Path Protection in an MPLS Network

The JUNOS software implementation of Mutiprotocol Label Switching (MPLS) provides several complementary mechanisms for protecting against Resource Reservation Protocol (RSVP)-signaled LSP failures, including path protection (primary and secondary paths), and local protection (the fast reroute statement, link protection, and node-link protection). This chapter describes path protection supported by the JUNOS software. (See Table 5.)

Table 5: Checklist for Path Protection

Path Protection Tasks	Command or Action
Path Protection Overview
Configuring and Verifying a Primary Path
Configure a Primary Path	[edit] edit protocols mpls [edit protocols mpls] set path path-name address < strict | loose > set label-switched-path lsp-path-name to destination [edit protocols mpls label-switched-path lsp-path-name] set primary primary-name set primary primary-name bandwidth bandwidth set primary primary-name priority reservation-priority      setup-priority show commit
Verify That the Primary Path Is Operational	show mpls lsp extensive ingress show rsvp interface
Configuring and Verifying a Secondary Path
Configure a Standby Secondary Path	[edit] edit protocols mpls [edit protocols mpls] set path path-name destination loose set label-switched-path lsp-path-name secondary      secondary-name standby show commit
Verify That the Secondary Path Is Established	Deactivate a link or node critical to the primary path. show mpls lsp extensive
Ensuring That Secondary Paths Establish When Resources Are Diminished	Configure different bandwidth values for the primary and secondary paths. For example: [edit protocols mpls] edit label-switched-path lsp-path-name set primary primary-name bandwidth bandwidth show commit In this example, no bandwidth is configured for the secondary path.
Preventing Use of a Path That Previously Failed	Configure only multiple secondary paths.