Static cellular system IPv4 mode

In the static cellular system IPv4 mode of operation, the unnumbered interface under the PDN router interface is configured as the system interface. When the cellular port associated with the PDN interface attaches to the cellular network, the cellular network statically assigns an IP address to the node for the Access Point Name (APN) and associated installed Subscriber Identity Module (SIM). The system interface is then configured with the IP address that matches the cellular network-assigned IP address. The result is that the IP address provided by the cellular network for the PDN router interface and the system IP address of the node are identical.

A PDN router interface is considered operationally up only when the associated cellular port attaches to the network and an IP address is learned from the cellular attachment. The system checks whether the LTE network-assigned IP address matches the system IP address configured on the PDN interface. If it does not match, the PDN router interface is considered down and an alarm is raised.

The CLI output below shows an example of a PDN interface configured for static cellular system IPv4 mode.

*A:DUT# config# router
                interface "system"
                   address 88.0.0.1/32
                   no shutdown
                exit
                interface "pdn1-sim1" pdn
                   port 1/1/1
                   unnumbered "system"
                   no shutdown
                exit
           exit
      exit

When operating in static cellular system IPv4 mode, the following points apply.

  • Only one cellular IP address can be used on the node. This affects dual SIM operation. If the PDN router interface of one of the dual SIM cellular ports is operating in static cellular system IPv4 mode, then the other PDN router interface must also operate in static cellular system IPv4 mode. The cellular network for each SIM must allocate the same system IP address when the node attaches to the cellular network over either cellular port.

  • Some wireless service providers require that all packets entering their network from user equipment (UE) attached to their network have a source IP address that matches the IP address that the cellular network assigned to the UE. When this is a requirement and the node is using static cellular system IP mode, the PDN interface must be configured with an IP filter that allows only egress packets with a source IP address that matches the system IP address.

  • The NSP NFM-P does not require an in-band management VPRN service to manage the node. Instead, the NSP NFM-P uses the system IP address to reach the node.