How it Works

UPF directly connects gNB on N3 router or Server on N6 router in the same subnet. UPF ICSR will not be visible to gNB/N3 and Server/N6.

The L2 switch supports BFD. On all N3 and N6 subnets, the switch must have an IP address.

UPF requires Chassis-Chassis (C-R) BFD and Chassis-Router (C-R) BFD for the L2 ICSR solution to work. To avoid the Active-Active state, BFD runs between C-C and C-R. C-C BFD must have a higher timeout value than C-R BFD.

For a two-leaf network design and non-bonded UPF interfaces, each UPF connects to a separate leaf. The IP addresses of the L2 switch are part of the leaf.

The following figure illustrates the high-level diagram of L2 switch wiring for non-bonded interfaces.

L2 Switch Wiring for Non-Bonded Interfaces