If one node cannot exchange signaling messages—that is, if both signaling Ethernet ports of the Linux bonding driver are unavailable—it tries to send messages via the partner node as long as the cross-channel is available.
In case of signalling network failure, there will be a call processing outage for the affected node.
Connected devices can switch their signaling to the IP address of the partner node. But in a shared network configuration, connected devices are usually configured with only one IP address relying on this virtual IP address to move to the partner node. This however, is only done after a node failure.
Parent topic: Cluster Redundancy
Double Failures with Collocated Nodes