| 摘要 |
<p>An hierarchical LSP is established to transport packets belonging to a FEC attached to an egress LSR and includes an egress LSR LSP that is common for each of the FECs attached to the egress LSR and forms a path from the ingress LSR through intermediate LSR(s) to the egress LSR. The egress LSR LSP is used when label switching packets destined for the FECs attached to the egress LSR. The hierarchical LSP also includes a unique FEC LSP for each FEC that is used by the egress LSR to identify and forward packets to that FEC. Responsive to a topology change that changes a next-hop of the ingress LSR to reach the egress LSR, the ingress LSR modifies an entry in a forwarding structure to change the next-hop for the egress LSR LSP and does not modify substantially any forwarding structure entities for the FEC LSPs.</p> |
