Understanding Chassis Cluster

Chassis clustering provides network node redundancy by grouping a pair of the same kind of supported J-series devices or SRX-series devices into a cluster. The devices must be running JUNOS software. The control links on the respective nodes are connected over Gigabit Ethernet links to form a control plane that synchronizes configuration, kernel, and session state across the cluster to facilitate high availability of interfaces and services. Similarly, the fabric interfaces of the two nodes are connected to form a data plane to process transit traffic and to manage flow processing and session state redundancy.

When configured as a chassis cluster, the two nodes back up each other, with one node acting as the primary device and the other as the secondary device, ensuring stateful failover of processes and services in the event of system or hardware failure. If the primary device fails, the secondary device takes over processing of traffic.

Note: For an SRX-series chassis cluster, the fabric interfaces can also be connected over 10-Gigabit Ethernet links.

Note: For a chassis cluster with SRX 5600 or SRX 5800 devices, nodes must be interconnected with a fiber optic cable.

Chassis cluster functionality includes:

• Resilient system architecture, with a single active control plane for the entire cluster and multiple Packet Forwarding Engines. This architecture presents a single device view of the cluster.
• Synchronization of configuration and dynamic runtime states between nodes within a cluster.
• Monitoring of physical interfaces, and failover if the failure parameters cross a configured threshold.

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