Specifications

ALAXALA Ring Configuration Guide (Edition 1)

2.3.3 Operation during recovery from a failure

In the multi-ring, there are the following types of failure recovery:

(a) Non shared-link failure recovery in a shared link monitoring ring (O-shaped ring)

(b) Non shared-link failure recovery in a shared link non-monitoring ring (C-shaped ring)

These failure recovery operations are basically the same as the single ring operation.

When a shared link failure is resolved (failure type (c)), the Ring Protocol works as follows:

Figure 2.3-3 Operation during shared link failure recovery

(1) Operation of the shared link monitoring master node

The shared link monitoring master node works in the same way as the master node does when a failure is

resolved in a single ring. When a failure of the monitored shared link is resolved, the master node can receive

HC(M)s on one of the ring ports and detects recovery from a ring failure. Recovery operation is the same as the

operation when a failure is resolved in a single ring.

(2) Operation of the shared link non-monitoring master node

The shared link non-monitoring master node does not handle a shared link failure as a failure and thus does

nothing when the failure is resolved. However, when the shared link failure is resolved, the node begins to

receive HC(M)s that it has been temporarily unable to receive.

(3) Operation of transit and shared nodes

Transit nodes and shared nodes in the shared link monitoring ring (O-shaped ring) work in the same way as a

node does when a failure is resolved in a single ring.

Transit nodes in the shared link non-monitoring ring (C-shaped ring) continue their normal operation.

M1: Shared link monitoring master node

M2: Shared link non-monitoring master node

T1 - T2: Transit node

S1 - S2: Shared node

HC(M): HC from the master node

HC(S): HC from the shared node

Shared link non-monitoring ring

Shared link monitoring ring

Shared link

Ring VLAN: FWD -> BLK

M1 S1 T2

T1 S2 M2

The failure

is resolved.

HC(M)

Flush

control

frames

HC(S)

HC(M)