Path Computation Element (PCE)
Protocol Extensions for Stateful PCE usage for
Point-to-Multipoint Traffic Engineering Label Switched
PathsHuawei TechnologiesDivyashree Techno Park, WhitefieldBangaloreKarnataka560066Indiaudayasreereddy@gmail.comHuawei
TechnologiesDivyashree Techno Park, WhitefieldBangaloreKarnataka560066Indiadhruv.ietf@gmail.comNTT Communications
CorporationGranpark Tower3-4-1 Shibaura, Minato-kuTokyo108-8118Japanyosuke.tanaka@ntt.comJuniper Networksvbeeram@juniper.net
Routing
PCE Working GroupThe Path Computation Element (PCE) has been identified as
an appropriate technology for the determination of the paths
of point-to-multipoint (P2MP) TE LSPs.
This document provides
extensions required for Path Computation Element communication Protocol (PCEP) so as to enable the usage of a
stateful PCE capability in supporting P2MP TE LSPs.As per
, the Path Computation Element (PCE)
is an entity that is capable of computing a network path or
route based on a network graph, and applying computational
constraints. A Path Computation Client (PCC) may make
requests to a PCE for paths to be computed. describes how to set up
point-to-multipoint (P2MP) Traffic Engineering Label Switched
Paths (TE LSPs) for use in Multiprotocol Label Switching
(MPLS) and Generalized MPLS (GMPLS) networks. The PCE has
been identified as a suitable application for the computation
of paths for P2MP TE LSPs ().The PCEP is designed as a communication protocol between
PCCs and PCEs for point-to-point (P2P) path computations and
is defined in
. The extensions of PCEP to request
path computation for P2MP TE LSPs are described in
.Stateful PCEs are shown to be helpful in many application
scenarios, in both MPLS and GMPLS networks, as illustrated in
. These
scenarios apply equally to P2P and P2MP TE LSPs.
provides the
fundamental extensions needed for stateful PCE to support
general functionality for P2P TE LSP. provides
the an extensions needed for stateful PCE-initiated
P2P TE LSP.
Complementarily, this
document focuses on the extensions that are necessary in
order for the deployment of stateful PCEs to support P2MP TE
LSPs. This document describes the setup, maintenance and
teardown of PCE-initiated P2MP LSPs under the stateful PCE
model.The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL
NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED",
"MAY", and "OPTIONAL" in this document are to be interpreted as
described in BCP 14 when, and only when, they
appear in all capitals, as shown here.Terminology used in this document is same as terminology
used in
,
, and
. presents several use cases, demonstrating scenarios
that benefit from the deployment of a stateful PCE
including optimization, recovery, etc which are equally
applicable to P2MP TE LSPs.
defines the
extensions to PCEP for P2P TE LSPs. Complementarily, this
document focuses on the extensions that are necessary in
order for the deployment of stateful PCEs to support P2MP TE
LSPs.In addition to that, the stateful nature of a PCE
simplifies the information conveyed in PCEP messages since
it is possible to refer to the LSPs via PLSP-ID
(). For P2MP
this is an added advantage, where the size of message is
much larger. In case of stateless PCE, a modification of
P2MP tree requires encoding of all leaves along with the
paths in PCReq message, but using a stateful PCE with P2MP
capability, the PCEP message can be used to convey only the
modifications (the other information can be retrieved from
the P2MP LSP identifier in the LSP database (LSPDB)).In environments where the P2MP TE LSP
placement needs to change in response to application
demands, it is useful to support dynamic creation and tear
down of P2MP TE LSPs. The ability for a PCE to trigger the
creation of P2MP TE LSPs on demand can be seamlessly
integrated into a controller-based network architecture,
where intelligence in the controller can determine when and
where to set up paths. Section 3 of
further describes the motivation behind the
PCE-Initiation capability, which are equally applicable for
P2MP TE LSPs.The objectives for the protocol extensions to support
P2MP TE LSP for stateful PCE are same as the objectives
described in section 3.2 of
. specifies new
functions to support a stateful PCE. It also specifies that a
function can be initiated either from a PCC towards a PCE
(C-E) or from a PCE towards a PCC (E-C).This document extends these functions to support P2MP TE
LSPs.both
the PCC and the PCE must announce during PCEP session
establishment that they support PCEP Stateful PCE
extensions for P2MP using mechanisms defined in
.after the
session between the PCC and a stateful PCE with P2MP
capability is initialized, the PCE must learn the state
of a PCC's P2MP TE LSPs before it can perform path
computations or update LSP attributes in a PCC.a stateful PCE
with P2MP capability requests modification of attributes
on a PCC's P2MP TE LSP.a PCC sends an LSP
state report to a PCE whenever the state of a P2MP TE LSP
changes.a PCC
grants to a PCE the right to update LSP attributes on one
or more P2MP TE LSPs; the PCE becomes the authoritative
source of the LSP's attributes as long as the delegation
is in effect (See Section 5.7 of
); the
PCC may withdraw the delegation or the PCE may give up
the delegation at any time.a PCE
sends an LSP Initiate Message to a PCC to instantiate or
delete a P2MP TE LSP.New PCEP messages are defined in
to support
stateful PCE for P2P TE LSPs. In this document these
messages are extended to support P2MP TE LSPs.
Each P2MP TE LSP State Report in a PCRpt message can
contain actual P2MP TE LSP path attributes, LSP status,
etc. An LSP State Report carried on a PCRpt message is
also used in delegation or revocation of control of a
P2MP TE LSP to/from a PCE. The extension of PCRpt
message is described in
.
Each P2MP TE LSP Update Request in a PCUpd message MUST
contain all LSP parameters that a PCE wishes to set for
a given P2MP TE LSP. An LSP Update Request carried on a
PCUpd message is also used to return LSP delegations if
at any point PCE no longer desires control of a P2MP TE
LSP. The PCUpd message is described in
.A new PCEP message is defined in
to support
stateful PCE instantiation of P2P TE LSPs. In this document this
message is extended to support P2MP TE LSPs.
is a PCEP message sent by a PCE to a PCC to trigger P2MP TE LSP
instantiation or deletion. The PCInitiate message is described in
.
The path computation request (PCReq) and path computation reply (PCRep)
messages are also extended to support stateful PCE for P2P TE LSP in
. In this document these
messages are extended to support P2MP TE LSPs as well.During PCEP Initialization Phase, as per Section 7.1.1
of
, PCEP
speakers advertises Stateful capability via Stateful PCE
Capability TLV in open message.
Two new flags are defined for the STATEFUL-PCE-CAPABILITY TLV
defined in and
updated in
and .
Three new bits N (P2MP-CAPABILITY), M (P2MP-LSP-UPDATE-CAPABILITY), and
P (P2MP-LSP-INSTANTIATION-CAPABILITY)
are added in this document:if
set to 1 by a PCC, the N Flag
indicates that the PCC is willing to send P2MP LSP State Reports whenever
P2MP LSP parameters or operational status changes.; if
set to 1 by a PCE, the N Flag indicates that the PCE is interested
in receiving LSP State Reports whenever LSP parameters or
operational status changes. The P2MP-CAPABILITY Flag must be
advertised by both a PCC and a PCE for PCRpt messages P2MP extension to be
allowed on a PCEP session.if
set to 1 by a PCC, the M Flag
indicates that the PCC allows modification of P2MP LSP parameters; if
set to 1 by a PCE, the M Flag indicates that the PCE is capable of
updating P2MP LSP parameters. The P2MP-LSP-UPDATE-CAPABILITY Flag must be
advertised by both a PCC and a PCE for PCUpd messages P2MP extension to be
allowed on a PCEP session.
If set to 1 by a PCC, the P Flag indicates that the PCC
allows instantiation of an P2MP LSP by a PCE. If
set to 1
by a PCE, the P flag indicates that the PCE supports
P2MP LSP instantiation. The P2MP-LSP-INSTANTIATION-CAPABILITY
flag must be set by both PCC and PCE in order to support
PCE-initiated P2MP LSP instantiation.A PCEP speaker should continue to advertise the basic P2MP
capability via mechanisms as described in
.
When PCCs are LSRs participating in the IGP (OSPF or IS-IS), and PCEs
are either LSRs or servers also participating in the IGP, an
effective mechanism for PCE discovery within an IGP routing domain
consists of utilizing IGP advertisements. Extensions for the
advertisement of PCE Discovery Information are defined for OSPF and
for IS-IS in and respectively.The PCE-CAP-FLAGS sub-TLV, defined in , is an optional sub-
TLV used to advertise PCE capabilities. It MAY be present within the
PCED sub-TLV carried by OSPF or IS-IS. and
provide the description and processing rules for this sub-TLV when
carried within OSPF and IS-IS, respectively.The format of the PCE-CAP-FLAGS sub-TLV is included below for easy
reference: Type: 5 Length: Multiple of 4. Value: This contains an array of units of 32 bit flags with the most
significant bit as 0. Each bit represents one PCE capability. PCE capability bits are defined in [RFC5088]. This document defines
new capability bits for the stateful PCE with P2MP as follows:Note that while active, passive or initiation stateful PCE with P2MP capabilities may be
advertised during discovery, PCEP Speakers that wish to use stateful
PCEP MUST advertise stateful PCEP capabilities during PCEP session
setup, as specified in the current document. A PCC MAY initiate
stateful PCEP P2MP capability advertisement at PCEP session setup even if it
did not receive any IGP PCE capability advertisements.State Synchronization operations described in Section
5.6 of
are
applicable for P2MP TE LSPs as well. The optimizations
described in
can also be applied for P2MP.LSP delegation operations described in Section 5.7 of
are
applicable for P2MP TE LSPs as well.LSP operations for passive stateful PCE described in
Section 5.8.1 of
are
applicable for P2MP TE LSPs as well.The Path Computation Request and Response message
format for P2MP TE LSPs is described in Section 3.4 and
Section 3.5 of respectively.The Request and Response message for P2MP TE LSPs are
extended to support encoding of LSP object, so that it is
possible to refer to a LSP with a unique identifier and
simplify the PCEP message exchange. For example, in case of
modification of one leaf in a P2MP tree, there should be
no need to carry the full P2MP tree in PCReq
message.The extension for the Request and Response message for
passive stateful operations on P2MP TE LSPs are described
in and
. The extension for the
Path Computation LSP State Report (PCRpt) message is
described in .LSP operations for active stateful PCE described in
Section 5.8.2 of
are
applicable for P2MP TE LSPs as well.The extension for the Path Computation LSP Update
(PCUpd) message for
active stateful operations on P2MP TE LSPs are described
in .As per section 5.1 of
, the
PCE sends a Path Computation LSP Initiate Request
(PCInitiate) message to the PCC to suggest instantiation or
deletion of a
P2P TE LSP. This document extends the PCInitiate message to
support P2MP TE LSP (see details in
).P2MP TE LSP suggested instantiation and deletion operations are
same as P2P LSP as described in section 5.3
and 5.4 of
. The Instantiation operation of P2MP TE LSP is same as
defined in section 5.3 of
including handling of PLSP-ID, SYMBOLIC-PATH-NAME TLV etc.
Rules of processing and error codes remains unchanged.
The N
bit MUST be set in LSP object in PCInitiate message by PCE
to specify the instantiation is for P2MP TE LSP.Though N bit is set in the LSP object,
P2MP-LSP-IDENTIFIER TLV MUST
NOT be included in the LSP object in PCIntiitate message as
it SHOULD be generated by PCC and carried in PCRpt message.The deletion operation of P2MP TE LSP is same as defined
in section 5.4 of
by
sending an LSP Initiate Message with an LSP object carrying
the PLSP-ID of the LSP to be removed and an SRP object with
the R flag set (LSP-REMOVE as per section 5.2 of
).
Rules of processing and error codes remains unchanged.Adding of new leaves and Pruning of old Leaves for
the PCE initiated P2MP TE LSP MUST be carried in PCUpd message
as per
for P2MP TE LSP extensions.
As defined in , leaf type = 1 for
adding of new leaves, leaf type = 2 for pruning of old leaves of
P2MP END-POINTS Object are used in PCUpd message.PCC MAY use the Incremental State Update mechanism as described
in to signal adding and pruning
of leaves.P2MP TE LSP delegation and cleanup operations are same
as defined in section 6 of
.
Rules of processing and error codes remains unchanged.As per Section 6.1 of
, PCRpt
message is used to report the current state of a P2P TE
LSP. This document extends the PCRpt message in reporting
the status of P2MP TE LSP.The format of PCRpt message is as follows:The P2MP END-POINTS object defined in
is mandatory for specifying
address of P2MP leaves grouped based on leaf types.New leaves to add (leaf type = 1)Old leaves to remove (leaf type = 2)Old leaves whose path can be modified/reoptimized (leaf type = 3)Old leaves whose path must be left unchanged (leaf type = 4)When reporting the status of a P2MP TE LSP, the
destinations are grouped in END-POINTS object based on the operational status (O
field in S2LS object) and leaf type (in END-POINTS). This way the leaves that share the same operational status are grouped together.
For reporting the status of delegated P2MP TE LSP, leaf-type = 3, where as for non-delegated
P2MP TE LSP, leaf-type = 4 is used.For delegated P2MP TE LSP configuration changes are reported via PCRpt message. For example,
adding of new leaves END-POINTS (leaf-type = 1) is used where as removing of old leaves (leaf-type = 2) is used. Note that we preserve compatibility with the
definition
of <state-report>. At least one instance of
<END-POINTS> MUST be present in this message for P2MP LSP.During state synchronization, the PCRpt message must report the status of the full P2MP TE LSP.The S2LS object MUST be carried in PCRpt
message along with END-POINTS object when N bit is set in
LSP object for P2MP TE LSP. If the S2LS object is missing, the receiving
PCE MUST send a PCErr message with Error-type=6 (Mandatory Object
missing) and Error-value=TBD11 (S2LS object missing). If the
END-POINTS object is missing, the receiving
PCE MUST send a PCErr message with Error-type=6 (Mandatory Object
missing) and Error-value=3 (END-POINTS object missing) (defined
in .As per Section 6.2 of
, PCUpd
message is used to update P2P TE LSP attributes. This
document extends the PCUpd message in updating the
attributes of P2MP TE LSP.The format of a PCUpd message is as follows:Note that we preserve compatibility with the
definition
of <update-request>.The PCC MAY use the make-before-break or sub-group-based
procedures described in based
on a local policy decision.The END-POINTS object MUST be carried in PCUpd
message when N bit is set in
LSP object for P2MP TE LSP. If the
END-POINTS object is missing, the receiving
PCC MUST send a PCErr message with Error-type=6 (Mandatory Object
missing) and Error-value=3 (END-POINTS object missing) (defined
in .As per Section 3.4 of
, PCReq
message is used for a P2MP path computation request.
This document extends the PCReq message such that a PCC MAY
include the LSP object in the PCReq message if the stateful PCE
P2MP capability has been negotiated on a PCEP session between
the PCC and a PCE.The format of PCReq message is as follows:As per Section 3.5 of
, PCRep
message is used for a P2MP path computation reply.
This document extends the PCRep message such that a PCE MAY
include the LSP object in the PCRep message if the stateful PCE
P2MP capability has been negotiated on a PCEP session between
the PCC and a PCE.The format of PCRep message is as follows:As defined in section 5.1 of
, PCE
sends a PCInitiate message to a PCC to recommend instantiation
of a P2P TE
LSP, this document extends the format of PCInitiate message
for the creation of P2MP TE LSPs but the creation and
deletion operations of P2MP TE LSP are same to the P2P TE
LSP.The format of PCInitiate message is as follows:The PCInitiate message with an LSP object with N bit
(P2MP) set is used to convey operation on a P2MP TE LSP.
The SRP object is used to correlate between initiation
requests sent by the PCE and the error reports and state
reports sent by the PCC as described in
.The END-POINTS object MUST be carried in PCInitiate
message when N bit is set in
LSP object for P2MP TE LSP. If the
END-POINTS object is missing, the receiving
PCC MUST send a PCErr message with Error-type=6 (Mandatory Object
missing) and Error-value=3 (END-POINTS object missing) (defined
in .LSP Update Request message is sent by an active
stateful PCE to update the P2MP TE LSP parameters or
attributes. An example of a PCUpd message for P2MP TE LSP
is described below:In this example, a stateful PCE request updation of
path taken by some of the leaves in a P2MP tree. The
update request uses the END-POINT type 3
(modified/reoptimized). The ERO list represents the S2LS
path after modification. The update message does not need
to encode the full P2MP tree in this case.LSP State Report message is sent by a PCC to report or
delegate the P2MP TE LSP. An example of a PCRpt message
for a delegated P2MP TE LSP is described below to add new leaves to
an existing P2MP TE LSP:An example of a PCRpt message for P2MP TE LSP is
described below to prune leaves from an existing P2MP TE
LSP:An example of a PCRpt message for a delegated P2MP TE LSP is
described below to report status of leaves in an
existing P2MP TE LSP:An example of a PCRpt message for a non-delegated P2MP TE LSP is
described below to report status of leaves:The PCEP TLV defined in this document is compliant with
the PCEP TLV format defined in
.LSP Object is defined in Section 7.3 of
. It
specifies PLSP-ID to uniquely identify an LSP that is
constant for the life time of a PCEP session. Similarly for
P2MP tunnel, PLSP-ID identify a P2MP TE LSP uniquely.
This document adds the following flags to the LSP
Object:If the bit is set to 1, it
specifies the message is for P2MP TE LSP which MUST be
set in PCRpt or PCUpd message for a P2MP TE LSP.If the bit is set
to 1, it specifies the message is fragmented.If P2MP bit is set, the following P2MP-LSP-IDENTIFIER
TLV MUST be present in LSP object.The P2MP LSP Identifier TLV MUST be included in the LSP
object in PCRpt message for RSVP-TE signaled P2MP TE LSPs. If
the TLV is missing, the PCE will generate an error with
error-type 6 (mandatory object missing) and error-value TBD12
(P2MP-LSP-IDENTIFIER TLV missing) and close the PCEP
session.The P2MP LSP Identifier TLV MAY be included in the LSP
object in PCUpd message for RSVP-TE signaled P2MP TE LSPs. The
special value of all zeros for this TLV is used to refer to
all paths pertaining to a particular PLSP-ID.There are two P2MP LSP Identifier TLVs, one for IPv4 and
one for IPv6.The format of the IPV4-P2MP-LSP-IDENTIFIER TLV is shown
in the following figure:The type (16-bit) of the TLV is TBD9 to be assigned by IANA. The length (16-bit) has a fixed value
of 16 octets. The value contains the following fields:contains the
sender node's IPv4 address, as defined in
, Section 4.6.2.1 for the
LSP_TUNNEL_IPv4 Sender Template Object.contains the 16-bit 'LSP ID'
identifier defined in
, Section 4.6.2.1 for the
LSP_TUNNEL_IPv4 Sender Template Object.contains the 16-bit 'Tunnel
ID' identifier defined in
, Section 4.6.1.1 for the
LSP_TUNNEL_IPv4 Session Object. contains the 32-bit
'Extended Tunnel ID' identifier defined in
, Section 4.6.1.1 for the
LSP_TUNNEL_IPv4 Session Object.contains the 32-bit 'P2MP ID'
identifier defined in Section 19.1.1 of
for the P2MP LSP Tunnel IPv4
SESSION Object.The format of the IPV6-P2MP-LSP-IDENTIFIER TLV is shown
in the following figure:The type of the TLV is TBD10 to be assigned by IANA. The length (16-bit) has a fixed length
of 40 octets. The value contains the following fields:contains the
sender node's IPv6 address, as defined in
, Section 4.6.2.2 for the
LSP_TUNNEL_IPv6 Sender Template Object.contains the 16-bit 'LSP ID'
identifier defined in
, Section 4.6.2.2 for the
LSP_TUNNEL_IPv6 Sender Template Object.contains the 16-bit 'Tunnel
ID' identifier defined in
, Section 4.6.1.2 for the
LSP_TUNNEL_IPv6 Session Object. contains the 128-bit
'Extended Tunnel ID' identifier defined in
, Section 4.6.1.2 for the
LSP_TUNNEL_IPv6 Session Object.As defined above in
IPV4-P2MP-LSP-IDENTIFIERS TLV.Tunnel ID remains
constant over the life time of a tunnel.The S2LS (Source-to-Leaves) Object is used to report RSVP-TE
state of one or more destinations (leaves) encoded within the
END-POINTS object for a P2MP TE LSP. It MUST be carried in PCRpt
message along with END-POINTS object when N bit is set in
LSP object.S2LS Object-Class is TBD19.S2LS Object-Types is 1.The format of the S2LS object is shown in the following
figure:the O Field
represents the operational status of the group of
destinations. The values are as per Operational field in LSP object defined in Section 7.3 of
.When N bit is set in LSP object then the O field in LSP
object represents the operational status of the full P2MP TE LSP and
the O field in S2LS object represents the operational status
of a group of destinations encoded within the END-POINTS
object.Future documents MAY define optional TLVs that MAY be included
in the S2LS Object.The total PCEP message length, including the common
header, is 16 bytes. In certain scenarios the P2MP report
and update request may not fit into a single PCEP message
(e.g. initial report or update). The F-bit is used in the LSP
object to signal that the initial report, update, or initiate
message was too
large to fit into a single message and will be fragmented
into multiple messages. In order to identify the single
report or update each message will use the same
PLSP-ID. In order to identify that a series of PCInitiate messages
represents a single Initiate, each message will use the
same PLSP-ID (in this case 0) and SRP-ID-number.Fragmentation procedure described below for report or
update message is similar to
which describes request and
response message fragmentation.If the initial report is too large to fit into a
single report message, the PCC will split the report over
multiple messages. Each message sent to the PCE, except
the last one, will have the F-bit set in the LSP object
to signify that the report has been fragmented into
multiple messages. In order to identify that a series of
report messages represents a single report, each message
will use the same PLSP-ID.To indicate P2MP message fragmentation errors associated
with a P2MP Report, a Error-Type (18) for "P2MP Fragmentation Error" and a new
error-value TBD13 is used if a PCE has not received the last
piece of the fragmented message, it should send an error
message to the PCC to signal that it has received an
incomplete message (i.e., "Fragmented Report failure").Once the PCE computes and updates a path for some or
all leaves in a P2MP TE LSP, an update message is sent to
the PCC. If the update is too large to fit into a single
update message, the PCE will split the update over
multiple messages. Each update message sent by the PCE,
except the last one, will have the F-bit set in the LSP
object to signify that the update has been fragmented
into multiple messages. In order to identify that a
series of update messages represents a single update,
each message will use the same PLSP-ID and
SRP-ID-number.To indicate P2MP message fragmentation errors associated
with a P2MP Update request, a Error-Type (18) for "P2MP Fragmentation Error" and a new
error-value TBD14 is used if a PCC has not received the last
piece of the fragmented message, it should send an error
message to the PCE to signal that it has received an
incomplete message (i.e., "Fragmented Update failure").Once the PCE initiates to set up the P2MP TE LSP, a
PCInitiate message is sent to the PCC. If the PCInitiate is
too large to fit into a single PCInitiate message, the PCE
will split the PCInitiate over multiple messages. Each
PCInitiate message sent by the PCE, except the last one,
will have the F-bit set in the LSP object to signify that
the PCInitiate has been fragmented into multiple messages.
In order to identify that a series of PCInitiate messages
represents a single Initiate, each message will use the
same PLSP-ID (in this case 0) and SRP-ID-number.To indicate P2MP message fragmentation errors associated
with a P2MP PCInitiate, a Error-Type (18) for "P2MP Fragmentation Error" and a new
error-value TBD15 is used if a PCC has not received the last
piece of the fragmented message, it should send an error
message to the PCE to signal that it has received an
incomplete message (i.e., "Fragmented Instantiation failure").The PCEP protocol extensions described in this document
for stateful PCEs with P2MP capability MUST NOT be used if
PCE has not advertised its stateful capability with P2MP as
per
.
If the PCEP Speaker on the PCC supports the extensions of this
draft (understands the P2MP flag in the LSP object) but did not
advertise this capability, then upon receipt
of PCUpd message from the PCE, it SHOULD generate a PCErr with
error-type 19 (Invalid Operation), error-value TBD17 (Attempted
LSP Update Request for P2MP if active stateful PCE capability
for P2MP was not advertised). If the PCEP Speaker on the PCE
supports the extensions of this draft (understands the P2MP
flag in the LSP object) but did not advertise this
capability, then upon receipt of a PCRpt message from the PCC, it
SHOULD generate a PCErr with error-type 19 (Invalid Operation),
error-value TBD16 (Attempted LSP State Report for P2MP if stateful PCE
capability for P2MP was not advertised) and it will
terminate the PCEP session.If a Stateful PCE receives a P2MP TE LSP report message
and the PCE does not understand the P2MP flag in the LSP
object, and therefore the PCEP extensions described in this
document, then the Stateful PCE would act as per
.The PCEP protocol extensions described in this document
for PCC or PCE with instantiation capability for P2MP TE LSPs
MUST NOT be used if PCC or PCE has not advertised its
stateful capability with Instantiation and P2MP capability as
per
.
If the PCEP Speaker on the PCC supports the extensions of this
draft (understands the P (P2MP-LSP-INSTANTIATION-CAPABILITY) flag
in the LSP object) but did not
advertise this capability, then upon receipt
of PCInitiate message from the PCE, it SHOULD generate a PCErr with
error-type 19 (Invalid Operation), error-value TBD18 (Attempted
LSP Instantiation Request for P2MP if stateful PCE instantiation capability
for P2MP was not advertised).All manageability requirements and considerations listed in
, ,
, and
apply to PCEP protocol extensions defined in this document. In
addition, requirements and considerations listed in this section
apply.A PCE or PCC implementation MUST allow configuring the
stateful PCEP capability, the LSP Update
capability, and the LSP Initiation capability for P2MP LSPs.The PCEP YANG module
SHOULD be extended to include advertised P2MP stateful capabilities,
P2MP synchronization status, and delegation status of P2MP LSP etc. The
statistics module should also count P2MP LSP related data.Mechanisms defined in this document do not imply any new liveness detection
and monitoring requirements in addition to those already listed in
.Mechanisms defined in this document do not imply any new operation
verification requirements in addition to those already listed in
, ,
, and
.Mechanisms defined in this document do not imply any new requirements
on other protocols.Mechanisms defined in this document do not have any impact on
network operations in addition to those already listed in
, ,
, and
.Stateful PCE feature for P2MP LSP would help with network operations.This document requests IANA actions to allocate code
points for the protocol elements defined in this document.IANA is requested to allocate new bits in the OSPF Parameters "PCE
Capability Flags" registry, as follows:
The STATEFUL-PCE-CAPABILITY TLV is defined in
and a registry is requested to be
created to manage the flags in the TLV. IANA is requested to make
the following allocations in the aforementioned registry.The LSP object is defined in and a registry is created to
manage the Flags field of the LSP object. IANA is requested to make the following allocations in the aforementioned registry.IANA is requested to allocate new error values within
the "PCEP-ERROR Object Error Types and Values" sub-registry of the
PCEP Numbers registry, as follows:IANA is requested to make the
assignment of a new value for the existing "PCEP TLV Type Indicators"
registry as follows:IANA is requested to allocate new object-class values and object
types within the "PCEP Objects" sub-registry of the PCEP Numbers
registry, as follows.
This document requests that a new sub-registry, named "S2LS Object
Flag Field", is created within the "Path Computation Element Protocol
(PCEP) Numbers" registry to manage the Flag field of the S2LS
object.New values are to be assigned by Standards Action .
Each bit should be tracked with the following qualities:
Bit number (counting from bit 0 as the most significant bit)Capability descriptionDefining RFCThe following values are defined in this document:The stateful operations on P2MP TE LSP are more
CPU-intensive and also utilize more bandwidth on wire. In the event of
an unauthorized stateful P2MP operations, or a denial of service
attack, the subsequent PCEP operations may be disruptive
to the network. Consequently, it is important that implementations
conform to the relevant security requirements of
, and
, and
.
Further discusses an
enhanced approach to provide secure transport for PCEP via
Transport Layer Security (TLS).Thanks to Quintin Zhao, Avantika and Venugopal Reddy for his comments.