System and method for measuring round trip delay of voice packets in a telephone system
View Patent ↗Systems and methods measure a round trip delay of voice packets through a telephone system that includes a plurality of cabinets connected through a network. Each cabinet includes a link for communicating with other cabinets through the network by passing information such as voice packets. Each link includes a field programmable gate array (FPGA) that inserts and reads information in the voice packets to measure a time delay of the network. A first cabinet link sets a transmit bit in a voice packet directed to a second cabinet and starts a timer. The second cabinet monitors the transmit bit in received voice packets to determine if the bit is set. If so, the second cabinet sets a receive bit in the next outgoing voice packet directed to the first cabinet. The first cabinet monitors the receive bit in incoming voice packets and if set, stops the timer. The resulting value in the timer reflects the network delay.
1. A network device for use in a network transmitting voice packets, the device comprising:
a timer for measuring round trip delay of voice packets; and
a processor operable for setting a transmit bit in an outgoing voice packet to a network and starting the timer when the transmit bit is set, and for reading a receive bit in a received voice packet from the network and stopping the timer when the receive bit is read, and for monitoring a round trip voice packet delay time of the network based on the timer.
2. The network device in accordance with claim 1 further comprising:
an interface coupled to the processor, the interface operable for coupling the network device to the network and for transmitting the outgoing voice packet.
3. The network device in accordance with claim 1 wherein the processor is further operable for reading a set transmit bit in the received voice packet and for setting a receive bit in another outgoing voice packet in response to reading the set transmit bit in the received voice packet.
4. The network device in accordance with claim 1 further comprising:
a round trip register operable for receiving a value from the timer.
5. The network device in accordance with claim 4 wherein the processor is further operable for comparing the value in the round trip data register to a predetermined value and sending an indication to a user when the value in the round trip data register is greater than the predetermined value.
6. The network device in accordance with claim 1 further comprising:
a round trip register operable for receiving a value from the timer;
and
wherein the processor is further operable for comparing the value in the round trip data register to a predetermined value and sending an indication to a user when the value in the round trip data register is greater than the predetermined value.
7. A device for use in a network transmitting voice packets, the device comprising:
a timer for measuring round trip delay of voice packets;
a transmitting state machine operable for setting a transmit bit in an outgoing voice packet and starting the timer when the transmit bit is set; and
a receiving state machine operable for reading a receive bit in a received voice packet and stopping the timer when the receive bit is read.
8. The device in accordance with claim 7 further comprising:
an interface coupled to the transmitting state machine, the interface operable for coupling the device to the network and for transmitting the outgoing voice packet.
9. The device in accordance with claim 7 wherein the receiving state machine is further operable for reading a set transmit bit in the received voice packet and for setting a receive bit in another outgoing voice packet in response to reading the set transmit bit in the received voice packet.
10. The device in accordance with claim 7 further comprising:
a round trip register operable for receiving a value from the timer.
11. The device in accordance with claim 10 further comprising a processing means operable for comparing the value in the round trip data register to a predetermined value and sending an indication to a user when the value in the round trip data register is greater than the predetermined value.
12. A system for use in timing the transmission of voice packets through a network, the system comprising:
a timer for measuring round trip delay of voice packets;
a processor operable for constructing an outgoing first voice packet to a network, for setting a transmit bit in the outgoing first voice packet to the network, and for starting the timer when the transmit bit is set, and for monitoring a round trip voice packet delay time of the network based on the timer.
13. The system in accordance with claim 12 further comprising:
an interface coupled to the processor, the interface operable for coupling the system to the network and for transmitting the outgoing first voice packet.
14. The system in accordance with claim 13 wherein the interface is operable for receiving a second voice packet, and the processor is operable for checking the second voice packet to determine if a receive bit is set and stopping the timer if the receive bit is set.
15. The system in accordance with claim 14 further comprising:
a round trip data register operable for receiving a value from the timer.
16. The system in accordance with claim 15 wherein the processor is further operable for comparing the value in the round trip data register to a predetermined value and sending an indication to a user when the value in the round trip data register is greater than the predetermined value.
17. The system in accordance with claim 12 wherein the processor is further operable for receiving a second voice packet and checking the second voice packet to determine if the transmit bit is set, and further operable for constructing an outgoing third voice packet and setting a receive bit in the outgoing third voice packet if the transmit bit is set in the received second voice packet.
18. A network device for use in a network transmitting voice packets, the network device comprising:
a link for communicating with external devices over the network, the link comprising,
an interface operable for coupling the link to the network and for transmitting and receiving voice packets,
a timer for measuring round trip delay of voice packets, and
a processor coupled to the interface, the processor operable for setting a transmit bit in an outgoing voice packet to the network, and starting the timer when the transmit bit is set, and for reading a receive bit in a received voice packet from the network, and stopping the timer when the receive bit is read, and for monitoring a round trip voice packet delay time of the network based on the timer.
19. The network device in accordance with claim 18 wherein the processor is further operable for reading a set transmit bit in the received voice packet and setting a receive bit in another outgoing voice packet in response to reading the set transmit bit in the received voice packet.