Internet Engineering Task Force (IETF) IJ. Wijnands
Request for Comments: 9658 Individual
Updates: 7307 M. Mishra, Ed.
Category: Standards Track K. Raza
ISSN: 2070-1721 Cisco Systems, Inc.
Z. Zhang
Juniper Networks
A. Gulko
Edward Jones
October 2024
Multipoint LDP Extensions for Multi-Topology Routing
Abstract
Multi-Topology Routing (MTR) is a technology that enables service
differentiation within an IP network. The Flexible Algorithm (FA) is
another mechanism for creating a sub-topology within a topology using
defined topology constraints and computation algorithms. In order to
deploy Multipoint LDP (mLDP) in a network that supports MTR, FA, or
other methods of signaling non-default IGP Algorithms (IPAs), mLDP is
required to become topology and algorithm aware. This document
specifies extensions to mLDP to support the use of MTR/IPAs such
that, when building multipoint Label Switched Paths (LSPs), the LSPs
can follow a particular topology and algorithm. This document
updates RFC 7307 by allocating eight bits from a previously reserved
field to be used as the "IPA" field.
Status of This Memo
This is an Internet Standards Track document.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 7841.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
https://www.rfc-editor.org/info/rfc9658.
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
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Table of Contents
1. Introduction
2. Terminology
2.1. Abbreviations
2.2. Specification of Requirements
3. MT-Scoped mLDP FECs
3.1. MP FEC Extensions for MT
3.1.1. MP FEC Element
3.1.2. MT IP Address Families
3.1.3. MT MP FEC Element
3.2. Topology IDs
4. MT Multipoint Capability
5. MT Applicability on FEC-Based Features
5.1. Typed Wildcard MP FEC Elements
5.2. End-of-LIB
6. Topology-Scoped Signaling and Forwarding
6.1. Upstream LSR Selection
6.2. Downstream Forwarding Interface Selection
7. LSP Ping Extensions
8. Security Considerations
9. IANA Considerations
10. References
10.1. Normative References
10.2. Informative References
Contributors
Acknowledgments
Authors' Addresses
1. Introduction
Multi-Topology Routing (MTR) is a technology that enables service
differentiation within an IP network. IGPs (e.g., OSPF and IS-IS)
and LDP have already been extended to support MTR. To support MTR,
an IGP maintains distinct IP topologies referred to as "Multi-
Topologies" (or "MTs"), and computes and installs routes specific to
each topology. OSPF extensions (see [RFC4915]) and IS-IS extensions
(see [RFC5120]) specify the MT extensions under respective IGPs. To
support IGP MT, similar LDP extensions (see [RFC7307]) have been
specified to make LDP be MT aware and to be able to set up unicast
Label Switched Paths (LSPs) along IGP MT routing paths.
A more lightweight mechanism to define constraint-based topologies is
the Flexible Algorithm (FA) (see [RFC9350]). The FA is another
mechanism for creating a sub-topology within a topology using defined
topology constraints and computation algorithms. This can be done
within an MTR topology or the default topology. An instance of such
a sub-topology is identified by a 1-octet value (Flexible Algorithm)
as documented in [RFC9350]. At the time of writing, an FA is a
mechanism to create a sub-topology; in the future, different
algorithms might be defined for this purpose. Therefore, in the
remainder of this document, we'll refer to this as the "IGP
Algorithm" or "IPA". The "IPA" field (see Sections 3.1.2 and 5.1) is
an 8-bit identifier for the algorithm. The permissible values are
tracked in the "IGP Algorithm Types" registry [IANA-IGP].
Throughout this document, the term "Flexible Algorithm" (or "FA")
shall denote the process of generating a sub-topology and signaling
it through the IGP. However, it is essential to note that the
procedures outlined in this document are not exclusively applicable
to the FA: they are extendable to any non-default algorithm as well.
"Multipoint LDP" (or "mLDP") refers to extensions in LDP to set up
multipoint LSPs (i.e., point-to-multipoint (P2MP) or multipoint-to-
multipoint (MP2MP) LSPs) by means of a set of extensions and
procedures defined in [RFC6388]. In order to deploy mLDP in a
network that supports MTR and the FA, mLDP is required to become
topology and algorithm aware. This document specifies extensions to
mLDP to support the use of MTR/IPAs such that, when building
multipoint LSPs, it can follow a particular topology and algorithm.
Therefore, the identifier for the particular topology to be used by
mLDP has to become a 2-tuple {MTR Topology Id, IPA}.
2. Terminology
2.1. Abbreviations
FA: Flexible Algorithm
FEC: Forwarding Equivalence Class
IGP: Interior Gateway Protocol
IPA: IGP Algorithm
LDP: Label Distribution Protocol
LSP: Label Switched Path
mLDP: Multipoint LDP
MP: Multipoint
MP2MP: Multipoint-to-Multipoint
MT: Multi-Topology
MT-ID: Multi-Topology Identifier
MTR: Multi-Topology Routing
MVPN: Multicast VPN in Section 2.3 of [RFC6513]
P2MP: Point-to-Multipoint
PMSI: Provider Multicast Service Interfaces [RFC6513]
2.2. Specification of Requirements
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.
3. MT-Scoped mLDP FECs
As defined in [RFC7307], an MPLS Multi-Topology Identifier (MT-ID) is
used to associate an LSP with a certain MTR topology. In the context
of MP LSPs, this identifier is part of the mLDP FEC encoding; this is
so that LDP peers are able to set up an MP LSP via their own defined
MTR policy. In order to avoid conflicting MTR policies for the same
mLDP FEC, the MT-ID needs to be a part of the FEC. This ensures that
different MT-ID values will result in unique MP-LSP FEC elements.
The same applies to the IPA. The IPA needs to be encoded as part of
the mLDP FEC to create unique MP LSPs. The IPA is also used to
signal to the mLDP (hop-by-hop) which algorithm needs to be used to
create the MP LSP.
Since the MT-ID and IPA are part of the FEC, they apply to all the
LDP messages that potentially include an mLDP FEC element.
3.1. MP FEC Extensions for MT
The following subsections define the extensions to bind an mLDP FEC
to a topology. These mLDP MT extensions reuse some of the extensions
specified in [RFC7307].
3.1.1. MP FEC Element
The base mLDP specification ([RFC6388]) defines the MP FEC element 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MP FEC type | Address Family | AF Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Root Node Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Opaque Length | Opaque Value |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
~ ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: MP FEC Element Format
Where the "Root Node Address" field encoding is defined according to
the given "Address Family" field with its length (in octets)
specified by the "AF Length" field.
To extend MP FEC elements for MT, the {MT-ID, IPA} tuple is relevant
in the context of the root address of the MP LSP. This tuple
determines the (sub-)topology in which the root address needs to be
resolved. As the {MT-ID, IPA} tuple should be considered part of the
mLDP FEC, it is most naturally encoded as part of the root address.
3.1.2. MT IP Address Families
[RFC7307] specifies new address families, named "MT IP" and "MT
IPv6," to allow for the specification of an IP prefix within a
topology scope. In addition to using these address families for
mLDP, 8 bits of the 16-bit "Reserved" field that was described in RFC
7307 are utilized to encode the IPA. The resulting format of the
data associated with these new address families is 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv4 Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved | IPA | MT-ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv6 Address |
| |
| |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved | IPA | MT-ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2: Modified Format for MT IP Address Families
Where:
IPv4 Address and IPv6 Address: An IP address corresponding to the
"MT IP" and "MT IPv6" address families, respectively.
IPA: The IGP Algorithm.
Reserved: This 8-bit field MUST be zero on transmission and MUST be
ignored on receipt.
3.1.3. MT MP FEC Element
When using the extended "MT IP" address family, the resulting MT-
Scoped MP FEC element should be encoded 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MP FEC type | AF (MT IP/ MT IPv6) | AF Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Root Node Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved | IPA | MT-ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Opaque Length | Opaque Value |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
~ ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 3: Format for an IP MT-Scoped MP FEC Element
In the context of this document, the applicable LDP FECs for MT mLDP
([RFC6388]) include:
* MP FEC elements:
- P2MP (type 0x6)
- MP2MP-up (type 0x7)
- MP2MP-down (type 0x8)
* Typed Wildcard FEC Element (type 0x5 defined in [RFC5918])
In the case of the Typed Wildcard FEC Element, the FEC element type
MUST be one of the MP FECs listed above.
This specification allows the use of topology-scoped mLDP FECs in LDP
labels and notification messages, as applicable.
[RFC6514] defines the PMSI tunnel attribute for MVPN and specifies
that:
* when the Tunnel Type is set to mLDP P2MP LSP, the Tunnel
Identifier is a P2MP FEC element, and
* when the Tunnel Type is set to mLDP MP2MP LSP, the Tunnel
Identifier is an MP2MP FEC element.
When the extension defined in this specification is in use, the IP
MT-Scoped MP FEC element form of the respective FEC elements MUST be
used in these two cases.
3.2. Topology IDs
This document assumes the same definitions and procedures associated
with MPLS MT-ID as specified in [RFC7307].
4. MT Multipoint Capability
The "MT Multipoint" capability is a new LDP capability, defined in
accordance with the LDP capability definition guidelines outlined in
[RFC5561]. An mLDP speaker advertises this capability to its peers
to announce its support for MTR and the procedures specified in this
document. This capability MAY be sent either in an Initialization
message at session establishment or dynamically during the session's
lifetime via a Capability message, provided that the "Dynamic
Announcement" capability from [RFC5561] has been successfully
negotiated with the peer.
The format of this capability is 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|U|F| MT Multipoint Capability | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|S| Reserved |
+-+-+-+-+-+-+-+-+
Figure 4: Format for the MT Multipoint Capability TLV
Where:
U and F bits: MUST be 1 and 0, respectively, as per Section 3 of
[RFC5561].
MT Multipoint Capability: The TLV type.
Length: This field specifies the length of the TLV in octets. The
value of this field MUST be 1, as there is no capability-specific
data [RFC5561] following the TLV.
S bit: Set to 1 to announce and 0 to withdraw the capability (as per
[RFC5561]).
An mLDP speaker that has successfully advertised and negotiated the
"MT Multipoint" capability MUST support the following:
1. Topology-scoped mLDP FECs in LDP messages (Section 3.1)
2. Topology-scoped mLDP forwarding setup (Section 6)
5. MT Applicability on FEC-Based Features
5.1. Typed Wildcard MP FEC Elements
[RFC5918] extends the base LDP and defines the Typed Wildcard FEC
Element framework. A Typed Wildcard FEC Element can be used in any
LDP message to specify a wildcard operation for a given type of FEC.
The MT extensions defined in this document do not require any
extension to procedures for support of the Typed Wildcard FEC Element
[RFC5918], and these procedures apply as is to Multipoint MT FEC
wildcarding. Similar to the Typed Wildcard MT Prefix FEC element, as
defined in [RFC7307], the MT extensions allow the use of "MT IP" or
"MT IPv6" in the "Address Family" field of the Typed Wildcard MP FEC
Element. This is done in order to use wildcard operations for MP
FECs in the context of a given (sub-)topology as identified by the
"MT-ID" and "IPA" fields.
This document defines the following format and encoding for a Typed
Wildcard MP FEC Element:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Typed Wcard (5)| Type = MP FEC | Len = 6 | AF = MT IP ..|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|... or MT IPv6 | Reserved | IPA | MT-ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|MT-ID (cont.) |
+-+-+-+-+-+-+-+-+
Figure 5: Format for the Typed Wildcard MT MP FEC Element
Where:
Type: One of the MP FEC element types (P2MP, MP2MP-up, or MP2MP-
down)
MT-ID: MPLS MT-ID
IPA: The IGP Algorithm
The defined format allows a Label Switching Router (LSR) to perform
wildcard MP FEC operations under the scope of a (sub-)topology.
5.2. End-of-LIB
[RFC5919] specifies extensions and procedures that allow an LDP
speaker to signal its End-of-LIB (Label Information Base) for a given
FEC type to a peer. By leveraging the End-of-LIB message, LDP
ensures that label distribution remains consistent and reliable, even
during network disruptions or maintenance activities. The MT
extensions for MP FEC do not require any modifications to these
procedures and apply as they are to MT MP FEC elements.
Consequently, an MT mLDP speaker MAY signal its convergence per
(sub-)topology using the MT Typed Wildcard MP FEC Element.
6. Topology-Scoped Signaling and Forwarding
Since the {MT-ID, IPA} tuple is part of an mLDP FEC, there is no need
to support the concept of multiple (sub-)topology forwarding tables
in mLDP. Each MP LSP will be unique due to the tuple being part of
the FEC. There is also no need to have specific label forwarding
tables per topology, and each MP LSP will have its own unique local
label in the table. However, in order to implement MTR in an mLDP
network, the selection procedures for an upstream LSR and a
downstream forwarding interface need to be changed.
6.1. Upstream LSR Selection
The procedures described in Section 2.4.1.1 of [RFC6388] depend on
the best path to reach the root. When the {MT-ID, IPA} tuple is
signaled as part of the FEC, the tuple is also used to select the
(sub-)topology that must be used to find the best path to the root
address. Using the next-hop from this best path, an LDP peer is
selected following the procedures defined in [RFC6388].
6.2. Downstream Forwarding Interface Selection
Section 2.4.1.2 of [RFC6388] describes the procedures for how a
downstream forwarding interface is selected. In these procedures,
any interface leading to the downstream LDP neighbor can be
considered to be a candidate forwarding interface. When the {MT-ID,
IPA} tuple is part of the FEC, this is no longer true. An interface
must only be selected if it is part of the same (sub-)topology that
was signaled in the mLDP FEC element. Besides this restriction, the
other procedures in [RFC6388] apply.
7. LSP Ping Extensions
[RFC6425] defines procedures to detect data plane failures in
multipoint MPLS LSPs. Section 3.1.2 of [RFC6425] defines new sub-
types and sub-TLVs for Multipoint LDP FECs to be sent in the "Target
FEC Stack" TLV of an MPLS Echo Request message [RFC8029].
To support LSP ping for MT MP LSPs, this document uses existing sub-
types "P2MP LDP FEC Stack" and "MP2MP LDP FEC Stack" defined in
[RFC6425]. The LSP ping extension is to specify "MT IP" or "MT IPv6"
in the "Address Family" field, set the "Address Length" field to 8
(for MT IP) or 20 (for MT IPv6), and encode the sub-TLV with
additional {MT-ID, IPA} information as an extension to the "Root LSR
Address" field. The resultant format of sub-TLV is 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Address Family (MT IP/MT IPv6) | Address Length| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
~ Root LSR Address (Cont.) ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved | IPA | MT-ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Opaque Length | Opaque Value ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
~ ~
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 6: Multipoint LDP FEC Stack Sub-TLV Format for MT
The rules and procedures of using this new sub-TLV in an MPLS Echo
Request message are the same as defined for the P2MP/MP2MP LDP FEC
Stack sub-TLV in [RFC6425]. The only difference is that the "Root
LSR Address" field is now (sub-)topology scoped.
8. Security Considerations
This extension to mLDP does not introduce any new security
considerations beyond what is already applied to the base LDP
specification [RFC5036], the LDP extensions for Multi-Topology
specification [RFC7307], the base mLDP specification [RFC6388], and
the MPLS security framework specification [RFC5920].
9. IANA Considerations
This document defines a new LDP capability parameter TLV called the
"MT Multipoint Capability". IANA has assigned the value 0x0510 from
the "TLV Type Name Space" registry in the "Label Distribution
Protocol (LDP) Parameters" group as the new code point.
+========+===============+===========+=========================+
| Value | Description | Reference | Notes/Registration Date |
+========+===============+===========+=========================+
| 0x0510 | MT Multipoint | RFC 9658 | |
| | Capability | | |
+--------+---------------+-----------+-------------------------+
Table 1: MT Multipoint Capability
10. References
10.1. Normative References
[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>.
[RFC4915] Psenak, P., Mirtorabi, S., Roy, A., Nguyen, L., and P.
Pillay-Esnault, "Multi-Topology (MT) Routing in OSPF",
RFC 4915, DOI 10.17487/RFC4915, June 2007,
<https://www.rfc-editor.org/info/rfc4915>.
[RFC5120] Przygienda, T., Shen, N., and N. Sheth, "M-ISIS: Multi
Topology (MT) Routing in Intermediate System to
Intermediate Systems (IS-ISs)", RFC 5120,
DOI 10.17487/RFC5120, February 2008,
<https://www.rfc-editor.org/info/rfc5120>.
[RFC6388] Wijnands, IJ., Ed., Minei, I., Ed., Kompella, K., and B.
Thomas, "Label Distribution Protocol Extensions for Point-
to-Multipoint and Multipoint-to-Multipoint Label Switched
Paths", RFC 6388, DOI 10.17487/RFC6388, November 2011,
<https://www.rfc-editor.org/info/rfc6388>.
[RFC6425] Saxena, S., Ed., Swallow, G., Ali, Z., Farrel, A.,
Yasukawa, S., and T. Nadeau, "Detecting Data-Plane
Failures in Point-to-Multipoint MPLS - Extensions to LSP
Ping", RFC 6425, DOI 10.17487/RFC6425, November 2011,
<https://www.rfc-editor.org/info/rfc6425>.
[RFC6513] Rosen, E., Ed. and R. Aggarwal, Ed., "Multicast in MPLS/
BGP IP VPNs", RFC 6513, DOI 10.17487/RFC6513, February
2012, <https://www.rfc-editor.org/info/rfc6513>.
[RFC6514] Aggarwal, R., Rosen, E., Morin, T., and Y. Rekhter, "BGP
Encodings and Procedures for Multicast in MPLS/BGP IP
VPNs", RFC 6514, DOI 10.17487/RFC6514, February 2012,
<https://www.rfc-editor.org/info/rfc6514>.
[RFC7307] Zhao, Q., Raza, K., Zhou, C., Fang, L., Li, L., and D.
King, "LDP Extensions for Multi-Topology", RFC 7307,
DOI 10.17487/RFC7307, July 2014,
<https://www.rfc-editor.org/info/rfc7307>.
[RFC8029] Kompella, K., Swallow, G., Pignataro, C., Ed., Kumar, N.,
Aldrin, S., and M. Chen, "Detecting Multiprotocol Label
Switched (MPLS) Data-Plane Failures", RFC 8029,
DOI 10.17487/RFC8029, March 2017,
<https://www.rfc-editor.org/info/rfc8029>.
[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>.
[RFC9350] Psenak, P., Ed., Hegde, S., Filsfils, C., Talaulikar, K.,
and A. Gulko, "IGP Flexible Algorithm", RFC 9350,
DOI 10.17487/RFC9350, February 2023,
<https://www.rfc-editor.org/info/rfc9350>.
10.2. Informative References
[IANA-IGP] IANA, "IGP Algorithm Types",
<https://www.iana.org/assignments/igp-parameters>.
[RFC5036] Andersson, L., Ed., Minei, I., Ed., and B. Thomas, Ed.,
"LDP Specification", RFC 5036, DOI 10.17487/RFC5036,
October 2007, <https://www.rfc-editor.org/info/rfc5036>.
[RFC5561] Thomas, B., Raza, K., Aggarwal, S., Aggarwal, R., and JL.
Le Roux, "LDP Capabilities", RFC 5561,
DOI 10.17487/RFC5561, July 2009,
<https://www.rfc-editor.org/info/rfc5561>.
[RFC5918] Asati, R., Minei, I., and B. Thomas, "Label Distribution
Protocol (LDP) 'Typed Wildcard' Forward Equivalence Class
(FEC)", RFC 5918, DOI 10.17487/RFC5918, August 2010,
<https://www.rfc-editor.org/info/rfc5918>.
[RFC5919] Asati, R., Mohapatra, P., Chen, E., and B. Thomas,
"Signaling LDP Label Advertisement Completion", RFC 5919,
DOI 10.17487/RFC5919, August 2010,
<https://www.rfc-editor.org/info/rfc5919>.
[RFC5920] Fang, L., Ed., "Security Framework for MPLS and GMPLS
Networks", RFC 5920, DOI 10.17487/RFC5920, July 2010,
<https://www.rfc-editor.org/info/rfc5920>.
Contributors
Anuj Budhiraja
Cisco Systems
Acknowledgments
The authors would like to acknowledge Eric Rosen for his input on
this specification.
Authors' Addresses
IJsbrand Wijnands
Individual
Email: ice@braindump.be
Mankamana Mishra (editor)
Cisco Systems, Inc.
821 Alder Drive
Milpitas, CA 95035
United States of America
Email: mankamis@cisco.com
Kamran Raza
Cisco Systems, Inc.
2000 Innovation Drive
Kanata ON K2K-3E8
Canada
Email: skraza@cisco.com
Zhaohui Zhang
Juniper Networks
10 Technology Park Dr.
Westford, MA 01886
United States of America
Email: zzhang@juniper.net
Arkadiy Gulko
Edward Jones Wealth Management
United States of America
Email: Arkadiy.gulko@edwardjones.com
