Specifications

ALAXALA Ring Configuration Guide (Edition 1)

2.3.2 Operation during a failure

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

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

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

In types (a) and (b), the basic operation is the same as the single ring operation.

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

Figure 2.3-2 Operation during a shared link failure

(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 occurs

in a single ring. When a ring failure occurs on a monitored shared link, the master node can no longer receive

HC(M)s in both directions and detects the failure. Failure operation is the same as the operation when a failure

occurs in a single ring.

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

The shared link non-monitoring master node can no longer receive HC(M)s but continues to receive HC(S)s in

both directions from shared nodes. At this point, the master node does not determine that any ring failure has

occurred and does not perform any failure operation.

(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 occurs in a single ring.

Because no failure operation is performed in the shared link non-monitoring ring (C-shaped ring), transit nodes

in this 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: BLK -> FWD

M1 S1 T2

T1 S2 M2

A failure

occurs.

HC(M)

Flush

control

frames

HC(S)

HC(M)