LABEL ASSIGNING METHOD, LABEL REPLACING METHOD AND LABEL SWITCHING ROUTER

摘要

A label assigning method for use when a label being used in a unicast Label Switched Path (LSP) between an upstream Label Switching Router (LSR) and a downstream LSR is to be used in a multicast LSP between the upstream LSR and the downstream LSR. The assignment method includes the steps of releasing the label in the unicast LSP, and assigning the label to the multicast LSP. A label replacing method for use when a first label being used in a unicast LSP between an upstream LSR and a downstream LSR is to be used in another LSP between the upstream LSR and the downstream LSR. The replacement method includes the steps of re-assigning a second label for the unicast LSP and releasing the first label in the unicast LSP. These two processes are directed to efficiently establishing a multicast LSP when a conflict of labels occurs between the multicast LSP and an existing unicast LSP.