4G LTE Failover or Failover to Cellular (F2C) allows enterprises to efficiently change over to an always available connection when a disruption occurs on the primary, wired internet line. An outage scenario is inevitable. Those with distributed sites, like in the retail industry, are all too familiar with it. When a POS system stops working, organizations are faced with losing business and money, with the cost of downtime at $260,000 per hour.[1] Not being able to process payments, customers will have to go elsewhere or an organization can take a riskier route and manually write down credit card numbers. This opens up a wide range of liability and non-PCI (Payment Card Industry) compliance.
However, if an enterprise has a Failover to Cellular solution in place, or equipment with this capability built in, they are ensured always on network connectivity. If the primary wired internet connection is lost, Failover to Cellular kicks in. Providing speed to keep the network running smoothly, and continued internet connectivity for remote LANs and equipment over 4G LTE, engineers are able to restore the WAN without the need of manual intervention or impacting normal operations. They are then able to automatically activate a secondary connection to reestablish in and outbound network access.
Working similar to the 4G LTE technology on a smart phone, this kind of connection allows enterprises to pay per unit of data. Ensuring a consistent monthly cost depending on the carrier chosen to use, it can be deployed by simply plugging the SIM card from the carrier into the networking equipment.
Failover To Cellular With Opengear
In Opengear devices, Failover To Cellular is built-in with the internal or external PSTN modems that can be used for this. Once it is enabled, the equipment is able to detect failures by sending ICMP ping requests from the network to a primary and secondary probe address remotely. If these requests fail, the primary connection has been reestablished and the devices automatically fail forward. Opengear devices have three operation modes.
Always Up Out-Of-Band Mode
This is the default mode when no failover scheme has been configured. Failover detection is disabled. Only inbound connections on the cellular interface are routed back out the cellular interface, to enable Out-of-Band access from remote networks, like through incoming SSH. Otherwise outbound network connections, like through a VPN client tunnel or SNMP alerts, are established according to the main static routing table, regardless of network state.
Failover Mode
Failover detection is enabled on the primary interface. The secondary interface remains in a down state with no network configuration. When failover is initiated, the secondary network interface is started and configured. If a default route is installed on the secondary interfaces, it takes precedence over the default route on the failed primary interface. During failover, the outbound network traffic is established from the secondary connection.
Dormant Failover Mode
This mode combines Always Up and Failover mode. Failover detection is enabled, however the secondary interface is kept in a dormant up state. Only inbound connections on the cellular interface are routed back out the cellular interface, to enable Out-of-Band access from remote networks.
When failover is initiated, the default route of the secondary interface takes precedence over the failed primary interface. Outbound network traffic is established out the secondary connection during failover.
Implementing Failover To Cellular
There are many advantages to having Failover To Cellular. Providing remote access even when the WAN and LAN networks are down, engineers have the ability to quickly remediate the issue while having full network visibility. Failover To Cellular is a necessity for enterprises looking to ensure resilience and keep the network running at all times. To learn more about this technology, visit https://opengear.com/solution/failover-to-cellular.
[1] https://www.aberdeen.com/techpro-essentials/stat-of-the-week-the-rising-cost-of-downtime/
