Ethernet Ring Protection node

摘要

Systems and methods are disclosed for providing redundancy in a network node implementing a ring protection protocol. Each of the two ring ports connecting the node to other nodes in a ring supporting the protocol may be maintained by a separate line card. Should one line card fail, traffic passing through the node may be redirected through the remaining ring port under the control of the surviving state machine. The two state machines may be coordinated over the backplane of the node to maintain a common state, making them transparent to other nodes. Additionally, the backplane link between the state machines may be monitored for failures that may be addressed with messages used to respond to general ring failures and by assigning one state machine to block a ring port upon recovery to prevent a loop within the ring until the ring protection link can be blocked.

主权项

1. A redundant ring node comprising:
a first line card used to implement a ring node, the first line card comprising:
a first front port serving as a first ring port of two ring ports defined for ring nodes supporting a ring protection protocol, anda first state machine implementing a state machine consistent with the ring protection protocol; a second line card used to implement the ring node, the second line card comprising:
a second front port serving as a second ring port of the two ring ports defined for ring nodes supporting the ring protection protocol, anda second state machine also implementing a state machine consistent with the ring protection protocol; and a backplane providing communication infrastructure between multiple line cards residing at the ring node; an inter-card communication link implemented over the backplane between a first virtual port at the first line card and a second virtual port at the second line card; a first update module of the first state machine operable to update the first state machine according to the ring protection protocol and in response to a state message arriving at the first ring port; a forwarding module residing on the first line card and operable to forward the state message through the first virtual port and over the inter-card communication link supported by the backplane to the second state machine residing on the second line card; and a second update module of the second state machine operable to respond to the state message received at the second virtual port according to the ring protection protocol as though the state message were received at the second ring port so that the second update module updates the second state machine to the updated state such that the first state machine and the second state machine share a common state for the ring node.