Safety Island Cluster 0 Bridge

Introduction

The Safety Island Cluster 0 Bridge is a software application running on the Safety Island Cluster 0 that acts as a network bridge connecting together the network interfaces with the other Safety Island clusters and the network interface with the Host. The code for the application can be found at components/safety_island/zephyr/src/apps/bridge.

Architecture

Components

The bridge is a Zephyr application making use of its Ethernet Bridging API.

It is not VLAN-aware, as none of the traffic on the bridged networks (the external network and all the inter-cluster networks) is VLAN-tagged.

The current Zephyr bridge functionality does not feature a learning process, which means that incoming packets on a registered interface are sent to all other registered interfaces at all times.

Diagram

Interfaces

The network interfaces added to the bridge forward all incoming packets to the other registered interfaces without processing the packets. It means that those interfaces can’t respond to Internet Control Message Protocol (ICMP) echo requests from other network nodes and can’t be used for other purposes by the application.

The network interface to the Primary Compute can respond to ICMP echo requests but has no functional use.

Validation

See Integration Tests Validating the Safety Island Cluster 0 Bridge.