1. A TAP domain comprising:
A. a test data input;
B. a test data output;
C. a test clock input;
D. a test mode select input;
E. a serial instruction register having a serial data input connected to the test data input, a serial data output, an instruction register control bus output, and a control bus input;
F. a serial data register having a serial data input connected to the test data input, a serial data output, and a control input connected to the instruction register control bus output;
G. multiplexer circuitry coupling the serial data output of the instruction register and the serial data output of the data register to the test data output, and having a control input;
H. TAP control circuitry having a clock input connected to the test clock input, a mode select input connected to the test mode select input, and a TAP control bus output connected to the control bus input of the instruction register and the control input of the multiplexer circuitry;
I. at least one auxiliary interface terminal separate from the test data input, the test data output, the test clock input, and the test mode select input; and
J. auxiliary circuitry having a data input coupled to the test data input, a data output coupled to the test data output, an auxiliary lead coupled to the at least one auxiliary interface terminal, instruction register control terminals connected to the instruction register control bus output, and TAP control bus terminals connected to the TAP control bus output.
2. The TAP domain of claim 1 in which the auxiliary circuitry is one of a debug circuit, emulation circuit, in-circuit programming circuit, IO communication circuit, triggering circuit, and breakpoint circuit.
3. The TAP domain of claim 1 in which the auxiliary circuitry is a digital test circuit.
4. The TAP domain of claim 1 in which the auxiliary circuitry is an analog test circuit.
5. The TAP domain of claim 1 in which the auxiliary interface terminal carries input and output signals.
6. The TAP domain of claim 1 in which there are auxiliary leads, and including an input buffer and an output buffer connecting the auxiliary interface terminal and the auxiliary circuitry leads.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A method of distributing digital content, the method comprising:
receiving a data packet at a first video distribution hub via a first link;
determining whether a second link has failed, wherein the first video distribution hub communicates with a second video distribution hub via a primary network path that includes the second link;
when the second link has failed, determining a backup network path to send the data packet, or a copy thereof, to the second video distribution hub, the backup network path determined based on data stored at the first video distribution hub; and
sending the data packet, or the copy thereof, to the second video distribution hub via the backup network path, wherein the backup network path does not include the second link.
2. The method of claim 1, further comprising sending a copy of the data packet to the second distribution hub via the second link when the second link has not failed.
3. The method of claim 1, wherein the backup network path includes the first link.
4. The method of claim 3, wherein:
the first link includes at least a first fiber optics line and a second fiber optics line;
the data packet is received at the first distribution hub via the first fiber optics line; and
the backup network path includes the second fiber optics line.
5. The method of claim 4, wherein the first fiber optics line is associated with downstream data traffic sent by a video head-end and the second fiber optics line is associated with upstream data traffic sent to the video head-end.
6. The method of claim 1, wherein the first video distribution hub and the second video distribution hub are two of a plurality of nodes of a network ring architecture.
7. The method of claim 6, wherein the primary network path carries data in a first direction along the network ring architecture and the backup network path carries data in a second direction along the network ring architecture, wherein the second direction is opposite to the first direction.
8. The method of claim 6, wherein the data packet is received at the first distribution hub from a previous distribution hub of the network ring architecture, the previous distribution hub coupled to the first distribution hub via the first link.
9. The method of claim 6, wherein the data packet is received at the first distribution hub from a primary video head-end of the network ring architecture, the primary video head-end coupled to the first distribution hub via the first link.
10. The method of claim 9, wherein the data packet is received at the first distribution hub via the first link from a backup video head-end of the network ring architecture when the primary video head-end loses contact with a content source.
11. The method of claim 6, wherein the plurality of nodes are connected via a plurality of Multi-Protocol Packet Label Switching (MPLS) links that include the first link and the second link.
12. The method of claim 6, wherein the network ring is one of a plurality of network rings of a cascaded network ring architecture that includes the network ring and a plurality of overlapping network rings.
13. The method of claim 12, wherein the first video distribution hub receives the data packet from a shared video distribution hub that is a node of the network ring and is a node of another network ring of the cascaded network ring architecture.
14. The method of claim 12, further comprising selecting the backup network path from a plurality of backup network paths.
15. The method of claim 14, wherein the plurality of backup network paths includes a first backup associated with the network ring and a second backup network path associated with an adjacent one of the plurality of overlapping network rings, wherein the first video distribution hub and the second video distribution hub are nodes of the network ring and of the adjacent overlapping network ring.
16. The method of claim 15, wherein the backup network path is selected based on failure of at least one network link within the cascaded network ring architecture, failure of at least one network node within the cascaded network ring architecture, a data traffic volume associated with each of the plurality of backup network paths, a number of hops associated with each of the plurality of backup network paths, a transmission speed of each of the plurality of network backup paths, an available bandwidth of each of the plurality of network backup paths, or any combination thereof.
17. The method of claim 16, wherein, when a primary video head-end node of the network ring fails, the first video distribution hub receives the data packet from a backup video head-end of the network ring and the backup network path is associated with the adjacent overlapping network ring.
18. A system to distribute digital content, the system comprising a first video distribution hub coupled to a first link and coupled to a second link, the first video distribution hub adapted to receive a data packet via the first link and to communicate the data packet, or a copy thereof, to a second video distribution hub via a primary network path that includes the second link when the second link has not failed, and via a backup network path that does not include the second link when the second link has failed, the backup network path determined based on data stored at the first video distribution hub.
19. The method of claim 18, wherein the distribution hub includes a plurality of devices, each of the plurality of devices adapted to receive the data packet, determine whether the second link has failed, store data indicating at least one backup network path, determine the backup network path, send the data packet or the copy thereof to the second distribution hub, or any combination thereof.
20. The system of claim 18, wherein:
the data packet is sent by a video head-end of a first network ring that includes the video head-end, the first video distribution hub, and the second video distribution hub;
the first video distribution hub is adapted to send a copy of the data packet to a third video distribution hub via a third link according to a primary network path of a second network ring, the third video distribution hub being a node of the second network ring and the first video distribution hub being a node of the first network ring and the second network ring; and
the distribution hub is adapted to send the copy of the data packet to the third distribution hub via a second backup network path when the third link has failed, the second backup network path determined based on data stored at the first video distribution hub.
21. The system of claim 18, wherein the data packet is an Internet Protocol (IP) based data packet.
22. The system of claim 21, wherein the data packet is a video data packet.
23. A computer-readable medium tangibly embodying instructions executable to:
determine whether a link between a first video distribution hub and a second video distribution hub has failed, wherein the first distribution hub communicates with the second distribution hub via a primary network path that includes the link;
determine, when the second link has failed, a backup network path to send a data packet from the first video distribution hub to the second video distribution hub, the backup network path determined based on data stored at the first video distribution hub; and
send the data packet to the second video distribution hub via the backup network path, wherein the backup network path does not include the link.
24. The computer-readable medium of claim 23, further comprising instructions to select the backup network path from a plurality of backup network paths, wherein each of the plurality of backup network paths is associated with a separate network ring of a cascaded network ring architecture.
25. The system of claim 23, wherein the data packet is a non-video data packet.
26. A network, comprising:
a plurality of nodes including a first video distribution hub and a second video distribution hub, wherein the plurality of nodes are connected via a plurality of Multi-Protocol Packet Label Switching (MPLS) links to form at least one network ring;
wherein a data packet including video content is routed from the first video distribution hub to the second video distribution hub via a primary network path when a MPLS link connecting the first video distribution hub to the second video distribution hub has not failed; and
wherein the data packet is re-routed from the first video distribution hub to the second video distribution hub via a backup network path that does not include the MPLS link when the MPLS link has failed, the backup network path pre-defined at the first video distribution hub.
27. The network of claim 26, wherein the plurality of nodes includes a video head-end and a single copy of the data packet is sent by the video head-end and is propagated throughout all video distribution hubs of the at least one network ring.
28. The network of claim 26, wherein a link cost is assigned to each of the plurality of MPLS links to produce a data flow direction of at least one primary path within the at least one network ring.
29. The network of claim 26, wherein the plurality of nodes form multiple overlapping network rings.
30. The network of claim 29, wherein a data flow direction is determined for each of the multiple overlapping network rings such that less than all overlapping links of the multiple overlapping network rings comprise double bandwidth links.
31. The network of claim 30, wherein the data flow direction assigned to each of the multiple overlapping network rings is clockwise or counterclockwise.
32. The network of claim 29, wherein:
the plurality of nodes includes a primary video head-end and a backup video head-end and the first video distribution hub and the second video distribution hub are nodes common to a first network ring and to a second network ring;
when the primary video head-end cannot transmit data traffic, the data packet is sent by the backup video head-end to the second video distribution hub and is routed from the second video distribution hub to the first video distribution hub via a reverse primary network path when the MPLS link connecting the first video distribution hub and the second video distribution hub has not failed; and
the data packet is re-routed from the second video distribution hub to the first video distribution hub via a second backup network path that does not include the MPLS link connecting the first video distribution hub and the second video distribution hub when the MPLS link has failed, the backup network path pre-defined at the second video distribution hub and including at least one primary network path or backup network path of the second network ring.
33. The network of claim 26, wherein the data packet includes multicast video content, real-time video content, or any combination thereof.
34. The network of claim 33, wherein re-routing the data packet via the backup network path results in a recovery time of approximately fifty milliseconds (50 ms).
35. The network of claim 26, wherein each of the video distribution hubs of the at least one network ring sends video content carried by the data packet to user multimedia communication devices within a sub-region of a geographic area associated with the network.