< draft-ietf-mpls-lsp-ping-lag-multipath-06.txt   draft-ietf-mpls-lsp-ping-lag-multipath-07.txt >
Internet Engineering Task Force N. Akiya Internet Engineering Task Force N. Akiya
Internet-Draft Big Switch Networks Internet-Draft Big Switch Networks
Updates: 8029 (if approved) G. Swallow Updates: 8029 (if approved) G. Swallow
Intended status: Standards Track Cisco Systems Intended status: Standards Track Cisco Systems
Expires: September 6, 2019 S. Litkowski Expires: October 5, 2019 S. Litkowski
B. Decraene B. Decraene
Orange Orange
J. Drake J. Drake
Juniper Networks Juniper Networks
M. Chen M. Chen
Huawei Huawei
March 05, 2019 April 03, 2019
Label Switched Path (LSP) Ping/Trace Multipath Support for Label Switched Path (LSP) Ping/Trace Multipath Support for
Link Aggregation Group (LAG) Interfaces Link Aggregation Group (LAG) Interfaces
draft-ietf-mpls-lsp-ping-lag-multipath-06 draft-ietf-mpls-lsp-ping-lag-multipath-07
Abstract Abstract
This document defines extensions to the MPLS Label Switched Path This document defines extensions to the MPLS Label Switched Path
(LSP) Ping and Traceroute mechanisms as specified in RFC 8029. The (LSP) Ping and Traceroute mechanisms as specified in RFC 8029. The
extensions allow the MPLS LSP Ping and Traceroute mechanisms to extensions allow the MPLS LSP Ping and Traceroute mechanisms to
discover and exercise specific paths of Layer 2 (L2) Equal-Cost discover and exercise specific paths of Layer 2 (L2) Equal-Cost
Multipath (ECMP) over Link Aggregation Group (LAG) interfaces. Multipath (ECMP) over Link Aggregation Group (LAG) interfaces.
Additionally, a mechanism is defined to enable determination of the Additionally, a mechanism is defined to enable determination of the
capabilities of an LSR supported. capabilities of an LSR supported.
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Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/. Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on September 6, 2019. This Internet-Draft will expire on October 5, 2019.
Copyright Notice Copyright Notice
Copyright (c) 2019 IETF Trust and the persons identified as the Copyright (c) 2019 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
(https://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
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3 1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3
1.2. Background . . . . . . . . . . . . . . . . . . . . . . . 4 1.2. Background . . . . . . . . . . . . . . . . . . . . . . . 4
2. Overview of Solution . . . . . . . . . . . . . . . . . . . . 4 2. Overview of Solution . . . . . . . . . . . . . . . . . . . . 4
3. LSR Capability Discovery . . . . . . . . . . . . . . . . . . 6 3. LSR Capability Discovery . . . . . . . . . . . . . . . . . . 6
3.1. Initiator LSR Procedures . . . . . . . . . . . . . . . . 7 3.1. Initiator LSR Procedures . . . . . . . . . . . . . . . . 7
3.2. Responder LSR Procedures . . . . . . . . . . . . . . . . 7 3.2. Responder LSR Procedures . . . . . . . . . . . . . . . . 7
4. Mechanism to Discover L2 ECMP Multipath . . . . . . . . . . . 8 4. Mechanism to Discover L2 ECMP Multipath . . . . . . . . . . . 7
4.1. Initiator LSR Procedures . . . . . . . . . . . . . . . . 8 4.1. Initiator LSR Procedures . . . . . . . . . . . . . . . . 7
4.2. Responder LSR Procedures . . . . . . . . . . . . . . . . 8 4.2. Responder LSR Procedures . . . . . . . . . . . . . . . . 8
4.3. Additional Initiator LSR Procedures . . . . . . . . . . . 10 4.3. Additional Initiator LSR Procedures . . . . . . . . . . . 10
5. Mechanism to Validate L2 ECMP Traversal . . . . . . . . . . . 11 5. Mechanism to Validate L2 ECMP Traversal . . . . . . . . . . . 11
5.1. Incoming LAG Member Links Verification . . . . . . . . . 11 5.1. Incoming LAG Member Links Verification . . . . . . . . . 11
5.1.1. Initiator LSR Procedures . . . . . . . . . . . . . . 11 5.1.1. Initiator LSR Procedures . . . . . . . . . . . . . . 11
5.1.2. Responder LSR Procedures . . . . . . . . . . . . . . 12 5.1.2. Responder LSR Procedures . . . . . . . . . . . . . . 12
5.1.3. Additional Initiator LSR Procedures . . . . . . . . . 12 5.1.3. Additional Initiator LSR Procedures . . . . . . . . . 12
5.2. Individual End-to-End Path Verification . . . . . . . . . 13 5.2. Individual End-to-End Path Verification . . . . . . . . . 14
6. LSR Capability TLV . . . . . . . . . . . . . . . . . . . . . 14 6. LSR Capability TLV . . . . . . . . . . . . . . . . . . . . . 14
7. LAG Description Indicator Flag: G . . . . . . . . . . . . . . 15 7. LAG Description Indicator Flag: G . . . . . . . . . . . . . . 15
8. Local Interface Index Sub-TLV . . . . . . . . . . . . . . . . 16 8. Local Interface Index Sub-TLV . . . . . . . . . . . . . . . . 16
9. Remote Interface Index Sub-TLV . . . . . . . . . . . . . . . 17 9. Remote Interface Index Sub-TLV . . . . . . . . . . . . . . . 16
10. Detailed Interface and Label Stack TLV . . . . . . . . . . . 17 10. Detailed Interface and Label Stack TLV . . . . . . . . . . . 17
10.1. Sub-TLVs . . . . . . . . . . . . . . . . . . . . . . . . 19 10.1. Sub-TLVs . . . . . . . . . . . . . . . . . . . . . . . . 19
10.1.1. Incoming Label Stack Sub-TLV . . . . . . . . . . . . 19 10.1.1. Incoming Label Stack Sub-TLV . . . . . . . . . . . . 19
10.1.2. Incoming Interface Index Sub-TLV . . . . . . . . . . 20 10.1.2. Incoming Interface Index Sub-TLV . . . . . . . . . . 20
11. Rate Limiting On Echo Request/Reply Messages . . . . . . . . 21 11. Rate Limiting On Echo Request/Reply Messages . . . . . . . . 21
12. Security Considerations . . . . . . . . . . . . . . . . . . . 21 12. Security Considerations . . . . . . . . . . . . . . . . . . . 21
13. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 21 13. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 21
13.1. LSR Capability TLV . . . . . . . . . . . . . . . . . . . 21 13.1. LSR Capability TLV . . . . . . . . . . . . . . . . . . . 21
13.1.1. LSR Capability Flags . . . . . . . . . . . . . . . . 22 13.1.1. LSR Capability Flags . . . . . . . . . . . . . . . . 22
13.2. Local Interface Index Sub-TLV . . . . . . . . . . . . . 22 13.2. Local Interface Index Sub-TLV . . . . . . . . . . . . . 22
13.2.1. Interface Index Flags . . . . . . . . . . . . . . . 22 13.2.1. Interface Index Flags . . . . . . . . . . . . . . . 22
13.3. Remote Interface Index Sub-TLV . . . . . . . . . . . . . 23 13.3. Remote Interface Index Sub-TLV . . . . . . . . . . . . . 23
13.4. Detailed Interface and Label Stack TLV . . . . . . . . . 23 13.4. Detailed Interface and Label Stack TLV . . . . . . . . . 23
13.4.1. Sub-TLVs for TLV Type TBD4 . . . . . . . . . . . . . 23 13.4.1. Sub-TLVs for TLV Type TBD4 . . . . . . . . . . . . . 23
13.4.2. Interface and Label Stack Address Types . . . . . . 24
13.5. DS Flags . . . . . . . . . . . . . . . . . . . . . . . . 24 13.5. DS Flags . . . . . . . . . . . . . . . . . . . . . . . . 24
14. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 24 14. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 24
15. References . . . . . . . . . . . . . . . . . . . . . . . . . 24 15. References . . . . . . . . . . . . . . . . . . . . . . . . . 25
15.1. Normative References . . . . . . . . . . . . . . . . . . 24 15.1. Normative References . . . . . . . . . . . . . . . . . . 25
15.2. Informative References . . . . . . . . . . . . . . . . . 25 15.2. Informative References . . . . . . . . . . . . . . . . . 25
Appendix A. LAG with intermediate L2 Switch Issues . . . . . . . 25 Appendix A. LAG with intermediate L2 Switch Issues . . . . . . . 26
A.1. Equal Numbers of LAG Members . . . . . . . . . . . . . . 25 A.1. Equal Numbers of LAG Members . . . . . . . . . . . . . . 26
A.2. Deviating Numbers of LAG Members . . . . . . . . . . . . 26 A.2. Deviating Numbers of LAG Members . . . . . . . . . . . . 26
A.3. LAG Only on Right . . . . . . . . . . . . . . . . . . . . 26 A.3. LAG Only on Right . . . . . . . . . . . . . . . . . . . . 27
A.4. LAG Only on Left . . . . . . . . . . . . . . . . . . . . 26 A.4. LAG Only on Left . . . . . . . . . . . . . . . . . . . . 27
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 26 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 27
1. Introduction 1. Introduction
1.1. Terminology 1.1. Terminology
The following acronyms/terms are used in this document: The following acronyms/terms are used in this document:
o MPLS - Multiprotocol Label Switching. o MPLS - Multiprotocol Label Switching.
o LSP - Label Switched Path. o LSP - Label Switched Path.
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[RFC8029] are powerful tools designed to diagnose all available Layer [RFC8029] are powerful tools designed to diagnose all available Layer
3 (L3) paths of LSPs, including diagnostic coverage of L3 Equal-Cost 3 (L3) paths of LSPs, including diagnostic coverage of L3 Equal-Cost
Multipath (ECMP). In many MPLS networks, Link Aggregation Group Multipath (ECMP). In many MPLS networks, Link Aggregation Group
(LAG) as defined in [IEEE802.1AX], which provides Layer 2 (L2) ECMP, (LAG) as defined in [IEEE802.1AX], which provides Layer 2 (L2) ECMP,
is often used for various reasons. MPLS LSP Ping and Traceroute is often used for various reasons. MPLS LSP Ping and Traceroute
tools were not designed to discover and exercise specific paths of L2 tools were not designed to discover and exercise specific paths of L2
ECMP. This raises a limitation for the following scenario when an ECMP. This raises a limitation for the following scenario when an
LSP traverses over a LAG: LSP traverses over a LAG:
o Label switching over some member links of the LAG is successful, o Label switching over some member links of the LAG is successful,
but will be failed over other member links of the LAG. but fails over other member links of the LAG.
o MPLS echo request for the LSP over the LAG is load balanced on one o MPLS echo request for the LSP over the LAG is load balanced on one
of the member links which is label switching successfully. of the member links which is label switching successfully.
With the above scenario, MPLS LSP Ping and Traceroute will not be With the above scenario, MPLS LSP Ping and Traceroute will not be
able to detect the label switching failure of the problematic member able to detect the label switching failure of the problematic member
link(s) of the LAG. In other words, lack of L2 ECMP diagnostic link(s) of the LAG. In other words, lack of L2 ECMP diagnostic
coverage can produce an outcome where MPLS LSP Ping and Traceroute coverage can produce an outcome where MPLS LSP Ping and Traceroute
can be blind to label switching failures over a problematic LAG can be blind to label switching failures over a problematic LAG
interface. It is, thus, desirable to extend the MPLS LSP Ping and interface. It is, thus, desirable to extend the MPLS LSP Ping and
Traceroute to have deterministic diagnostic coverage of LAG Traceroute to have deterministic diagnostic coverage of LAG
interfaces. interfaces.
The need for a solution of this problem was motivated by issues The need for a solution of this problem was motivated by issues
encountered in live networks. encountered in live networks.
2. Overview of Solution 2. Overview of Solution
This document defines an optional TLV to discover the capabilities of This document defines an new TLV to discover the capabilities of a
a responder LSR and extensions for use with the MPLS LSP Ping and responder LSR and extensions for use with the MPLS LSP Ping and
Traceroute mechanisms to describe Multipath Information for Traceroute mechanisms to describe Multipath Information for
individual LAG member links, thus allowing MPLS LSP Ping and individual LAG member links, thus allowing MPLS LSP Ping and
Traceroute to discover and exercise specific paths of L2 ECMP over Traceroute to discover and exercise specific paths of L2 ECMP over
LAG interfaces. The reader is expected to be familiar with mechanics LAG interfaces. The reader is expected to be familiar with mechanics
Downstream Detailed Mapping TLV (DDMAP) described in Section 3.4 of Downstream Detailed Mapping TLV (DDMAP) described in Section 3.4 of
[RFC8029]. [RFC8029].
The solution consists of the MPLS echo request containing a DDMAP TLV The solution consists of the MPLS echo request containing a DDMAP TLV
and the optional LSR capability TLV to indicate that separate load and the new LSR Capability TLV to indicate that separate load
balancing information for each L2 nexthop over LAG is desired in the balancing information for each L2 nexthop over LAG is desired in the
MPLS echo reply. The Responder LSR places the same optional LSR MPLS echo reply. The Responder LSR places the same LSR capability
capability TLV in the MPLS echo reply to provide acknowledgement back TLV in the MPLS echo reply to provide acknowledgement back to the
to the initiator LSR. It also adds, for each downstream LAG member, initiator LSR. It also adds, for each downstream LAG member, load
load balance information (i.e., multipath information and interface balance information (i.e., multipath information and interface
index). This mechanism is applicable to all types of LSPs which can index). This mechanism is applicable to all types of LSPs which can
traverse over LAG interfaces. Many LAGs are built from p2p links, traverse over LAG interfaces. Many LAGs are built from p2p links,
with router X and router X+1 having direct connectivity and the same with router X and router X+1 having direct connectivity and the same
number of LAG members. It is possible to build LAGs asymmetrically number of LAG members. It is possible to build LAGs asymmetrically
by using Ethernet switches between two routers. Appendix A lists by using Ethernet switches between two routers. Appendix A lists
some use cases for which the mechanisms defined in this document may some use cases for which the mechanisms defined in this document may
not be applicable. Note that the mechanisms described in this not be applicable. Note that the mechanisms described in this
document do not impose any changes to scenarios where an LSP is document do not impose any changes to scenarios where an LSP is
pinned down to a particular LAG member (i.e. the LAG is not treated pinned down to a particular LAG member (i.e. the LAG is not treated
as one logical interface by the LSP). as one logical interface by the LSP).
The following figure and description provides an example using an LDP The following figure and description provides an example using an LDP
network. network.
<----- LDP Network -----> <----- LDP Network ----->
+-------+ +-------+
| | | |
A-------B=======C-------E A-------B=======C-------E
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To allow the initiator LSR to disambiguate the above differences, To allow the initiator LSR to disambiguate the above differences,
this document defines the LSR Capability TLV (described in this document defines the LSR Capability TLV (described in
Section 6). When the initiator LSR wishes to discover the Section 6). When the initiator LSR wishes to discover the
capabilities of the responder LSR, the initiator LSR includes the LSR capabilities of the responder LSR, the initiator LSR includes the LSR
Capability TLV in the MPLS echo request message. When the responder Capability TLV in the MPLS echo request message. When the responder
LSR receives an MPLS echo request message with the LSR Capability TLV LSR receives an MPLS echo request message with the LSR Capability TLV
included, if it knows the LSR Capability TLV, then it MUST include included, if it knows the LSR Capability TLV, then it MUST include
the LSR Capability TLV in the MPLS echo reply message with the LSR the LSR Capability TLV in the MPLS echo reply message with the LSR
Capability TLV describing features and extensions supported by the Capability TLV describing features and extensions supported by the
local LSR. Otherwise, an MPLS echo reply MUST be sent back to the local LSR. Otherwise, an MPLS echo reply must be sent back to the
initiator LSR with the return code set to "One or more of the TLVs initiator LSR with the return code set to "One or more of the TLVs
was not understood". Then the initiator LSR can send another MPLS was not understood", according to the rules as defined Section 3 of
echo request without including the LSR Capability TLV. [RFC8029]. Then the initiator LSR can send another MPLS echo request
without including the LSR Capability TLV.
It is RECOMMENDED that implementations supporting the LAG Multipath It is RECOMMENDED that implementations supporting the LAG Multipath
extensions defined in this document include the LSR Capability TLV in extensions defined in this document include the LSR Capability TLV in
MPLS echo request messages. MPLS echo request messages.
3.1. Initiator LSR Procedures 3.1. Initiator LSR Procedures
If an initiator LSR does not know what capabilities a responder LSR If an initiator LSR does not know what capabilities a responder LSR
can support, it can send an MPLS each request message and carry the can support, it can send an MPLS each request message and carry the
LSR Capability TLV to the responder to discover the capabilities that LSR Capability TLV to the responder to discover the capabilities that
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* Set the "Downstream LAG Info Accommodation flag" if the * Set the "Downstream LAG Info Accommodation flag" if the
responder LSR is capable of describing outgoing LAG member responder LSR is capable of describing outgoing LAG member
links separately; otherwise, clear the "Downstream LAG Info links separately; otherwise, clear the "Downstream LAG Info
Accommodation flag". Accommodation flag".
* Set the "Upstream LAG Info Accommodation flag" if responder LSR * Set the "Upstream LAG Info Accommodation flag" if responder LSR
is capable of describing incoming LAG member links separately; is capable of describing incoming LAG member links separately;
otherwise, clear the "Upstream LAG Info Accommodation flag". otherwise, clear the "Upstream LAG Info Accommodation flag".
o If the responder LSR does not understand the "LAG Description
Indicator flag":
* Clear both the "Downstream LAG Info Accommodation flag" and the
"Upstream LAG Info Accommodation flag".
If the responder does not know the LSR Capability TLV, an MPLS echo
reply with the return code set to "One or more of the TLVs was not
understood" MUST be sent back to the initiator LSR.
4. Mechanism to Discover L2 ECMP Multipath 4. Mechanism to Discover L2 ECMP Multipath
4.1. Initiator LSR Procedures 4.1. Initiator LSR Procedures
Through the "LSR Capability Discovery" as defined in Section 3, the Through the "LSR Capability Discovery" as defined in Section 3, the
initiator LSR can understand whether the responder LSR can describe initiator LSR can understand whether the responder LSR can describe
incoming/outgoing LAG member links separately in the DDMAP TLV. incoming/outgoing LAG member links separately in the DDMAP TLV.
Once the initiator LSR knows the capabilities that a responder Once the initiator LSR knows that a responder can support this
supports, then it sends an MPLS echo request carrying a DDMAP with meachanims, then it sends an MPLS echo request carrying a DDMAP TLV
the "LAG Description Indicator flag" (G) set to the responder LSR. with the "LAG Description Indicator flag" (G) set to the responder
The "LAG Description Indicator flag" (G) indicates that separate load LSR. The "LAG Description Indicator flag" (G) indicates that
balancing information for each L2 nexthop over a LAG is desired in separate load balancing information for each L2 nexthop over a LAG is
the MPLS echo reply. The new "LAG Description Indicator flag" is desired in the MPLS echo reply. The new "LAG Description Indicator
described in Section 7. flag" is described in Section 7.
4.2. Responder LSR Procedures 4.2. Responder LSR Procedures
When a responder LSR received an MPLS echo request message with the When a responder LSR received an MPLS echo request message with the
"LAG Description Indicator flag" set, if the responder LSR "LAG Description Indicator flag" set in the DDMAP TLV, if the
understands the "LAG Description Indicator flag" and is capable of responder LSR understands the "LAG Description Indicator flag" and is
describing outgoing LAG member links separately, the following capable of describing outgoing LAG member links separately, the
procedures are used, regardless of whether or not outgoing interfaces following procedures are used, regardless of whether or not outgoing
include LAG interfaces: interfaces include LAG interfaces:
o For each downstream that is a LAG interface: o For each downstream that is a LAG interface:
* The responder LSR MUST include a DDMAP TLV when sending the * The responder LSR MUST include a DDMAP TLV when sending the
MPLS echo reply. MPLS echo reply.There is a single DDMAP TLV for the LAG
interface, with member links described using sub-TLVs.
* The responder LSR MUST set the "LAG Description Indicator flag" * The responder LSR MUST set the "LAG Description Indicator flag"
in the DS Flags field of the DDMAP TLV. in the DS Flags field of the DDMAP TLV.
* In the DDMAP TLV, the Local Interface Index Sub-TLV, Remote * In the DDMAP TLV, the Local Interface Index Sub-TLV, Remote
Interface Index Sub-TLV and Multipath Data Sub-TLV are used to Interface Index Sub-TLV and Multipath Data Sub-TLV are used to
describe each LAG member link. All other fields of the DDMAP describe each LAG member link. All other fields of the DDMAP
TLV are used to describe the LAG interface. TLV are used to describe the LAG interface.
* For each LAG member link of the LAG interface: * For each LAG member link of the LAG interface:
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Based on the procedures described above, every LAG member link will Based on the procedures described above, every LAG member link will
have a Local Interface Index Sub-TLV and a Multipath Data Sub-TLV have a Local Interface Index Sub-TLV and a Multipath Data Sub-TLV
entries in the DDMAP TLV. The order of the Sub-TLVs in the DDMAP TLV entries in the DDMAP TLV. The order of the Sub-TLVs in the DDMAP TLV
for a LAG member link MUST be Local Interface Index Sub-TLV for a LAG member link MUST be Local Interface Index Sub-TLV
immediately followed by Multipath Data Sub-TLV. A LAG member link immediately followed by Multipath Data Sub-TLV. A LAG member link
MAY also have a corresponding Remote Interface Index Sub-TLV. When a MAY also have a corresponding Remote Interface Index Sub-TLV. When a
Local Interface Index Sub-TLV, a Remote Interface Index-Sub-TLV and a Local Interface Index Sub-TLV, a Remote Interface Index-Sub-TLV and a
Multipath Data Sub-TLV are placed in the DDMAP TLV to describe a LAG Multipath Data Sub-TLV are placed in the DDMAP TLV to describe a LAG
member link, they MUST be placed in the order of Local Interface member link, they MUST be placed in the order of Local Interface
Index Sub-TLV, Remote Interface Index-Sub-TLV and Multipath Data Sub- Index Sub-TLV, Remote Interface Index-Sub-TLV and Multipath Data Sub-
TLV. TLV. The block of local interface index, (optional remote interface
index) and multipath data sub-TLVs for each member link MUST appear
adjacent to each other in order of increasing local interface index.
A responder LSR possessing a LAG interface with two member links A responder LSR possessing a LAG interface with two member links
would send the following DDMAP for this LAG interface: would send the following DDMAP for this LAG interface:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ DDMAP fields describing LAG interface with DS Flags G set ~ ~ DDMAP fields describing LAG interface with DS Flags G set ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|[MANDATORY] Local Interface Index Sub-TLV of LAG member link #1| | Local Interface Index Sub-TLV of LAG member link #1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|[OPTIONAL] Remote Interface Index Sub-TLV of LAG member link #1| | Remote Interface Index Sub-TLV of LAG member link #1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|[MANDATORY] Multipath Data Sub-TLV LAG member link #1 | | Multipath Data Sub-TLV LAG member link #1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|[MANDATORY] Local Interface Index Sub-TLV of LAG member link #2| | Local Interface Index Sub-TLV of LAG member link #2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|[OPTIONAL] Remote Interface Index Sub-TLV of LAG member link #2| | Remote Interface Index Sub-TLV of LAG member link #2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|[MANDATORY] Multipath Data Sub-TLV LAG member link #2 | | Multipath Data Sub-TLV LAG member link #2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Label Stack Sub-TLV | | Label Stack Sub-TLV |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2: Example of DDMAP in MPLS Echo Reply Figure 2: Example of DDMAP in MPLS Echo Reply
When none of the received multipath information maps to a particular When none of the received multipath information maps to a particular
LAG member link, then the responder LSR MUST still place the Local LAG member link, then the responder LSR MUST still place the Local
Interface Index Sub-TLV and the Multipath Data Sub-TLV for that LAG Interface Index Sub-TLV and the Multipath Data Sub-TLV for that LAG
member link in the DDMAP TLV, the value of Multipath Length field of member link in the DDMAP TLV. The value of Multipath Length field of
the Multipath Data Sub-TLV is set to zero. the Multipath Data Sub-TLV is set to zero.
4.3. Additional Initiator LSR Procedures 4.3. Additional Initiator LSR Procedures
The procedures above allow an initiator LSR to: The procedures above allow an initiator LSR to:
o Identify whether or not the responder LSR can describe outgoing o Identify whether or not the responder LSR can describe outgoing
LAG member links separately, by looking at the LSR Capability TLV. LAG member links separately, by looking at the LSR Capability TLV.
o Utilize the value of the "LAG Description Indicator flag" in DS o Utilize the value of the "LAG Description Indicator flag" in DS
skipping to change at page 12, line 7 skipping to change at page 12, line 7
5.1.1. Initiator LSR Procedures 5.1.1. Initiator LSR Procedures
An MPLS echo request carrying a DDMAP TLV with the "Interface and An MPLS echo request carrying a DDMAP TLV with the "Interface and
Label Stack Object Request flag" and "LAG Description Indicator flag" Label Stack Object Request flag" and "LAG Description Indicator flag"
set is sent to indicate the request for Detailed Interface and Label set is sent to indicate the request for Detailed Interface and Label
Stack TLV with additional LAG member link information (i.e. Stack TLV with additional LAG member link information (i.e.
interface index) in the MPLS echo reply. interface index) in the MPLS echo reply.
5.1.2. Responder LSR Procedures 5.1.2. Responder LSR Procedures
A responder LSR that understands the "LAG Description Indicator flag" When received an echo request with the "LAG Description Indicator
and is capable of describing incoming LAG member link MUST use the flag" set, a responder LSR that understands the "LAG Description
following procedures, regardless of whether or not incoming interface Indicator flag" and is capable of describing incoming LAG member link
was a LAG interface: SHOULD use the following procedures, regardless of whether or not
incoming interface was a LAG interface:
o When the "I" flag ( "Interface and Label Stack Object Request o When the "I" flag ( "Interface and Label Stack Object Request
flag") of the DDMAP TLV in the received MPLS echo request is set: flag") of the DDMAP TLV in the received MPLS echo request is set:
* The responder LSR MUST add the Detailed Interface and Label * The responder LSR MUST add the Detailed Interface and Label
Stack TLV (described in Section 10) in the MPLS echo reply. Stack TLV (described in Section 10) in the MPLS echo reply.
* If the incoming interface is a LAG, the responder LSR MUST add * If the incoming interface is a LAG, the responder LSR MUST add
the Incoming Interface Index Sub-TLV (described in the Incoming Interface Index Sub-TLV (described in
Section 10.1.2) in the Detailed Interface and Label Stack TLV. Section 10.1.2) in the Detailed Interface and Label Stack TLV.
skipping to change at page 12, line 45 skipping to change at page 12, line 46
o The expected load balance information of every LAG member link, at o The expected load balance information of every LAG member link, at
LSR with TTL=n. LSR with TTL=n.
o With specific entropy, the expected interface index of the o With specific entropy, the expected interface index of the
outgoing LAG member link at TTL=n. outgoing LAG member link at TTL=n.
o With specific entropy, the interface index of the incoming LAG o With specific entropy, the interface index of the incoming LAG
member link at TTL=n+1. member link at TTL=n+1.
Expectation is that there's a relationship between the interface Depending on the LAG traffic division algorithm, the messages may or
index of the outgoing LAG member link at TTL=n and the interface may not traverse different member links. The expectation is that
index of the incoming LAG member link at TTL=n+1 for all discovered there's a relationship between the interface index of the outgoing
entropies. In other words, set of entropies that load balances to LAG member link at TTL=n and the interface index of the incoming LAG
outgoing LAG member link X at TTL=n should all reach the nexthop on member link at TTL=n+1 for all entropies examined. In other words,
same incoming LAG member link Y at TTL=n+1. set of entropies that load balances to outgoing LAG member link X at
TTL=n should all reach the nexthop on same incoming LAG member link Y
at TTL=n+1.
With additional logic, the initiator LSR can perform the following With additional logic, the initiator LSR can perform the following
checks in a scenario where the initiator LSR knows that there is a checks in a scenario where the initiator LSR knows that there is a
LAG, with two LAG members, between TTL=n and TTL=n+1, and has the LAG, with two LAG members, between TTL=n and TTL=n+1, and has the
multipath information to traverse the two LAG member links. multipath information to traverse the two LAG member links.
The initiator LSR sends two MPLS echo request messages to traverse The initiator LSR sends two MPLS echo request messages to traverse
the two LAG member links at TTL=n+1: the two LAG member links at TTL=n+1:
o Success case: o Success case:
skipping to change at page 13, line 33 skipping to change at page 13, line 35
links. links.
o Error case: o Error case:
* One MPLS echo request message reaches TTL=n+1 on an LAG member * One MPLS echo request message reaches TTL=n+1 on an LAG member
link 1. link 1.
* The other MPLS echo request message also reaches TTL=n+1 on an * The other MPLS echo request message also reaches TTL=n+1 on an
LAG member link 1. LAG member link 1.
* One or both MPLS echo request messages cannot reach the
immediate downstream LSR on whichever link.
One or two MPLS echo request messages sent by the initiator LSR One or two MPLS echo request messages sent by the initiator LSR
cannot reach the immediate downstream LSR, or the two MPLS echo cannot reach the immediate downstream LSR, or the two MPLS echo
request messages reach at the immediate downstream LSR from the request messages reach at the immediate downstream LSR from the
same LAG member link. same LAG member link.
Note that the above defined procedures will provide a deterministic Note that the above defined procedures will provide a deterministic
result for LAG interfaces that are back-to-back connected between result for LAG interfaces that are back-to-back connected between
LSRs (i.e. no L2 switch in between). If there is a L2 switch between LSRs (i.e. no L2 switch in between). If there is a L2 switch between
the LSR at TTL=n and the LSR at TTL=n+1, there is no guarantee that the LSR at TTL=n and the LSR at TTL=n+1, there is no guarantee that
traversal of every LAG member link at TTL=n will result in reaching traversal of every LAG member link at TTL=n will result in reaching
skipping to change at page 14, line 15 skipping to change at page 14, line 20
follows the procedures described in Section 4.3. follows the procedures described in Section 4.3.
The DDMAP validation procedures for the downstream responder LSR are The DDMAP validation procedures for the downstream responder LSR are
then updated to include the comparison of the incoming LAG member then updated to include the comparison of the incoming LAG member
link to the interface index described in the Remote Interface Index link to the interface index described in the Remote Interface Index
Sub-TLV in the DDMAP TLV. Failure of this comparison results in the Sub-TLV in the DDMAP TLV. Failure of this comparison results in the
return code being set to "Downstream Mapping Mismatch (5)". return code being set to "Downstream Mapping Mismatch (5)".
6. LSR Capability TLV 6. LSR Capability TLV
This document defines a new optional TLV which is referred to as the This document defines a new TLV which is referred to as the "LSR
"LSR Capability TLV. It MAY be included in the MPLS echo request Capability TLV. It MAY be included in the MPLS echo request message
message and the MPLS echo reply message. An MPLS echo request and the MPLS echo reply message. An MPLS echo request message and an
message and an MPLS echo reply message MUST NOT include more than one MPLS echo reply message MUST NOT include more than one LSR Capability
LSR Capability TLV. The presence of an LSR Capability TLV in an MPLS TLV. The presence of an LSR Capability TLV in an MPLS echo request
echo request message is a request that a responder LSR includes an message is a request that a responder LSR includes an LSR Capability
LSR Capability TLV in the MPLS echo reply message, with the LSR TLV in the MPLS echo reply message, with the LSR Capability TLV
Capability TLV describing features and extensions that the responder describing features and extensions that the responder LSR supports.
LSR supports.
When a responder LSR received an MPLS echo request message that
carries an LSR Capability TLV, if the responder LSR knows how to
process the LSR Capability TLV, an LSR Capability TLV MUST be
included in the MPLS echo reply message. Otherwise, if the responder
does not know the LSR Capability TLV, an MPLS echo reply with the
return code set to "One or more of the TLVs was not understood" MUST
be sent back to the initiator LSR.
The format of the LSR Capability TLV is as below: The format of the LSR Capability TLV is as below:
LSR Capability TLV Type is TBD1. Length is 4. The value field of LSR Capability TLV Type is TBD1. Length is 4. The value field of
the LSR Capability TLV has following format: the LSR Capability TLV has following format:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | | Type | Length |
skipping to change at page 15, line 13 skipping to change at page 15, line 8
The Type field is 2 octets in length and the value is TBD1. The Type field is 2 octets in length and the value is TBD1.
The Length field is 2 octets in length, and the value is 4. The Length field is 2 octets in length, and the value is 4.
The "LSR Capability Flags" field is 4 octets in length, this The "LSR Capability Flags" field is 4 octets in length, this
document defines the following flags: document defines the following flags:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Must Be Zero (Reserved) |U|D| | Reserved (Must Be Zero) |U|D|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
This document defines two flags. The remaining flags MUST be set This document defines two flags. The unallocated flags MUST be
to zero when sending and ignored on receipt. Both the U and the D set to zero when sending and ignored on receipt. Both the U and
flag MUST be cleared in the MPLS echo request message when the D flag MUST be cleared in the MPLS echo request message when
sending, and ignored on receipt. Neither, either or both the U sending, and ignored on receipt. Neither, either or both the U
and the D flag MAY be set in the MPLS echo reply message. and the D flag MAY be set in the MPLS echo reply message.
Flag Name and Meaning Flag Name and Meaning
---- ---------------- ---- ----------------
U Upstream LAG Info Accommodation U Upstream LAG Info Accommodation
An LSR sets this flag when the LSR is capable of An LSR sets this flag when the LSR is capable of
describing a LAG member link in the Incoming Interface describing a LAG member link in the Incoming Interface
skipping to change at page 16, line 7 skipping to change at page 15, line 50
for detailed LAG information from the responder LSR. In the MPLS for detailed LAG information from the responder LSR. In the MPLS
echo reply message, the "G" flag MUST be set if the DDMAP TLV echo reply message, the "G" flag MUST be set if the DDMAP TLV
describes a LAG interface. It MUST be cleared otherwise. describes a LAG interface. It MUST be cleared otherwise.
The "G" flag is defined as below: The "G" flag is defined as below:
The Bit Number is TBD5. The Bit Number is TBD5.
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
| MBZ |G|MBZ|I|N| | MBZ |G|E|L|I|N|
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
RFC-Editor-Note: Please update above figure to place the G flag in RFC-Editor-Note: Please update above figure to place the G flag in
the bit number TBD5. the bit number TBD5.
Flag Name and Meaning Flag Name and Meaning
---- ---------------- ---- ----------------
G LAG Description Indicator G LAG Description Indicator
When this flag is set in the MPLS echo request, the responder LSR When this flag is set in the MPLS echo request, the responder LSR
is requested to respond with detailed LAG information. When this is requested to respond with detailed LAG information. When this
skipping to change at page 17, line 4 skipping to change at page 16, line 43
Figure 5: Local Interface Index Sub-TLV Figure 5: Local Interface Index Sub-TLV
Where: Where:
o The "Type" field is 2 octets in length, the value is TBD2. o The "Type" field is 2 octets in length, the value is TBD2.
o The "Length" filed 2 octets in length, and the value is 4. o The "Length" filed 2 octets in length, and the value is 4.
o The "Local Interface Index" field is 4 octets in length, it is an o The "Local Interface Index" field is 4 octets in length, it is an
interface index assigned by a local LSR to an egress interface. interface index assigned by a local LSR to an egress interface.
It's normally an unsigned integer and in network byte order.
9. Remote Interface Index Sub-TLV 9. Remote Interface Index Sub-TLV
The Remote Interface Index Sub-TLV is an optional TLV, it describes The Remote Interface Index Sub-TLV is an optional TLV, it describes
the interface index assigned by a downstream LSR to an ingress the interface index assigned by a downstream LSR to an ingress
interface. One or more Remote Interface Index sub-TLVs MAY appear in interface. One or more Remote Interface Index sub-TLVs MAY appear in
a DDMAP TLV. a DDMAP TLV.
The format of the Remote Interface Index Sub-TLV is as below: The format of the Remote Interface Index Sub-TLV is as below:
skipping to change at page 17, line 32 skipping to change at page 17, line 25
Figure 6: Remote Interface Index Sub-TLV Figure 6: Remote Interface Index Sub-TLV
Where: Where:
o The "Type" field is 2 octets in length, and the value is TBD3. o The "Type" field is 2 octets in length, and the value is TBD3.
o The "Length" field is 2 octets in length, and the value is 4. o The "Length" field is 2 octets in length, and the value is 4.
o The "Remote Interface Index" is 4 octets in length, it is an o The "Remote Interface Index" is 4 octets in length, it is an
interface index assigned by a downstream LSR to an ingress interface index assigned by a downstream LSR to an ingress
interface. interface. It's normally an unsigned integer and in network byte
order.
10. Detailed Interface and Label Stack TLV 10. Detailed Interface and Label Stack TLV
The "Detailed Interface and Label Stack" object is a TLV that MAY be The "Detailed Interface and Label Stack" object is a TLV that MAY be
included in an MPLS echo reply message to report the interface on included in an MPLS echo reply message to report the interface on
which the MPLS echo request message was received and the label stack which the MPLS echo request message was received and the label stack
that was on the packet when it was received. A responder LSR MUST that was on the packet when it was received. A responder LSR MUST
NOT insert more than one instance of this TLV into the MPLS echo NOT insert more than one instance of this TLV into the MPLS echo
reply message. This TLV allows the initiator LSR to obtain the exact reply message. This TLV allows the initiator LSR to obtain the exact
interface and label stack information as it appears at the responder interface and label stack information as it appears at the responder
skipping to change at page 18, line 10 skipping to change at page 18, line 10
Sub-TLV Length (sum of Sub-TLVs). K is the sum of all fields of this Sub-TLV Length (sum of Sub-TLVs). K is the sum of all fields of this
TLV prior to Sub-TLVs, but the length of K depends on the Address TLV prior to Sub-TLVs, but the length of K depends on the Address
Type. Details of this information is described below. The Value Type. Details of this information is described below. The Value
field has following format: field has following format:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | | Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Address Type | Must Be Zero | | Address Type | Reserved (Must Be Zero) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IP Address (4 or 16 octets) | | IP Address (4 or 16 octets) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface (4 or 16 octets) | | Interface (4 or 16 octets) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
. . . .
. List of Sub-TLVs . . List of Sub-TLVs .
. . . .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 7: Detailed Interface and Label Stack TLV Figure 7: Detailed Interface and Label Stack TLV
The Detailed Interface and Label Stack TLV format is derived from the The Detailed Interface and Label Stack TLV format is derived from the
Interface and Label Stack TLV format (from [RFC8029]). Two changes Interface and Label Stack TLV format (from [RFC8029]). Two changes
are introduced. The first is that the label stack is converted into are introduced. The first is that the label stack is converted into
a sub-TLV. The second is that a new sub-TLV is added to describe an a sub-TLV. The second is that a new sub-TLV is added to describe an
interface index. These fields of Detailed Interface and Label Stack interface index. The other fields of Detailed Interface and Label
TLV have the same use and meaning as in [RFC8029]. A summary of Stack TLV have the same use and meaning as in [RFC8029]. A summary
these fields is as below: of these fields is as below:
Address Type Address Type
The Address Type indicates if the interface is numbered or The Address Type indicates if the interface is numbered or
unnumbered. It also determines the length of the IP Address unnumbered. It also determines the length of the IP Address
and Interface fields. The resulting total length of the and Interface fields. The resulting total length of the
initial part of the TLV is listed as "K Octets". The Address initial part of the TLV is listed as "K Octets". The Address
Type is set to one of the following values: Type is set to one of the following values:
Type # Address Type K Octets Type # Address Type K Octets
skipping to change at page 20, line 20 skipping to change at page 20, line 20
interface which received the MPLS echo request message. interface which received the MPLS echo request message.
Incoming Interface Index Sub-TLV Type is 2. Length is 8, and its Incoming Interface Index Sub-TLV Type is 2. Length is 8, and its
format is as below: format is as below:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | | Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface Index Flags | Must Be Zero | | Interface Index Flags | Reserved (Must Be Zero) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Incoming Interface Index | | Incoming Interface Index |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 9: Incoming Interface Index Sub-TLV Figure 9: Incoming Interface Index Sub-TLV
Interface Index Flags Interface Index Flags
Interface Index Flags field is a bit vector with following format. Interface Index Flags field is a bit vector with following format.
0 1 0 1
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Must Be Zero (Reserved) |M| | Reserved (Must Be Zero) |M|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
One flag is defined: M. The remaining flags MUST be set to zero One flag is defined: M. The remaining flags MUST be set to zero
when sending and ignored on receipt. when sending and ignored on receipt.
Flag Name and Meaning Flag Name and Meaning
---- ---------------- ---- ----------------
M LAG Member Link Indicator M LAG Member Link Indicator
When this flag is set, interface index described in When this flag is set, interface index described in
this sub-TLV is a member of a LAG. this sub-TLV is a member of a LAG.
Incoming Interface Index Incoming Interface Index
An Index assigned by the LSR to this interface. An Index assigned by the LSR to this interface. It's normally an
unsigned integer and in network byte order.
11. Rate Limiting On Echo Request/Reply Messages 11. Rate Limiting On Echo Request/Reply Messages
For an LSP path, it may be over several LAGs. Each LAG may have many For an LSP path, it may be over several LAGs. Each LAG may have many
member links. To exercise all the links, many Echo Request/Reply member links. To exercise all the links, many Echo Request/Reply
messages will be sent in a short period. It's possible that those messages will be sent in a short period. It's possible that those
messages may traverse a common path as a burst. Under some messages may traverse a common path as a burst. Under some
circumstances this might cause congestion at the common path. To circumstances this might cause congestion at the common path. To
avoid potential congestion, it is RECOMMENDED that implementations to avoid potential congestion, it is RECOMMENDED that implementations to
randomly delay the Echo Request and Reply messages at the Initiating randomly delay the Echo Request and Reply messages at the Initiating
LSRs and Responder LSRs. LSRs and Responder LSRs. Rate limiting of ping traffic is further
specified in [RFC8029] (Section 5) and [RFC6425] (Section 4.1) which
apply to this document as well.
12. Security Considerations 12. Security Considerations
This document extends LSP Traceroute mechanism [RFC8029] to discover This document extends LSP Traceroute mechanism [RFC8029] to discover
and exercise L2 ECMP paths to determine problematic member link(s) of and exercise L2 ECMP paths to determine problematic member link(s) of
a LAG. These on-demand diagnostic mechanisms are used by an operator a LAG. These on-demand diagnostic mechanisms are used by an operator
within an MPLS control domain. within an MPLS control domain.
[RFC8029] reviews the possible attacks and approaches to mitigate [RFC8029] reviews the possible attacks and approaches to mitigate
possible threats when using these mechanisms. possible threats when using these mechanisms.
skipping to change at page 21, line 37 skipping to change at page 21, line 39
responder LSR MUST only accept MPLS echo request messages from responder LSR MUST only accept MPLS echo request messages from
designated trusted sources via filtering source IP address field of designated trusted sources via filtering source IP address field of
received MPLS echo request messages. As noted in [RFC8029], spoofing received MPLS echo request messages. As noted in [RFC8029], spoofing
attacks only have a small window of opportunity. If these messages attacks only have a small window of opportunity. If these messages
are indeed hijacked (non-delivery) by an intermediate node, the use are indeed hijacked (non-delivery) by an intermediate node, the use
of these mechanisms will determine the data plane is not working (as of these mechanisms will determine the data plane is not working (as
it should). Hijacking of a responder node such that it provides a it should). Hijacking of a responder node such that it provides a
legitimate reply would involve compromising the node itself and the legitimate reply would involve compromising the node itself and the
MPLS control domain. [RFC5920] provides additional MPLS network-wide MPLS control domain. [RFC5920] provides additional MPLS network-wide
operation recommendations to avoid attacks and recommendations to operation recommendations to avoid attacks and recommendations to
follow. follow. Please note that source IP address filtering provides only a
weak form of access control and is not, in general, a reliable
security mechanism. Nonetheless, it is required here in the absence
of any more robust mechanism that might be used.
13. IANA Considerations 13. IANA Considerations
13.1. LSR Capability TLV 13.1. LSR Capability TLV
The IANA is requested to assign new value TBD1 for LSR Capability TLV The IANA is requested to assign new value TBD1 (from the range
from the "Multiprotocol Label Switching Architecture (MPLS) Label 4-16383) for LSR Capability TLV from the "Multiprotocol Label
Switched Paths (LSPs) Ping Parameters - TLVs" registry. Switching Architecture (MPLS) Label Switched Paths (LSPs) Ping
Parameters - TLVs" registry.
Value Meaning Reference Value Meaning Reference
----- ------- --------- ----- ------- ---------
TBD1 LSR Capability TLV this document TBD1 LSR Capability TLV this document
13.1.1. LSR Capability Flags 13.1.1. LSR Capability Flags
The IANA is requested to create and maintain a registry entitled "LSR The IANA is requested to create and maintain a registry entitled "LSR
Capability Flags" with following registration procedures: Capability Flags" with following registration procedures:
skipping to change at page 22, line 24 skipping to change at page 22, line 28
31 D: Downstream LAG Info Accommodation this document 31 D: Downstream LAG Info Accommodation this document
30 U: Upstream LAG Info Accommodation this document 30 U: Upstream LAG Info Accommodation this document
0-29 Unassigned 0-29 Unassigned
Assignments of LSR Capability Flags are via Standards Action Assignments of LSR Capability Flags are via Standards Action
[RFC8126]. [RFC8126].
13.2. Local Interface Index Sub-TLV 13.2. Local Interface Index Sub-TLV
The IANA is requested to assign new value TBD2 (from the range The IANA is requested to assign new value TBD2 (from the range
4-31743) for the Local Interface Index Sub-TLV from the 4-16383) for the Local Interface Index Sub-TLV from the
"Multiprotocol Label Switching Architecture (MPLS) Label Switched "Multiprotocol Label Switching Architecture (MPLS) Label Switched
Paths (LSPs) Ping Parameters - TLVs" registry, "Sub-TLVs for TLV Paths (LSPs) Ping Parameters - TLVs" registry, "Sub-TLVs for TLV
Types 20" sub-registry. Types 20" sub-registry.
Value Meaning Reference Value Meaning Reference
----- ------- --------- ----- ------- ---------
TBD2 Local Interface Index Sub-TLV this document TBD2 Local Interface Index Sub-TLV this document
13.2.1. Interface Index Flags 13.2.1. Interface Index Flags
skipping to change at page 23, line 25 skipping to change at page 23, line 31
"Multiprotocol Label Switching Architecture (MPLS) Label Switched "Multiprotocol Label Switching Architecture (MPLS) Label Switched
Paths (LSPs) Ping Parameters - TLVs" registry, "Sub-TLVs for TLV Paths (LSPs) Ping Parameters - TLVs" registry, "Sub-TLVs for TLV
Types 20" sub-registry. Types 20" sub-registry.
Value Meaning Reference Value Meaning Reference
----- ------- --------- ----- ------- ---------
TBD3 Remote Interface Index Sub-TLV this document TBD3 Remote Interface Index Sub-TLV this document
13.4. Detailed Interface and Label Stack TLV 13.4. Detailed Interface and Label Stack TLV
The IANA is requested to assign new value TBD4 for Detailed Interface The IANA is requested to assign new value TBD4 (from the range
and Label Stack TLV from the "Multiprotocol Label Switching 4-16383) for Detailed Interface and Label Stack TLV from the
Architecture (MPLS) Label Switched Paths (LSPs) Ping Parameters - "Multiprotocol Label Switching Architecture (MPLS) Label Switched
TLVs" registry ([IANA-MPLS-LSP-PING]). Paths (LSPs) Ping Parameters - TLVs" registry ([IANA-MPLS-LSP-PING]).
Value Meaning Reference Value Meaning Reference
----- ------- --------- ----- ------- ---------
TBD4 Detailed Interface and Label Stack TLV this document TBD4 Detailed Interface and Label Stack TLV this document
13.4.1. Sub-TLVs for TLV Type TBD4 13.4.1. Sub-TLVs for TLV Type TBD4
The IANA is requested to create and maintain a sub-registry entitled The IANA is requested to create and maintain a sub-registry entitled
"Sub-TLVs for TLV Type TBD4" under "Multiprotocol Label Switching "Sub-TLVs for TLV Type TBD4" under "Multiprotocol Label Switching
Architecture (MPLS) Label Switched Paths (LSPs) Ping Parameters - Architecture (MPLS) Label Switched Paths (LSPs) Ping Parameters -
TLVs" registry. TLVs" registry.
Initial values for this sub-registry, "Sub-TLVs for TLV Types TBD4", Initial values for this sub-registry, "Sub-TLVs for TLV Types TBD4",
are described below. are described below.
Sub-Type Name Reference Sub-Type Name Reference
----------- -------------------------------------- --------- ----------- -------------------------------------- ---------
1 Incoming Label Stack this document 1 Incoming Label Stack this document
2 Incoming Interface Index this document 2 Incoming Interface Index this document
3-16383 Unassigned (mandatory TLVs) 3-16383 Unassigned (mandatory TLVs)
16384-31743 Experimental 16384-31743 Specification Required
32768-49161 Unassigned (optional TLVs) 32768-49161 Unassigned (optional TLVs)
49162-64511 Experimental 49162-64511 Specification Required
Assignments of Sub-Types in the mandatory and optional spaces are via Assignments of Sub-Types in the mandatory and optional spaces are via
Standards Action [RFC8126]. Assignments of Sub-Types in the Standards Action [RFC8126]. Assignments of Sub-Types in the
experimental space is via Specification Required [RFC8126]. Specification Required space is via Specification Required [RFC8126].
13.4.2. Interface and Label Stack Address Types
Since the "Detailed Interface and Label Stack TLV" shares the
"Interface and Label Stack Address Types" with the "Interface and
Label Stack TLV". IANA is requested to update the "Interface and
Label Stack Address Types" registry to reflect this.
For example, change the registry name to "Interface and Label Stack
and Detailed Interface and Label Stack Address Types", and add a
reference to this document.
13.5. DS Flags 13.5. DS Flags
The IANA is requested to assign a new bit number from the "DS flags" The IANA is requested to assign a new bit number from the "DS flags"
sub-registry from the "Multi-Protocol Label Switching (MPLS) Label sub-registry from the "Multi-Protocol Label Switching (MPLS) Label
Switched Paths (LSPs) Ping Parameters - TLVs" registry Switched Paths (LSPs) Ping Parameters - TLVs" registry
([IANA-MPLS-LSP-PING]). ([IANA-MPLS-LSP-PING]).
Note: the "DS flags" sub-registry is created by [RFC8029]. Note: the "DS flags" sub-registry is created by [RFC8029].
skipping to change at page 25, line 5 skipping to change at page 25, line 24
Requirement Levels", BCP 14, RFC 2119, Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>. <https://www.rfc-editor.org/info/rfc2119>.
[RFC8029] Kompella, K., Swallow, G., Pignataro, C., Ed., Kumar, N., [RFC8029] Kompella, K., Swallow, G., Pignataro, C., Ed., Kumar, N.,
Aldrin, S., and M. Chen, "Detecting Multiprotocol Label Aldrin, S., and M. Chen, "Detecting Multiprotocol Label
Switched (MPLS) Data-Plane Failures", RFC 8029, Switched (MPLS) Data-Plane Failures", RFC 8029,
DOI 10.17487/RFC8029, March 2017, DOI 10.17487/RFC8029, March 2017,
<https://www.rfc-editor.org/info/rfc8029>. <https://www.rfc-editor.org/info/rfc8029>.
[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>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>. May 2017, <https://www.rfc-editor.org/info/rfc8174>.
15.2. Informative References 15.2. Informative References
[IANA-MPLS-LSP-PING] [IANA-MPLS-LSP-PING]
IANA, "Multi-Protocol Label Switching (MPLS) Label IANA, "Multi-Protocol Label Switching (MPLS) Label
Switched Paths (LSPs) Ping Parameters", Switched Paths (LSPs) Ping Parameters",
<http://www.iana.org/assignments/mpls-lsp-ping-parameters/ <http://www.iana.org/assignments/mpls-lsp-ping-parameters/
skipping to change at page 25, line 26 skipping to change at page 26, line 5
[IEEE802.1AX] [IEEE802.1AX]
IEEE Std. 802.1AX, "IEEE Standard for Local and IEEE Std. 802.1AX, "IEEE Standard for Local and
metropolitan area networks - Link Aggregation", November metropolitan area networks - Link Aggregation", November
2008. 2008.
[RFC5920] Fang, L., Ed., "Security Framework for MPLS and GMPLS [RFC5920] Fang, L., Ed., "Security Framework for MPLS and GMPLS
Networks", RFC 5920, DOI 10.17487/RFC5920, July 2010, Networks", RFC 5920, DOI 10.17487/RFC5920, July 2010,
<https://www.rfc-editor.org/info/rfc5920>. <https://www.rfc-editor.org/info/rfc5920>.
[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>.
[RFC7439] George, W., Ed. and C. Pignataro, Ed., "Gap Analysis for [RFC7439] George, W., Ed. and C. Pignataro, Ed., "Gap Analysis for
Operating IPv6-Only MPLS Networks", RFC 7439, Operating IPv6-Only MPLS Networks", RFC 7439,
DOI 10.17487/RFC7439, January 2015, DOI 10.17487/RFC7439, January 2015,
<https://www.rfc-editor.org/info/rfc7439>. <https://www.rfc-editor.org/info/rfc7439>.
[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>.
Appendix A. LAG with intermediate L2 Switch Issues Appendix A. LAG with intermediate L2 Switch Issues
Several flavors of "LAG with L2 switch" provisioning models and the Several flavors of "LAG with L2 switch" provisioning models and the
corresponding MPLS data plane ECMP traversal validation issues are corresponding MPLS data plane ECMP traversal validation issues are
described in this section . described in this section .
A.1. Equal Numbers of LAG Members A.1. Equal Numbers of LAG Members
R1 ==== S1 ==== R2 R1 ==== S1 ==== R2
skipping to change at page 26, line 9 skipping to change at page 26, line 38
get load balanced by S1 towards Router 2 (R2). Therefore, MPLS echo get load balanced by S1 towards Router 2 (R2). Therefore, MPLS echo
request messages traversing a specific LAG member from R1 to S1 can request messages traversing a specific LAG member from R1 to S1 can
actually reach R2 via any of the LAG members, and the sender of MPLS actually reach R2 via any of the LAG members, and the sender of MPLS
echo request messages has no knowledge of this nor no way to control echo request messages has no knowledge of this nor no way to control
this traversal. In the worst case, MPLS echo request messages with this traversal. In the worst case, MPLS echo request messages with
specific entropies to exercise every LAG members from R1 to S1 can specific entropies to exercise every LAG members from R1 to S1 can
all reach R2 via same LAG member. Thus it is impossible for MPLS all reach R2 via same LAG member. Thus it is impossible for MPLS
echo request sender to verify that packets intended to traverse echo request sender to verify that packets intended to traverse
specific LAG member from R1 to S1 did actually traverse that LAG specific LAG member from R1 to S1 did actually traverse that LAG
member, and to deterministically exercise "receive" processing of member, and to deterministically exercise "receive" processing of
every LAG member on R2. every LAG member on R2. (Notes, AFAICT there's not a better option
than "try a bunch of entropy labels and see what responses you can
get back" and that's the same remedy in all the described
topologies.)
A.2. Deviating Numbers of LAG Members A.2. Deviating Numbers of LAG Members
____ ____
R1 ==== S1 ==== R2 R1 ==== S1 ==== R2
There are deviating number of LAG members on the two sides of the L2 There are deviating number of LAG members on the two sides of the L2
switch. The issue with this LAG provisioning model is the same as switch. The issue with this LAG provisioning model is the same as
previous model, sender of MPLS echo request messages have no previous model, sender of MPLS echo request messages have no
knowledge of L2 load balance algorithm nor entropy values to control knowledge of L2 load balance algorithm nor entropy values to control
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