One document matched: draft-dhodylee-pce-pcep-te-data-extn-02.xml
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<rfc ipr="trust200902" category="exp" docName="draft-dhodylee-pce-pcep-te-data-extn-02" obsoletes="" updates="" submissionType="IETF" xml:lang="en">
<front>
<title abbrev="PCEP-TED-EXT">PCEP Extension for Transporting TE Data</title>
<author initials="D" surname="Dhody" fullname="Dhruv Dhody">
<organization>Huawei Technologies</organization>
<address>
<postal>
<street>Divyashree Techno Park, Whitefield</street>
<city>Bangalore</city>
<region>Karnataka</region>
<code>560037</code>
<country>India</country>
</postal>
<email>dhruv.ietf@gmail.com</email>
</address>
</author>
<author fullname="Young Lee" initials="Y" surname="Lee">
<organization>Huawei Technologies</organization>
<address>
<postal>
<street>5340 Legacy Drive, Building 3</street>
<city>Plano</city>
<region>TX</region>
<code>75023</code>
<country>USA</country>
</postal>
<email>leeyoung@huawei.com</email>
</address>
</author>
<author initials="D" fullname="Daniele Ceccarelli" surname="Ceccarelli">
<organization>Ericsson</organization>
<address>
<postal>
<street>Torshamnsgatan,48</street>
<city>Stockholm</city>
<region></region>
<code></code>
<country>Sweden</country>
</postal>
<email>daniele.ceccarelli@ericsson.com</email>
</address>
</author>
<date month="March" year="2015" />
<area>Routing</area>
<workgroup>PCE Working Group</workgroup>
<abstract>
<t>In order to compute and provide optimal paths, Path Computation
Elements (PCEs) require an accurate and timely Traffic Engineering
Database (TED). Traditionally this TED has been obtained from a link
state routing protocol supporting traffic engineering extensions.</t>
<t>This document extends the Path Computation Element Communication
Protocol (PCEP) with TED population capability. </t>
</abstract>
</front>
<middle>
<section title="Introduction" toc="default">
<t>In Multiprotocol Label Switching (MPLS) and Generalized MPLS
(GMPLS), a Traffic Engineering Database (TED) is used in computing
paths for connection oriented packet services and for circuits. The
TED contains all relevant information that a Path Computation
Element (PCE) needs to perform its computations. It is important
that the TED be complete and accurate each time, the PCE performs a
path computation.</t>
<t>In MPLS and GMPLS, interior gateway routing protocols (IGPs) have
been used to create and maintain a copy of the TED at each node
running the IGP. One of the benefits of the PCE architecture
<xref target="RFC4655"/> is the use of computationally more sophisticated path
computation algorithms and the realization that these may need
enhanced processing power not necessarily available at each node
participating in an IGP.</t>
<t>Section 4.3 of <xref target="RFC4655"/> describes the potential load of the TED on
a network node and proposes an architecture where the TED is
maintained by the PCE rather than the network nodes. However, it
does not describe how a PCE would obtain the information needed to
populate its TED. PCE may construct its TED by participating in the
IGP (<xref target="RFC3630"/> and <xref target="RFC5305"/> for MPLS-TE; <xref target="RFC4203"/> and <xref target="RFC5307"/>
for GMPLS). An alternative is offered by BGP-LS <xref target="I-D.ietf-idr-ls-distribution"/> .</t>
<t><xref target="I-D.lee-pce-transporting-te-data"/> proposes some other approaches for creating and maintaining
the TED directly on a PCE as an alternative to IGPs and BGP flooding
and investigate the impact from the PCE, routing protocol, and node
perspectives.</t>
<t><xref target="RFC5440"/> describes the specifications for the Path Computation
Element Communication Protocol (PCEP). PCEP specifies the
communication between a Path Computation Client (PCC) and a Path
Computation Element (PCE), or between two PCEs based on the PCE
architecture <xref target="RFC4655"/>.</t>
<t>This document specifies a PCEP extension for TED population capability
to support functionalities described in <xref target="I-D.lee-pce-transporting-te-data"/>.</t>
<section title="Requirements Language" toc="default">
<t>The key words "MUST", "MUST NOT", "REQUIRED", "SHALL",
"SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY",
and "OPTIONAL" in this document are to be interpreted as
described in <xref target="RFC2119"/>.</t>
</section>
</section>
<section title="Terminology" toc="default">
<t>The terminology is as per <xref target="RFC4655"/> and <xref target="RFC5440"/>.</t>
</section>
<section title="Applicability" toc="default">
<t>As per <xref target="I-D.lee-pce-transporting-te-data"/>, the
mechanism specified in this draft is applicable to:
<list style="symbols">
<t>Where there is no IGP-TE or BGP-LS running at the PCE to learn TED. </t>
<t>Where there is IGP-TE or BGP-LS running but with a need for a faster TED population and convergence at the PCE.
<list style="symbols">
<t>A PCE may receive partial information (say basic TE) from IGP-TE and other information (optical and impairment) from PCEP.</t>
<t>A PCE may receive full information from both IGP-TE and PCEP.</t>
</list>
</t>
</list>
</t>
<t>A PCC may further choose to send only local TE information or both local and remote learned TED information. </t>
<t>How a PCE manages the TED information is implementation specific and thus out of scope of this document.</t>
</section>
<section title="Requirements for PCEP extension" toc="default" anchor="sec_req">
<t>Following key requirements associated with TED population are identified for PCEP:
<list style="numbers">
<t>The PCEP speaker supporting this draft MUST be a mechanism to advertise the TED capability.</t>
<t>PCC supporting this draft MUST have the capability to report the TED to
the PCE. This includes self originated TE information and remote TE information
learned via routing protocols. PCC MUST be capable to do the initial bulk sync at
the time of session initialization as well as changes to TED after.</t>
<t>A PCE MAY learn TED from PCEP as well as from existing mechanism like
IGP-TE/BGP-LS. PCEP extension MUST have a mechanism to link the TED information
learned via other means. There MUST NOT be any changes to the existing TED
population mechanism
via IGP-TE/BGP-LS. PCEP extension SHOULD keep the TE properties in a
routing protocol (IGP-TE or BGP-LS) neutral way, such that an implementation
which do want to learn about a Link-state topology do not need to know about
any OSPF or IS-IS or BGP protocol specifics.</t>
<t>It SHOULD be possible to encode only the changes in TED properties
(after the initial sync) in
PCEP messages.</t>
<t>The same mechanism should be used for both MPLS TE as well as GMPLS,
optical and impairment aware properties.</t>
<t>The extension in this draft SHOULD be extensible to support various
architecture options listed in <xref target="I-D.lee-pce-transporting-te-data"/>.</t>
</list>
</t>
</section>
<section title="New Functions to Support TED via PCEP">
<t>Several new functions are required in PCEP to support TED population.
A function can be initiated either from a PCC towards a PCE (C-E) or
from a PCE towards a PCC (E-C). The new functions are:
<list style="symbols">
<t>Capability advertisement (E-C,C-E): both the PCC and the PCE must
announce during PCEP session establishment that they support PCEP
extensions for TED population defined in this document.</t>
<t>TE synchronization (C-E): after the session between the PCC
and a PCE is initialized, the PCE must learn
PCC's TED before it can perform path computations. In case
of stateful PCE it is RECOMENDED that this operation be done before LSP
state synchronization. </t>
<t>TE Report (C-E): a PCC sends a TE report to a PCE
whenever the TED changes.</t>
</list> </t>
</section>
<section title="Overview of Extension to PCEP" toc="default" anchor="sec_overview">
<section title="New Messages">
<t>In this document, we define a new PCEP messages called TE Report (TERpt),
a PCEP message sent by a PCC
to a PCE to report TED. Each TE Report in a TERpt message can contain
the TE node or TE Link properties. An unique PCEP specific TE identifier (TE-ID) is
also carried in the message to identify the TE node or link and that remains constant for the
lifetime of a PCEP session. This identifier on its own is sufficient
when no IGP-TE or BGP-LS running in the network for PCE to learn TED.
Incase PCE learns some information from PCEP and some
from the existing mechanism, the PCC SHOULD include the mapping of IGP-TE or BGP-LS
identifier to map the TED information populated via PCEP with IGP-TE/BGP-LS.
See <xref target="sec_terpt"/> for details.</t>
</section>
<section title="Capability Advertisement">
<t>During PCEP Initialization Phase, PCEP Speakers (PCE or PCC)
advertise their support of TED population PCEP extensions. A PCEP Speaker
includes the "TED Capability" TLV, described in <xref target="sec_obj"/>,
in the OPEN Object to advertise its support for PCEP
TED extensions. The presence of the TED Capability TLV in PCC's OPEN Object
indicates that the PCC is willing to send TE Reports whenever
local TE information changes. The presence of the TED Capability TLV in PCE's OPEN message
indicates that the PCE is interested in receiving TE Reports
whenever local TE changes.</t>
<t>The PCEP protocol extensions for TED population MUST NOT be used if
one or both PCEP Speakers have not included the TED
Capability TLV in their respective OPEN message. If the PCE that
supports the extensions of this draft 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 TBD1 (Attempted TE Report if TED
capability was not advertised) and it will
terminate the PCEP session.</t>
<t>The TE reports sent by PCC MAY carry the remote TE information
learned via existing means like IGP-TE and BGP-LS
only if both PCEP Speakers set the R (remote) Flag in the
"TED Capability" TLV to 'Remote Allowed (R Flag = 1)'. If this
is not the case and TE reports carry remote TE information, then a
PCErr with error-type 19 (Invalid Operation) and
error-value TBD1 (Attempted TE Report if TED
capability was not advertised) and it will
terminate the PCEP session.</t>
</section>
<section title="Initial TED Synchronization">
<t>The purpose of TED Synchronization is to provide a checkpoint-in-
time state replica of a PCC's TED in a PCE. State
Synchronization is performed immediately after the Initialization
phase (see <xref target="RFC5440"/>]). In case of stateful PCE
(<xref target="I-D.ietf-pce-stateful-pce"/>)
it is RECOMENDED that the TED synchronization should be done
before LSP state synchronization.</t>
<t>During TED Synchronization, a PCC first takes a snapshot of the
state of its TED, then sends the snapshot to a PCE in a
sequence of TE Reports. Each TE Report sent during
TE Synchronization has the SYNC Flag in the TE Object set to 1.
The end of synchronization marker is a TERpt message with the SYNC
Flag set to 0 for an TE Object with TED-ID equal to the reserved
value 0. If the
PCC has no TED state to synchronize, it will only send the end of
synchronization marker.</t>
<t>Either the PCE or the PCC MAY terminate the session using the PCEP
session termination procedures during the synchronization phase. If
the session is terminated, the PCE MUST clean up state it received
from this PCC. The session re-establishment MUST be re-attempted per
the procedures defined in <xref target="RFC5440"/>, including use of a back-off
timer.</t>
<t>If the PCC encounters a problem which prevents it from completing the
TED population, it MUST send a PCErr message with error-type TBD2 (TE
Synchronization Error) and error-value 5 (indicating an
internal PCC error) to the PCE and terminate the session.</t>
<t>The PCE does not send positive acknowledgements for properly received
TED synchronization messages. It MUST respond with a PCErr message with
error-type TBD2 (TE Synchronization Error) and error-value 1
(indicating an error in processing the TERpt) if it
encounters a problem with the TE Report it received from the
PCC and it MUST terminate the session.</t>
<t>The TE reports may carry local as well as remote TED information depending on the R flag in TED capability
TLV.</t>
<t>The successful TED Synchronization sequences is shown in <xref target="F1"/>.</t>
<figure title="Successful state synchronization"
suppress-title="false" align="left" alt="" width="" height="" anchor="F1">
<artwork><![CDATA[
+-+-+ +-+-+
|PCC| |PCE|
+-+-+ +-+-+
| |
|-----TERpt, SYNC=1----->| (Sync start)
| |
|-----TERpt, SYNC=1----->|
| . |
| . |
| . |
|-----TERpt, SYNC=1----->|
| . |
| . |
| . |
| |
|-----TERpt, SYNC=0----->| (End of sync marker
| | TE Report
| | for TED-ID=0)
| | (Sync done)
]]></artwork>
</figure>
<t>The sequence where the PCE fails during the TED Synchronization
phase is shown in <xref target="F2"/>.</t>
<figure title="Failed TED synchronization (PCE failure)"
suppress-title="false" align="left" alt="" width="" height="" anchor="F2">
<artwork><![CDATA[
+-+-+ +-+-+
|PCC| |PCE|
+-+-+ +-+-+
| |
|-----TERpt, SYNC=1----->|
| |
|-----TERpt, SYNC=1----->|
| . |
| . |
| . |
|-----TERpt, SYNC=1----->|
| |
|-TERpt, SYNC=1 |
| \ ,-PCErr---|
| \ / |
| \/ |
| /\ |
| / `-------->| (Ignored)
|<--------` |
]]></artwork>
</figure>
<t>The sequence where the PCC fails during the TED Synchronization
phase is shown in <xref target="F3"/>.</t>
<figure title="Failed TED synchronization (PCC failure)"
suppress-title="false" align="left" alt="" width="" height="" anchor="F3">
<artwork><![CDATA[
+-+-+ +-+-+
|PCC| |PCE|
+-+-+ +-+-+
| |
|-----TERpt, SYNC=1----->|
| |
|-----TERpt, SYNC=1----->|
| . |
| . |
| . |
|-------- PCErr--------->|
| |
]]></artwork>
</figure>
<section title="Optimizations for TED Synchronization">
<t>TBD</t>
</section>
</section>
<section title="TE Report">
<t>The PCC MUST report any changes in the TEDB to the PCE by sending a
TE Report carried on a TERpt message to the PCE, indicating that the
TE state. Each TE node and TE Link would be uniquely identified by a
PCEP TE identifier (TE-ID). The TE reports may carry local as well as
remote TED information depending on the R flag in TED capability
TLV.
In case R flag is set, It MAY also include the mapping of IGP-TE or BGP-LS
identifier to map the TED information populated via PCEP with IGP-TE/BGP-LS.</t>
<t>More details about TERpt message are in <xref target="sec_terpt"/>.</t>
</section>
</section>
<section title="Transport" toc="default">
<t>A permanent PCEP session MUST be established between a PCE
and PCC supporting TED population via PCEP. In the case of session failure,
session re-establishment
MUST be re-attempted per the procedures defined in
<xref target="RFC5440"/>.</t>
</section>
<section title="PCEP Messages" toc="default" anchor="sec_msg">
<t>As defined in <xref target="RFC5440"/>, a PCEP message consists of a common header
followed by a variable-length body made of a set of objects that can
be either mandatory or optional. An object is said to be mandatory
in a PCEP message when the object must be included for the message to
be considered valid. For each PCEP message type, a set of rules is
defined that specify the set of objects that the message can carry.
An implementation MUST form the PCEP messages using the object
ordering specified in this document.</t>
<section title="TE Report Message" anchor="sec_terpt">
<t>A PCEP TE Report message (also referred to as
TERpt message) is a PCEP message sent by a PCC to a PCE to report the
TED state. A TERpt message can carry more than one TE
Reports. The Message-Type field of the PCEP common header
for the PCRpt message is set to [TBD3].</t>
<t>The format of the PCRpt message is as follows:</t>
<figure title=""
suppress-title="true" align="left" alt="" width="" height="" >
<artwork><![CDATA[
<TERpt Message> ::= <Common Header>
<te-report-list>
Where:
<te-report-list> ::= <TE>[<te-report-list>]
]]></artwork>
</figure>
<t>The TE object is a mandatory object which carries TE information of
a TE node or a TE link. Each TE object has an unique TE-ID as described
in <xref target="sec_te_obj"/>. If the TE
object is missing, the receiving PCE MUST send a PCErr message with
Error-type=6 (Mandatory Object missing) and Error-value=[TBD4] (TE
object missing).</t>
<t>A PCE may choose to implement a limit on the TE information a single PCC
can populate. If a TERpt is received that causes the PCE to exceed
this limit, it MUST send a PCErr message with error-type 19 (invalid
operation) and error-value 4 (indicating resource limit exceeded) in
response to the TERpt message triggering this condition and MAY
terminate the session.</t>
</section>
<section title="The PCErr Message" anchor="sec_pcerr">
<t>If a PCEP speaker has advertised the TED capability on the PCEP
session, the PCErr message MAY include the TE object. If the error
reported is the result of an TE report, then the TE-ID
number MUST be the one from the TERpt that triggered the error.</t>
<t>The format of a PCErr message from <xref target="RFC5440"/> is
extended as follows:</t>
<t>The format of the PCRpt message is as follows:</t>
<figure title=""
suppress-title="true" align="left" alt="" width="" height="" >
<artwork><![CDATA[
<PCErr Message> ::= <Common Header>
( <error-obj-list> [<Open>] ) | <error>
[<error-list>]
<error-obj-list>::=<PCEP-ERROR>[<error-obj-list>]
<error>::=[<request-id-list> | <te-id-list>]
<error-obj-list>
<request-id-list>::=<RP>[<request-id-list>]
<te-id-list>::=<TE>[<te-id-list>]
<error-list>::=<error>[<error-list>]
]]></artwork>
</figure>
</section>
</section>
<section title="Objects and TLV" toc="default" anchor="sec_obj">
<t>The PCEP objects defined in this document are compliant with the PCEP
object format defined in <xref target="RFC5440"/>. The P flag and the I flag of the
PCEP objects defined in this document MUST always be set to 0 on
transmission and MUST be ignored on receipt since these flags are
exclusively related to path computation requests.</t>
<section title="Open Object">
<t>This document defines a new optional TLV for use in the OPEN
Object.</t>
<section title="TED Capability TLV">
<t>The TED-CAPABILITY TLV is an optional TLV for use in the
OPEN Object for TED population via PCEP capability
advertisement. Its format is shown in the following figure:</t>
<figure title=""
suppress-title="true" align="left" alt="" width="" height="" >
<artwork><![CDATA[
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type=[TBD5] | Length=4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flags |R|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
]]></artwork>
</figure>
<t>The type of the TLV is [TBD5] and it has a fixed length of 4 octets.</t>
<t>The value comprises a single field - Flags (32 bits):
<list style="symbols">
<t>R (remote - 1 bit): if set to 1 by a PCC, the R Flag
indicates that the PCC allows reporting of remote TED information
learned via other means like IGP-TE and BGP-LS; if
set to 1 by a PCE, the R Flag indicates that the PCE is capable of
receiving remote TED information (from the PCC point of view).
The R Flag must be
advertised by both a PCC and a PCE for TERpt messages to report
remote as well as local TE information on a PCEP session. The
TLVs related to IGP-TE/BGP-LS identifier MUST be encoded when
both PCEP speakers have the R Flag set.</t>
</list>
</t>
<t>Unassigned bits are considered reserved. They MUST be set to 0 on
transmission and MUST be ignored on receipt.</t>
<t>Advertisement of the TED capability implies support of local TE
population, as well as the objects, TLVs and
procedures defined in this document.</t>
</section>
</section>
<section title="TE Object" anchor="sec_te_obj">
<t>The TE (traffic engineering) object MUST be carried
within TERpt messages and MAY be carried within PCErr
messages. The TE object contains a set of fields used to specify
the target TE node or link. It also
contains a flag indicating to a PCE that the TED
synchronization is in progress. The TLVs used with the TE object
correlate with the IGP-TE/BGP-LS TE encodings.</t>
<t>TE Object-Class is [TBD6].</t>
<t>Two Object-Type values are defined for the TE object:
<list style="symbols">
<t>TE Node: TE Object-Type is 1. </t>
<t>TE Link: TE Object-Type is 2.</t>
</list>
</t>
<t>The format of the TE object body is as follows:</t>
<figure title=""
suppress-title="true" align="center" alt="" width="" height="" >
<artwork align="center"><![CDATA[
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Protocol-ID | Flag |R|S|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TE-ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// TLVs //
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
]]></artwork>
</figure>
<t>Protocol-ID (8-bit): The field provide the source information.
Incase PCC only provides local information (R flag is not set),
it MUST use Protocol-ID
as Direct. The following values are defined (same as
<xref target="I-D.ietf-idr-ls-distribution"/>):</t>
<figure title=""
suppress-title="true" align="center" alt="" width="" height="" >
<artwork align="center"><![CDATA[
+-------------+----------------------------------+
| Protocol-ID | Source protocol |
+-------------+----------------------------------+
| 1 | IS-IS Level 1 |
| 2 | IS-IS Level 2 |
| 3 | OSPFv2 |
| 4 | Direct |
| 5 | Static configuration |
| 6 | OSPFv3 |
+-------------+----------------------------------+
]]></artwork>
</figure>
<t>Flags (32-bit):
<list style="symbols">
<t>S (SYNC - 1 bit): the S Flag MUST be set to 1 on each TERpt sent
from a PCC during TED Synchronization. The S Flag MUST be set
to 0 in other TERpt messages sent from the PCC.</t>
<t>R (Remove - 1 bit): On TERpt messages the R Flag indicates that the
TE node/link has been removed from the PCC and the PCE SHOULD remove
from its database. Upon receiving an TE Report with
the R Flag set to 1, the PCE SHOULD
remove all state for the TE node/link identified by the TE Identifiers
from its database.</t>
</list>
</t>
<t>TE-ID(32-bit): A PCEP-specific identifier for the TE node or
link. A PCC creates a unique TE-ID for each TE node/link that is
constant for the lifetime of a PCEP session. The PCC will
advertise the same TE-ID on all PCEP sessions it maintains at a
given times. All
subsequent PCEP messages then address the TE node/link by the TE-ID.
The
values of 0 and 0xFFFFFFFF are reserved.</t>
<t>Unassigned bits are considered reserved. They MUST be set to 0 on
transmission and MUST be ignored on receipt.</t>
<t>TLVs that may be included in the TE Object are described in the
following sections.</t>
<section title="Routing Universe TLV">
<t>In case of remote TED population when existing IGP-TE/BGP-LS are
also used,
OSPF and IS-IS may run multiple routing protocol instances over
the same link as described in <xref target="I-D.ietf-idr-ls-distribution"/>.
See <xref target="RFC6822"/> and <xref target="RFC6549"/>.
These instances define
independent "routing universes". The 64-Bit 'Identifier' field is
used to identify the "routing universe" where the TE object belongs.
The
TE objects representing IGP objects (nodes or links) from the
same routing universe MUST have the same 'Identifier' value; TE objects
with different 'Identifier' values MUST be considered to be from
different routing universes. </t>
<t>The format of the ROUTING-UNIVERSE TLV is shown in the following
figure:</t>
<figure title=""
suppress-title="true" align="center" alt="" width="" height="" >
<artwork align="center"><![CDATA[
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type=[TBD7] | Length=8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Identifier |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
]]></artwork>
</figure>
<t>Below table lists the 'Identifier'
values that are defined as well-known in this draft (same as
<xref target="I-D.ietf-idr-ls-distribution"/>).</t>
<figure title=""
suppress-title="true" align="center" alt="" width="" height="" >
<artwork align="center"><![CDATA[
+------------+---------------------+
| Identifier | Routing Universe |
+------------+---------------------+
| 0 | L3 packet topology |
| 1 | L1 optical topology |
+------------+---------------------+
]]></artwork>
</figure>
<t>If this TLV is not present the default value 0 is assumed.</t>
</section>
<section title="Local TE Node Descriptors TLV">
<t>As described in <xref target="I-D.ietf-idr-ls-distribution"/>,
each link is anchored by a pair of Router-IDs that are used by the
underlying IGP, namely, 48 Bit ISO System-ID for IS-IS and 32 bit
Router-ID for OSPFv2 and OSPFv3. Incase of additional auxiliary
Router-IDs used for TE, these MUST also be included in the TE link
attribute TLV (see <xref target="node_attr"/>).</t>
<t>It is desirable that the Router-ID assignments inside the TE Node
Descriptor are globally unique. Autonomous System (AS) Number and
PCEP-TED Identifier in order to disambiguate the Router-IDs, as
described in <xref target="I-D.ietf-idr-ls-distribution"/>.</t>
<t>The Local TE Node Descriptors TLV contains Node Descriptors for the node
anchoring the local end of the link. This TLV MUST be included in the TE Report
when during a given PCEP session a TE node/link is first reported to a PCE.
A PCC sends to a PCE the first TE Report either during State
Synchronization, or when a new TE node/link is learned at the PCC.
The value
contains one or more Node Descriptor Sub-TLVs, which
allows specification of a flexible key for any given Node/Link
information such that global uniqueness of the TE node/link is ensured.</t>
<figure title=""
suppress-title="true" align="center" alt="" width="" height="" >
<artwork align="center"><![CDATA[
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type=[TBD8] | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
// Node Descriptor Sub-TLVs (variable) //
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
]]></artwork>
</figure>
<t>The value contains
one or more Node Descriptor Sub-TLVs defined in
<xref target="node_subtlv"/>.</t>
</section>
<section title="Remote TE Node Descriptors TLV">
<t>The Remote TE Node Descriptors contains Node Descriptors for the node
anchoring the remote end of the link. This TLV MUST be included in the TE Report
when during a given PCEP session a TE link is first reported to a PCE.
A PCC sends to a PCE the first TE Report either during State
Synchronization, or when a new TE link is learned at the PCC. The length of this TLV is
variable. The value contains
one or more Node Descriptor Sub-TLVs defined in <xref target="node_subtlv"/>.</t>
<figure title=""
suppress-title="true" align="center" alt="" width="" height="" >
<artwork align="center"><![CDATA[
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type=[TBD9] | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
// Node Descriptor Sub-TLVs (variable) //
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
]]></artwork>
</figure>
</section>
<section title="TE Node Descriptors Sub-TLVs" anchor="node_subtlv">
<t>The Node Descriptor Sub-TLV type Type and lengths are listed in
the following table:</t>
<figure title=""
suppress-title="true" align="center" alt="" width="" height="" >
<artwork align="center"><![CDATA[
+--------------------+-------------------+----------+
| Sub-TLV | Description | Length |
+--------------------+-------------------+----------+
| TBD10 | Autonomous System | 4 |
| TBD11 | BGP-LS Identifier | 4 |
| TBD12 | OSPF Area-ID | 4 |
| TBD13 | Router-ID | Variable |
+--------------------+-------------------+----------+
]]></artwork>
</figure>
<t>The sub-TLV values in Node Descriptor TLVs are defined
as follows (similar to <xref target="I-D.ietf-idr-ls-distribution"/>):
<list style="symbols">
<t>Autonomous System: opaque value (32 Bit AS Number)</t>
<t>BGP-LS Identifier: opaque value (32 Bit ID). In conjunction with
ASN, uniquely identifies the BGP-LS domain as described in <xref target="I-D.ietf-idr-ls-distribution"/>.
This sub-TLV is present only if the node implements BGP-LS and the ID is set by the operator.
</t>
<t>Area ID: It is used to identify the 32 Bit area to which the TE object
belongs. Area Identifier allows the different TE objects of the same
router to be discriminated.</t>
<t> Router ID: opaque value. Usage is
described in <xref target="I-D.ietf-idr-ls-distribution"/> for IGP Router ID. In case only
local TE information is transported and PCE learns TED only from PCEP, it contain the unique local TE IPv4 or IPv6 router ID.</t>
<t>There can be at most one instance of each sub-TLV type present in
any Node Descriptor.</t>
</list>
</t>
</section>
<section title="TE Link Descriptors TLV">
<t>The TE Link Descriptors TLV contains Link Descriptors for each TE
link. This TLV MUST be included in the TE Report
when during a given PCEP session a TE link is first reported to a PCE.
A PCC sends to a PCE the first TE Report either during State
Synchronization, or when a new TE link is learned at the PCC. The length of this
TLV is variable. The value contains one or more TE Link Descriptor Sub-TLVs</t>
<t>The 'TE Link descriptor' TLVs uniquely identify a link among
multiple parallel
links between a pair of anchor routers similar to
<xref target="I-D.ietf-idr-ls-distribution"/>. </t>
<figure title=""
suppress-title="true" align="center" alt="" width="" height="" >
<artwork align="center"><![CDATA[
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type=[TBD14] | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
// Link Descriptor Sub-TLVs (variable) //
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
]]></artwork>
</figure>
<t>The Link Descriptor Sub-TLV type and lengths are listed in
the following table:</t>
<figure title=""
suppress-title="true" align="center" alt="" width="" height="" >
<artwork align="center"><![CDATA[
+-----------+---------------------+---------------+-----------------+
| Sub-TLV | Description | IS-IS TLV | Value defined |
| | | /Sub-TLV | in: |
+-----------+---------------------+---------------+-----------------+
| TBD15 | Link Local/Remote | 22/4 | [RFC5307]/1.1 |
| | Identifiers | | |
| TBD16 | IPv4 interface | 22/6 | [RFC5305]/3.2 |
| | address | | |
| TBD17 | IPv4 neighbor | 22/8 | [RFC5305]/3.3 |
| | address | | |
| TBD18 | IPv6 interface | 22/12 | [RFC6119]/4.2 |
| | address | | |
| TBD19 | IPv6 neighbor | 22/13 | [RFC6119]/4.3 |
| | address | | |
+-----------+---------------------+---------------+-----------------+
]]></artwork>
</figure>
<t>The format and semantics of the 'value' fields in most 'Link
Descriptor' sub-TLVs correspond to the format and semantics of value
fields in IS-IS Extended IS Reachability sub-TLVs, defined in
<xref target="RFC5305"/>, <xref target="RFC5307"/> and <xref target="RFC6119"/>. Although the encodings for 'Link
Descriptor' TLVs were originally defined for IS-IS, the TLVs can
carry data sourced either by IS-IS or OSPF or direct.</t>
<t>The information about a link present in the LSA/LSP originated by the
local node of the link determines the set of sub-TLVs in the Link
Descriptor of the link as described in
<xref target="I-D.ietf-idr-ls-distribution"/>.</t>
</section>
<section title="TE Node Attributes TLV" anchor="node_attr">
<t>This is an optional, non-transitive attribute that is used to
carry TE node attributes. The TE node attribute TLV may be encoded in the TE node Object.</t>
<figure title=""
suppress-title="true" align="center" alt="" width="" height="" >
<artwork align="center"><![CDATA[
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type=[TBD20] | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
// Node Attributes Sub-TLVs (variable) //
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
]]></artwork>
</figure>
<t>The Node Attributes Sub-TLV type and lengths are listed in
the following table:</t>
<figure title=""
suppress-title="true" align="center" alt="" width="" height="" >
<artwork align="center"><![CDATA[
+--------------+-----------------------+----------+-----------------+
| Sub TLV | Description | Length | Value defined |
| | | | in: |
+--------------+-----------------------+----------+-----------------+
| TBD21 | Node Flag Bits | 1 | [I-D.ietf-idr- |
| | | | ls-distribution]|
| | | | /3.3.1.1 |
| TBD22 | Opaque Node | variable | [I-D.ietf-idr- |
| | Properties | | ls-distribution]|
| | | | /3.3.1.5 |
| TBD23 | Node Name | variable | [I-D.ietf-idr- |
| | | | ls-distribution]|
| | | | /3.3.1.3 |
| TBD24 | IS-IS Area Identifier | variable | [I-D.ietf-idr- |
| | | | ls-distribution]|
| | | | /3.3.1.2 |
| TBD25 | IPv4 Router-ID of | 4 | [RFC5305]/4.3 |
| | Local Node | | |
| TBD26 | IPv6 Router-ID of | 16 | [RFC6119]/4.1 |
| | Local Node | | |
+--------------+-----------------------+----------+-----------------+
]]></artwork>
</figure>
</section>
<section title="TE Link Attributes TLV" >
<t>TE Link attribute TLV may be encoded in the TE Link Object. The format
and semantics of the 'value' fields in some 'Link Attribute' sub-TLVs
correspond to the format and semantics of value fields in IS-IS
Extended IS Reachability sub-TLVs, defined in <xref target="RFC5305"/>,
<xref target="RFC5307"/> and <xref target="I-D.ietf-idr-ls-distribution"/>.
Although the encodings for 'Link Attribute' TLVs were originally
defined for IS-IS, the TLVs can carry data sourced either by IS-IS or
OSPF or direct.</t>
<figure title=""
suppress-title="true" align="center" alt="" width="" height="" >
<artwork align="center"><![CDATA[
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type=[TBD27] | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
// Link Attributes Sub-TLVs (variable) //
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
]]></artwork>
</figure>
<t>The following 'Link Attribute' sub-TLVs are are valid :</t>
<figure title=""
suppress-title="true" align="center" alt="" width="" height="" >
<artwork align="center"><![CDATA[
+-----------+---------------------+--------------+------------------+
| Sub-TLV | Description | IS-IS TLV | Defined in: |
| | | /Sub-TLV | |
| | | BGP-LS TLV | |
+-----------+---------------------+--------------+------------------+
| TBD28 | IPv4 Router-ID of | 134/--- | [RFC5305]/4.3 |
| | Local Node | | |
| TBD29 | IPv6 Router-ID of | 140/--- | [RFC6119]/4.1 |
| | Local Node | | |
| TBD30 | IPv4 Router-ID of | 134/--- | [RFC5305]/4.3 |
| | Remote Node | | |
| TBD31 | IPv6 Router-ID of | 140/--- | [RFC6119]/4.1 |
| | Remote Node | | |
| TBD32 | Link Local/Remote | 22/4 | [RFC5307]/1.1 |
| | Identifiers | | |
| TBD33 | Administrative | 22/3 | [RFC5305]/3.1 |
| | group (color) | | |
| TBD34 | Maximum link | 22/9 | [RFC5305]/3.3 |
| | bandwidth | | |
| TBD35 | Max. reservable | 22/10 | [RFC5305]/3.5 |
| | link bandwidth | | |
| TBD36 | Unreserved | 22/11 | [RFC5305]/3.6 |
| | bandwidth | | |
| TBD37 | TE Default Metric | 22/18 | [I-D.ietf-idr- |
| | | | ls-distribution] |
| | | | /3.3.2.3 |
| TBD38 | Link Protection | 22/20 | [RFC5307]/1.2 |
| | Type | | |
| TBD39 | MPLS Protocol Mask | 1094 | [I-D.ietf-idr- |
| | | | ls-distribution] |
| | | | /3.3.2.2 |
| TBD40 | IGP Metric | 1095 | [I-D.ietf-idr- |
| | | | ls-distribution] |
| | | | /3.3.2.4 |
| TBD41 | Shared Risk Link | 1096 | [I-D.ietf-idr- |
| | Group | | ls-distribution] |
| | | | /3.3.2.5 |
| TBD42 | Opaque link | 1097 | [I-D.ietf-idr- |
| | attributes | | ls-distribution] |
| | | | /3.3.2.6 |
| TBD43 | Link Name attribute | 1098 | [I-D.ietf-idr- |
| | | | ls-distribution] |
| | | | /3.3.2.7 |
+-----------+---------------------+--------------+------------------+
]]></artwork>
</figure>
</section>
</section>
</section>
<section title="Other Considerations" toc="default">
<section title="Inter-AS Links" toc="default">
<t>The main source of TE information is the IGP, which is not active on
inter-AS links. In some cases, the IGP may have information of
inter-AS links (<xref target="RFC5392"/>, <xref target="RFC5316"/>). In other cases, an
implementation SHOULD provide a means to inject inter-AS links into
PCEP. The exact mechanism used to provision the inter-AS links is
outside the scope of this document.</t>
</section>
</section>
<section title="Security Considerations" toc="default">
<t>This document extends PCEP to support TED population including a new
TERpt message with new object and TLVs. Procedures and protocol extensions
defined in this document do not effect the overall PCEP security model.
See <xref target="RFC5440"/>, <xref target="I-D.ietf-pce-pceps"/>.
Tampering with the TERpt message
may have an effect on path computations at PCE. It also provides adversaries
an opportunity to eavesdrop and learn sensitive information and plan
sophisticated attacks on the network infrastructure. The PCE implementation
SHOULD provide mechanisms to prevent strains created by network flaps and
amount of TED information. Thus it is suggested
that any mechanism used for securing the transmission of other PCEP
message be applied here as well. As a general precaution, it is
RECOMMENDED that these PCEP extensions only be activated on
authenticated and encrypted sessions belonging to the same
administrative authority.</t>
</section>
<section title="Manageability Considerations" toc="default">
<t>All manageability requirements and considerations listed in <xref target="RFC5440"/>
apply to PCEP protocol extensions defined in this document. In
addition, requirements and considerations listed in this section
apply.</t>
<section title="Control of Function and Policy" toc="default">
<t>In addition to configuring specific PCEP session parameters, as
specified in section 8.1 of <xref target="RFC5440"/>, a PCE or PCC
implementation MUST
allow configuring the TED PCEP capability. A PCC SHOULD allow the operator to specify an
TED population policy where TERpt are sent to which PCE. </t>
</section>
<section title="Information and Data Models" toc="default">
<t>PCEP session configuration and information in the PCEP MIB module
SHOULD be extended to include advertised TED capabilities,
TED synchronization status and TED etc.</t>
</section>
<section title="Liveness Detection and Monitoring" toc="default">
<t>PCEP protocol extensions defined in this document do not require any
new mechanisms beyond those already defined in section 8.3 of <xref target="RFC5440"/>.
</t>
</section>
<section title="Verify Correct Operations" toc="default">
<t>Mechanisms defined in section 8.4 of <xref target="RFC5440"/> also apply to PCEP
protocol extensions defined in this document. In addition to
monitoring parameters defined in <xref target="RFC5440"/>, a PCEP
implementation with TED SHOULD provide the following parameters:
<list style="symbols">
<t>Total number of TE Reports</t>
<t>Number of TE nodes and links</t>
<t>Number of dropped TERpt messages</t>
</list></t>
</section>
<section title="Requirements On Other Protocols" toc="default">
<t>PCEP protocol extensions defined in this document do not put new
requirements on other protocols.</t>
</section>
<section title="Impact On Network Operations" toc="default">
<t>Mechanisms defined in section 8.6 of <xref target="RFC5440"/> also apply to PCEP
protocol extensions defined in this document.</t>
<t>Additionally, a PCEP implementation SHOULD allow a limit to be placed
on the amount and rate of TERpt messages sent by a PCEP speaker and
processed by the peer.
It SHOULD also allow sending a notification when a rate threshold is
reached.</t>
</section>
</section>
<section title="IANA Considerations" toc="default">
<t>
<figure title="" suppress-title="false" align="left" alt="" width="" height="">
<artwork xml:space="preserve" name="" type="" align="left" alt="" width="" height=""><![CDATA[
]]></artwork>
</figure>
</t>
</section>
<section title="Acknowledgments" toc="default">
<t>This document borrows some of the structure and text from the
<xref target="I-D.ietf-pce-stateful-pce"/>.
</t>
</section>
</middle>
<back>
<references title="Normative References">
<?rfc include="reference.RFC.2119.xml" ?>
<?rfc include="reference.RFC.5440.xml" ?>
</references>
<references title="Informative References">
<?rfc include="reference.RFC.3630.xml" ?>
<?rfc include="reference.RFC.4203.xml" ?>
<?rfc include="reference.RFC.4655.xml" ?>
<?rfc include="reference.RFC.5305.xml" ?>
<?rfc include="reference.RFC.5307.xml" ?>
<?rfc include="reference.RFC.5316.xml" ?>
<?rfc include="reference.RFC.5392.xml" ?>
<?rfc include="reference.RFC.6119.xml" ?>
<?rfc include="reference.RFC.6549.xml" ?>
<?rfc include="reference.RFC.6822.xml" ?>
<?rfc include="reference.I-D.ietf-pce-stateful-pce"?>
<?rfc include="reference.I-D.ietf-pce-pceps"?>
<?rfc include="reference.I-D.ietf-idr-ls-distribution"?>
<?rfc include="reference.I-D.lee-pce-transporting-te-data"?>
</references>
<section title="Contributor Addresses" toc="default">
<t>
<figure title="" suppress-title="false" align="left" alt="" width="" height="">
<artwork xml:space="preserve" name="" type="" align="left" alt="" width="" height=""><![CDATA[
Udayasree Palle
Huawei Technologies
Divyashree Techno Park, Whitefield
Bangalore, Karnataka 560037
India
EMail: udayasree.palle@huawei.com
Sergio Belotti
Alcatel-Lucent
Italy
EMail: sergio.belotti@alcatel-lucent.com
]]></artwork>
</figure>
</t>
</section>
</back>
</rfc>
| PAFTECH AB 2003-2026 | 2026-04-24 01:20:16 |