Provides guidelines for managing cellular interfaces as circuits of last resort or active circuits. These configurations impact bandwidth consumption and control connection stability on edge devices.
Circuit of last resort
Configure an interface as a circuit of last resort to ensure it remains dormant and is skipped during control connection calculations while primary interfaces are active. Use the last-resort-circuit command to enable this functionality on cellular or GigabitEthernet interfaces.
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Ensure that when primary interfaces establish BFD connections, the circuit of last resort shuts down to prevent unnecessary traffic.
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Recognize that the circuit of last resort activates only when all primary interfaces lose their connections, which triggers BFD TLOC Down and Control TLOC Down alarms.
Active circuit
Optimize bandwidth usage when using a cellular interface as an active circuit by adjusting control packet timers and prioritizing non-cellular interfaces for control traffic.
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Increase control packet timers using omp timers advertisement-interval and bfd color hello-interval to reduce the frequency of OMP update packets and BFD hello packets.
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Configure the vmanage-connection-preference command on tunnel interfaces to prioritize non-cellular paths for Cisco SD-WAN Manager control traffic, ensuring at least one interface maintains a non-zero preference value.