MPLS Working Group
Internet Engineering Task Force (IETF) IJ. Wijnands
Internet-Draft
Request for Comments: 9658 Individual
Updates: 7307 (if approved) M. Mishra (Editor)
Intended status: Mishra, Ed.
Category: Standards Track K. Raza
Expires: 21 November 2024
ISSN: 2070-1721 Cisco Systems, Inc.
Z. Zhang
Juniper Networks
A. Gulko
Edward Jones wealth management
20 May
September 2024
mLDP
Multipoint LDP Extensions for Multi-Topology Routing
draft-ietf-mpls-mldp-multi-topology-09
Abstract
Multi-Topology Routing (MTR) is a technology to enable that enables service
differentiation within an IP network. The Flexible Algorithm (FA) is
another mechanism of for creating a sub-topology within a topology using
defined topology constraints and computation algorithm. algorithms. In order to
deploy mLDP (Multipoint label distribution protocol) Multipoint LDP (mLDP) in a network that supports MTR, FA, or
other methods of signaling non-default IGP
algorithms, Algorithms (IPAs), mLDP is
required to become topology and algorithm aware. This document
specifies extensions to mLDP to support MTR, with an
algorithm, in order for Multipoint LSPs(Label the use of MTR/IPAs such
that, when building multipoint Label Switched Paths) to Paths (LSPs), it can
follow a particular topology and algorithm. It This document updates [RFC7307]
RFC 7307 by allocating eight bits from a previously reserved field to
be used as the IGP Algorithm (IPA) "IPA" field.
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 an Internet Standards Track document.
This document is a product of the Internet Engineering Task Force
(IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list It represents the consensus of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid the IETF community. It has
received public review and has been approved for a maximum publication by the
Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of six months RFC 7841.
Information about the current status of this document, any errata,
and how to provide feedback on it may be updated, replaced, or obsoleted by other documents obtained 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 21 November 2024.
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)
(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 extracted from this document must
include Revised BSD License text as described in Section 4.e of the
Trust Legal Provisions and are provided without warranty as described
in the Revised BSD License.
Table of Contents
1. Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
3.
2. Terminology
2.1. Abbreviations
2.2. Specification of Requirements . . . . . . . . . . . . . . . . 4
4. MT Scoped
3. MT-Scoped mLDP FECs . . . . . . . . . . . . . . . . . . . . . 4
4.1.
3.1. MP FEC Extensions for MT . . . . . . . . . . . . . . . . 5
4.1.1.
3.1.1. MP FEC Element . . . . . . . . . . . . . . . . . . . 5
4.1.2.
3.1.2. MT IP Address Families . . . . . . . . . . . . . . . 6
4.1.3.
3.1.3. MT MP FEC Element . . . . . . . . . . . . . . . . . . 6
4.2.
3.2. Topology IDs . . . . . . . . . . . . . . . . . . . . . . 7
5.
4. MT Multipoint Capability . . . . . . . . . . . . . . . . . . 8
6.
5. MT Applicability on FEC-based features . . . . . . . . . . . 9
6.1. FEC-Based Features
5.1. Typed Wildcard MP FEC Elements . . . . . . . . . . . . . 9
6.2.
5.2. End-of-LIB . . . . . . . . . . . . . . . . . . . . . . . 10
7.
6. Topology-Scoped Signaling and Forwarding . . . . . . . . . . 10
7.1.
6.1. Upstream LSR selection . . . . . . . . . . . . . . . . . 10
7.2. Selection
6.2. Downstream forwarding interface selection . . . . . . . . 10
8. Forwarding Interface Selection
7. LSP Ping Extensions . . . . . . . . . . . . . . . . . . . . . 11
9. Implementation Status . . . . . . . . . . . . . . . . . . . . 11
9.1. Cisco Systems . . . . . . . . . . . . . . . . . . . . . . 12
10.
8. Security Considerations . . . . . . . . . . . . . . . . . . . 12
11.
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12
12. Contributor . . . . . . . . . . . . . . . . . . . . . . . . . 13
13. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 13
14.
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 13
14.1.
10.1. Normative References . . . . . . . . . . . . . . . . . . 13
14.2.
10.2. Informative References . . . . . . . . . . . . . . . . . 14
Contributors
Acknowledgments
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 15
1. Glossary
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 (P2MP or MP2MP)
MP2MP - Multipoint-to-Multipoint
MT - Multi-Topology
MT-ID - Multi-Topology Identifier
MTR - Multi-Topology Routing
MVPN - Multicast over Virtual Private Network defined in section
2.3 of [RFC6513]
P2MP - Point-to-Multipoint
PMSI - Provider Multicast Service Interfaces [RFC6513]
2. Introduction
Multi-Topology Routing (MTR) is a technology to enable that enables service
differentiation within an IP network. IGP protocols (OSPF IGPs (e.g., OSPF and IS-IS)
and LDP have already been extended to support MTR. To support MTR,
an IGP maintains independent distinct IP topologies, termed topologies referred to as "Multi-
Topologies" (MT), (or "MTs"), and computes/installs computes and installs routes per specific to
each topology. OSPF extensions [RFC4915] (see [RFC4915]) and IS-IS extensions [RFC5120]
(see [RFC5120]) specify the MT extensions under respective IGPs. To
support IGP MT, similar LDP extensions [RFC7307] (see [RFC7307]) have been
specified to make LDP MT-aware be MT aware and to be able to setup 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) [RFC9350]. (see [RFC9350]). The FA can be seen as 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. topology. An instance of such
a sub-topology is identified by a 1 octet 1-octet value (Flex-Algorithm) as
documented in [RFC9350]. A flexible Algorithm At the time of writing, an FA is a
mechanism to create a sub-
topology, but sub-topology; in the future, different
algorithms might be defined for how to achieve that. For that reason, this purpose. Therefore, in the
remainder of this document, we'll refer to this as the IGP Algorithm. "IGP
Algorithm" or "IPA". The IGP
Algorithm (IPA) Field Section 4.1.2 Section 6.1 "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 IANA IGP "IGP Algorithm Types Types" registry [IANA-IGP-ALGO-TYPES].
Throughout this document, the term Flexible Algorithm (FA) "Flexible Algorithm" (or "FA")
shall denote the process of generating a sub-topology and signaling
it through Interior Gateway Protocol (IGP). the IGP. However, it is essential to note that the
procedures outlined in this document are not exclusively applicable
to Flexible Algorithm but the FA: they are extendable to any non-default algorithm as well.
Multipoint LDP (mLDP)
"Multipoint LDP" (or "mLDP") refers to extensions in LDP to setup multi-
point set up
multipoint LSPs (point-to-multipoint (i.e., point-to-multipoint (P2MP) or multipoint-to-multipoint
(MP2MP)), 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 MTR/IGP
Algorithm the use of MTR/IPAs such that that, when building a Multi-Point LSPs
multipoint LSPs, it can follow a particular topology and algorithm. This means that
Therefore, the identifier for the particular topology to be used by
mLDP have has to become a 2-tuple (MTR {MTR Topology Id, IPA}.
2. Terminology
2.1. Abbreviations
FA: Flexible Algorithm
FEC: Forwarding Equivalence Class
IGP: Interior Gateway Protocol
IPA: IGP Algorithm).
3. 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.
4. MT Scoped
3. MT-Scoped mLDP FECs
As defined in [RFC7307], an MPLS Multi-Topology Identifier (MT-ID) is an
identifier that 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 encoding; this is
so that LDP peers are able to setup 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, so FEC. This ensures that
different MT-ID values will result in unique MP-LSP FEC elements.
The same applies to the IGP Algorithm. IPA. The IGP Algorithm IPA needs to be encoded as part of
the mLDP FEC to create unique MP-LSPs. MP LSPs. The IGP
Algorithm IPA is also used to
signal to the mLDP (hop-by-hop) which Algorithm algorithm needs to be used to
create the MP-LSP. MP LSP.
Since the MT-ID and IGP Algorithm IPA are part of the FEC, they apply to all the
LDP messages that potentially include an mLDP FEC element.
4.1.
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].
4.1.1.
3.1.1. MP FEC Element
Base
The base mLDP specification [RFC6388] ([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 [RFC6388]
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 (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.
4.1.2.
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 "Reserved" field that was described in RFC
7307 are utilized to encode the
IGP Algorithm. IPA. The resulting format of the
data associated with these new Address Families 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 Data Format for MT IP Address Families Data Format
Where:
IPv4/IPv6
IPv4 Address and IPv6 Address: An IP address corresponding to the
"MT IP" and "MT IPv6" address families families, respectively.
IPA: The IGP Algorithm.
Reserved: This 8-bit field MUST be zero on transmission and MUST be
ignored on receipt.
4.1.3.
3.1.3. MT MP FEC Element
By
When using the extended MT IP Address Family, "MT IP" address family, the resulting MT 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: Data Format for an IP MT-Scoped MP FEC Element Format
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] ) [RFC5918])
In the case of "Typed the Typed Wildcard FEC Element", Element, the FEC Element type
MUST be one of the MP FECs listed above.
This specification allows the use of Topology-scoped topology-scoped mLDP FECs in LDP
label
labels and notification messages, as applicable.
[RFC6514] defines the PMSI tunnel attribute for MVPN, MVPN and specifies
that
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 Multipoint-to-Multipoint (MP2MP) MP2MP LSP, the Tunnel
Identifier is an MP2MP FEC Element.
When the extension defined in this specification is in use, the "IP IP
MT-Scoped MP FEC Element Format" form of the respective FEC elements MUST be
used in these two cases.
4.2.
3.2. Topology IDs
This document assumes the same definitions and procedures associated
with MPLS MT-ID as specified in [RFC7307] specification.
5. [RFC7307].
4. MT Multipoint Capability
The "MT Multipoint Capability" Multipoint" capability is a new LDP capability, defined in
accordance with the LDP Capability 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: Data Format for the MT Multipoint Capability TLV Format
Where:
U-
U and F-bits: F bits: MUST be 1 and 0, respectively, as per Section 3 of
LDP Capabilities
[RFC5561].
MT Multipoint Capability: The TLV type.
Length: The length (in octets) of TLV. The value of this field
MUST be 1 as there is no Capability-specific data [RFC5561] that
follows in the TLV. 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 capability-specific
data [[RFC5561]] [RFC5561] following the TLV.
S-bit:
S bit: Set to 1 to announce and 0 to withdraw the capability (as per [RFC5561].
[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 4.1) 3.1)
2. Topology-scoped mLDP forwarding setup (Section 7)
6. 6)
5. MT Applicability on FEC-based features
6.1. 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, extensions defined in this document, document do not require any
extension to procedures for support of the Typed Wildcard FEC Element support
[RFC5918], and these procedures apply as-is 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 "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 (sub-)topology as identified by the
MT-ID
"MT-ID" and IPA field. "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 (contd.)
|MT-ID (cont.) |
+-+-+-+-+-+-+-+-+
Figure 5: Data Format for the Typed Wildcard MT MP FEC Element
Where:
Type: One of the MP FEC Element type types (P2MP, MP2MPup, MP2MP-down).
MT ID: MP2MP-up, or MP2MP-
down)
MT-ID: MPLS MT ID MT-ID
IPA: The IGP Algorithm
The defined format allows an LSR a Label Switching Router (LSR) to perform
wildcard MP FEC operations under the scope of a (sub-)topology.
6.2.
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-is 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.
7.
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 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.
7.1.
6.1. Upstream LSR selection Selection
The procedures as described in RFC-6388 section-2.4.1.1 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, this 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, a an LDP peer is
selected following the procedures as defined in [RFC6388].
7.2.
6.2. Downstream forwarding interface selection
The Forwarding Interface Selection
Section 2.4.1.2 of [RFC6388] describes the procedures as described in RFC-6388 section-2.4.1.2 describe for how a
downstream forwarding interface is selected. In these procedures,
any interface leading to the downstream LDP neighbor can be
considered as 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.
8.
7. LSP Ping Extensions
[RFC6425] defines procedures to detect data plane failures in
Multipoint
multipoint MPLS LSPs. Section 3.1.2 of [RFC6425] defines new Sub-
Types sub-
types and Sub-TLVs sub-TLVs for Multipoint LDP FECs to be sent in the "Target
FEC Stack" TLV of an MPLS echo request Echo Request message [RFC8029].
To support LSP ping for MT Multipoint MP LSPs, this document uses existing sub-types sub-
types "P2MP LDP FEC Stack" and "MP2MP LDP FEC Stack" defined in
[RFC6425]. The LSP Ping 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 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 Echo
Request message are the same as defined for the P2MP/MP2MP LDP FEC
Stack
Sub-TLV sub-TLV in [RFC6425]. The only difference is that the Root "Root
LSR
address Address" field is now (sub-)topology scoped.
9. Implementation Status
[Note to the RFC Editor - remove this section before publication, as
well as remove the reference to [RFC7942]
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 [RFC7942] .
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.
According to [RFC7942] , "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".
9.1. Cisco Systems
The feature has been implemented on IOS-XR.
* Organization: Cisco Systems
* Implementation: Cisco systems IOS-XR has an implementation.
Capability has been used from [RFC7307] and plan to update the
value once IANA assigns new value.
* Description: The implementation has been done.
* Maturity Level: Product
* Contact: mankamis@cisco.com
10.
8. Security Considerations
This extension to mLDP does not introduce any new security
considerations beyond that what is already applied to the base LDP
specification [RFC5036], the LDP extensions for Multi-Topology
specification [RFC7307] [RFC7307], the base mLDP specification [RFC6388], and
the MPLS security framework specification [RFC5920].
11.
9. IANA Considerations
This document defines a new LDP capability parameter TLV. TLV called the
"MT Multipoint Capability". IANA is
requested to assign has assigned the lowest available value after 0x0500 0x0510 from
the "TLV Type Name Space" registry in the "Label Distribution
Protocol (LDP) Parameters" registry within "Label Distribution Protocol (LDP) Name
Spaces" group as the new code point for the LDP TLV code point.
+-----+------------------+---------------+-------------------------+
|Value|
+========+===============+===========+=========================+
| Value | Description | Reference | Notes/Registration Date |
+-----+------------------+---------------+-------------------------+
+========+===============+===========+=========================+
| TBA 0x0510 | MT Multipoint | This document RFC 9658 | |
| | Capability | | |
+-----+------------------+---------------+-------------------------+
Figure 7: IANA Code Point
12. Contributor
Anuj Budhiraja Cisco systems
13. Acknowledgments
The authors would like to acknowledge Eric Rosen for his input on
this specification.
14.
+--------+---------------+-----------+-------------------------+
Table 1: MT Multipoint Capability
10. References
14.1.
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>.
[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>.
[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>.
14.2.
10.2. Informative References
[IANA-IGP-ALGO-TYPES]
IANA, "IGP Algorithm Types", <https://www.iana.org/assignments/
igp-parameters/igp-parameters.xhtml#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 Wealth Management
United States of America
Email: Arkadiy.gulko@edwardjones.com