Packet interception and timestamping for error estimation in active measurement protocols

A network device, the network device operable to be deployed in a network and coupled with another network device by a link, the network device operable to estimate a time delay between when a software timestamp is generated for an active measurement protocol test packet and when the active measurement protocol test packet is transmitted from the network device onto a link, the network device comprising:

• a network interface;
• an error estimation packet generation module that is operable to generate an error estimation packet;
• a software timestamp generation module that is operable to generate a software timestamp for the error estimation packet;
• a packet interceptor module that is operable to intercept the error estimation packet before it is transmitted from the network interface onto the link;
• an interception timestamp generation module that is operable to generate an interception timestamp for the error estimation packet in response to the interception of the error estimation packet;
• and
• an error estimation module that is operable to estimate the time delay based on a difference between the interception timestamp and the software timestamp.

A method, in a TWAMP sender network device, of estimating a time delay between when a software timestamp is generated for a TWAMP test packet and when the TWAMP test packet is transmitted from the TWAMP sender network device onto a link, the method comprising steps of:

• generating an error estimation packet;
• generating a software timestamp for the error estimation packet;
• transmitting the error estimation packet toward a network interface;
• capturing the error estimation packet before it is transmitted from the network device onto the link, with a packet capture module, based on a source IP address and a source port of the error estimation packet;
• generating an interception timestamp for the error estimation packet in response to intercepting the error estimation packet;
• and
• estimating the time delay based on a difference between the interception timestamp and the software timestamp.

A TWAMP sender network device, the TWAMP sender network device operable to be deployed in a network and coupled with a TWAMP reflector network device by a link, the TWAMP sender network device operable to estimate a time delay between when a software timestamp is generated for a TWAMP test packet and when the TWAMP test packet is transmitted from the TWAMP sender network device onto a link, the TWAMP sender network device comprising:

• a network interface;
• an error estimation packet generation module that is operable to generate an error estimation packet;
• a software timestamp generation module that is operable to generate a software timestamp for the error estimation packet;
• a packet capture module operable to capture the error estimation packet before it is transmitted from the network interface onto the link based on a source IP address and a source port of the error estimation packet;
• an interception timestamp generation module that is operable to generate an interception timestamp for the error estimation packet in response to the interception of the error estimation packet;
• and
• an error estimation module that is operable to estimate the delay based at least in part on a difference between the interception timestamp and the software timestamp.