draft-ietf-mpls-app-aware-tldp-09.txt   rfc8223.txt 
MPLS Working Group Santosh Esale Internet Engineering Task Force (IETF) S. Esale
INTERNET-DRAFT Raveendra Torvi Request for Comments: 8223 R. Torvi
Updates: 7473 (if approved) Juniper Networks Updates: 7473 Juniper Networks
Intended Status: Proposed Standard Luay Jalil Category: Standards Track L. Jalil
Expires: December 29, 2017 Verizon ISSN: 2070-1721 Verizon
Uma Chunduri U. Chunduri
Huawei Huawei
Kamran Raza K. Raza
Cisco Systems, Inc. Cisco Systems, Inc.
June 27, 2017 August 2017
Application-aware Targeted LDP Application-Aware Targeted LDP
draft-ietf-mpls-app-aware-tldp-09
Abstract Abstract
Recent targeted Label Distribution Protocol (tLDP) applications such Recent Targeted Label Distribution Protocol (tLDP) applications, such
as remote loop-free alternate (LFA) and BGP auto discovered as remote Loop-Free Alternates (LFAs) and BGP auto-discovered
pseudowire may automatically establish a tLDP session to any Label pseudowires, may automatically establish a tLDP session with any
Switching Router (LSR) in a network. The initiating LSR has Label Switching Router (LSR) in a network. The initiating LSR has
information about the targeted applications to administratively information about the targeted applications to administratively
control initiation of the session. However, the responding LSR has no control initiation of the session. However, the responding LSR has
such information to control acceptance of this session. This document no such information to control acceptance of this session. This
defines a mechanism to advertise and negotiate Targeted Applications document defines a mechanism to advertise and negotiate the Targeted
Capability (TAC) during LDP session initialization. As the Application Capability (TAC) during LDP session initialization. As
responding LSR becomes aware of targeted applications, it may the responding LSR becomes aware of targeted applications, it may
establish a limited number of tLDP sessions for certain applications. establish a limited number of tLDP sessions for certain applications.
In addition, each targeted application is mapped to LDP Forwarding In addition, each targeted application is mapped to LDP Forwarding
Equivalence Class (FEC) Elements to advertise only necessary LDP FEC- Equivalence Class (FEC) elements to advertise only necessary LDP FEC
label bindings over the session. This document updates RFC 7473 for label bindings over the session. This document updates RFC 7473 for
enabling advertisement of LDP FEC-label bindings over the session. enabling advertisement of LDP FEC label bindings over the session.
Status of this Memo
This Internet-Draft is submitted to IETF in full conformance with the Status of This Memo
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering This is an Internet Standards Track document.
Task Force (IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as
Internet-Drafts.
Internet-Drafts are draft documents valid for a maximum of six months This document is a product of the Internet Engineering Task Force
and may be updated, replaced, or obsoleted by other documents at any (IETF). It represents the consensus of the IETF community. It has
time. It is inappropriate to use Internet-Drafts as reference received public review and has been approved for publication by the
material or to cite them other than as "work in progress." Internet Engineering Steering Group (IESG). Further information on
The list of current Internet-Drafts can be accessed at Internet Standards is available in Section 2 of RFC 7841.
http://www.ietf.org/1id-abstracts.html
The list of Internet-Draft Shadow Directories can be accessed at Information about the current status of this document, any errata,
http://www.ietf.org/shadow.html and how to provide feedback on it may be obtained at
https://www.rfc-editor.org/info/rfc8223.
Copyright and License Notice Copyright Notice
Copyright (c) 2017 IETF Trust and the persons identified as the Copyright (c) 2017 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (https://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 1. Introduction ....................................................3
1.1 Conventions Used in This Document . . . . . . . . . . . . . 4 1.1. Conventions Used in This Document ..........................4
1.2 Terminology . . . . . . . . . . . . . . . . . . . . . . . . 5 1.2. Terminology ................................................4
2. Targeted Application Capability . . . . . . . . . . . . . . . . 5 2. Targeted Application Capability .................................5
2.1 Encoding . . . . . . . . . . . . . . . . . . . . . . . . . . 5 2.1. Encoding ...................................................5
2.2 Procedures . . . . . . . . . . . . . . . . . . . . . . . . . 6 2.2. Procedures .................................................5
2.3 LDP message procedures . . . . . . . . . . . . . . . . . . . 8 2.3. LDP Message Procedures .....................................8
2.3.1 Initialization message . . . . . . . . . . . . . . . . . 8 2.3.1. Initialization Message ..............................8
2.3.2 Capability message . . . . . . . . . . . . . . . . . . . 9 2.3.2. Capability Message ..................................8
3. Targeted Application FEC Advertisement Procedures . . . . . . . 9 3. Targeted Application FEC Advertisement Procedures ...............9
4. Interaction of Targeted Application Capabilities and State 4. Interaction of Targeted Application Capabilities and State
Advertisement Control Capabilities . . . . . . . . . . . . . . 10 Advertisement Control Capabilities .............................10
5. Use cases . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 5. Use Cases ......................................................12
5.1 Remote LFA Automatic Targeted session . . . . . . . . . . . 12 5.1. Remote LFA Automatic Targeted Session .....................12
5.2 FEC 129 Auto Discovery Targeted session . . . . . . . . . . 13 5.2. FEC 129 Auto-discovery Targeted Session ...................13
5.3 LDP over RSVP and Remote LFA targeted session . . . . . . . 13 5.3. LDP over RSVP and Remote LFA Targeted Session .............13
5.4 mLDP node protection targeted session . . . . . . . . . . . 13 5.4. mLDP Node Protection Targeted Session .....................13
6. Security Considerations . . . . . . . . . . . . . . . . . . . . 14 6. Security Considerations ........................................14
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 14 7. IANA Considerations ............................................14
8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . 15 8. References .....................................................15
9. Contributing Authors . . . . . . . . . . . . . . . . . . . . . 15 8.1. Normative References ......................................15
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 16 8.2. Informative References ....................................16
10.1 Normative References . . . . . . . . . . . . . . . . . . . 16 Acknowledgments ...................................................17
10.2 Informative References . . . . . . . . . . . . . . . . . . 16 Contributors ......................................................17
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 17 Authors' Addresses ................................................18
1 Introduction 1. Introduction
LDP uses the extended discovery mechanism to establish the tLDP LDP uses the Extended Discovery mechanism to establish the
adjacency and subsequent session as described in [RFC5036]. A LSR Targeted LDP (tLDP) adjacency and subsequent session, as described in
initiates extended discovery by sending tLDP Hello to specific [RFC5036]. A Label Switching Router (LSR) initiates Extended
address. The remote LSR decides to either accept or ignore the tLDP Discovery by sending a tLDP Hello to a specific address. The remote
Hello based on local configuration only. Targeted LDP application is LSR decides to either accept or ignore the tLDP Hello based on local
an application that uses tLDP session to exchange information such as configuration only. A tLDP application is an application that uses a
FEC-Label bindings with a peer LSR in the network. For an application tLDP session to exchange information such as FEC label bindings
such as FEC 128 pseudowire, the remote LSR is configured with the ("FEC" stands for "Forwarding Equivalence Class") with a peer LSR in
source LSR address so that it can use that information to accept or the network. For an application such as FEC 128 pseudowire, the
ignore given tLDP Hello. remote LSR is configured with the source LSR address so that it can
use that information to accept or ignore a given tLDP Hello.
However, applications such as Remote LFA and BGP auto discovered However, applications such as remote Loop-Free Alternates (LFAs) and
pseudowire automatically initiate asymmetric extended discovery to BGP auto-discovered pseudowires automatically initiate asymmetric
any LSR in a network based on local state only. With these Extended Discovery to any LSR in a network based on local state only.
applications, the remote LSR is not explicitly configured with the With these applications, the remote LSR is not explicitly configured
source LSR address. So the remote LSR either responds or ignores all with the source LSR address. So, the remote LSR either responds to
tLDP Hellos. all tLDP Hellos or ignores them.
In addition, since the session is initiated and established after In addition, since the session is initiated and established after
adjacency formation, the responding LSR has no targeted applications adjacency formation, the responding LSR has no information on
information available to choose a session with targeted application targeted applications available from which it can choose a session
that it is configured to support. Also, the initiating LSR may employ with a targeted application that it is configured to support. Also,
a limit per application on locally initiated automatic tLDP sessions, the initiating LSR may employ a limit per application on locally
however the responding LSR has no such information to employ a initiated automatic tLDP sessions; however, the responding LSR has
similar limit on the incoming tLDP sessions. Further, the responding no such information to employ a similar limit on the incoming tLDP
LSR does not know whether the source LSR is establishing a tLDP sessions. Further, the responding LSR does not know whether the
session for configured, automatic or both applications. source LSR is establishing a tLDP session for configured
applications, automatic applications, or both.
This document proposes and describes a solution to advertise Targeted This document proposes and describes a solution to advertise the
Application Capability (TAC), consisting of a targeted application Targeted Application Capability (TAC), consisting of a list of
list, during initialization of a tLDP session. It also defines a targeted applications, during initialization of a tLDP session. It
mechanism to enable an new application and disable an old application also defines a mechanism to enable a new application and disable an
after session establishment. This capability advertisement provides old application after session establishment. This capability
the responding LSR with the necessary information to control the advertisement provides the responding LSR with the necessary
acceptance of tLDP sessions per application. For instance, an LSR may information to control the acceptance of tLDP sessions
accept all BGP auto discovered tLDP sessions as defined in [RFC6074] per application. For instance, an LSR may accept all BGP
but may only accept limited number of Remote LFA tLDP sessions as auto-discovered tLDP sessions as described in [RFC6074] but may only
defined in [RFC7490] accept a limited number of remote LFA tLDP sessions as described
in [RFC7490].
Also, the targeted LDP application is mapped to LDP FEC element type Also, the tLDP application is mapped to LDP FEC element types to
to advertise specific application FECs only, avoiding the advertise specific application FECs only, avoiding the advertisement
advertisement of other unnecessary FECs over a tLDP session. of other unnecessary FECs over a tLDP session.
1.1 Conventions Used in This Document 1.1. Conventions Used in This Document
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in RFC "OPTIONAL" in this document are to be interpreted as described in
2119 [RFC2119] and RFC 8174 [RFC8174] when, and only when, they BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
appear in all capitals, as shown here. capitals, as shown here.
1.2 Terminology 1.2. Terminology
In addition to the terminology defined in [RFC7473], this document In addition to the terminology defined in [RFC7473], this document
uses the following terms: uses the following terms:
tLDP : Targeted LDP tLDP : Targeted LDP
TAC : Targeted Application Capability TAC : Targeted Application Capability
TAE : Targeted Application Element TAE : Targeted Application Element
TA-Id : Targeted Application Identifier TA-Id : Targeted Application Identifier
SAC : State Advertisement Control Capability SAC : State Advertisement Control
LSR : Label Switching Router LSR : Label Switching Router
mLDP : Multipoint LDP mLDP : Multipoint LDP
PQ : Remote-LFA nexthops PQ node : Remote LFA next hops
RSVP-TE : RSVP Traffic Engineering RSVP-TE : RSVP Traffic Engineering
P2MP : Point-to-Multipoint P2MP : Point-to-Multipoint
PW : Pseudowire PW : Pseudowire
P2P-PW : Point-to-point Psuedowire P2P-PW : Point-to-Point Pseudowire
MP2MP : Multipoint-to-Multipoint MP2MP : Multipoint-to-Multipoint
HSMP LSP: Hub and Spoke Multipoint Label Switched Path HSMP LSP: Hub and Spoke Multipoint Label Switched Path
LSP : Label Switched Path LSP : Label Switched Path
MP2P : Multipoint-to-point MP2P : Multipoint-to-Point
MPT : Merge Point MPT : Merge Point
2. Targeted Application Capability 2. Targeted Application Capability
2.1 Encoding 2.1. Encoding
An LSR MAY advertise that it is capable of negotiating a targeted LDP An LSR MAY advertise that it is capable of negotiating a tLDP
application list over a tLDP session by using the Capability application list over a tLDP session by using the capability
Advertisement as defined in [RFC5561] and encoded as follows: advertisement as defined in [RFC5561] and encoded as follows:
0 1 2 3 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 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| TLV Code Point | Length | |U|F| TLV Code Point | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|S| Reserved | | |S| Reserved | |
+-+-+-+-+-+-+-+-+ Capability Data | +-+-+-+-+-+-+-+-+ Capability Data |
| +-+-+-+-+-+-+-+-+ | +-+-+-+-+-+-+-+-+
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
This document defines a new optional capability TLV of type TBD1
called 'Targeted Application Capability (TAC)'. Flag "U" MUST be
set to 1 to indicate that this capability must be silently ignored
if unknown. The TAC's Capability Data contains the Targeted
Application Element (TAE) information encoded as follows:
Targeted Application Element(TAE) Flag "U" MUST be set to 1 to indicate that this capability must be
silently ignored if unknown. The TAC's Capability Data field
contains the Targeted Application Element (TAE) information, encoded
as follows:
0 1 2 3 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 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Targ. Appl. Id |E| Reserved | | TA-Id |E| Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Targeted Application Identifier (TA-Id): TA-Id: A 16-bit Targeted Application Identifier value.
a 16 bit Targeted Application Identifier value.
E-bit: The enable bit indicates whether the sender is E: E-bit (Enable bit). Indicates whether the sender is
advertising or withdrawing the TAE. The E-bit value is used as advertising or withdrawing the TAE. The E-bit value is used
follows: as follows:
1 - The TAE is advertising the targeted application. 1 - The TAE is advertising the targeted application.
0 - The TAE is withdrawing the targeted application. 0 - The TAE is withdrawing the targeted application.
2.2 Procedures 2.2. Procedures
At tLDP session establishment time, a LSR MAY include a new At tLDP session establishment time, an LSR MAY include a new
capability TLV, TAC TLV, as an optional TLV in the LDP Initialization capability TLV, the TAC TLV, as an optional TLV in the LDP
message. The TAC TLV's Capability data MAY consist of zero or more Initialization message. The TAC TLV's Capability data MAY consist of
TAEs each pertaining to a unique TA-Id that a LSR supports over the zero or more TAEs, each pertaining to a unique TA-Id that an LSR
session. If the receiver LSR receives the same TA-Id in more than one supports over the session. If the receiver LSR receives the same
TAE, it MUST process the first element and ignore the duplicate TA-Id in more than one TAE, it MUST process the first element and
elements. If the receiver LSR receives an unknown TA-Id in the TAE, ignore the duplicate elements. If the receiver LSR receives an
it MUST silently ignore such a TAE and continue processing the rest unknown TA-Id in the TAE, it MUST silently ignore such a TAE and
of the TLV. continue processing the rest of the TLV.
If the receiver LSR does not receive the TAC TLV in the If the receiver LSR does not receive the TAC TLV in the
Initialization message or it does not understand the TAC TLV, the TAC Initialization message or it does not understand the TAC TLV, the TAC
negotiation is considered unsuccessful and the session establishment negotiation is considered unsuccessful and the session establishment
proceeds as per [RFC5036]. On the receipt of a valid TAC TLV, an LSR proceeds as per [RFC5036]. On receipt of a valid TAC TLV, an LSR
MUST generate its own TAC TLV with TAEs consisting of unique TA-Ids MUST generate its own TAC TLV with TAEs consisting of unique TA-Ids
that it supports over the tLDP session. If there is at least one TAE that it supports over the tLDP session. If there is at least one
common between the TAC TLV it has received and its own, the session common TAE between the TAC TLV it has received and its own, the
MUST proceed to establishment as per [RFC5036]. If not, A LSR MUST session MUST proceed to establishment as per [RFC5036]. If not, an
send a 'Session Rejected/Targeted Application Capability Mis-Match' LSR MUST send a 'Session Rejected/Targeted Application Capability
Notification message to the peer and close the session. The Mismatch' Notification message to the peer and close the session.
initiating LSR SHOULD tear down the corresponding tLDP adjacency The initiating LSR SHOULD tear down the corresponding tLDP adjacency
after sent or receipt of a 'Session Rejected/Targeted Application after sending or receiving a 'Session Rejected/Targeted Application
Capability Mis-Match' Notification message to or from the responding Capability Mismatch' Notification message to or from the responding
LSR respectively. LSR, respectively.
If both the peers support TAC TLV, an LSR decides to establish or If both of the peers support the TAC TLV, an LSR decides to establish
close a tLDP session based on the negotiated targeted application or close a tLDP session based on the negotiated list of targeted
list. For example, an initiating LSR advertises A, B and C as TA-Ids, applications. For example, an initiating LSR advertises A, B, and C
and the responding LSR advertises C, D and E as TA-Ids. Then the as TA-Ids, and the responding LSR advertises C, D, and E as TA-Ids.
negotiated TA-Id as per both the LSRs is C. Another example, an Then, the negotiated TA-Id as per both LSRs is C. In another
initiating LSR advertises A, B and C as TA-Ids, and the responding example, an initiating LSR advertises A, B, and C as TA-Ids, and the
LSR, which acts as a passive LSR, advertises all the applications - responding LSR, which acts as a passive LSR, advertises all of the
A, B, C, D and E - as TA-Ids that it supports over this session. Then applications -- A, B, C, D, and E -- as TA-Ids that it supports over
the negotiated targeted applications as per both the LSRs are A, B this session. The negotiated targeted applications as per both LSRs
and C. Finally, If the initiating LSR advertises A, B and C as a TA- are then A, B, and C. Finally, if the initiating LSR advertises A,
Ids and the responding LSR advertises D and E as TA-Ids, then the B, and C as TA-Ids and the responding LSR advertises D and E as
negotiated targeted applications as per both the LSRs are none. TA-Ids, then the negotiated targeted applications as per both LSRs
Therefore, if the intersection of the sets of received and sent TA-Id are "none". Therefore, if the intersection of the sets of received
is null, then LSR sends 'Session Rejected/Targeted Application and sent TA-Ids is null, then the LSR sends a 'Session
Capability Mis-Match' Notification message to the peer LSR and closes Rejected/Targeted Application Capability Mismatch' Notification
the session. message to the peer LSR and closes the session.
When the responding LSR playing the active role [RFC5036] in LDP When the responding LSR playing the active role [RFC5036] in LDP
session establishment receives a 'Session Rejected/Targeted session establishment receives a 'Session Rejected/Targeted
Application Capability Mis-Match' Notification message, it MUST set Application Capability Mismatch' Notification message, it MUST set
its session setup retry interval to a maximum value, as such 0xffff. its session setup retry interval to a maximum value -- that is,
The session MAY stay in NON EXISTENT state. When it detects a change 0xFFFF. The session MAY stay in a non-existent state. When it
in the initiating LSR or local LSR configuration pertaining to TAC detects a change in the initiating LSR or local LSR configuration
TLV, it MUST clear the session setup back off delay associated with pertaining to the TAC TLV, it MUST clear the session setup backoff
the session to re-attempt the session establishment. A LSR detects delay associated with the session to reattempt session establishment.
configuration change on the other LSR with the receipt of tLDP Hello An LSR detects the configuration change on the other LSR upon receipt
message that has a higher configuration sequence number than the of a tLDP Hello message that has a higher configuration sequence
earlier tLDP Hello message. number than the earlier tLDP Hello message.
When the initiating LSR playing the active role in LDP session When the initiating LSR playing the active role in LDP session
establishment receives a 'Session Rejected/Targeted Application establishment receives a 'Session Rejected/Targeted Application
Capability Mis-Match' Notification message, either it MUST close the Capability Mismatch' Notification message, it MUST either (1) close
session and tear down the corresponding tLDP adjacency or it MUST set the session and tear down the corresponding tLDP adjacency or (2) set
its session setup retry interval to a maximum value, as such 0xffff. its session setup retry interval to a maximum value -- that is,
0xFFFF.
If the initiating LSR decides to tear down the associated tLDP If the initiating LSR decides to tear down the associated tLDP
adjacency, the session is closed on the initiating as well as the adjacency, the session is closed on the initiating LSR as well as the
responding LSR. It MAY also take appropriate actions. For instance, responding LSR. It MAY also take appropriate actions. For instance,
if an automatic session intended to support the Remote LFA if an automatic session intended to support the remote LFA
application is rejected by the responding LSR, the initiating LSR may application is rejected by the responding LSR, the initiating LSR may
inform the IGP to calculate another PQ node [RFC7490] for the route inform the IGP to calculate another PQ node [RFC7490] for the route
or set of routes. More specific actions are a local matter and or set of routes. More specific actions are a local matter and are
outside the scope of this document. outside the scope of this document.
If the initiating LSR sets the session setup retry interval to If the initiating LSR sets the session setup retry interval to
maximum, the session MAY stay in a non-existent state. When this LSR maximum, the session MAY stay in a non-existent state. When this LSR
detects a change in the responding LSR configuration or its own detects a change in the responding LSR configuration or its own
configuration pertaining to TAC TLV, it MUST clear the session setup configuration pertaining to the TAC TLV, it MUST clear the session
back off delay associated with the session in order to re-attempt the setup backoff delay associated with the session in order to reattempt
session establishment. session establishment.
After a tLDP session has been established with TAC capability, the After a tLDP session using the TAC mechanism has been established,
initiating and responding LSR MUST distribute FEC-label bindings for the initiating and responding LSRs MUST distribute FEC label bindings
the negotiated applications only. For instance, if the tLDP session for the negotiated applications only. For instance, if the tLDP
is established for BGP auto discovered pseudowire, only FEC 129 label session is established for a BGP auto-discovered pseudowire, only FEC
bindings MUST be distributed over the session. Similarly, a LSR 129 label bindings MUST be distributed over the session. Similarly,
operating in downstream on demand mode MUST request FEC-label an LSR operating in downstream on-demand mode MUST request FEC label
bindings for the negotiated applications only. bindings for the negotiated applications only.
If the Targeted Application Capability and Dynamic Capability, If the TAC and the Dynamic Capability [RFC5561] are negotiated during
described in [RFC5561], are negotiated during session initialization, session initialization, the TAC MAY be renegotiated after session
TAC MAY be re-negotiated after session establishment by sending an establishment by sending an updated TAC TLV in the LDP Capability
updated TAC TLV in LDP Capability message. The updated TAC TLV message. The updated TAC TLV carries TA-Ids with an incremental
carries TA-Ids with incremental update only. The updated TLV MUST update only. The updated TLV MUST consist of one or more TAEs with
consist of one or more TAEs with E-bit set or E-bit off to advertise the E-bit set (1) or off (0), to advertise or withdraw the new
or withdraw the new and old application respectively. This may lead application and the old application, respectively. This may lead to
to advertisements or withdrawals of certain types of FEC-Label advertisements or withdrawals of certain types of FEC label bindings
bindings over the session or tear down of the tLDP adjacency and over the session or to teardown of the tLDP adjacency and,
subsequently the session. subsequently, the session.
The Targeted Application Capability is advertised on tLDP session The TAC is advertised on the tLDP session only. If the tLDP session
only. If the tLDP session changes to link session, a LSR SHOULD changes to a link session, an LSR SHOULD withdraw it with the S-bit
withdraw it with S bit set to 0. Similarly, if the link session set to 0. Similarly, if the link session changes to tLDP, an LSR
changes to tLDP, a LSR SHOULD advertise it via the Capability SHOULD advertise it via the Capability message. If the capability
message. If the capability negotiation fails, this may lead to negotiation fails, this may lead to destruction of the tLDP session.
destruction of the tLDP session.
By default, LSR SHOULD accept tLDP hellos in order to then accept or By default, an LSR SHOULD accept tLDP Hellos in order to then accept
reject the tLDP session based on the application information. or reject the tLDP session based on the application information.
In addition, LSR SHOULD allow the configuration of any TA-Id in order In addition, an LSR SHOULD allow the configuration of any TA-Id in
to facilitate private TA-Id's usage by a network operator. order to facilitate the use of private TA-Ids by a network operator.
2.3 LDP message procedures 2.3. LDP Message Procedures
2.3.1 Initialization message 2.3.1. Initialization Message
1. The S-bit of the Targeted Application Capability TLV MUST be 1. The S-bit of the TAC TLV MUST be set to 1 to advertise the TAC and
set to 1 to advertise Targeted Application Capability and SHOULD be ignored on receipt, as described in [RFC5561].
SHOULD be ignored on the receipt as defined in [RFC5561]
2. The E-bit of the Targeted Application Element MUST be set to 1 to 2. The E-bit of the TAE MUST be set to 1 to enable the targeted
enable Targeted application and SHOULD be ignored on the receipt. application and SHOULD be ignored on receipt.
3. An LSR MAY add State Control Capability by mapping Targeted 3. An LSR MAY add the State Advertisement Control Capability by
Application Element to State Advertisement Control (SAC) Elements mapping the TAE to the State Advertisement Control (SAC) elements
as defined in Section 4. as defined in Section 4.
2.3.2 Capability message 2.3.2. Capability Message
The initiating or responding LSR may re-negotiate the TAC after local After a change to local configuration, the initiating or responding
configuration change with the Capability message. LSR may renegotiate the TAC via the Capability message.
1. The S-bit of TAC is set to 1 or 0 to advertise or withdraw it. 1. The S-bit of the TAC is set to 1 or 0 to advertise or withdraw it.
2. After configuration change, If there is no common TAE between 2. After the configuration change, if there is no common TAE between
its new TAE list and peers TAE list, the LSR MUST send a its new TAE list and the peer's TAE list, the LSR MUST send a
'Session Rejected/Targeted Application Capability Mis-Match' 'Session Rejected/Targeted Application Capability Mismatch'
Notification message and close the session. Notification message and close the session.
3. If there is a common TAE, a LSR MAY also update SAC Capability 3. If there is a common TAE, an LSR MAY also update the SAC
based on updated TAC as described in section 4 and send the Capability based on the updated TAC, as described in Section 4,
updated TAC and SAC capabilities in a Capability message to and send the updated TAC and SAC Capability in a Capability
the peer. message to the peer.
4. A receiving LSR processes the Capability message with TAC TLV. 4. A receiving LSR processes the Capability message with the TAC TLV.
If the S-bit is set to 0, the TAC is disabled for the session. If the S-bit is set to 0, the TAC is disabled for the session.
5. If the S-bit is set to 1, a LSR process a list of TAEs from 5. If the S-bit is set to 1, the LSR processes a list of TAEs from
TACs capability data with E-bit set to 1 or 0 to update the the TAC's data with the E-bit set to 1 or 0 to update the
peer's TAE. peer's TAE.
3. Targeted Application FEC Advertisement Procedures 3. Targeted Application FEC Advertisement Procedures
The targeted LDP application MUST be mapped to LDP FEC element types The tLDP application MUST be mapped to LDP FEC element types as
as follows to advertise only necessary LDP FEC-Label bindings over follows to advertise only necessary LDP FEC label bindings over the
the tLDP session. tLDP session.
Targeted Application Description FEC mappings Targeted Application Description FEC Mappings
+----------------------+------------------------+------------------+ +----------------------+------------------------+------------------+
|LDPv4 Tunneling | LDP IPv4 over RSVP-TE | IPv4 prefix | |LDPv4 Tunneling | LDP IPv4 over RSVP-TE | IPv4 prefix |
| | or other MPLS tunnel | | | | or other MPLS tunnel | |
+----------------------+------------------------+------------------+ +----------------------+------------------------+------------------+
| | | | | | | |
|LDPv6 Tunneling | LDP IPv6 over RSVP-TE | IPv6 prefix | |LDPv6 Tunneling | LDP IPv6 over RSVP-TE | IPv6 prefix |
| | or other MPLS tunnel | | | | or other MPLS tunnel | |
+----------------------+------------------------+------------------+ +----------------------+------------------------+------------------+
|mLDP Tunneling | mLDP over RSVP-TE or | P2MP | |mLDP Tunneling | mLDP over RSVP-TE or | P2MP |
| | or other MPLS tunnel | MP2MP-up | | | other MPLS tunnel | MP2MP-up |
| | | MP2MP-down | | | | MP2MP-down |
| | | HSMP-downstream | | | | HSMP-downstream |
| | | HSMP-upstream | | | | HSMP-upstream |
+----------------------+------------------------+------------------+ +----------------------+------------------------+------------------+
| | | | | | | |
|LDPv4 Remote LFA | LDPv4 over LDPv4 or | IPv4 prefix | |LDPv4 remote LFA | LDPv4 over LDPv4 or | IPv4 prefix |
| | other MPLS tunnel | | | | other MPLS tunnel | |
+----------------------+------------------------+------------------+ +----------------------+------------------------+------------------+
|LDPv6 Remote LFA | LDPv6 over LDPv6 or | IPv6 prefix | |LDPv6 remote LFA | LDPv6 over LDPv6 or | IPv6 prefix |
| | other MPLS tunnel | | | | other MPLS tunnel | |
+----------------------+------------------------+------------------+ +----------------------+------------------------+------------------+
| | | | | | | |
|LDP FEC 128 PW | LDP FEC 128 Pseudowire | PWid FEC Element | |LDP FEC 128 PW | LDP FEC 128 Pseudowire | PWid FEC element |
+----------------------+------------------------+------------------+ +----------------------+------------------------+------------------+
| | | | | | | |
|LDP FEC 129 PW | LDP FEC 129 Pseudowire | Generalized PWid | |LDP FEC 129 PW | LDP FEC 129 Pseudowire | Generalized PWid |
| | | FEC Element | | | | FEC element |
+----------------------+------------------------+------------------+ +----------------------+------------------------+------------------+
| | | FEC types as | | | | FEC types as |
|LDP Session Protection| LDP session protection | per protected | |LDP Session Protection| LDP session protection | per protected |
| | | session | | | | session |
+----------------------+------------------------+------------------+ +----------------------+------------------------+------------------+
|LDP ICCP | LDP Inter-chasis | | |LDP ICCP | LDP Inter-Chassis | |
| | control protocol | None | | | Communication Protocol | None |
+----------------------+------------------------+------------------+ +----------------------+------------------------+------------------+
| | | | | | | |
|LDP P2MP PW | LDP P2MP Pseudowire | P2MP PW Upstream | |LDP P2MP PW | LDP P2MP Pseudowire | P2MP PW Upstream |
| | | FEC Element | | | | FEC element |
+----------------------+------------------------+------------------+ +----------------------+------------------------+------------------+
| | | P2MP | | | | P2MP |
|mLDP Node Protection | mLDP node protection | MP2MP-up | |mLDP Node Protection | mLDP node protection | MP2MP-up |
| | | MP2MP-down | | | | MP2MP-down |
| | | HSMP-downstream | | | | HSMP-downstream |
| | | HSMP-upstream | | | | HSMP-upstream |
+----------------------+------------------------+------------------+ +----------------------+------------------------+------------------+
| | | | | | | |
|IPv4 intra-area FECs | IPv4 intra-area FECs | IPv4 prefix | |IPv4 intra-area FECs* | IPv4 intra-area FECs* | IPv4 prefix |
+----------------------+------------------------+------------------+ +----------------------+------------------------+------------------+
| | | | | | | |
|IPv6 intra-area FECs | IPv6 intra-area FECs | IPv6 prefix | |IPv6 intra-area FECs* | IPv6 intra-area FECs* | IPv6 prefix |
+----------------------+------------------------+------------------+ +----------------------+------------------------+------------------+
Intra-area FECs : FECs that are on the shortest path tree and not * Intra-area FECs: FECs that are on the shortest-path tree and
leafs of the shortest path tree. are not leafs of the shortest-path tree.
4. Interaction of Targeted Application Capabilities and State
Advertisement Control Capabilities
4. Interaction of Targeted Application Capabilities and State
Advertisement Control Capabilities
As described in this document, the set of TAEs negotiated between two As described in this document, the set of TAEs negotiated between two
LDP peers advertising TAC represents the willingness of both peers to LDP peers advertising the TAC represents the willingness of both
advertise state information for a set of applications. The set of peers to advertise state information for a set of applications. The
applications negotiated by the TAC mechanism is symmetric between the set of applications negotiated by the TAC mechanism is symmetric
two LDP peers. In the absence of further mechanisms, two LDP peers between the two LDP peers. In the absence of further mechanisms, two
will both advertise state information for the same set of LDP peers will both advertise state information for the same set of
applications. applications.
As described in [RFC7473], State Advertisement Control(SAC) TLV can As described in [RFC7473], the SAC TLV can be used by an LDP speaker
be used by an LDP speaker to communicate its interest or disinterest to communicate its interest or disinterest in receiving state
in receiving state information from a given peer for a particular information from a given peer for a particular application. Two LDP
application. Two LDP peers can use the SAC mechanism to create peers can use the SAC mechanism to create asymmetric advertisements
asymmetric advertisement of state information between the two peers. of state information between the two peers.
The TAC negotiation facilitates the awareness of targeted The TAC negotiation facilitates the awareness of targeted
applications to both the peers. It enables them to advertise only applications to both of the peers. It enables them to advertise only
necessary LDP FEC-label bindings corresponding to negotiated necessary LDP FEC label bindings corresponding to negotiated
applications. With the SAC, the responding LSR is not aware of applications. With the SAC, the responding LSR is not aware of
targeted applications. Thus it may be unable to communicate its targeted applications. Thus, it may be unable to communicate its
interest or disinterest to receive state information from the peer. interest or disinterest in receiving state information from the peer.
Therefore, when the responding LSR is not aware of targeted Therefore, when the responding LSR is not aware of targeted
applications such a remote LFA and BGP auto discovered pseudowires, applications such as remote LFAs and BGP auto-discovered pseudowires,
TAC mechanism should be used and when the responding LSR is aware the TAC mechanism should be used, and when the responding LSR is
(with appropriate configuration) of targeted applications such as FEC aware (with appropriate configuration) of targeted applications such
128 pseudowire, SAC mechanism should be used. Also after TAC as FEC 128 pseudowire, the SAC mechanism should be used. Also, after
mechanism makes the responding LSR aware of targeted application, the the TAC mechanism makes the responding LSR aware of targeted
SAC mechanism may be used to communicate its disinterest in receiving applications, the SAC mechanism may be used to communicate its
state information from the peer for a particular negotiated disinterest in receiving state information from the peer for a
application, creating asymmetric advertisements. particular negotiated application, creating asymmetric
advertisements.
Thus, the TAC mechanism enables two LDP peers to symmetrically Thus, the TAC mechanism enables two LDP peers to symmetrically
advertise state information for negotiated targeted applications. advertise state information for negotiated targeted applications.
Further, the SAC mechanism enables both of them to asymmetrically Further, the SAC mechanism enables both of them to asymmetrically
disable receipt of state information for some of the already disable receipt of state information for some of the already-
negotiated targeted applications. Collectively, both TAC and SAC negotiated targeted applications. Collectively, the TAC mechanism
mechanisms can be used to control the FEC-label bindings that are and the SAC mechanism can both be used to control the FEC label
advertised over the tLDP session. For instance, suppose the bindings that are advertised over the tLDP session. For instance,
initiating LSR establishes a tLDP session to the responding LSR for suppose that the initiating LSR establishes a tLDP session, using the
Remote LFA and FEC 129 PW targeted applications with TAC. So each LSR TAC mechanism, with the responding LSR for remote LFA and FEC 129 PW
advertises the corresponding FEC-Label bindings. Further, suppose targeted applications. So, each LSR advertises the corresponding FEC
the initiating LSR is not the PQ node for responding LSRs Remote LFA label bindings. Further, suppose that the initiating LSR is not the
IGP calculations. In such a case, the responding LSR may use the SAC PQ node for the responding LSR's remote LFA IGP calculations. In
mechanism to convey its disinterest in receiving state information such a case, the responding LSR may use the SAC mechanism to convey
for Remote LFA targeted LDP application. its disinterest in receiving state information for remote LFA tLDP
applications.
For a given tLDP session, the TAC mechanism can be used without the For a given tLDP session, the TAC mechanism can be used without the
SAC mechanism, and the SAC mechanism can be used without the TAC SAC mechanism, and the SAC mechanism can be used without the TAC
mechanism. It is useful to discuss the behavior when TAC and SAC mechanism. It is useful to discuss the behavior that occurs when the
mechanisms are used on the same tLDP session. The TAC mechanism MUST TAC and SAC mechanisms are used on the same tLDP session. The TAC
take precedence over the SAC mechanism with respect to enabling mechanism MUST take precedence over the SAC mechanism with respect to
applications for which state information will be advertised. For a enabling applications for which state information will be advertised.
tLDP session using the TAC mechanism, the LDP peers MUST NOT For a tLDP session using the TAC mechanism, the LDP peers MUST NOT
advertise state information for an application that has not been advertise state information for an application that has not been
negotiated in the most recent TAE list (referred to as an un- negotiated in the most recent TAE list (referred to as a
negotiated application). This is true even if one of the peers non-negotiated application). This is true even if one of the peers
announces its interest in receiving state information that announces its interest in receiving state information that
corresponds to the un-negotiated application by sending a SAC TLV. corresponds to the non-negotiated application by sending a SAC TLV.
In other words, when TAC is being used, SAC cannot and should not In other words, when the TAC mechanism is being used, the SAC
enable state information advertisement for applications that have not mechanism cannot and should not enable state information
been enabled by TAC. advertisements for applications that have not been enabled by the TAC
mechanism.
On the other hand, the SAC mechanism MUST take precedence over the On the other hand, the SAC mechanism MUST take precedence over the
TAC mechanism with respect to disabling state information TAC mechanism with respect to disabling state information
advertisements. If an LDP speaker has announced its disinterest in advertisements. If an LDP speaker has announced its disinterest in
receiving state information for a given application to a given peer receiving state information for a given application to a given peer
using the SAC mechanism, its peer MUST NOT send state information for using the SAC mechanism, its peer MUST NOT send state information for
that application, even if the two peers have negotiated that the that application, even if the two peers have negotiated the
corresponding application via the TAC mechanism. corresponding application via the TAC mechanism.
For the purposes of determining the correspondence between targeted For the purposes of determining the correspondence between targeted
applications defined in this document and application state as applications defined in this document and application state as
defined in [RFC7473] an LSR MUST use the following mappings: defined in [RFC7473], an LSR MUST use the following mappings:
LDPv4 Tunneling - IPv4 Prefix-LSPs LDPv4 Tunneling - IPv4 Prefix-LSPs
LDPv6 Tunneling - IPv6 Prefix-LSPs LDPv6 Tunneling - IPv6 Prefix-LSPs
LDPv4 Remote LFA - IPv4 Prefix-LSPs LDPv4 Remote LFA - IPv4 Prefix-LSPs
LDPv6 Remote LFA - IPv6 Prefix-LSPs LDPv6 Remote LFA - IPv6 Prefix-LSPs
LDP FEC 128 PW - FEC128 P2P-PW LDP FEC 128 PW - FEC 128 P2P-PW
LDP FEC 129 PW - FEC129 P2P-PW LDP FEC 129 PW - FEC 129 P2P-PW
An LSR MUST map Targeted Application to LDP capability as follows: An LSR MUST map the targeted application to the LDP capability
as follows:
mLDP Tunneling - P2MP Capability, MP2MP Capability mLDP Tunneling - P2MP Capability, MP2MP Capability, and HSMP LSP
and HSMP LSP Capability TLV Capability TLV
mLDP node protection - P2MP Capability, MP2MP Capability
and HSMP LSP Capability TLV
5. Use cases mLDP Node Protection - P2MP Capability, MP2MP Capability, and HSMP
LSP Capability TLV
5.1 Remote LFA Automatic Targeted session 5. Use Cases
The LSR determines that it needs to form an automatic tLDP session to 5.1. Remote LFA Automatic Targeted Session
remote LSR based on IGP calculation as described in [RFC7490] or some
other mechanism, which is outside the scope of this document. The LSR The LSR determines that it needs to form an automatic tLDP session
with a remote LSR based on IGP calculation as described in [RFC7490]
or some other mechanism outside the scope of this document. The LSR
forms the tLDP adjacency and constructs an Initialization message forms the tLDP adjacency and constructs an Initialization message
with TAC TLV with TAE as Remote LFA during session establishment. The with the TAC TLV consisting of the TAE as the remote LFA during
receiver LSR processes the LDP Initialization message and verifies session establishment. The receiver LSR processes the LDP
whether it is configured to accept a Remote LFA tLDP session. If it Initialization message and verifies whether it is configured to
is, it may further verify that establishing such a session does not accept a remote LFA tLDP session. If it is, it may further verify
exceed the configured limit for Remote LFA sessions. If all these that establishing such a session does not exceed the configured limit
conditions are met, the receiver LSR may respond back with an for remote LFA sessions. If all of these conditions are met, the
Initialization message with TAC corresponding to Remote LFA, and receiver LSR may respond back with an Initialization message with the
subsequently the session may be established. TAC corresponding to the remote LFA, and subsequently the session
may be established.
After the session has been established with TAC capability, the After the session using the TAC mechanism has been established, the
sender and receiver LSR distribute IPv4 or IPv6 FEC label bindings sender and receiver LSRs distribute IPv4 or IPv6 FEC label bindings
over the session. Further, the receiver LSR may determine that it over the session. Further, the receiver LSR may determine that it
does not need these FEC label bindings. So it may disable the receipt does not need these FEC label bindings. So, it may disable the
of these FEC label bindings by mapping targeted application element receipt of these FEC label bindings by mapping the TAE to the State
to state control capability as described in section 4. Advertisement Control Capability as described in Section 4.
5.2 FEC 129 Auto Discovery Targeted session 5.2. FEC 129 Auto-discovery Targeted Session
BGP auto discovery may determine whether the LSR needs to initiate an BGP auto-discovery may determine whether the LSR needs to initiate an
auto-discovery tLDP session with a border LSR. Multiple LSRs may try auto-discovery tLDP session with a border LSR. Multiple LSRs may try
to form an auto discovered tLDP session with a border LSR. So, a to form an auto-discovered tLDP session with a border LSR. So, a
service provider may want to limit the number of auto discovered tLDP service provider may want to limit the number of auto-discovered tLDP
sessions a border LSR can accept. As described in Section 2, LDP may sessions that a border LSR can accept. As described in Section 2,
convey targeted applications with TAC TLV to border LSR. A border LSR LDP may convey targeted applications with the TAC TLV to a border
may establish or reject the tLDP session based on local LSR. A border LSR may establish or reject the tLDP session based on
administrative policy. Also, as the receiver LSR becomes aware of local administrative policy. Also, as the receiver LSR becomes aware
targeted applications, it can also employ an administrative policy of targeted applications, it can also employ an administrative policy
for security. For instance, it can employ a policy to accept all for security. For instance, it can employ a policy to accept all
auto-discovered session from source-list. auto-discovered sessions from a source addresses list.
Moreover, the sender and receiver LSR must exchange FEC 129 label Moreover, the sender and receiver LSRs must exchange FEC 129 label
bindings only over the tLDP session. bindings only over the tLDP session.
5.3 LDP over RSVP and Remote LFA targeted session 5.3. LDP over RSVP and Remote LFA Targeted Session
A LSR may want to establish a tLDP session to a remote LSR for LDP An LSR may want to establish a tLDP session with a remote LSR for
over RSVP tunneling and Remote LFA applications. The sender LSR may LDP-over-RSVP tunneling and remote LFA applications. The sender LSR
add both these applications as a unique Targeted Application Element may add both of these applications as a unique TAE in the TAC data of
in the Targeted Application Capability data of a TAC TLV. The a TAC TLV. The receiver LSR may have reached a configured limit for
receiver LSR may have reached a configured limit for accepting Remote accepting remote LFA automatic tLDP sessions, but it may have been
LFA automatic tLDP sessions, but it may have been configured to configured to accept LDP-over-RSVP tunneling. In such a case, the
accept LDP over RSVP tunneling. In such a case, the tLDP session is tLDP session is formed for both LDP-over-RSVP tunneling and remote
formed for both LDP over RSVP and Remote LFA applications as both LFA applications, as both need the same FECs -- IPv4, IPv6, or both.
need same FECs - IPv4 or IPv6 or both.
5.4 mLDP node protection targeted session 5.4. mLDP Node Protection Targeted Session
A merge point LSR may determine that it needs to form automatic tLDP
session to the upstream point of local repair (PLR) LSR for MP2P and
MP2MP LSP [RFC6388] node protection as described in the [RFC7715].
The MPT LSR may add a new targeted LDP application - mLDP protection
- as a unique TAE in the Targeted Application Capability Data of a
TAC TLV and send it in the Initialization message to the PLR. If the
PLR is configured for mLDP node protection and establishing this
session does not exceed the limit of either mLDP node protection
sessions or automatic tLDP sessions, the PLR may decide to accept
this session. Also, the PLR may respond back with the initialization
message with a TAC TLV that has one of the TAEs as - mLDP protection,
and the session proceeds to establishment as per [RFC5036].
6. Security Considerations A Merge Point (MPT) LSR may determine that it needs to form an
automatic tLDP session with the upstream point of local repair (PLR)
LSR for MP2P and MP2MP LSP [RFC6388] node protection as described in
[RFC7715]. The MPT LSR may add a new tLDP application -- mLDP
protection -- as a unique TAE in the TAC data of a TAC TLV and send
it in the Initialization message to the PLR. If the PLR is
configured for mLDP node protection and establishing this session
does not exceed the limit of either mLDP node protection sessions or
automatic tLDP sessions, the PLR may decide to accept this session.
Also, the PLR may respond back with the Initialization message with a
TAC TLV that has one of the TAEs as mLDP protection, and the session
proceeds to establishment as per [RFC5036].
The Capability procedure described in this document does not 6. Security Considerations
introduce any change to LDP Security Considerations section described
in [RFC5036]. The procedures described in this document do not introduce any
changes to LDP security considerations as described in [RFC5036].
As described in [RFC5036], DoS attacks via Extended Hellos, which are As described in [RFC5036], DoS attacks via Extended Hellos, which are
required to establish a tLDP session, can be addressed by filtering required to establish a tLDP session, can be addressed by filtering
Extended Hellos using access lists that define addresses with which Extended Hellos using access lists that define addresses with which
Extended Discovery is permitted. Further, as described in section Extended Discovery is permitted. Further, as described in
5.2 of this document, a LSR can employ a policy to accept all auto- Section 5.2 of this document, an LSR can employ a policy to accept
discovered Extended Hellos from the configured source addresses all auto-discovered Extended Hellos from the configured source
list. addresses list.
Also for the two LSRs supporting TAC, the tLDP session is only Also, for the two LSRs supporting the TAC, the tLDP session is only
established after successful negotiation of the TAC. The initiating established after successful negotiation of the TAC. The initiating
and receiving LSR MUST only advertise TA-Ids that they support. In and receiving LSRs MUST only advertise TA-Ids that they support --
other words, what they are configured for over the tLDP session. in other words, what they are configured for over the tLDP session.
7. IANA Considerations 7. IANA Considerations
This document requires the assignment of a new code point for a IANA has assigned the following code point for the new Capability
Capability Parameter TLVs from the IANA managed LDP registry "TLV Parameter TLV defined in this document. The code point has been
Type Name Space", corresponding to the advertisement of the Targeted assigned from the "TLV Type Name Space" sub-registry of the "Label
Applications capability. IANA is requested to assign the lowest Distribution Protocol (LDP) Parameters" registry.
available value after 0x050B.
Value Description Reference Value Description Reference
----- -------------------------------- --------- ------ ------------------------------- ---------
TBD1 Targeted Applications capability [this document] 0x050F Targeted Application Capability RFC 8223
This document requires the assignment of a new code point for a IANA has assigned a new status code from the "Status Code Name Space"
status code from the IANA managed registry "STATUS CODE NAME SPACE" sub-registry of the "Label Distribution Protocol (LDP) Parameters"
on the Label Distribution Protocol (LDP) Parameters page, registry.
corresponding to the notification of session Rejected/Targeted
Application Capability Mis-Match. IANA is requested to assign the
lowest available value after 0x0000004B.
Value E Description Reference Value E Description Reference
----- - -------------------------------- --------- ---------- --- ----------------------------------- ---------
TBD2 1 Session Rejected/Targeted 0x0000004C 1 Session Rejected/Targeted
Application Capability Mis-Match [this document] Application Capability Mismatch RFC 8223
This document also creates a new name space 'the LDP Targeted IANA has created a new registry called "LDP Targeted Application
Application Identifier' on the Label Distribution Protocol (LDP) Identifier" in the "Label Distribution Protocol (LDP) Parameters"
Parameters page, that is to be managed by IANA. The range is 0x0001- registry. The range is 0x0001-0xFFFE. Values in the range
0xFFFE, with the following values requested in this document. 0x0001-0x1FFF in this registry shall be allocated according to the
"IETF Review" procedure [RFC8126]; values in the range 0x2000-0xF7FF
shall be allocated according to the "First Come First Served"
procedure [RFC8126]. The initial values are as follows.
Value Description Reference Value Description Reference
-------- ------------------------- --------------- --------------- ------------------------------- ---------
0x0000 Reserved [this document] 0x0000 Reserved RFC 8223
0x0001 LDPv4 Tunneling [this document] 0x0001 LDPv4 Tunneling RFC 8223
0x0002 LDPv6 Tunneling [this document] 0x0002 LDPv6 Tunneling RFC 8223
0x0003 mLDP Tunneling [this document] 0x0003 mLDP Tunneling RFC 8223
0x0004 LDPv4 Remote LFA [this document] 0x0004 LDPv4 Remote LFA RFC 8223
0x0005 LDPv6 Remote LFA [this document] 0x0005 LDPv6 Remote LFA RFC 8223
0x0006 LDP FEC 128 PW [this document] 0x0006 LDP FEC 128 PW RFC 8223
0x0007 LDP FEC 129 PW [this document] 0x0007 LDP FEC 129 PW RFC 8223
0x0008 LDP Session Protection [this document] 0x0008 LDP Session Protection RFC 8223
0x0009 LDP ICCP [this document] 0x0009 LDP ICCP RFC 8223
0x000A LDP P2MP PW [this document] 0x000A LDP P2MP PW RFC 8223
0x000B mLDP Node Protection [this document] 0x000B mLDP Node Protection RFC 8223
0x000C LDPv4 Intra-area FECs [this document] 0x000C LDPv4 Intra-area FECs RFC 8223
0x000D LDPv6 Intra-area FECs [this document] 0x000D LDPv6 Intra-area FECs RFC 8223
0x0001 - 0x1FFF Available for assignment 0x000E-0xF7FF Unassigned
by IETF Review 0xF800-0xFBFF Available for Private Use
0x2000 - 0F7FF Available for assignment 0xFC00-0xFFFE Available for Experimental Use
as first come first served 0xFFFF Reserved RFC 8223
0xF800 - 0xFBFF Available for private use
0xFC00 - 0xFFFE Available for experimental use
0xFFFF Reserved [this document]
8. Acknowledgments 8. References
8.1. 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>.
[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>.
[RFC7473] Raza, K. and S. Boutros, "Controlling State Advertisements
of Non-negotiated LDP Applications", RFC 7473,
DOI 10.17487/RFC7473, March 2015,
<https://www.rfc-editor.org/info/rfc7473>.
[RFC7715] Wijnands, IJ., Ed., Raza, K., Atlas, A., Tantsura, J., and
Q. Zhao, "Multipoint LDP (mLDP) Node Protection",
RFC 7715, DOI 10.17487/RFC7715, January 2016,
<https://www.rfc-editor.org/info/rfc7715>.
[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>.
8.2. Informative References
[RFC6074] Rosen, E., Davie, B., Radoaca, V., and W. Luo,
"Provisioning, Auto-Discovery, and Signaling in Layer 2
Virtual Private Networks (L2VPNs)", RFC 6074,
DOI 10.17487/RFC6074, January 2011,
<https://www.rfc-editor.org/info/rfc6074>.
[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>.
[RFC7490] Bryant, S., Filsfils, C., Previdi, S., Shand, M., and N.
So, "Remote Loop-Free Alternate (LFA) Fast Reroute (FRR)",
RFC 7490, DOI 10.17487/RFC7490, April 2015,
<https://www.rfc-editor.org/info/rfc7490>.
[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>.
Acknowledgments
The authors wish to thank Nischal Sheth, Hassan Hosseini, Kishore The authors wish to thank Nischal Sheth, Hassan Hosseini, Kishore
Tiruveedhul, Loa Andersson, Eric Rosen, Yakov Rekhter, Thomas Tiruveedhula, Loa Andersson, Eric Rosen, Yakov Rekhter, Thomas
Beckhaus, Tarek Saad, Lizhong Jin and Bruno Decraene for doing the Beckhaus, Tarek Saad, Lizhong Jin, and Bruno Decraene for their
detailed review. Thanks to Manish Gupta and Martin Ehlers for their detailed reviews. Thanks to Manish Gupta and Martin Ehlers for their
input to this work and many helpful suggestions. input to this work and many helpful suggestions.
9. Contributing Authors Contributors
The following people contributed substantially to the content of this
document and should be considered co-authors:
Chris Bowers Chris Bowers
Juniper Networks Juniper Networks
1133 Innovation Way 1133 Innovation Way
Sunnyvale, CA 94089 Sunnyvale, CA 94089
USA United States of America
EMail: cbowers@juniper.net Email: cbowers@juniper.net
Zhenbin Li Zhenbin Li
Huawei Huawei
Bld No.156 Beiqing Rd Bldg. No. 156 Beiqing Rd.
Beijing 100095 Beijing 100095
China China
Email: lizhenbin@huawei.com Email: lizhenbin@huawei.com
10. References Authors' Addresses
10.1 Normative References
[RFC5036] Andersson, L., Ed., Minei, I., Ed., and B. Thomas, Ed.,
"LDP Specification", RFC 5036, October 2007,
<http://www.rfc-editor.org/info/rfc5036>.
[RFC5561] Thomas, B., Raza, K., Aggarwal, S., Aggarwal, R., and JL.
Le Roux, "LDP Capabilities", RFC 5561, July 2009,
<http://www.rfc-editor.org/info/rfc5561>.
[RFC7473] Kamran Raza, Sami Boutros, "Controlling State
Advertisements of Non-negotiated LDP Applications", RFC
7473, March 2015, <http://www.rfc-
editor.org/info/rfc7473>.
[RFC7715] IJ. Wijnands, E. Rosen, K. Raza, J. Tantsura, A. Atlas, Q.
Zhao, "mLDP Node Protection", RFC 7715, January 2016,
<http://www.rfc-editor.org/info/rfc7715>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>.
[RFC8174] B. Leiba, "Ambiguity of Uppercase vs Lowercase in RFC 2119
Key Words", BCP 14, RFC8174, May 2017, <http://www.rfc-
editor.org/info/rfc8174>.
10.2 Informative References Santosh Esale
Juniper Networks
1133 Innovation Way
Sunnyvale, CA 94089
United States of America
[RFC7490] S. Bryant, C. Filsfils, S. Previdi, M. Shand, N. So, Email: sesale@juniper.net
"Remote Loop-Free Alternate (LFA) Fast Reroute (FRR)",
April 2015.
[RFC6074] E. Rosen, B. Davie, V. Radoaca, and W. Luo, "Provisioning, Raveendra Torvi
Auto-Discovery, and Signaling in Layer 2 Virtual Private Juniper Networks
Networks (L2VPNs)", January 2011. 10 Technology Park Drive
Westford, MA 01886
United States of America
[RFC6388] IJ. Wijnands, I. Minei, K. Kompella, B. Thomas, "Label Email: rtorvi@juniper.net
Distribution Protocol Extensions for Point-to-Multipoint
and Multipoint-to-Multipoint Label Switched Paths",
November 2011.
Authors' Addresses Luay Jalil
Verizon
1201 East Arapaho Road
Richardson, TX 75081
United States of America
Santosh Esale Email: luay.jalil@verizon.com
Juniper Networks
1133 Innovation Way
Sunnyvale, CA 94089
USA
EMail: sesale@juniper.net
Raveendra Torvi Uma Chunduri
Juniper Networks Huawei
10 Technology Park Drive 2330 Central Expressway
Westford, MA 01886 Santa Clara, CA 95050
USA United States of America
EMail: rtorvi@juniper.net
Luay Jalil Email: uma.chunduri@huawei.com
Verizon
1201 E Arapaho Rd
Richardson, TX 75081
USA
Email: luay.jalil@verizon.com
Uma Chunduri Kamran Raza
Huawei Cisco Systems, Inc.
2330 Central Expy 2000 Innovation Drive
Santa Clara, CA 95050 Ottawa, ON K2K-3E8
USA Canada
Email: uma.chunduri@huawei.com
Kamran Raza Email: skraza@cisco.com
Cisco Systems, Inc.
2000 Innovation Drive
Ottawa, ON K2K-3E8
Canada
E-mail: skraza@cisco.com
 End of changes. 129 change blocks. 
525 lines changed or deleted 546 lines changed or added

This html diff was produced by rfcdiff 1.45. The latest version is available from http://tools.ietf.org/tools/rfcdiff/