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Use Case for SRX Chassis Clusters

Enterprise and service provider networks employ various redundancy and resiliency methods at the customer edge network tier. As this tier represents the entrance or peering point to the Internet, its stability and uptime are of great importance. Customer transactional information, email, Voice over IP (VoIP), and site-to-site traffic can all utilize this single entry point to the public network. In environments where a site-to-site VPN is the only interconnect between customer sites and the headquarter site, this link becomes even more vital.

Traditionally, multiple devices with discreet configurations have been used to provide redundancy at this network layer with mixed results. In these configurations, the enterprise relies on routing and redundancy protocols to enable a highly available and redundant customer edge. These protocols are often slow to recognize failure and do not typically allow for the synchronization required to properly handle stateful traffic. Given that a fair amount of enterprise traffic passing through the edge (to/from the Internet, or between customer sites) is stateful, a consistent challenge in the configuration of this network tier has been ensuring session state is not lost when failover or reversion occurs.

Another challenge in configuration of redundant devices is the need to configure, manage, and maintain separate physical devices with different configurations. Synchronizing those configurations can also be a challenge because as the need and complexity of security measures increase, so too does the probability that configurations are mismatched. In a secure environment, a mismatched configuration can cause something as simple as a loss of connectivity or as complex and costly as a total security breech. Any anomalous event on the customer edge can affect uptime, which consequently impacts the ability to service customers, or possibly the ability to keep customer data secure.

An answer to the problem of redundant customer edge configuration is to introduce a state-aware clustering architecture that allows two or more devices to operate as a single device. Devices in this type of architecture are able to share session information between all devices to allow for near instantaneous failover and reversion of stateful traffic. A key measure of success in this space is the ability of the cluster to fail over and revert traffic while maintaining the state of active sessions.

Using the SRX Chassis Cluster configuration described in Example: Configuring an SRX Series Services Gateway as a Full Mesh Chassis Cluster will reduce your downtime and save you money.

Devices in an effective clustering architecture can also be managed as a single device; sharing a single control plane. This function is vital as it reduces the OpEx associated with managing multiple devices. Rather than managing and operating separate devices with different configurations and management portals, you can manage multiple devices that serve the same function through a single management point.

Finally, in a cluster configuration, devices have the ability to monitor active interfaces to determine their service state. An effective cluster proactively monitors all revenue interfaces and should fail over to backup interfaces if a failure is detected. This should be done at nearly instantaneous intervals to minimize the impact of a service failure and reduce costs associated with a service failure such as lost revenue, dropped customer calls, and so on.