Specifications

ALAXALA Ring Configuration Guide (Edition 1)

2.3 Operation in multi-ring configuration with shared links

2.3.1 Normal operation

During normal operation in a multi-ring with shared links, the Ring Protocol works as shown in the figure

below.

If the multi-ring has no shared links, each ring runs in the same way as a single ring does.

Figure

2.3-1 Normal multi-ring operation

(1) Master node operation

The master nodes in both rings of a multi-ring (shared link monitoring master node and shared link

non-monitoring master node) configure their two ring ports as the primary and secondary ports, in the same way

as in a single ring configuration. The ring VLAN status for data transfer on the secondary port is set to BLK. The

master nodes also periodically send HC(M)s from both of their ring ports to monitor the status of the rings.

The shared link monitoring master node monitors whether sent HC(M)s come back normally and determines

that the ring status is normal as long as the node receives the HC(M)s. During normal operation, the ring VLAN

status on the secondary port is set to BLK so that the port can discard data frames to avoid a loop.

The shared link non-monitoring master node monitors not only HC(M)s it sends, but also HC(S)s sent from

shared nodes. During normal operation, the ring VLAN status on the secondary port is set to BLK so that the port

can discard data frames to avoid a loop.

(2) Transit node operation

When a transit node receives HC(M)s sent from the master node or HC(S)s sent from shared nodes, the transit

node forwards the received HC frames to the next node (to a different ring port than the ring port on which the

HC frames are received).

(3) Shared node operation

When a shared node receives HC(M)s sent from the master node, the shared node, like a transit node, forwards

the received HC(M) frames to the next node (to a different ring port than the ring port on which the HC(M)

frames are received).

Also, in the shared link non-monitoring ring, shared nodes send HC(S)s to the master node from their ports not

belonging to shared links.

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

M1 S1 T2

T1 S2 M2

HC(S)

HC(M)

Shared link

Non-monitoring

ring

HC(M)

Shared link

monitoring

ring