Explicit Notification for LDP-IGP Synchronization
A fundamental concept in Label Distribution Protocol - Interior Gateway Protocol (LDP-IGP) Synchronization is that LDP is fully established before the IGP path is switched for IP forwarding. This document proposes a mechanism to affirm the switching time accurately by propagating a explicit notification from downstream. The interoperability with other Label Switched Routers (LSRs), which may not support the mechanism, is also considered.