Wrap path for communication ring access control
View Patent ↗Ring access control circuitry comprises a receive interface, a host interface coupled to the receive interface, a mate interface coupled to the host interface, a flow control agent coupled to the mate interface, a transmit interface coupled to the flow control agent, and a wrap path coupled from between the flow control agent and the transmit interface to between the receive interface and the host interface. A wrap is initiated over the wrap path in response to a link failure. The ring being controlled could be a resilient packet ring.
1. Ring access control circuitry comprising:
a receive interface;
a host interface coupled to the receive interface;
a mate interface coupled to the host interface;
a flow control agent coupled to the mate interface;
a transmit interface coupled to the flow control agent; and
a wrap path coupled from between the flow control agent and the transmit interface to between the receive interface and the host interface.
2. The ring access control circuitry of claim 1 wherein the receive interface is configured to detect a link failure that initiates a wrap over the wrap path.
3. The ring access control circuitry of claim 1 further comprising a packet boundary detector configured to initiate a wrap over the wrap path at a packet boundary.
4. The ring access control circuitry of claim 1 wherein the receive interface comprises a framer receive FIFO and the transmit interface comprises a framer transmit FIFO.
5. The ring access control circuitry of claim 1 wherein the host interface comprises a transit buffer.
6. The ring access control circuitry of claim 1 wherein the host interface is configured to provide a host system with ring access.
7. The ring access control circuitry of claim 1 wherein the mate interface is configured to exchange traffic with a ring access control mate.
8. The ring access control circuitry of claim 1 wherein the flow control agent is configured to control a transfer rate in response to a fairness packet.
9. The ring access control circuitry of claim 1 wherein the flow control agent is configured to generate a fairness packet indicating a transfer rate over a congested link.
10. The ring access control circuitry of claim 1 wherein a ring controlled by the ring access control circuitry comprises a resilient packet ring.
11. A method of providing ring access control using circuitry comprising a receive interface, a host interface coupled to the receive interface, a mate interface coupled to the host interface, a flow control agent coupled to the mate interface, and a transmit interface coupled to the flow control agent, the method comprising:
detecting a link failure; and
in response to the link failure, providing a wrap path from between the flow control agent and the transmit interface to between the receive interface and the host interface.
12. The method of claim 11 wherein the receive interface is configured to detect the link failure.
13. The method of claim 11 further comprising initiating a wrap over the wrap path at a packet boundary.
14. The method of claim 11 wherein the receive interface comprises a framer receive FIFO and the transmit interface comprises a framer transmit FIFO.
15. The method of claim 11 wherein the host interface comprises a transit buffer.
16. The method of claim 11 further comprising, in the host interface, providing a host system with ring access.
17. The method of claim 11 further comprising, the mate interface, exchange traffic with a ring access control mate.
18. The method of claim 11 further comprising, in the flow control agent, controlling a transfer rate in response to a fairness packet.
19. The method of claim 11 further comprising, in the flow control agent, generating a fairness packet indicating a transfer rate over a congested link.
20. The method of claim 11 wherein a ring controlled by the ring access control circuitry comprises a resilient packet ring.