Features that strengthen redundancy and prevent device lag time support operational efficiency
In manufacturing plants, warehouses, mines, and large technology-dependent spaces, private 5G networks are becoming essential. But among the influx of private 5G rollouts, challenges do arise — especially related to problems with the network controllers, which house the cellular core.
What do you do when user devices don't reattach or reauthenticate during network controller failure or restart? And when most private 5G deployments feature a primary and backup controller housed in the same spot, how do you address the likely scenario of both going down at the same time?
With private 5G, failover is directly tied to the fact that most robust private 5G deployments involve two network controllers, in case issues arise with the primary controller.
Session continuity and georedundancy are two complementary private 5G features that work together to make failover as reliable and fast as possible — an important capability for the business-critical applications that enterprises run on private 5G networks.
Session continuity keeps operations moving
Historically, Ericsson Private 5G deployments used a pair of network controllers configured as active-active for both the control plane and the user plane. In that scenario, basebands load-balanced traffic across the two active controllers. If one controller failed, all devices attached to that controller would fail over to the other controller while preserving the devices' IP addresses.
However, the failover process required the affected devices to reattach to the backup network controller, a process that could take 20 seconds to more than a minute. In some cases, devices failed to reconnect automatically and required manual intervention, increasing downtime for the applications that depended on those connections.
Today, Ericsson Private 5G's session continuity feature reduces those interruptions when the primary controller fails over to the secondary controller. The network controllers are synchronized: When the sessions on the first controller are interrupted, those same sessions continue running on the secondary controller, without devices having to reattach.
How does this work? Device sessions are replicated across the two controllers so that session state is available to either one. Basebands still load balance control plane sessions across both network controllers in an active-active configuration, but the user plane operates in an active-standby mode so an active controller can hand off user-plane traffic to the standby controller instantly.
Because sessions are already replicated and available on the second controller, most existing sessions are taken over immediately. In short, session continuity reduces time to availability for devices and minimizes downtime for business-critical applications.
Geographic redundancy: The secret to always-on private networks
Geographic redundancy, or georedundancy, addresses a different but related risk: the possibility that both controllers could fail simultaneously if they are co-located and affected by the same site-level event.
Some private 5G scenarios involve the two controllers being directly connected and co-located, which can leave deployments vulnerable to single-site failures. To reduce this risk, enterprise IT teams sometimes require redundant equipment to be housed in different locations.
Ericsson Private 5G's optional georedundancy feature lets an enterprise place the secondary controller in a different city, state, or even country while using the enterprise transport network to connect the two physically separated controllers and to connect the controllers to the basebands. Encrypted IPsec tunnels can be used to secure any sensitive traffic between sites.
Physically separating the primary and secondary controllers dramatically lowers the likelihood that both will fail at the same time. Georedundancy already is a common practice with Wi-Fi deployments and now is a practical option for private cellular networks as well.
Together, session continuity and georedundancy offer a powerful combination: Session continuity minimizes downtime for devices and accelerates failover at the session level, while georedundancy improves resiliency of the network through reducing the chance of simultaneous controller failures by distributing critical infrastructure across different locations.
Learn more about the value of full-stack private 5G solutions.
