Path Computation Element - Cisco CRS Configuration Manual

Implementing MPLS Traffic Engineering
Bandwidth configuration
Load shares are not dependent on any configuration other than the load share and bandwidth configured
Note
on the tunnel and the state of the global configuration switch.
Related Topics
Setting Unequal Load Balancing Parameters, on page 278
Enabling Unequal Load Balancing, on page 279
Configure Unequal Load Balancing: Example, on page 350

Path Computation Element

Path Computation Element (PCE) solves the specific issue of inter-domain path computation for MPLS-TE
label switched path (LSPs), when the head-end router does not possess full network topology information
(for example, when the head-end and tail-end routers of an LSP reside in different IGP areas).
PCE uses area border routers (ABRs) to compute a TE LSP spanning multiple IGP areas as well as computation
of Inter-AS TE LSP.
PCE is usually used to define an overall architecture, which is made of several components, as follows:
Path Computation Element (PCE)
Path Computation Client (PCC)
PCC-PCE communication protocol (PCEP)
If a tunnel is not configured with load-sharing parameters, the tunnel bandwidth and load-share values
are considered equivalent for load-share calculations between tunnels, and a direct comparison between
bandwidth and load-share configuration values is calculated.
Represents a software module (which can be a component or application) that enables the router to
compute paths applying a set of constraints between any pair of nodes within the router's TE topology
database. PCEs are discovered through IGP.
Represents a software module running on a router that is capable of sending and receiving path
computation requests and responses to and from PCEs. The PCC is typically an LSR (Label Switching
Router).
Specifies that PCEP is a TCP-based protocol defined by the IETF PCE WG, and defines a set of messages
and objects used to manage PCEP sessions and to request and send paths for multi-domain TE LSPs.
PCEP is used for communication between PCC and PCE (as well as between two PCEs) and employs
IGP extensions to dynamically discover PCE.
Cisco IOS XR MPLS Configuration Guide for the Cisco CRS Router, Release 5.1.x
Path Computation Element
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