Allocating and distributing labels for packet encapsulation

摘要

In one example, a network device receives a packet to be forwarded according to a label switching protocol, determines a service to be performed on the packet by a service network device, sends a label request message to the service network device, wherein the label request message indicates support for labels having a particular length, wherein the particular length is larger than twenty bits (e.g., forty bits), and wherein the label request message specifies the service to be performed on the packet, receives, in response to the label request message, a label mapping message defining a label of the particular length, appends the label to the packet to form a Multi-Protocol Label Switching (MPLS)-encapsulated packet, and forwards the MPLS-encapsulated packet according to the label switching protocol.

主权项

1. A method comprising:
sending, by a first network device, a label request message to request a label mapping from a second network device, wherein the label request message indicates support for labels having a particular length larger than twenty bits, and wherein the label request message specifies a service provided by the second network device and to be performed on packets subsequently forwarded to the second network device in accordance with the label mapping; receiving, in response to the label request message, a label mapping message including a type value indicating that the label mapping message includes a label having the particular length larger than twenty bits and specifying the label of the particular length, wherein the type value of the label mapping message is different than a type value for label mapping messages that define twenty-bit labels; appending, by the first network device, the label to a packet to form a Multi-Protocol Label Switching (MPLS)-encapsulated packet; and forwarding, by the first network device, the MPLS-encapsulated packet according to a label switching protocol.