1. A non-transitory machine-readable storage medium having code stored therein, which when executed by a processor, cause the processor to perform operations comprising:
identifying a congested link from a plurality of links of a packet data network, the congested link having traffic from a plurality of packet traffic groups, wherein the plurality of packet traffic groups are prioritized using priority weights and each one of the plurality of packet traffic groups is assigned a priority weight;
determining a throttle rate for a packet traffic group of the congested link based on the assigned priority weight of the group and a current traffic rate of the group; and
sending by a central controller the determined throttle rate to an ingress network element of the packet data network, the ingress network element receiving packets of the packet traffic group and wherein the ingress network element is to drop at least one packet from the received packets of the packet traffic group based on the determined throttle rate.
2. The non-transitory machine-readable storage medium of claim 1, wherein identifying the congested link comprises receiving a congestion message from a reporting network element of the packet data network.
3. The non-transitory machine-readable storage medium of claim 2, wherein the operations further comprise sending a traffic statistics request to the ingress network element in response to the congestion message.
4. The non-transitory machine-readable storage medium of claim 3, wherein the operations further comprise receiving traffic statistics from the ingress network element and wherein determining the throttle rate includes determining the throttle rate using the received traffic statistics.
5. The non-transitory machine-readable storage medium of claim 4, wherein receiving the traffic statistics includes receiving values for traffic rates of packet groups on a link related to the received congestion message.
6. The non-transitory machine-readable storage medium of claim 1, wherein the operations further comprise gathering traffic statistics from network elements of the packet data network and wherein identifying the congested link includes determining a current packet data traffic load for the congested link using the gathered traffic statistics and comparing the current packet data traffic load to a traffic bandwidth for the congested link.
7. The non-transitory machine-readable storage medium of claim 6, wherein determining the current packet data traffic load comprises requesting packet data traffic statistics from network elements of the packet data network.
8. The non-transitory machine-readable storage medium of claim 1, wherein determining the throttle rate comprises comparing the current traffic rate of the packet traffic group to a traffic bandwidth for the congested link.
9. The non-transitory machine-readable storage medium of claim 8, wherein the priority weight for the packet traffic group provides a portion of the congested link traffic bandwidth that may be used by the packet traffic group.
10. The non-transitory machine-readable storage medium of claim 1, wherein the throttle rate is proportional to a comparison of the current traffic rate to an allowed traffic rate.
11. The non-transitory machine-readable storage medium of claim 1, wherein each packet traffic group comprises at least one of packets having a common port number, packets having a common source IP address, packets having a common destination IP address, and packets having common users.
12. A method of controlling congestion in a packet data network, the method comprising:
identifying a congested link from a plurality of links of the packet data network, the congested link having traffic from a plurality of packet traffic groups, wherein the plurality of packet traffic groups are prioritized using priority weights and each one of the plurality of packet traffic groups is assigned a priority weight;
determining a throttle rate for a packet traffic group of the congested link based on the assigned priority weight of the group and a current traffic rate of the group; and
sending by a central controller the determined throttle rate to an ingress network element of the packet data network, the ingress network element receiving packets of the packet traffic group and wherein the ingress network element is to drop at least one packet from the packets of the packet traffic group based on the determined throttle rate.
13. The method of claim 12, wherein identifying the congested link comprises receiving a congestion message from a reporting network element of the packet data network.
14. The method of claim 13, further comprising sending a traffic statistics request to the ingress network element in response to the congestion message.
15. The method of claim 14, further comprising receiving traffic statistics from the ingress network element and wherein determining the throttle rate includes determining the throttle rate using the received traffic statistics.
16. The method of claim 15, wherein receiving the traffic statistics includes receiving values for traffic rates of packet groups on a link related to the received congestion message.
17. The method of claim 12, further comprising gathering traffic statistics from network elements of the packet data network and wherein identifying the congested link includes determining a current packet data traffic load for the congested link using the gathered traffic statistics and comparing the current packet data traffic load to a traffic bandwidth for the congested link.
18. The method of claim 17, wherein determining the current packet data traffic load comprises requesting packet data traffic statistics from network elements of the packet data network.
19. The method of claim 12, wherein determining the throttle rate comprises comparing the current traffic rate of the packet traffic group to a traffic bandwidth for the congested link.
20. The method of claim 19, wherein the priority weight for the packet traffic group provides a portion of the congested link traffic bandwidth that may be used by the packet traffic group.
21. The method of claim 12, wherein the throttle rate is proportional to a comparison of the current traffic rate to an allowed traffic rate.
22. The method of claim 12, wherein each packet traffic group comprises at least one of packets having a common port number, packets having a common source IP address, packets having a common destination IP address, and packets having common users.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
What is claimed is:
1. A radiation detector comprising:
a radiation sensor which provides an output as a function of difference between target temperature and sensor temperature over a design range of target temperatures and a design range of sensor temperatures;
an amplifier in circuit with the radiation sensor which amplifies the sensor output;
an analog-to-digital converter which generates a multibit digital output from the amplified output over a voltage range of the amplified sensor output; and
a variable reference to maintain analog-to-digital converter resolution over the design ranges of target and sensor temperatures, the resolution being greater than would be obtained with a fixed reference over a full design range of target temperature and a design range of sensor temperatures.
2. A radiation detector as claimed in claim 1 wherein the reference is variable to offset the amplified output by an offset level approximating sensor temperature.
3. A radiation detector as claimed in claim 2 wherein the amplified output approximates target temperature.
4. A radiation detector as claimed in claim 2 further comprising a switch to isolate the radiation sensor from the amplifier, the reference being varied to provide an amplified output which approximates sensor temperature while the radiation sensor is isolated from the amplifier.
5. A radiation detector as claimed in claim 4 further comprising a switch to isolate a resistor which balances the resistance of the radiation sensor.
6. A radiation detector as claimed in claim 1 wherein the reference is set at one of two levels depending on whether target temperature is above or below sensor temperature.
7. A radiation detector as claimed in claim 6 further comprising a switch to isolate the radiation sensor from the amplifier, the reference being varied to provide an amplified output at one of the two levels while the radiation sensor is isolated from the amplifier.
8. A radiation detector as claimed in claim 7 further comprising a switch to isolate a resistor which balances the resistance of the radiation sensor.
9. A radiation detector as claimed in claim 1 wherein a measurement offset resulting from the reference is subtracted from the multibit digital output prior to digital computation of target temperature therefrom.
10. A radiation detector as claimed in claim 1, wherein the variable reference is applied to the amplifier.
11. A method of detecting temperature comprising:
amplifying the output of a radiation sensor with an amplifier and applying the amplified output to an analog-to-digital converter; and
varying a reference to maintain analog-to-digital converter resolution over design ranges of target and sensor temperatures, the resolution being greater than would be obtained with a fixed reference over a fall design range of target temperatures and design range of sensor temperatures.
12. A method as claimed in claim 11 wherein the reference is varied to offset the amplified output by an offset level approximating sensor temperature.
13. A method as claimed in claim 12 wherein the amplified output approximates target temperature.
14. A method as claimed in claim 12 further comprising varying the reference by isolating the radiation sensor from the amplifier and, while the radiation sensor is isolated from the amplifier bearing the reference to provide an amplified output which approximates sensor temperature.
15. A method as claimed in claim 14 further comprising isolating a resistor which balances the resistance of the isolated radiation sensor.
16. A method as claimed in claim 11 wherein the reference is set at one of two level depending on whether target temperature is above or below sensor temperature.
17. A method as claimed in claim 16 wherein the reference is varied with the radiation sensor isolated from the amplifier to provide an amplified output at one of the two levels.
18. A method as claimed in claim 16 wherein the reference is initially set at an intermediate level and, if the amplified output is out of range of the analog-to-digital converter, the reference is then set at one of said two levels.
19. A method as claimed in claim 11 wherein a measurement offset resulting from the reference is subtracted from the multibit digital output prior to digital computation of target temperature therefrom.
20. A method as claimed in claim 11 further comprising the step of varying the reference to the amplifier.