein the processor further removes the packet from the ingress queue, wherein the processor further processes the packet for preparation to be transmitted.
17. The networking device of claim 16 , wherein, after processing the packet, the processor places the packet in an egress queue.
18. The networking device of claim 17 , wherein the first timestamp and the first ART time correspond to when the packet is placed in the ingress queue, and wherein the second timestamp and the second ART time correspond to when the packet leaves the egress queue.
19. The networking device of claim 11 , wherein the networking device includes a commercial off the shelf network interface card.
20. A networking device, comprising:
a transceiver configured to forward a packet;
a first clock generating a first timestamp when the packet to be forwarded has been received;
a second clock generating a second timestamp when the packet to be forwarded has been transmitted;
an always running tinier (ART) capturing a first ART time corresponding to the first timestamp and capturing a second ART time corresponding to the second timestamp; and
a processor determining a forwarding delay based on the first and second timestamps and the first and second ART times,
wherein the ART is a modular component coupled to the networking device.