Interaction Between A Pce And A Pcc Using Pcep - Juniper ACX1000 Configuration Manual

ACX Series Universal Access Router Configuration Guide
698
The PCC re-signals an LSP based on the computed path it receives from a PCE. When
the PCEP session with the main PCE is terminated, the PCC elects a new main PCE, and
all delegated LSPs to the previously main PCE are delegated to the newly available main
PCE.
Path Computation Element Protocol
The Path Computation Element Protocol (PCEP) is used for communication between
PCC and PCE (as well as between two PCEs) (RFC 5440). PCEP is a TCP-based protocol
defined by the IETF PCE Working Group, and defines a set of messages and objects used
to manage PCEP sessions and to request and send paths for multidomain TE LSPs. The
PCEP interactions include PCC messages, as well as notifications of specific states
related to the use of a PCE in the context of MPLS RSVP-TE. When PCEP is used for
PCE-to-PCE communication, the requesting PCE assumes the role of a PCC.
Thus, the PCEP functions include:
LSP tunnel state synchronization between PCC and a stateful PCE.
Delegation of control over LSP tunnels to a stateful PCE.

Interaction Between a PCE and a PCC Using PCEP

Figure 38 on page 698 illustrates the relationship between a PCE, PCC, and the role of
PCEP in the context of MPLS RSVP-TE.
Figure 38: PCC and RSVP-TE
The PCE to PCC communication is enabled by the TCP-based PCEP. The PCC initiates
the PCEP session and stays connected to a PCE for the duration of the PCEP session.
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