PCE Path Profiles

PCEP peers advertise their capability to support path profile identifiers during the session initialization phase. They include the PATH-PROFILE-CAPABILITY TLV defined in as part of the OPEN object. A PCEP peer can only signal path profile identifiers if both peers advertised this capability. A peer MUST send a PCErr message with Error-Type=4 (Not supported object), Error-value=1 (Not supported object class) and close the session if it receives a message with a path profile identifier, it supports the extensions in this document and both peers did not advertise this capability.

A PCC MAY include a PATH-PROFILE object when sending a PCReq message. The PCE uses the path profile identifier to select path parameters or path policies to fulfill the request. The means by which the PCC learns about a particular path profile identifier and decides to include it in a PCReq message are outside the scope of this document. Similarly, the means by which the PCE selects a set of parameters or policies based on the profile identifier for a specific request are outside the scope of this document. The P flag of the PATH-PROFILE object MUST be set. A PCE may receive a path computation request with an unknown or invalid path profile identifier. The PCE sends a PCErr message with Error-Type=[TBA] (PATH-PROFILE Error), Error-value=1 (Unknown path profile) if the path profile identifier is not known to the PCE. The PCE sends a PCErr message with Error-Type=[TBA] (PATH-PROFILE Error), Error-value=2 (Invalid path profile) if the PCE knows about the path profile identifier, but considers the request invalid. As an example, the profile may be invalid because of the path type, the PCEP session type or the originating PCC. The PCEP-ERROR object SHOULD include the path profile identifiers that generated the error condition. The PCE will determine whether to consider any additional optional objects included in a PCReq message based on policy. As illustrated in and , the PCC MAY include other optional objects along with a PATH-PROFILE object as part of a path computation request. The PCC will use the processing-rule (P) flag in the common object header to signal whether it considers those objects mandatory or optional when the PCE performs path computation. Those objects may overlap with the path parameters that the PCE associates with the path profile identifier. PCE policy may place different kinds of restrictions on PCReq messages that include a PATH-PROFILE object and additional parameters. A PCE MUST send an error message if it receives a request with optional objects signaled as mandatory (P flag = 1) for path computation and PCE policy does not allow such behavior from the originating PCC. In that case, the PCE sends a PCErr message with Error-Type=[TBA] (PATH-PROFILE Error), Error-value=3 (Unexpected mandatory object). If the objects are signaled as optional (P flag = 0) for path computation, the PCE will decide based on policy whether to consider them or not. When sending the PCRep message for the request, the PCE will use the ignore (I) flag in the common object header to indicate to the PCC whether an object was ignored.

defines the basic structure of a PCReq message for point-to-point paths. This documents extends the message format as follows:

::= [] ]]> where:

::=[] ::=[] ::=

[] [] ]]>

where: <path-computation> is the list of optional objects used for path computation as defined initially in and modified in subsequent PCEP extensions. If present in a PCReq message, the PATH-PROFILE object MUST be the first optional object in the request portion of the message.

defines the basic structure of a PCReq message for point-to-multipoint paths. This documents extends the message format as follows: TBD

A PCE MAY include a PATH-PROFILE object when sending a PCInitiate message as defined in . The PCC uses the path profile identifier to select path parameters or path policies to be applied during the instantiation of the path. The means by which the PCE learns about a particular path profile identifier and decides to include it in a PCInitiate message are outside the scope of this document. Similarly, the means by which the PCC selects a set of parameters or policies based on the profile identifier for a specific path are outside the scope of this document. A PCC may receive a path instantiation request with an unknown or invalid path profile identifier. The PCC sends a PCErr message with Error-Type=[TBA] (PATH-PROFILE Error), Error-value=1 (Unknown path profile) if the path profile identifier is not known to the PCC. The PCC sends a PCErr message with Error-Type=[TBA] (PATH-PROFILE Error), Error-value=2 (Invalid path profile) if the PCC knows about the path profile identifier, but considers the request invalid. As an example, the profile may be invalid because of the path type, the PCEP session type or the originating PCE. The PCEP-ERROR object SHOULD include the path profile identifiers that generated the error condition. defines the basic structure of a PCInitiate message. This documents extends the message format as follows:

::=

Where: ::= [] ::= (| ) ::=

[PATH-PROFILE> [] ::= ]]>

where: <attribute-list> is defined in and extended by PCEP extensions.