Explanation

To avoid having to rebuild the LDP session altogether, you can protect it. When the LDP session

between two directly connected LSRs is protected, a targeted LDP session is built between the two

LSRs. When the directly connected link does go down between the two LSRs, the targeted LDP session

is kept up as long as an alternative path exists between the two LSRs.

For the protection to work, you need to enable it on both the LSRs. If this is not possible, you can

enable it on one LSR, and the other LSR can accept the targeted LDP Hellos by configuring the

command mpls ldp discovery targeted-hello accept.