Before You Configure Shared Interfaces

Before you configure shared interfaces, remember that on the Root System Domain (RSD), you configure the physical interface and then configure and assign each logical shared interface under it to a specific Protected System Domain (PSD).

On the PSD, you configure the physical interface as well and identify it as a shared interface. Then configure the assigned logical interfaces under it and bind each one to a peer interface on the Tunnel PIC owned by the PSD.

When you configure shared interfaces, the values for several parameters configured on the RSD and the PSD must match:

• On the physical SONET interface, Frame Relay encapsulation must be configured in both the RSD and the PSD. (Point-to-multipoint Frame Relay is not supported.) Frame Relay encapsulation enables a change in state to be communicated between the RSD and the PSD. Status is communicated through Local Management Interface (LMI) packets exchanged on data-link connection identifier (DLCI) 0. LMI packet exchanges are managed by the RSD.

  On the physical Gigabit Ethernet interface, VLAN tagging must be configured in both the RSD and the PSD.

• On the physical SONET interface, the same maximum transmission unit (MTU) size must be used in both the RSD and PSD. For example, in both the RSD and PSD, do not include any MTU configuration to allow the default MTU size to be applied to the physical interface. Or, in both the RSD and PSD, configure the same MTU size. For example, in both the RSD and PSD configuration, include the mtu 5000 statement under the [edit so-0/0/1] hierarchy level.
• The same logical unit number must be specified on the physical shared interface (so-fpc/pic/slot.logical unit-number, ge-fpc/pic/slot.logical unit-number, or xe-fpc/pic/slot.logical unit-number) and on the physical uplink tunnel interface (ut-fpc/pic/slot.logical unit-number) owned by the PSD. For example, in both the RSD and PSD configuration, specify so-0/0/0.1 as the logical SONET interface. In the PSD configuration, configure ut-0/0/0.1 as the logical peer tunnel interface.
• On the logical SONET interface, the same DLCI must be configured in both the RSD and the PSD. For example, at the [edit interfaces so-0/0/0.1] hierarchy level, include the dcli 101 statement in both the RSD and PSD configuration.

  On the logical Ethernet interface, the same virtual LAN (VLAN) identifier must be configured in both the RSD and the PSD. For example, at the [edit interfaces ge-0/0/0.2] hierarchy level, include the vlan-id 102 statement in both the RSD and PSD configuration.