NOTE: Starting with Junos OS Release 16.1, you can secure a PCEP session
using TCP-MD5 authentication as per RFC 5440. To enable the MD5 security
mechanism for a PCEP session, it is recommended that you define and bind
the MD5 authentication key at the [edit protocols pcep pce pce-id] hierarchy
level for a PCEP session. You can, however, also use a predefined keychain
from the [edit security authentication-key-chains key-chain] hierarchy level to
secure a PCEP session. In this case, you should bind the predefined keychain
into the PCEP session at the [edit protocols pcep pce pce-id] hierarchy level.
The PCE and PCC use the same key to verify the authenticity of each segment
sent on the TCP connection of the PCEP session, thereby securing the PCEP
communication between the devices, which might be subject to attacks and
can disrupt services on the network.
For more information on securing PCEP sessions using MD5 authentication,
see “TCP-MD5 Authentication for PCEP Sessions” on page 705.
Once the PCEP session is established, the PCC performs the following tasks:
1. LSP state synchronization—The PCC sends information about all the LSPs (local and
external) to all connected PCEs. For external LSPs, the PCC sends information about
any configuration change, RRO change, state change, and so on, to the PCE.
For PCE-initiated LSPs, there is no LSP configuration present on the PCC. The PCE
initiating the LSP sends the LSP parameters to the PCC that has indicated its capability
of supporting PCE-initiated LSPs.
NOTE: Support for PCE-initiated LSPs is provided in Junos OS Release
13.3 and later releases.
2. LSP delegation—After the LSP state information is synchronized, the PCC then
delegates the external LSPs to one PCE, which is the main active stateful PCE. Only
the main PCE can set parameters for the external LSP. The parameters that the main
PCE modifies include bandwidth, path (ERO), and priority (setup and hold). The
parameters specified in the local configuration are overridden by the parameters that
are set by the main PCE.
NOTE: 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.
In the case of PCE-initiated LSPs, the PCC creates the LSP using the parameters
received from the PCE. The PCC assigns the PCE-initiated LSP a unique LSP-ID, and
automatically delegates the LSP to the PCE. A PCC cannot revoke the delegation for
the PCE-initiated LSPs for an active PCEP session.
699Copyright © 2017, Juniper Networks, Inc.
Chapter 23: Configuring Path Computation Element Protocol (PCEP)
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