Dynamic cellular interface IPv4 mode

When a PDN router interface is configured for dynamic cellular interface IPv4 mode, consider the following points when setting up a service a over PDN router interface and its associated cellular port:

  • The system IP address used to manage the node is not the same as the cellular PDN interface IP address assigned during the cellular attachment procedure.

  • The PDN interface IP address changes every time the PDN reattaches to the cellular network

  • SDP configurations cannot be made from other nodes to the local node. The changing IP address of the PDN interface during each PDN attachment procedure inhibits the static configuration needed to manually configure SDPs.

  • T-LDP signaling sessions cannot be established toward the local node because the changing PDN interface IP address inhibits the static configuration of T-LDP sessions toward the PDN interface.

  • BGP sessions cannot be established toward the local node because the changing PDN interface IP address inhibits the static configuration of BGP sessions toward the PDN interface.

  • BGP sessions from the local node to peers where MP-BGP and BGP routing is required for services must use the PDN interface IP address as the source IP address for these sessions. Operators must specify the loopback interface of the PDN router interface when configuring the BGP local-address command. For information about configuring the BGP local address, see Using a router interface address as the BGP local address. When the local-address command is configured with the loopback interface of the PDN router interface, BGP sets the source IP address of session packets to the PDN interface IP address.

  • BGP far-end peering nodes to the local node must be configured with the dynamic-neighbor command using an IP address range that matches the possible PDN router interface attachment IP addresses on the local node. This allows the PDN interface IP address to dynamically change and re-establish BGP sessions to the same far-end peering node. For information about the dynamic-neighbor command, see the 7450 ESS, 7750 SR, 7950 XRS, and VSR Classic CLI Command Reference Guide.

  • Only services that use auto-bind or auto-gre-sdp can operate with dynamic cellular interface IP mode. The 7705 SAR-Hm series supports MP-BGP-based VPRN services with auto-bind, and BGP-VPLS and BGP-VPWS with auto-gre-sdp.

  • Dynamic cellular interface IP mode does not support the following services:

    • Layer 2 services that use T-LDP signaling

    • Layer 3 services that do not use auto-bind

When dual SIM operation is required, the points listed above must be considered for each PDN router interface configured for each SIM.