Label distribution device used for informing upper course to distribute label in label distribution protocol

Abstract

The invention provides a label distribution device used to inform upstream of distributing labels in the label distribution protocol. The device comprises: a carrying and sending unit positioned at the downstream and used to carry a special label type TLV in a label request message sent to the upstream; an analytic unit positioned at the upstream and used to analyze the special label type TLV after the label request message with the special label type TLV is received; and a distribution unit used to distribute the label with corresponding type for forwarding equivalence class according to the field value in the special label type TLV. So an upstream LSR as the penultimate hop of a certain FEC can distribute an implicit null label to the FEC to be taken as an out-label under the upstream label distribution mode, thereby realizing the pop-up of the penultimate hop.

Description

technical field [0001] The present invention relates to a label distribution protocol (Label Distribute Protocol, hereinafter referred to as LDP) technology in a multi-protocol label switching (Multi Protocol Label Switch, hereinafter referred to as MPLS) network, and more specifically, relates to a label distribution protocol used in A label dispensing device that distributes labels upstream is notified. Background technique [0002] Usually, at the last hop of a label switching path (Label Switch Path, hereinafter referred to as LSP), the label switching router (Label Switch Router, hereinafter referred to as LSR) will give the corresponding forwarding equivalence class (Forwading Equivalence Class, hereinafter referred to as For FEC) bind an empty label as an incoming label (either implicitly empty or explicitly empty). [0003] The purpose of allocating implicit null is to use this label to tell the LSR of the last hop that when receiving the label message sent to the F...

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Problems solved by technology

[0004] However, in the upstream distribution label mode, the upstream outbound label is distributed by the upstream itself, and the upstream cannot know that it is the last hop of the FEC, so it cannot assign an implicit empty label as its own outbound label, but only A normal label can be distributed, resulting in the inability to pop up at the last hop, and the packet still carries a normal label after reaching the last hop

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