Cisco Crosswork Planning Design 7.2.x User Guide

Actual paths

Updated: August 14, 2026

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Describes how actual paths are used in LSP routing simulations and how their states affect overall MPLS routing predictions.

Actual path is a path that

represents the real routes taken by routed LSP paths
is read from the live network, per LSP path, and
reflects current LSP path states, including successful and failed routings.

RSVP-TE routing is not always completely predictable because it depends on the order in which LSPs are established and reserve their bandwidth on the network. Cisco Crosswork Planning uses actual paths in LSP routing simulations to match the current LSP routing state of a network as accurately as possible.

When an LSP path is routed, the actual route is attempted first. If this routing fails due to CSPF constraints, such as not enough reservable bandwidth or affinity restrictions, Cisco Crosswork Planning reverts to the standard CSPF routing algorithm.

Example

Cisco Crosswork Planning routes all LSPs in its simulation according to the actual paths read from the network, and the routings completely match the network. If a circuit fails, only the LSPs through this circuit are rerouted. Because they cannot be established along their actual paths, standard CSPF is used. The result is a prediction of incremental routing changes that would occur on the current network if such a failure were to occur.

An LSP or an LSP path might have a corresponding actual path. An LSP path with no actual path inherits its LSP actual path, if available.

Two columns in the LSPs and LSP Paths tables are useful to refer to the result of actual paths on LSP routing.


Column	Description
Actual column in the LSP Paths table	The simulation can only use actual paths if they are resolved. If the network discovery was incomplete, this might not be possible. true = the simulation converted the actual path hops into a complete path from source to destination of the LSP false = the simulation did not convert the actual path hops into a complete path NA = not applicable; no actual path was available.
Routed column in the LSPs table	Actual = The LSP follows an actual path. Simulated = The LSP does not follow an actual path. Unrouted = Routing was not possible.

Deactivate actual paths for simulations

Normally, the simulation routes LSPs using actual paths based on current network state and LSP active path settings. For planning purposes, when state is not relevant, you can change this behavior to disregard actual paths.

Procedure

	1.	Open the plan file (refer to Open plan files). It opens in the Network Design page.
	2.	In the toolbar, click or choose Actions > Edit > Network options. The Network options page opens.
	3.	Click the Simulation tab.
	4.	To use or disregard actual paths and active paths in MPLS simulation, check or uncheck Use LSP actual paths, active paths check box.
	5.	Save your changes.

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