Refer to the exhibit.

Refer to the exhibit.

Router 1. Router 2. and Router 3 are co-located in an onsite data center of an office, but Router 4. Router 5. and Router 6 are installed in another data center 'eral miles away. A network engineer is troubleshooting an RSVP-TE issue on the network. On most of the devices, the engineer can move all LSPs away from a selected dace and take it down for maintenance without interrupting traffic. However, when an interface on Router 3 is taken down, traffic on the network is disrupted. What must the engineer enable to resolve the issue on Router 3?