Specifications

ALAXALA Ring Configuration Guide (Edition 1)

2.4.2 Operation during a failure

Failure operations in a network using both Ring Protocol and STP can be categorized into the following types:

(1) When a line failure occurs in the ring

A failure operation is performed in the ring, so the downstream STP operation is not affected.

The failure operation in this case is the same as the one in the single ring and multi-ring configurations

described above. See the related sections.

(2) When a line failure occurs between a Ring-STP node and an STP node

STP performs a failure operation, and flush frames are sent in the ring after the topology change.

Figure 2.4

-2 shows how the Ring Protocol works if such a failure occurs.

Figure 2.4-2 Line failure operation in STP when the Ring Protocol and STP are used

1. A failure occurs between the STP node and the Ring-STP node in base 2.

2. STP configured in base 2 detects the failure, changes the topology, and then clears the MAC address table

of nodes in that base.

3. The node selected as the root bridge in base 2 sends flush frames into the ring network to clear the MAC

address tables of the nodes belonging to the ring network in the other base (the nodes not in base 2 in the

above figure).

4. The MAC address tables in all the nodes are updated, restoring communication.

R: Ring node

S: STP node

RS: Ring-STP node

: Base

: Ring BLK port

: STP BLK port

: STP FWD port

Base: 2

Base: 1

Root bridge

Flush

frames