In physically in-path deployments, link state propagation (LSP) helps communicate link status between the devices connected to the SteelHead. When this feature is enabled, the link state of each SteelHead LAN and WAN pair is monitored. If either physical port loses link status, the link of the corresponding physical port is also brought down. Link state propagation allows link failure to quickly propagate through the SteelHead, and it is useful in environments where link status is used as a fast-fail trigger.

For example, in a physical in-path deployment where the SteelHead is connected to a router on its WAN port and a switch on its LAN port, if the cable to the router is disconnected, the SteelHead deactivates the link on its LAN port. This causes the switch interface that is connected to the SteelHead to also lose the link. The reverse is also true: if the cable to the switch is disconnected, the router interface that is connected to the SteelHead loses the link.

You can use LSP in a SteelHead serial cluster. In a serial cluster deployment, link state propagation can be useful to quickly propagate failure if the cables between SteelHeads are disconnected. For example, in a two-appliance SteelHead serial cluster, if you disconnect the cable between the SteelHeads, then both the WAN-side router and the LAN-side switch lose the link.

Link state propagation is supported on either all or none of the interfaces of a SteelHead; it cannot be used to selectively activate an in-path interface.

Connect to the SteelHead CLI and enter the following commands:

In RiOS v6.0 or later, link state propagation is enabled by default.

These SteelHead-v configurations do not support LSP: