PCEP extensions for Distribution of Link-State and TE Information
draft-ietf-pce-pcep-ls-02
| Document | Type | Active Internet-Draft (pce WG) | |
|---|---|---|---|
| Authors | Dhruv Dhody , Shuping Peng , Young Lee , Daniele Ceccarelli , Aijun Wang , Gyan Mishra | ||
| Last updated | 2024-10-20 | ||
| Replaces | draft-dhodylee-pce-pcep-ls | ||
| RFC stream | Internet Engineering Task Force (IETF) | ||
| Intended RFC status | (None) | ||
| Formats | |||
| Additional resources | Mailing list discussion | ||
| Stream | WG state | WG Document | |
| Document shepherd | (None) | ||
| IESG | IESG state | I-D Exists | |
| Consensus boilerplate | Unknown | ||
| Telechat date | (None) | ||
| Responsible AD | (None) | ||
| Send notices to | (None) |
draft-ietf-pce-pcep-ls-02
PCE Working Group D. Dhody
Internet-Draft S. Peng
Intended status: Experimental Huawei
Expires: 23 April 2025 Y. Lee
Samsung Electronics
D. Ceccarelli
Cisco
A. Wang
China Telecom
G. Mishra
Verizon Inc.
20 October 2024
PCEP extensions for Distribution of Link-State and TE Information
draft-ietf-pce-pcep-ls-02
Abstract
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 (LS) routing protocol supporting the traffic engineering
extensions.
This document extends the Path Computation Element Communication
Protocol (PCEP) with Link-State and TE Information as an experimental
extension to allow gathering more deployment and implementation
feedback on the use of PCEP in this way.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on 23 April 2025.
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Copyright Notice
Copyright (c) 2024 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents (https://trustee.ietf.org/
license-info) in effect on the date of publication of this document.
Please review these documents carefully, as they describe your rights
and restrictions with respect to this document. Code Components
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provided without warranty as described in the Revised BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Scope of the Experiment . . . . . . . . . . . . . . . . . 5
1.1.1. Evaluation of the Experiment . . . . . . . . . . . . 6
1.2. Requirements Language . . . . . . . . . . . . . . . . . . 7
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 7
3. Applicability . . . . . . . . . . . . . . . . . . . . . . . . 7
4. Requirements for PCEP Extensions . . . . . . . . . . . . . . 8
5. New Functions to distribute link-state (and TE) via PCEP . . 9
6. Overview of Extensions to PCEP . . . . . . . . . . . . . . . 9
6.1. New Messages . . . . . . . . . . . . . . . . . . . . . . 9
6.2. Capability Advertisement . . . . . . . . . . . . . . . . 10
6.3. Initial Link-State (and TE) Synchronization . . . . . . . 10
6.3.1. Optimizations for LS Synchronization . . . . . . . . 12
6.4. LS Report . . . . . . . . . . . . . . . . . . . . . . . . 13
7. Transport . . . . . . . . . . . . . . . . . . . . . . . . . . 13
8. PCEP Messages . . . . . . . . . . . . . . . . . . . . . . . . 13
8.1. LS Report Message . . . . . . . . . . . . . . . . . . . . 13
8.2. The PCErr Message . . . . . . . . . . . . . . . . . . . . 14
9. Objects and TLV . . . . . . . . . . . . . . . . . . . . . . . 14
9.1. TLV Format . . . . . . . . . . . . . . . . . . . . . . . 15
9.2. Open Object . . . . . . . . . . . . . . . . . . . . . . . 15
9.2.1. LS Capability TLV . . . . . . . . . . . . . . . . . . 15
9.3. LS Object . . . . . . . . . . . . . . . . . . . . . . . . 16
9.3.1. Routing Universe TLV . . . . . . . . . . . . . . . . 18
9.3.2. Route Distinguisher TLV . . . . . . . . . . . . . . . 18
9.3.3. Virtual Network TLV . . . . . . . . . . . . . . . . . 19
9.3.4. Local Node Descriptors TLV . . . . . . . . . . . . . 19
9.3.5. Remote Node Descriptors TLV . . . . . . . . . . . . . 20
9.3.6. Node Descriptors Sub-TLVs . . . . . . . . . . . . . . 20
9.3.7. Link Descriptors TLV . . . . . . . . . . . . . . . . 21
9.3.8. Prefix Descriptors TLV . . . . . . . . . . . . . . . 22
9.3.9. PCEP-LS Attributes . . . . . . . . . . . . . . . . . 22
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9.3.9.1. Node Attributes TLV . . . . . . . . . . . . . . . 22
9.3.9.2. Link Attributes TLV . . . . . . . . . . . . . . . 23
9.3.9.3. Prefix Attributes TLV . . . . . . . . . . . . . . 23
9.3.10. Removal of an Attribute . . . . . . . . . . . . . . . 24
10. Other Considerations . . . . . . . . . . . . . . . . . . . . 24
10.1. Inter-AS Links . . . . . . . . . . . . . . . . . . . . . 24
11. Security Considerations . . . . . . . . . . . . . . . . . . . 24
12. Manageability Considerations . . . . . . . . . . . . . . . . 25
12.1. Control of Function and Policy . . . . . . . . . . . . . 25
12.2. Information and Data Models . . . . . . . . . . . . . . 25
12.3. Liveness Detection and Monitoring . . . . . . . . . . . 26
12.4. Verify Correct Operations . . . . . . . . . . . . . . . 26
12.5. Requirements On Other Protocols . . . . . . . . . . . . 26
12.6. Impact On Network Operations . . . . . . . . . . . . . . 26
13. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 26
13.1. PCEP Messages . . . . . . . . . . . . . . . . . . . . . 26
13.2. PCEP Objects . . . . . . . . . . . . . . . . . . . . . . 27
13.3. LS Object . . . . . . . . . . . . . . . . . . . . . . . 27
13.4. PCEP-Error Object . . . . . . . . . . . . . . . . . . . 28
13.5. PCEP TLV Type Indicators . . . . . . . . . . . . . . . . 28
13.6. PCEP-LS Sub-TLV Type Indicators . . . . . . . . . . . . 29
14. TLV Code Points Summary . . . . . . . . . . . . . . . . . . . 29
15. Implementation Status . . . . . . . . . . . . . . . . . . . . 30
15.1. Hierarchical Transport PCE controllers . . . . . . . . . 31
15.2. ONOS-based Controller (MDSC and PNC) . . . . . . . . . . 31
16. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 32
17. References . . . . . . . . . . . . . . . . . . . . . . . . . 32
17.1. Normative References . . . . . . . . . . . . . . . . . . 32
17.2. Informative References . . . . . . . . . . . . . . . . . 33
Appendix A. Examples . . . . . . . . . . . . . . . . . . . . . . 36
A.1. All Nodes . . . . . . . . . . . . . . . . . . . . . . . . 36
A.2. Designated Node . . . . . . . . . . . . . . . . . . . . . 37
A.3. Between PCEs . . . . . . . . . . . . . . . . . . . . . . 38
Appendix B. Contributor Addresses . . . . . . . . . . . . . . . 39
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 40
1. Introduction
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. The TED must be 'complete
and accurate' each time the PCE performs a path computation.
In MPLS and GMPLS, Interior Gateway 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 [RFC4655] is the
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use of computationally more sophisticated path computation algorithms
and the realization that these may need enhanced processing power
(not necessarily available at each node).
Section 4.3 of [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
([RFC3630] and [RFC5305] for MPLS-TE; [RFC4203] and [RFC5307] for
GMPLS). An alternative mechanism is offered by BGP-LS
[I-D.ietf-idr-rfc7752bis] .
[RFC8231] describes a set of extensions to PCEP to provide stateful
control. A stateful PCE has access to not only the information
carried by the network's IGP, but also the set of active paths and
their reserved resources for its computations. Path Computation
Client (PCC) can delegate the rights to modify the LSP parameters to
an Active Stateful PCE. This requires PCE to quickly be updated on
any changes in the topology/TED, so that PCE can meet the need for
updating LSPs effectively and in a timely manner. The fastest way
for a PCE to be updated on TED changes is via a direct session with
each network node and with an incremental update from each network
node with only the attributes that get modified.
[RFC8281] describes the setup, maintenance, and teardown of PCE-
initiated LSPs under the stateful PCE model, without the need for
local configuration on the PCC, thus allowing for a dynamic network
that is centrally controlled and deployed. This model requires
timely topology and TED updates at the PCE.
[RFC5440] describes the specifications for the Path Computation
Element Communication Protocol (PCEP). PCEP specifies the
communication between a PCC and a PCE, or between two PCEs based on
the PCE architecture [RFC4655].
This document describes how link-state and TE information can be
collected from networks and shared with PCE using the PCEP itself.
This is achieved using a new PCEP message format. The mechanism is
applicable to physical and virtual links as well as further subjected
to various policies. This document is designated as "experimental"
to allow for the collection of more deployment and implementation
information regarding the use of PCEP for learning link state and
traffic engineering (TE) topology information before attempting to
standardize it (see Section 1.1).
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A network node maintains one or more databases for storing link-state
and TE information about nodes and links in any given area. Link
attributes stored in these databases include: local/remote IP
addresses, local/remote interface identifiers, link metric, and TE
metric, link bandwidth, reservable bandwidth, per CoS class
reservation state, preemption, and Shared Risk Link Groups (SRLG).
The node's PCEP process can retrieve topology from these databases
and distribute it to a PCE, either directly or via another PCEP
Speaker, using the encoding specified in this document.
Further [RFC6805] describes Hierarchical-PCE architecture, where a
Parent PCE maintains a domain topology map. To build this domain
topology map, the Child PCE can carry the border nodes and inter-
domain link information to the Parent PCE using the mechanism
described in this document. Further, as described in [RFC8637], the
Child PCE can also transport abstract Link-State and TE information
from a Child PCE to a Parent PCE using the mechanism described in
this document to build an abstract topology at the Parent PCE.
[RFC8231] describes LSP state synchronization between PCCs and PCEs
in the case of stateful PCE. This document does not make any changes
to the LSP state synchronization process. The mechanism described in
this document is on top of the existing LSP state synchronization.
1.1. Scope of the Experiment
The procedures described in this document are experimental. The
experiment is intended to enable research on the usage of PCEP to
populate the Link-State and TE Information from a PCC to the PCE.
For this purpose, this document specifies a new PCEP message, a new
PCEP object, and new TLVs.
The new message introduced by this document will not be understood by
legacy implementations. On receiving the message, a legacy
implementation will behave according to the rules for an unknown
message as per [RFC5440]. It is assumed that this experiment will be
conducted only when both the PCE and PCC form part of the experiment.
It is possible that a PCC or PCE can operate with peers, some of
which form part of the experiment and some that do not. In this
case, the capability exchange required before using this extension
would take care of the mismatch. A PCEP speaker that offers this
feature to its peer that does not support or does not wish to support
the feature will not receive the indication of support in the Open
message, and so is expected to not use the feature. Thus this
experimentation would not clash with or cause harm to existing
deployments. Further, since a PCEP speaker would use the new message
only after capability exchange, there is no danger of this
experimentation "escaping" to the wider Internet. A PCEP speaker
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that receives the new message (that is part of the feature when the
use of the feature has not been agreed upon) will send an error
message as described in Section 6.9 of [RFC5440]. A PCEP speaker
that receives the new object that is part of the feature when the use
of the feature has not been agreed, it will send an error message as
described in Section 7.2 of [RFC5440].
1.1.1. Evaluation of the Experiment
For every implementation of this feature, the information as per
[RFC7942] is collected and maintained in the Working Group (WG) wiki
[WIKI].
For every deployment of this feature, the following information is
collected and maintained in the wiki[WIKI]:
* Network Type
* Network Underlying Technology
* Network Size (nodes and links)
* Number of PCEP sessions with the feature enabled
* Number of paths in Stateful PCE
* The main reason for using this feature via PCEP over others
* Any challenges (deployment, management, scalability...)
The information can also be shared directly with the WG chairs who
can anonymise the deployment information if needed.
The experiment will end three years after the RFC is published. At
that point, the WG will determine how widely this has been
implemented and deployed. The WG will evaluate the success of this
feature by comparing its applicability in various deployments in
comparison to existing mechanisms. Key considerations include
whether the feature adversely affects the performance of the PCE and
if it is scalable. The Working Group will also monitor for any
issues related to the implementation, deployment, and management of
the feature.
When the results of implementation and deployment are available, this
document (or part thereof) will be updated and refined, and then it
could be moved from Experimental to Standards Track.
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1.2. Requirements Language
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 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
2. Terminology
The terminology is as per [RFC4655] and [RFC5440].
3. Applicability
The mechanism specified in this draft is applicable to deployments:
* Where there is no IGP or BGP-LS running in the network.
* Where there is no IGP or BGP-LS running at the PCE to learn link-
state and TE information.
* Where there is IGP or BGP-LS running but with a need for a faster
and direct TE and link-state population and convergence at the
PCE.
- A PCE may receive partial information (say basic TE, link-
state) from IGP and other information (optical and impairment)
from PCEP.
- A PCE may receive an incremental update (as opposed to the full
(entire) information of the node/link).
- A PCE may receive full information from both existing
mechanisms (IGP or BGP-LS) and PCEP.
* Where there is a need for transporting (abstract) Link-State and
TE information from Child PCE to a Parent PCE in H-PCE [RFC6805];
as well as for Provisioning Network Controller (PNC) to Multi-
Domain Service Coordinator (MDSC) in Abstraction and Control of TE
Networks (ACTN) [RFC8453].
* Where there is an existing PCEP session between all the nodes and
the PCE-based central controller (PCECC) [RFC8283], and the
operator would like to use PCEP as a direct southbound interface
to all the nodes in the network. This enables the operator to use
PCEP as a single direct protocol between the controller and all
the nodes in the network. In this mode, all nodes send only the
local information.
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Based on the local policy and deployment scenario, a PCC chooses to
send only local information or both local and remote learned
information. How a PCE manages the link-state (and TE) information
is implementation-specific and thus out of the scope of this
document.
The prefix information in PCEP-LS can also help in determining the
domain of the tunnel destination in the H-PCE (and ACTN) scenario.
Section 4.5 of [RFC6805] describes various mechanisms and procedures
that might be used, PCEP-LS provides a simple mechanism to exchange
this information within PCEP.
[RFC8453] defines three types of topology abstraction - (1) Native/
White Topology; (2) Black Topology; and (3) Grey Topology. Based on
the local policy, the PNC (or Child PCE) would share the domain
topology with the MDSC (or Parent PCE) based on the abstraction type.
The protocol extensions defined in this document can carry any type
of topology abstraction.
4. Requirements for PCEP Extensions
The following key requirements associated with link-state (and TE)
distribution are identified for PCEP:
1. The PCEP speaker supporting this draft MUST have a mechanism to
advertise the Link-State (and TE) distribution capability.
2. PCC supporting this draft MUST have the capability to report the
link-state (and TE) information to the PCE. This MUST include
self-originated (local) information and MAY also allow remote
information learned via routing protocols. PCC MUST be capable
of doing the initial bulk sync at the time of session
initialization as well as any changes thereafter.
3. A PCE MAY learn link-state (and TE) from PCEP as well as from
existing mechanisms like IGP/BGP-LS. PCEP extensions MUST have a
mechanism to correlate the information learned via other means.
There MUST NOT be any changes to the existing link-state (and TE)
population mechanism via IGP/BGP-LS. PCEP extension SHOULD keep
the properties in a protocol (IGP or BGP-LS) neutral way, such
that an implementation need not know about any OSPF or IS-IS or
BGP-LS protocol specifics.
4. It SHOULD be possible to encode only the changes in link-state
(and TE) properties (after the initial sync) in PCEP messages.
This leads to faster convergence.
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5. The same mechanism SHOULD be used for both MPLS TE as well as
GMPLS, optical, and impairment-aware properties.
6. The same mechanism SHOULD be used for PCE to PCE Link-state (and
TE) synchronization.
5. New Functions to distribute link-state (and TE) via PCEP
Several new functions are required in PCEP to support distribution of
link-state (and TE) information. 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:
* Capability advertisement (E-C,C-E): both the PCC and the PCE MUST
announce during the PCEP session establishment that they support
PCEP extensions for the distribution of link-state (and TE)
information defined in this document.
* Link-State (and TE) synchronization (C-E): after the session
between the PCC and a PCE is initialized, the PCE must learn Link-
State (and TE) information before it can perform path
computations. In the case of stateful PCE, it is RECOMMENDED that
this operation be done before LSP state synchronization.
* Link-State (and TE) Report (C-E): a PCC sends an LS (and TE)
report to a PCE whenever the Link-State and TE information
changes.
6. Overview of Extensions to PCEP
6.1. New Messages
In this document, we define a new PCEP message called LS Report
(LSRpt), a PCEP message sent by a PCC to a PCE to report link-state
(and TE) information. Each LS Report in an LSRpt message can contain
the node or link properties. A unique PCEP-specific LS identifier
(LS-ID) is also carried in the message to identify a node or a link
that remains constant for the lifetime of a PCEP session. This
identifier on its own is sufficient when no IGP or BGP-LS running in
the network for PCE to learn link-state (and TE) information. In
case PCE learns some information from PCEP and some from the existing
mechanism, the PCC SHOULD include the mapping of IGP or BGP-LS
identifier to map the information populated via PCEP with IGP/BGP-LS.
See Section 8.1 for details.
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6.2. Capability Advertisement
During the PCEP Initialization Phase, PCEP Speakers (PCE or PCC)
advertise their support of LS (and TE) distribution via PCEP
extensions. A PCEP Speaker includes the "LS Capability" TLV,
described in Section 9.2.1, in the OPEN Object to advertise its
support for PCEP-LS extensions. The presence of the LS Capability
TLV in PCC's OPEN Object indicates that the PCC is willing to send LS
Reports with local link-state (and TE) information. The presence of
the LS Capability TLV in PCE's Open message indicates that the PCE is
interested in receiving LS Reports with local link-state (and TE)
information.
The PCEP extensions for LS (and TE) distribution MUST NOT be used if
one or both PCEP Speakers have not included the LS Capability TLV in
their respective OPEN message. If the PCE supports the extensions
defined in this document but does not advertise this capability, then
upon receipt of an LSRpt message from the PCC, it SHOULD generate a
PCErr with error-type 19 (Invalid Operation), error-value TBD1
(Attempted LS Report if LS capability was not advertised) and it will
terminate the PCEP session.
The LS reports sent by PCC MAY carry the remote link-state (and TE)
information learned via existing means like IGP and BGP-LS only if
both PCEP Speakers set the R (remote) Flag in the "LS Capability" TLV
to 'Remote Allowed (R Flag = 1)'. If this is not the case and LS
reports carry remote link-state (and TE) information, then a PCErr
with error-type 19 (Invalid Operation) and error-value TBD1
(Attempted LS Report if LS remote capability was not advertised) and
it will terminate the PCEP session.
6.3. Initial Link-State (and TE) Synchronization
The purpose of LS Synchronization is to provide a checkpoint-in-time
state replica of a PCC's link-state (and TE) database in a PCE.
State Synchronization is performed immediately after the
Initialization phase (see [RFC5440]). In the case of stateful PCE
([RFC8231]) it is RECOMMENDED that the LS synchronization should be
done before LSP state synchronization.
During LS Synchronization, a PCC first takes a snapshot of the state
of its database, then sends the snapshot to a PCE in a sequence of LS
Reports. Each LS Report sent during LS Synchronization has the SYNC
Flag in the LS Object set to 1. The end of synchronization marker is
an LSRpt message with the SYNC Flag set to 0 for an LS Object with
LS-ID equal to the reserved value 0. If the PCC has no link-state to
synchronize, it will only send the end of synchronization marker.
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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 the state it
received from this PCC. The session re-establishment MUST be re-
attempted per the procedures defined in [RFC5440], including the use
of a back-off timer.
If the PCC encounters a problem which prevents it from completing the
LS synchronization, it MUST send a PCErr message with error-type TBD2
(LS Synchronization Error) and error-value 2 (indicating an internal
PCC error) to the PCE and terminate the session.
The PCE does not send positive acknowledgements for properly received
LS synchronization messages. It MUST respond with a PCErr message
with error-type TBD2 (LS Synchronization Error) and error-value 1
(indicating an error in processing the LSRpt) if it encounters a
problem with the LS Report it received from the PCC and it MUST
terminate the session.
The LS reports can carry local as well as remote link-state (and TE)
information depending on the R flag in the LS capability TLV.
The successful LS Synchronization sequence is shown in Figure 1.
+-+-+ +-+-+
|PCC| |PCE|
+-+-+ +-+-+
| |
|-----LSRpt, SYNC=1----->| (Sync start)
| |
|-----LSRpt, SYNC=1----->|
| . |
| . |
| . |
|-----LSRpt, SYNC=1----->|
| . |
| . |
| . |
| |
|-----LSRpt, SYNC=0----->| (End of sync marker
| | LS Report
| | for LS-ID=0)
| | (Sync done)
Figure 1: Successful LS synchronization
The sequence where the PCE fails during the LS Synchronization phase
is shown in Figure 2.
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+-+-+ +-+-+
|PCC| |PCE|
+-+-+ +-+-+
| |
|-----LSRpt, SYNC=1----->|
| |
|-----LSRpt, SYNC=1----->|
| . |
| . |
| . |
|-----LSRpt, SYNC=1----->|
| |
|---LSRpt,SYNC=1 |
| \ ,-PCErr---|
| \ / |
| \/ |
| /\ |
| / `-------->| (Ignored)
|<--------` |
Figure 2: Failed LS synchronization (PCE failure)
The sequence where the PCC fails during the LS Synchronization phase
is shown in Figure 3.
+-+-+ +-+-+
|PCC| |PCE|
+-+-+ +-+-+
| |
|-----LSRpt, SYNC=1----->|
| |
|-----LSRpt, SYNC=1----->|
| . |
| . |
| . |
|-------- PCErr--------->|
| |
Figure 3: Failed LS synchronization (PCC failure)
6.3.1. Optimizations for LS Synchronization
These optimizations are described in
[I-D.kondreddy-pce-pcep-ls-sync-optimizations].
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6.4. LS Report
The PCC MUST report any changes in the link-state (and TE)
information to the PCE by sending an LS Report carried on an LSRpt
message to the PCE. Each node and Link would be uniquely identified
by a PCEP LS identifier (LS-ID). The LS reports may carry local as
well as remote link-state (and TE) information depending on the R
flag in LS capability TLV. It MAY also include the mapping of IGP or
BGP-LS identifier to map the information populated via PCEP with IGP/
BGP-LS identifiers.
More details about the LSRpt message are in Section 8.1.
7. Transport
A permanent PCEP session (section 4.2.8 of [RFC5440]) MUST be
established between a PCE and PCC supporting link-state (and TE)
distribution via PCEP. In the case of session failure, session re-
establishment is re-attempted as per the procedures defined in
[RFC5440].
8. PCEP Messages
As defined in [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.
8.1. LS Report Message
A PCEP LS Report message (also referred to as LSRpt message) is a
PCEP message sent by a PCC to a PCE to report the link-state (and TE)
information. An LSRpt message can carry more than one LS Reports (LS
object). The Message-Type field of the PCEP common header for the
LSRpt message is set to [TBD3].
The format of the LSRpt message is as follows:
<LSRpt Message> ::= <Common Header>
<ls-report-list>
Where:
<ls-report-list> ::= <LS>[<ls-report-list>]
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The LS object is a mandatory object which carries LS information of a
node/prefix or a link. Each LS object has a unique LS-ID as
described in Section 9.3. If the LS object is missing, the receiving
PCE MUST send a PCErr message with Error-type=6 (Mandatory Object
missing) and Error-value=[TBD4] (LS object missing).
A PCE may choose to implement a limit on the LS information of a
single PCC can populate. If an LSRpt 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 LSRpt message triggering this condition
and SHOULD terminate the session.
8.2. The PCErr Message
If a PCEP speaker has advertised the LS capability on the PCEP
session, the PCErr message MAY include the LS object. If the error
reported is the result of an LS report, then the LS-ID number MUST be
the one from the LSRpt that triggered the error.
The format of a PCErr message from [RFC5440] is extended as follows:
<PCErr Message> ::= <Common Header>
( <error-obj-list> [<Open>] ) | <error>
[<error-list>]
<error-obj-list>::=<PCEP-ERROR>[<error-obj-list>]
<error>::=[<request-id-list> | <ls-id-list>]
<error-obj-list>
<request-id-list>::=<RP>[<request-id-list>]
<ls-id-list>::=<LS>[<ls-id-list>]
<error-list>::=<error>[<error-list>]
9. Objects and TLV
The PCEP objects defined in this document are compliant with the PCEP
object format defined in [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.
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9.1. TLV Format
The TLV and the sub-TLV format (and padding) in this document, are as
per section 7.1 of [RFC5440].
9.2. Open Object
This document defines a new optional TLV for use in the OPEN Object.
9.2.1. LS Capability TLV
The LS-CAPABILITY TLV is an optional TLV for use in the OPEN Object
for link-state (and TE) distribution via PCEP capability
advertisement. Its format is shown in the following figure:
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|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The type of the TLV is [TBD5] and it has a fixed length of 4 octets.
The value comprises a single field - Flags (32 bits):
* R (remote allowed - 1 bit): if set to 1 by a PCC, the R Flag
indicates that the PCC allows the reporting of remote LS
information learned via other means like IGP and BGP-LS; if set to
1 by a PCE, the R Flag indicates that the PCE is capable of
receiving remote LS information (from the PCC point of view). The
R Flag must be advertised by both PCC and PCE for LSRpt messages
to report remote as well as local LS information on a PCEP
session. The TLVs related to IGP/BGP-LS identifier MUST be
encoded when both PCEP speakers have the R Flag set.
Unassigned bits are considered reserved. They MUST be set to 0 on
transmission and MUST be ignored on receipt.
Advertisement of the LS capability implies support of local link-
state (and TE) distribution, as well as the objects, TLVs and
procedures defined in this document.
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9.3. LS Object
The LS (link-state) object MUST be carried within LSRpt messages and
MAY be carried within PCErr messages. The LS object contains a set
of fields used to specify the target node or link. It also contains
a flag indicating to a PCE that the LS synchronization is in
progress. The TLVs used with the LS object correlate with the IGP/
BGP-LS encodings.
LS Object-Class is TBD6.
Four Object-Type values are defined for the LS object so far:
* LS Node: LS Object-Type is 1.
* LS Link: LS Object-Type is 2.
* LS IPv4 Topology Prefix: LS Object-Type is 3.
* LS IPv6 Topology Prefix: LS Object-Type is 4.
The format of all types of LS objects are as follows:
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|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| LS-ID |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// TLVs //
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Protocol-ID (8-bit): The field provides the source information. The
protocol could be an IGP, BGP-LS, or an abstraction algorithm. In
case the PCC only provides local information of the PCC, it MUST use
Protocol-ID as Direct. The following values are defined (some of the
initial values are the same as [I-D.ietf-idr-rfc7752bis]):
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+-------------+----------------------------------+
| Protocol-ID | Source protocol |
+-------------+----------------------------------+
| 1 | IS-IS Level 1 |
| 2 | IS-IS Level 2 |
| 3 | OSPFv2 |
| 4 | Direct |
| 5 | Static configuration |
| 6 | OSPFv3 |
| 7 | BGP |
| 8 | RSVP-TE |
| 9 | Segment Routing |
| 10 | PCEP |
| 11 | Abstraction |
+-------------+----------------------------------+
Flags (24-bit):
* S (SYNC - 1 bit): the S Flag MUST be set to 1 on each LSRpt sent
from a PCC during LS Synchronization. The S Flag MUST be set to 0
in other LSRpt messages sent from the PCC.
* R (Remove - 1 bit): On LSRpt messages, the R Flag indicates that
the node/link/prefix has been removed from the PCC and the PCE
SHOULD remove from its database. Upon receiving an LS Report with
the R Flag set to 1, the PCE SHOULD remove all state for the
node/link/prefix identified by the LS Identifiers from its
database.
LS-ID(64-bit): A PCEP-specific identifier for the node, link, or
prefix information. A PCC creates a unique LS-ID for each node/link/
prefix that is constant for the lifetime of a PCEP session. The PCC
will advertise the same LS-ID on all PCEP sessions it maintains at a
given time. All subsequent PCEP messages then address the node/link/
prefix by the LS-ID. The values of 0 and 0xFFFFFFFFFFFFFFFF are
reserved.
Unassigned bits are considered reserved. They MUST be set to 0 on
transmission and MUST be ignored on receipt.
TLVs that may be included in the LS Object are described in the
following sections.
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9.3.1. Routing Universe TLV
In the case of remote link-state (and TE) population when existing
IGP/BGP-LS are also used, OSPF and IS-IS may run multiple routing
protocol instances over the same link as described in
[I-D.ietf-idr-rfc7752bis]. See [RFC8202] and [RFC6549] for more
information. These instances define an independent "routing
universe". The 64-bit 'Identifier' field is used to identify the
"routing universe" where the LS object belongs. The LS objects
representing IGP objects (nodes, links, or prefixes) from the same
routing universe MUST have the same 'Identifier' value; LS objects
with different 'Identifier' values MUST be considered to be from
different routing universes.
The format of the optional ROUTING-UNIVERSE TLV is shown in the
following figure:
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 |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The below table lists the 'Identifier' values that are defined as
well-known in this draft (same as [I-D.ietf-idr-rfc7752bis]).
+------------+-----------------------------------+
| Identifier | Routing Universe |
+------------+-----------------------------------+
| 0 | Default Layer 3 Routing topology |
+------------+-----------------------------------+
If this TLV is not present the default value 0 is assumed.
9.3.2. Route Distinguisher TLV
To allow identification of VPN link, node, and prefix information in
PCEP-LS, a Route Distinguisher (RD) [RFC4364] is used. The LS
objects from the same VPN MUST have the same RD; LS objects with
different RD values MUST be considered to be from different VPNs.
The ROUTE-DISTINGUISHER TLV is defined in [RFC9168] as a Flow
Specification TLVs with a separate registry. This document also adds
the ROUTE-DISTINGUISHER TLV with TBD15 in the PCEP TLV registry to be
used inside the LS object.
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9.3.3. Virtual Network TLV
To realize ACTN, the MDSC needs to build a multi-domain topology.
This topology is best served if this is an abstract view of the
underlying network resources of each domain. It is also important to
provide a customer view of the network slice for each customer.
There is a need to control the level of abstraction based on the
deployment scenario and business relationship between the
controllers.
Virtual service coordination function in ACTN incorporates customer
service-related knowledge of the virtual network operations in order
to seamlessly operate virtual networks while meeting customer's
service requirements. [I-D.ietf-teas-actn-requirements] describes
various VN operations initiated by a customer/application. In this
context, there is a need for associating the abstracted link-state
and TE topology with a VN "construct" to facilitate VN operations in
PCE architecture.
VIRTUAL-NETWORK-TLV as per [RFC9358] can be included in the LS object
to identify the link, node, and prefix information belongs to a
particular VN.
9.3.4. Local Node Descriptors TLV
As described in [I-D.ietf-idr-rfc7752bis], 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. In case of additional auxiliary Router-IDs used for TE,
these MUST also be included in the link attribute TLV (see
Section 9.3.9.2).
It is desirable that the Router-ID assignments inside the Node
Descriptors TLV are globally unique. Some considerations for
globally unique Node/Link/Prefix identifiers are described in
[I-D.ietf-idr-rfc7752bis].
The Local Node Descriptors TLV contains Node Descriptors for the node
anchoring the local end of the link. This TLV MUST be included in
the LS Report when during a given PCEP session a node/link/prefix is
first reported to a PCE. A PCC sends to a PCE the first LS Report
either during the State Synchronization, or when a new node/link/
prefix is learned at the PCC. The value contains one or more Node
Descriptor Sub-TLVs, which allows the specification of a flexible key
for any given node/link/prefix information such that the global
uniqueness of the node/link/prefix is ensured.
This TLV is applicable for all LS Object-Type.
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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) //
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The value contains one or more Node Descriptor Sub-TLVs defined in
Section 9.3.6.
9.3.5. Remote Node Descriptors TLV
The Remote Node Descriptors contain Node Descriptors for the node
anchoring the remote end of the link. This TLV MUST be included in
the LS Report when during a given PCEP session a link is first
reported to a PCE. A PCC sends to a PCE the first LS Report either
during the State Synchronization, or when a new 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 Section 9.3.6.
This TLV is applicable for LS Link Object-Type.
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) //
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
9.3.6. Node Descriptors Sub-TLVs
The Node Descriptors TLV (Local and Remote) carries one or more Node
Descriptor Sub-TLV follows the format of all PCEP TLVs as defined in
[RFC5440], however, the Type values are selected from a new PCEP-LS
sub-TLV IANA registry (see Section 13.6).
Type values are chosen so that there can be commonality with BGP-LS
[I-D.ietf-idr-rfc7752bis]. This is possible because the "BGP-LS Node
Descriptor, Link Descriptor, Prefix Descriptor, and Attribute TLVs"
registry marks 0-255 as reserved. Thus the space of the sub-TLV
values for the Type field can be partitioned as shown below -
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Range |
---------------+---------------------------------------------
0 | Reserved - must not be allocated.
|
1 .. 255 | New PCEP sub-TLV allocated according to the
| registry defined in this document.
|
256 .. 65535 | Per BGP registry defined by
| [I-D.ietf-idr-rfc7752bis].
| Not to be allocated in this registry.
All Node Descriptors TLVs defined for BGP-LS can then be used with
PCEP-LS as well. One new PCEP sub-TLVs for Node Descriptor are
defined in this document.
+----------+-------------------+----------+----------------+
| Sub-TLV | Description | Length |Value defined in|
+----------+-------------------+----------+----------------+
| 24 | SPEAKER-ENTITY-ID | Variable | [RFC8232] |
+----------+-------------------+----------+----------------+
A new sub-TLV type (24) is allocated for SPEAKER-ENTITY-ID sub-TLV.
The length and value fields are as per [RFC8232].
9.3.7. Link Descriptors TLV
The Link Descriptors TLV contains Link Descriptors for each link.
This TLV MUST be included in the LS Report when during a given PCEP
session a link is first reported to a PCE. A PCC sends to a PCE the
first LS Report either during State Synchronization, or when a new
link is learned at the PCC. The length of this TLV is variable. The
value contains one or more Link Descriptor Sub-TLVs.
The 'Link descriptor' TLVs uniquely identify a link among multiple
parallel links between a pair of anchor routers similar to
[I-D.ietf-idr-rfc7752bis].
This TLV is applicable for LS Link Object-Type.
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=[TBD10] | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
// Link Descriptor Sub-TLVs (variable) //
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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All Link Descriptors TLVs defined for BGP-LS can then be used with
PCEP-LS as well. No new PCEP sub-TLVs for Link Descriptor are
defined in this document.
The format and semantics of the 'value' fields in most 'Link
Descriptor' sub-TLVs correspond to the format and semantics of the
value fields in IS-IS Extended IS Reachability sub-TLVs, defined in
[RFC5305], [RFC5307] and [RFC6119]. Although the encodings for 'Link
Descriptor' TLVs were originally defined for IS-IS, the TLVs can
carry data sourced by IS-IS, OSPF, or direct.
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 [I-D.ietf-idr-rfc7752bis].
9.3.8. Prefix Descriptors TLV
The Prefix Descriptors TLV contains Prefix Descriptors that uniquely
identify an IPv4 or IPv6 Prefix originated by a Node. This TLV MUST
be included in the LS Report when during a given PCEP session a
prefix is first reported to a PCE. A PCC sends to a PCE the first LS
Report either during the State Synchronization, or when a new prefix
is learned at the PCC. The length of this TLV is variable.
This TLV is applicable for LS Prefix Object-Types for both IPv4 and
IPv6.
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=[TBD11] | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
// Prefix Descriptor Sub-TLVs (variable) //
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
All Prefix Descriptors TLVs defined for BGP-LS can then be used with
PCEP-LS as well. No new PCEP sub-TLVs for Prefix Descriptor are
defined in this document.
9.3.9. PCEP-LS Attributes
9.3.9.1. Node Attributes TLV
This is an optional attribute that is used to carry node attributes.
This TLV is applicable for LS Node Object-Type.
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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=[TBD12] | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
// Node Attributes Sub-TLVs (variable) //
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
All Node Attributes TLVs defined for BGP-LS can then be used with
PCEP-LS as well. No new PCEP sub-TLVs for Node Attributes are
defined in this document.
9.3.9.2. Link Attributes TLV
This TLV is applicable for LS Link Object-Type. The format and
semantics of the 'value' fields in some 'Link Attribute' sub-TLVs
correspond to the format and semantics of the 'value' fields in IS-IS
Extended IS Reachability sub-TLVs, defined in [RFC5305], [RFC5307]
and [I-D.ietf-idr-rfc7752bis]. Although the encodings for 'Link
Attribute' TLVs were originally defined for IS-IS, the TLVs can carry
data sourced by IS-IS, OSPF, or direct.
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=[TBD13] | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
// Link Attributes Sub-TLVs (variable) //
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
All Link Attributes TLVs defined for BGP-LS can then be used with
PCEP-LS as well. No new PCEP sub-TLVs for Link Attributes are
defined in this document.
9.3.9.3. Prefix Attributes TLV
This TLV is applicable for LS Prefix Object-Types for both IPv4 and
IPv6. Prefixes are learned from the IGP (IS-IS or OSPF) or BGP
topology with a set of IGP attributes (such as metrics, route tags,
etc.). This section describes the different attributes related to
the IPv4/IPv6 prefixes. Prefix Attributes TLVs SHOULD be encoded in
the LS Prefix Object.
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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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
// Prefix Attributes Sub-TLVs (variable) //
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
All Prefix Attributes TLVs defined for BGP-LS can then be used with
PCEP-LS as well. No new PCEP sub-TLVs for Prefix Attributes are
defined in this document.
9.3.10. Removal of an Attribute
One of the key objectives of PCEP-LS is to encode and carry only the
impacted attributes of a Node, a Link, or a Prefix. To accommodate
this requirement, in case of a removal of an attribute, the sub-TLV
MUST be included with no 'value' field and length=0 to indicate that
the attribute is removed. On receiving a sub-TLV with zero length,
the receiver removes the attribute from the database. An absence of
a sub-TLV that was included earlier MUST be interpreted as no change.
10. Other Considerations
10.1. Inter-AS Links
The main source of LS (and 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 ([RFC5392], [RFC9346]). 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.
11. Security Considerations
This document extends PCEP for LS (and TE) distribution including a
new LSRpt message with a new object and TLVs. Procedures and
protocol extensions defined in this document do not affect the
overall PCEP security model. See [RFC5440], [RFC8253]. Tampering
with the LSRpt 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
LS (and TE) information. Thus it is suggested that any mechanism
used for securing the transmission of other PCEP message be applied
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here as well. As a general precaution, it is RECOMMENDED that these
PCEP extensions only are activated on authenticated and encrypted
sessions belonging to the same administrative authority.
Further, as stated in [RFC6952], PCEP implementations SHOULD support
the TCP-AO [RFC5925] and not use TCP MD5 because of TCP MD5's known
vulnerabilities and weaknesses. PCEP also support Transport Layer
Security (TLS) [RFC8253] as per the recommendations and best current
practices in [RFC9325].
12. Manageability Considerations
All manageability requirements and considerations listed in [RFC5440]
apply to PCEP protocol extensions defined in this document. In
addition, requirements, and considerations listed in this section
apply.
12.1. Control of Function and Policy
A PCE or PCC implementation MUST allow configuring the PCEP-LS
capabilities as described in this document.
A PCC implementation SHOULD allow configuration to suggest if remote
information learned via routing protocols should be reported or not.
An implementation SHOULD allow the operator to specify the maximum
number of LS data to be reported.
An implementation SHOULD also allow the operator to create abstracted
topologies that are reported to the peers and create different
abstractions for different peers.
An implementation SHOULD allow the operator to configure a 64-bit
identifier for Routing Universe TLV.
12.2. Information and Data Models
An implementation SHOULD allow the operator to view the LS
capabilities advertised by each peer. To serve this purpose, the
PCEP YANG module [I-D.ietf-pce-pcep-yang] can be extended to include
advertised capabilities.
An implementation SHOULD also provide the following statistics:
* Total number of LSRpt sent/received, as well as per neighbour
* Number of errors received for LSRpt, per neighbour
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* Total number of locally originated Link-State Information
These statistics should be recorded as absolute counts since the
system or session start time. An implementation MAY also enhance
this information by recording peak per-second counts in each case.
An operator SHOULD define an import policy to limit inbound LSRpt to
"drop all LSRpt from a particular peer" as well as provide means to
limit inbound LSRpts.
12.3. Liveness Detection and Monitoring
Mechanisms defined in this document do not imply any new liveness
detection and monitoring requirements in addition to those already
listed in [RFC5440]".
12.4. Verify Correct Operations
Mechanisms defined in this document do not imply any new operation
verification requirements in addition to those already listed in
[RFC5440].
12.5. Requirements On Other Protocols
Mechanisms defined in this document do not imply any new requirements
on other protocols.
12.6. Impact On Network Operations
Mechanisms defined in this document do not have any impact on the
network operations in addition to those already listed in [RFC5440].
13. IANA Considerations
This document requests IANA actions to allocate code points for the
protocol elements defined in this document.
13.1. PCEP Messages
IANA created a registry for "PCEP Messages". Each PCEP message has a
message type value. This document defines a new PCEP message value.
Value Meaning Reference
TBD3 LSRpt [This I-D]
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13.2. PCEP Objects
This document defines the following new PCEP Object-classes and
Object-values:
Object-Class Value Name Reference
TBD6 LS Object [This I-D]
Object-Type=1
(LS Node)
Object-Type=2
(LS Link)
Object-Type=3
(LS IPv4 Prefix)
Object-Type=4
(LS IPv6 Prefix)
13.3. LS Object
This document requests that a new sub-registry, named "LS Object
Protocol-ID Field", is created within the "Path Computation Element
Protocol (PCEP) Numbers" registry to manage the Flag field of the LSP
object. New values are to be assigned by "IETF Review" [RFC8126].
Value Meaning Reference
0 Reserved [This I-D]
1 IS-IS Level 1 [This I-D]
2 IS-IS Level 2 [This I-D]
3 OSPFv2 [This I-D]
4 Direct [This I-D]
5 Static configuration [This I-D]
6 OSPFv3 [This I-D]
7 BGP [This I-D]
8 RSVP-TE [This I-D]
9 Segment Routing [This I-D]
10 PCEP [This I-D]
11 Abstraction [This I-D]
12-255 Unassigned
Further, this document also requests that a new sub-registry, named
"LS Object Flag Field", is created within the "Path Computation
Element Protocol (PCEP) Numbers" registry to manage the Flag field of
the LSP object. New values are to be assigned by "IETF Review"
[RFC8126]. Each bit should be tracked with the following qualities:
* Bit number (counting from bit 0 as the most significant bit)
* Capability description
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* Defining RFC
The following values are defined in this document:
Bit Description Reference
0-21 Unassigned
22 R (Remove bit) [This I-D]
23 S (Sync bit) [This I-D]
13.4. PCEP-Error Object
IANA is requested to make the following allocation in the "PCEP-ERROR
Object Error Types and Values" registry.
Error-Type Meaning Reference
6 Mandatory Object missing [RFC5440]
Error-Value=TBD4 [This I-D]
(LS object missing)
19 Invalid Operation [RFC8231]
Error-Value=TBD1 [This I-D]
(Attempted LS Report if LS
remote capability was not
advertised)
TBD2 LS Synchronization Error [This I-D]
Error-Value=1
(An error in processing the
LSRpt)
Error-Value=2
(An internal PCC error)
13.5. PCEP TLV Type Indicators
IANA is requested to make the following allocation in the "PCEP TLV
Type Indicators" registry.
Value Meaning Reference
TBD5 LS-CAPABILITY TLV [This I-D]
TBD7 ROUTING-UNIVERSE TLV [This I-D]
TBD15 ROUTE-DISTINGUISHER TLV [This I-D]
TBD8 Local Node Descriptors TLV [This I-D]
TBD9 Remote Node Descriptors TLV [This I-D]
TBD10 Link Descriptors TLV [This I-D]
TBD11 Prefix Descriptors TLV [This I-D]
TBD12 Node Attributes TLV [This I-D]
TBD13 Link Attributes TLV [This I-D]
TBD14 Prefix Attributes TLV [This I-D]
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13.6. PCEP-LS Sub-TLV Type Indicators
This document specifies the PCEP-LS Sub-TLVs. IANA is requested to
create a "PCEP-LS Sub-TLV Types" sub-registry for the sub-TLVs
carried in the PCEP-LS TLV (Local and Remote Node Descriptors TLV,
Link Descriptors TLV, Prefix Descriptors TLV, Node Attributes TLV,
Link Attributes TLV and Prefix Attributes TLV.
Allocations from this registry are to be made according to the
following assignment policies [RFC8126]:
Range | Assignment policy
---------------+---------------------------------------------------
0 | Reserved - must not be allocated.
|
1 .. 251 | Specification Required
|
252 .. 255 | Experimental Use
|
256 .. 65535 | Reserved - must not be allocated.
| Usage mirrors the BGP-LS TLV registry
| [I-D.ietf-idr-rfc7752bis]
|
IANA is requested to pre-populate this registry with values defined
in this document as follows, taking the new values from the range 1
to 251:
Value | Meaning
-------+------------------------
24 | SPEAKER-ENTITY-ID
14. TLV Code Points Summary
This section contains the global table of all TLVs in the LS object,
defined in this document.
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+-----------+---------------------+---------------+-----------------+
| TLV | Description | Ref TLV | Value defined |
| | | | in: |
+-----------+---------------------+---------------+-----------------+
| TBD7 | Routing Universe | -- | Sec 9.2.1 |
| TBD15 | Route | -- | Sec 9.2.2 |
| | Distinguisher | | |
| * | Virtual Network | -- | [ietf-pce- |
| | | | vn-association] |
| TBD8 | Local Node | 256 | [I-D.ietf-idr- |
| | | | rfc7752bis] |
| | Descriptors | | /3.2.1.2 |
| TBD9 | Remote Node | 257 | [I-D.ietf-idr- |
| | | | rfc7752bis] |
| | Descriptors | | /3.2.1.3 |
| TBD10 | Link Descriptors | -- | Sec 9.2.8 |
| TBD11 | Prefix Descriptors | -- | Sec 9.2.9 |
| TBD12 | Node Attributes | -- | Sec 9.2.10.1 |
| TBD13 | Link Attributes | -- | Sec 9.2.10.2 |
| TBD14 | Prefix Attributes | -- | Sec 9.2.10.3 |
+-----------+---------------------+---------------+-----------------+
* this TLV is defined in a different PCEP document
Figure 4: TLV Table
15. Implementation Status
[Note to RFC Editor: Please remove this section.]
This section records the status of known implementations of the
protocol defined by this specification at the time of posting of this
Internet-Draft, and is based on a proposal described in RFC 7942.
The description of implementations in this section is intended to
assist the IETF in its decision processes in progressing drafts to
RFCs. Please note that the listing of any individual implementation
here does not imply endorsement by the IETF. Furthermore, no effort
has been spent to verify the information presented here that was
supplied by IETF contributors. This is not intended as, and must not
be construed to be, a catalog of available implementations or their
features. Readers are advised to note that other implementations may
exist.
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According to RFC 7942, "this will allow reviewers and working groups
to assign due consideration to documents that have the benefit of
running code, which may serve as evidence of valuable experimentation
and feedback that have made the implemented protocols more mature.
It is up to the individual working groups to use this information as
they see fit".
The PCEP-LS protocol extensions as described in this I-D were
implemented and tested for a variety of applications. Apart from the
below implementation, there exist other experimental implementations
done for optical networks.
15.1. Hierarchical Transport PCE controllers
The PCEP-LS has been implemented as part of the IETF97 Hackathon and
Bits-N-Bites demonstration. The use-case demonstrated was the DCI
use-case of ACTN architecture in which to show the following
scenarios:
- connectivity services on the ACTN-based recursive hierarchical
SDN/PCE platform that has the three-tier level SDN controllers
(two-tier level MDSC and PNC) on the top of the PTN systems
managed by EMS.
- Integration test of two tier-level MDSC: The SBI of the low-
level MDSC is the YANG-based Korean national standards and one of
the high-level MDSC is the PCEP-LS based ACTN protocols.
- Performance test of three types of SDN controller based recovery
schemes including protection, reactive, and proactive restoration.
PCEP-LS protocol was used to demonstrate a quick report of failed
network components.
15.2. ONOS-based Controller (MDSC and PNC)
Huawei (PNC, MDSC) and SKT (MDSC) implemented PCEP-LS during the
Hackathon and IETF97 Bits-N-Bites demonstration. The demonstration
was ONOS-based ACTN architecture in which to show the following
capabilities:
Both packet PNC and optical PNC (with optical PCEP-LS extensions)
implemented PCEP-LS on its SBI as well as its NBI (towards MDSC).
SKT orchestrator (acting as MDSC) also supported PCEP-LS (as well
as RestConf) towards packet and optical PNCs on its SBI.
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Further description can be found at ONOS-PCEP
(https://wiki.onosproject.org/display/ONOS/PCEP+Protocol) and the
code at ONOS-PCEP-GITHUB
(https://github.com/opennetworkinglab/onos/tree/master/protocols/
pcep).
16. Acknowledgments
This document borrows some of the structure and text from the
[I-D.ietf-idr-rfc7752bis].
Thanks to Eric Wu, Venugopal Kondreddy, Mahendra Singh Negi,
Avantika, Zhengbin Li, Daniel King, and Adrian Farrel for the
reviews.
Thanks to Ramon Casellas for his comments and suggestions based on
his implementation experience.
17. References
17.1. Normative References
[I-D.ietf-idr-rfc7752bis]
Talaulikar, K., "Distribution of Link-State and Traffic
Engineering Information Using BGP", Work in Progress,
Internet-Draft, draft-ietf-idr-rfc7752bis-17, 25 August
2023, <https://datatracker.ietf.org/doc/html/draft-ietf-
idr-rfc7752bis-17>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC5305] Li, T. and H. Smit, "IS-IS Extensions for Traffic
Engineering", RFC 5305, DOI 10.17487/RFC5305, October
2008, <https://www.rfc-editor.org/info/rfc5305>.
[RFC5307] Kompella, K., Ed. and Y. Rekhter, Ed., "IS-IS Extensions
in Support of Generalized Multi-Protocol Label Switching
(GMPLS)", RFC 5307, DOI 10.17487/RFC5307, October 2008,
<https://www.rfc-editor.org/info/rfc5307>.
[RFC5440] Vasseur, JP., Ed. and JL. Le Roux, Ed., "Path Computation
Element (PCE) Communication Protocol (PCEP)", RFC 5440,
DOI 10.17487/RFC5440, March 2009,
<https://www.rfc-editor.org/info/rfc5440>.
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[RFC6119] Harrison, J., Berger, J., and M. Bartlett, "IPv6 Traffic
Engineering in IS-IS", RFC 6119, DOI 10.17487/RFC6119,
February 2011, <https://www.rfc-editor.org/info/rfc6119>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8232] Crabbe, E., Minei, I., Medved, J., Varga, R., Zhang, X.,
and D. Dhody, "Optimizations of Label Switched Path State
Synchronization Procedures for a Stateful PCE", RFC 8232,
DOI 10.17487/RFC8232, September 2017,
<https://www.rfc-editor.org/info/rfc8232>.
17.2. Informative References
[I-D.ietf-pce-pcep-yang]
Dhody, D., Beeram, V. P., Hardwick, J., and J. Tantsura,
"A YANG Data Model for Path Computation Element
Communications Protocol (PCEP)", Work in Progress,
Internet-Draft, draft-ietf-pce-pcep-yang-25, 21 May 2024,
<https://datatracker.ietf.org/doc/html/draft-ietf-pce-
pcep-yang-25>.
[I-D.ietf-teas-actn-requirements]
Lee, Y., Ceccarelli, D., Miyasaka, T., Shin, J., and K.
Lee, "Requirements for Abstraction and Control of TE
Networks", Work in Progress, Internet-Draft, draft-ietf-
teas-actn-requirements-09, 2 March 2018,
<https://datatracker.ietf.org/doc/html/draft-ietf-teas-
actn-requirements-09>.
[I-D.kondreddy-pce-pcep-ls-sync-optimizations]
Kondreddy, V. R. and M. S. Negi, "Optimizations of PCEP
Link-State(LS) Synchronization Procedures", Work in
Progress, Internet-Draft, draft-kondreddy-pce-pcep-ls-
sync-optimizations-01, 5 April 2024,
<https://datatracker.ietf.org/doc/html/draft-kondreddy-
pce-pcep-ls-sync-optimizations-01>.
[RFC3630] Katz, D., Kompella, K., and D. Yeung, "Traffic Engineering
(TE) Extensions to OSPF Version 2", RFC 3630,
DOI 10.17487/RFC3630, September 2003,
<https://www.rfc-editor.org/info/rfc3630>.
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[RFC4203] Kompella, K., Ed. and Y. Rekhter, Ed., "OSPF Extensions in
Support of Generalized Multi-Protocol Label Switching
(GMPLS)", RFC 4203, DOI 10.17487/RFC4203, October 2005,
<https://www.rfc-editor.org/info/rfc4203>.
[RFC4364] Rosen, E. and Y. Rekhter, "BGP/MPLS IP Virtual Private
Networks (VPNs)", RFC 4364, DOI 10.17487/RFC4364, February
2006, <https://www.rfc-editor.org/info/rfc4364>.
[RFC4655] Farrel, A., Vasseur, J.-P., and J. Ash, "A Path
Computation Element (PCE)-Based Architecture", RFC 4655,
DOI 10.17487/RFC4655, August 2006,
<https://www.rfc-editor.org/info/rfc4655>.
[RFC5392] Chen, M., Zhang, R., and X. Duan, "OSPF Extensions in
Support of Inter-Autonomous System (AS) MPLS and GMPLS
Traffic Engineering", RFC 5392, DOI 10.17487/RFC5392,
January 2009, <https://www.rfc-editor.org/info/rfc5392>.
[RFC5925] Touch, J., Mankin, A., and R. Bonica, "The TCP
Authentication Option", RFC 5925, DOI 10.17487/RFC5925,
June 2010, <https://www.rfc-editor.org/info/rfc5925>.
[RFC6549] Lindem, A., Roy, A., and S. Mirtorabi, "OSPFv2 Multi-
Instance Extensions", RFC 6549, DOI 10.17487/RFC6549,
March 2012, <https://www.rfc-editor.org/info/rfc6549>.
[RFC6805] King, D., Ed. and A. Farrel, Ed., "The Application of the
Path Computation Element Architecture to the Determination
of a Sequence of Domains in MPLS and GMPLS", RFC 6805,
DOI 10.17487/RFC6805, November 2012,
<https://www.rfc-editor.org/info/rfc6805>.
[RFC6952] Jethanandani, M., Patel, K., and L. Zheng, "Analysis of
BGP, LDP, PCEP, and MSDP Issues According to the Keying
and Authentication for Routing Protocols (KARP) Design
Guide", RFC 6952, DOI 10.17487/RFC6952, May 2013,
<https://www.rfc-editor.org/info/rfc6952>.
[RFC7942] Sheffer, Y. and A. Farrel, "Improving Awareness of Running
Code: The Implementation Status Section", BCP 205,
RFC 7942, DOI 10.17487/RFC7942, July 2016,
<https://www.rfc-editor.org/info/rfc7942>.
[RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for
Writing an IANA Considerations Section in RFCs", BCP 26,
RFC 8126, DOI 10.17487/RFC8126, June 2017,
<https://www.rfc-editor.org/info/rfc8126>.
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[RFC8202] Ginsberg, L., Previdi, S., and W. Henderickx, "IS-IS
Multi-Instance", RFC 8202, DOI 10.17487/RFC8202, June
2017, <https://www.rfc-editor.org/info/rfc8202>.
[RFC8231] Crabbe, E., Minei, I., Medved, J., and R. Varga, "Path
Computation Element Communication Protocol (PCEP)
Extensions for Stateful PCE", RFC 8231,
DOI 10.17487/RFC8231, September 2017,
<https://www.rfc-editor.org/info/rfc8231>.
[RFC8253] Lopez, D., Gonzalez de Dios, O., Wu, Q., and D. Dhody,
"PCEPS: Usage of TLS to Provide a Secure Transport for the
Path Computation Element Communication Protocol (PCEP)",
RFC 8253, DOI 10.17487/RFC8253, October 2017,
<https://www.rfc-editor.org/info/rfc8253>.
[RFC8281] Crabbe, E., Minei, I., Sivabalan, S., and R. Varga, "Path
Computation Element Communication Protocol (PCEP)
Extensions for PCE-Initiated LSP Setup in a Stateful PCE
Model", RFC 8281, DOI 10.17487/RFC8281, December 2017,
<https://www.rfc-editor.org/info/rfc8281>.
[RFC8283] Farrel, A., Ed., Zhao, Q., Ed., Li, Z., and C. Zhou, "An
Architecture for Use of PCE and the PCE Communication
Protocol (PCEP) in a Network with Central Control",
RFC 8283, DOI 10.17487/RFC8283, December 2017,
<https://www.rfc-editor.org/info/rfc8283>.
[RFC8453] Ceccarelli, D., Ed. and Y. Lee, Ed., "Framework for
Abstraction and Control of TE Networks (ACTN)", RFC 8453,
DOI 10.17487/RFC8453, August 2018,
<https://www.rfc-editor.org/info/rfc8453>.
[RFC8637] Dhody, D., Lee, Y., and D. Ceccarelli, "Applicability of
the Path Computation Element (PCE) to the Abstraction and
Control of TE Networks (ACTN)", RFC 8637,
DOI 10.17487/RFC8637, July 2019,
<https://www.rfc-editor.org/info/rfc8637>.
[RFC9168] Dhody, D., Farrel, A., and Z. Li, "Path Computation
Element Communication Protocol (PCEP) Extension for Flow
Specification", RFC 9168, DOI 10.17487/RFC9168, January
2022, <https://www.rfc-editor.org/info/rfc9168>.
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[RFC9325] Sheffer, Y., Saint-Andre, P., and T. Fossati,
"Recommendations for Secure Use of Transport Layer
Security (TLS) and Datagram Transport Layer Security
(DTLS)", BCP 195, RFC 9325, DOI 10.17487/RFC9325, November
2022, <https://www.rfc-editor.org/info/rfc9325>.
[RFC9346] Chen, M., Ginsberg, L., Previdi, S., and D. Xiaodong, "IS-
IS Extensions in Support of Inter-Autonomous System (AS)
MPLS and GMPLS Traffic Engineering", RFC 9346,
DOI 10.17487/RFC9346, February 2023,
<https://www.rfc-editor.org/info/rfc9346>.
[RFC9358] Lee, Y., Zheng, H., and D. Ceccarelli, "Path Computation
Element Communication Protocol (PCEP) Extensions for
Establishing Relationships between Sets of Label Switched
Paths and Virtual Networks", RFC 9358,
DOI 10.17487/RFC9358, February 2023,
<https://www.rfc-editor.org/info/rfc9358>.
[WIKI] "PCE WG Wiki - Path Computation Element",
<https://wiki.ietf.org/group/pce/>.
Appendix A. Examples
These examples are for illustration purposes only to show how the new
PCEP-LS message could be encoded. They are not meant to be an
exhaustive list of all possible use cases and combinations.
A.1. All Nodes
Each node (PCC) in the network chooses to provide its own local node
and link information, and in this way PCE can build the full link-
state and TE information.
+--------------------+ +--------------------+
| | | |
| RTA |192.0.2.0/24 | RTB |
| 11.11.11.11 |--------------------| 33.33.33.34 |
| Area 0 | 192.0.2.0/24 | Area 0 |
| | | |
+--------------------+ +--------------------+
RTA
---
LS Node
TLV - Local Node Descriptors
Sub-TLV - 514: OSPF Area-ID: 0.0.0.0
Sub-TLV - 515: IGP Router-ID: 11.11.11.11
TLV - Node Attributes TLV
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Sub-TLV(s)
LS Link
TLV - Local Node Descriptors
Sub-TLV - 514: OSPF Area-ID: 0.0.0.0
Sub-TLV - 515: IGP Router-ID: 11.11.11.11
TLV - Remote Node Descriptors
Sub-TLV - 514: OSPF Area-ID: 0.0.0.0
Sub-TLV - 515: IGP Router-ID: 22.22.22.22
TLV - Link Descriptors
Sub-TLV - 259: IPv4 interface: 192.0.2.1
Sub-TLV - 260: IPv4 neighbor: 192.0.2.2
TLV - Link Attributes TLV
Sub-TLV(s)
RTB
---
LS Node
TLV - Local Node Descriptors
Sub-TLV - 514: OSPF Area-ID: 0.0.0.0
Sub-TLV - 515: IGP Router-ID: 22.22.22.22
TLV - Node Attributes TLV
Sub-TLV(s)
LS Link
TLV - Local Node Descriptors
Sub-TLV - 514: OSPF Area-ID: 0.0.0.0
Sub-TLV - 515: IGP Router-ID: 22.22.22.22
TLV - Remote Node Descriptors
Sub-TLV - 514: OSPF Area-ID: 0.0.0.0
Sub-TLV - 515: IGP Router-ID: 11.11.11.11
TLV - Link Descriptors
Sub-TLV - 259: IPv4 interface: 192.0.2.2
Sub-TLV - 260: IPv4 neighbor: 192.0.2.1
TLV - Link Attributes TLV
Sub-TLV(s)
A similar example with IPv6 address (say 2001:db8::1 and 2001:db8::2)
for the links could be imagined with all other information as same
and just IPv6 interface and neighbour TLVs.
A.2. Designated Node
A designated node(s) in the network will provide its own local node
as well as all learned remote information, and in this way, PCE can
build the full link-state and TE information.
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As described in Appendix A.1, the same LS Node and Link objects will
be generated with a difference that it would be a designated router
say RTA that generates all this information.
A.3. Between PCEs
As per Hierarchical-PCE [RFC6805], Parent PCE builds an abstract
domain topology map with each domain as an abstract node and inter-
domain links as an abstract link. Each Child PCE may provide this
information to the Parent PCE. Considering the example in figure 1
of [RFC6805], following LS object will be generated:
PCE1
----
LS Node
TLV - Local Node Descriptors
Sub-TLV - 512: Autonomous System: 100 (Domain 1)
Sub-TLV - 515: IGP Router-ID: 11.11.11.11 (abstract)
LS Link
TLV - Local Node Descriptors
Sub-TLV - 512: Autonomous System: 100
Sub-TLV - 515: IGP Router-ID: 11.11.11.11 (abstract)
TLV - Remote Node Descriptors
Sub-TLV - 512: Autonomous System: 200 (Domain 2)
Sub-TLV - 515: IGP Router-ID: 22.22.22.22 (abstract)
TLV - Link Descriptors
Sub-TLV - 259: IPv4 interface: 192.0.2.1
Sub-TLV - 260: IPv4 neighbor: 192.0.2.2
TLV - Link Attributes TLV
Sub-TLV(s)
LS Link
TLV - Local Node Descriptors
Sub-TLV - 512: Autonomous System: 100
Sub-TLV - 515: IGP Router-ID: 11.11.11.11 (abstract)
TLV - Remote Node Descriptors
Sub-TLV - 512: Autonomous System: 200
Sub-TLV - 515: IGP Router-ID: 22.22.22.22 (abstract)
TLV - Link Descriptors
Sub-TLV - 259: IPv4 interface: 198.51.100.1
Sub-TLV - 260: IPv4 neighbor: 198.51.100.2
TLV - Link Attributes TLV
Sub-TLV(s)
LS Link
TLV - Local Node Descriptors
Sub-TLV - 512: Autonomous System: 100
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Sub-TLV - 515: IGP Router-ID: 11.11.11.11 (abstract)
TLV - Remote Node Descriptors
Sub-TLV - 512: Autonomous System: 400 (Domain 4)
Sub-TLV - 515: IGP Router-ID: 44.44.44.44 (abstract)
TLV - Link Descriptors
Sub-TLV - 259: IPv4 interface: 203.0.113.1
Sub-TLV - 260: IPv4 neighbor: 203.0.113.2
TLV - Link Attributes TLV
Sub-TLV(s)
* similar information will be generated by other PCE
to help form the abstract domain topology.
Further the exact border nodes and the abstract internal path between
the border nodes may also be transported to the Parent PCE to enable
ACTN as described in [RFC8637] using the similar LS node and link
objects encodings.
Appendix B. Contributor Addresses
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Gyan Mishra
Verizon Inc.
Email: [email protected]
Siva Sivabalan
Ciena Corporation
Email: [email protected]
Udayasree Palle
EMail: [email protected]
Sergio Belotti
Nokia
EMail: [email protected]
Satish Karunanithi
India
Email: [email protected]
Cheng Li
Huawei Technologies
Huawei Campus, No. 156 Beiqing Rd.
Beijing 100095
China
Email: [email protected]
Authors' Addresses
Dhruv Dhody
Huawei
India
Email: [email protected]
Shuping Peng
Huawei
Huawei Bld., No.156 Beiqing Rd.
Beijing
100095
China
Email: [email protected]
Dhody, et al. Expires 23 April 2025 [Page 40]
Internet-Draft PCEP-LS October 2024
Young Lee
Samsung Electronics
Seoul
South Korea
Email: [email protected]
Daniele Ceccarelli
Cisco
Email: [email protected]
Aijun Wang
China Telecom
Beiqijia Town, Changping District
Beijing
102209
China
Email: [email protected]
Gyan Mishra
Verizon Inc.
Email: [email protected]
Dhody, et al. Expires 23 April 2025 [Page 41]