One document matched: draft-ietf-mpls-p2mp-lsp-ping-08.txt
Differences from draft-ietf-mpls-p2mp-lsp-ping-07.txt
Network Working Group A. Farrel (Editor)
Internet-Draft Old Dog Consulting
Intended Status: Standards Track S. Yasukawa
Updates: RFC4379 NTT
Created: August 11, 2009
Expires: February 11, 2010
Detecting Data Plane Failures in Point-to-Multipoint Multiprotocol
Label Switching (MPLS) - Extensions to LSP Ping
draft-ietf-mpls-p2mp-lsp-ping-08.txt
Status of this Memo
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provisions of BCP 78 and BCP 79.
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http://www.ietf.org/1id-abstracts.txt.
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Abstract
Recent proposals have extended the scope of Multiprotocol Label
Switching (MPLS) Label Switched Paths (LSPs) to encompass
point-to-multipoint (P2MP) LSPs.
The requirement for a simple and efficient mechanism that can be
used to detect data plane failures in point-to-point (P2P) MPLS LSPs
has been recognized and has led to the development of techniques
for fault detection and isolation commonly referred to as "LSP Ping".
The scope of this document is fault detection and isolation for P2MP
MPLS LSPs. This documents does not replace any of the mechanisms of
LSP Ping, but clarifies their applicability to MPLS P2MP LSPs, and
extends the techniques and mechanisms of LSP Ping to the MPLS P2MP
environment.
Copyright Notice
Copyright (c) 2009 IETF Trust and the persons identified as the
document authors. All rights reserved.
Conventions used in this document
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The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].
Contents
1. Introduction.................................................... 4
1.1 Design Considerations.......................................... 5
2. Notes on Motivation............................................. 6
2.1. Basic Motivations for LSP Ping................................ 6
2.2. Motivations for LSP Ping for P2MP LSPs........................ 6
2.3 Bootstrapping Other OAM Procedures Using LSP Ping.............. 8
3. Operation of LSP Ping for a P2MP LSP............................ 8
3.1. Identifying the LSP Under Test................................ 9
3.1.1. Identifying a P2MP MPLS TE LSP.............................. 9
3.1.1.1. RSVP P2MP IPv4 Session Sub-TLV............................ 9
3.1.1.2. RSVP P2MP IPv6 Session Sub-TLV............................ 9
3.1.2. Identifying a Multicast LDP LSP............................ 10
3.1.2.1. Multicast LDP FEC Stack Sub-TLVs......................... 10
3.1.2.2. Applicability to Multipoint-to-Multipoint LSPs........... 11
3.2. Ping Mode Operation.......................................... 12
3.2.1. Controlling Responses to LSP Pings......................... 12
3.2.2. Ping Mode Egress Procedures................................ 12
3.2.3. Jittered Responses......................................... 12
3.2.4. P2MP Responder Identifier TLV and Sub-TLVs................. 13
3.2.4.1. Egress Address P2MP Responder Identifier Sub-TLVs........ 14
3.2.4.2. Node Address P2MP Responder Identifier Sub-TLVs.......... 14
3.2.5. Echo Jitter TLV............................................ 15
3.2.6. Echo Response Reporting.................................... 15
3.2.6.1 Ping Responses at Transit and Branch Nodes................ 16
3.2.6.2 Ping Responses at Egress and Bud Nodes.................... 16
3.3. Traceroute Mode Operation.................................... 16
3.3.1. Correlating Traceroute Responses........................... 17
3.3.2. Traceroute Responses at Transit Nodes...................... 18
3.3.3. Traceroute Responses at Branch Nodes....................... 18
3.3.4. Traceroute Responses at Egress Nodes....................... 19
3.3.5. Traceroute Responses at Bud Nodes.......................... 19
3.3.6. Non-Response to Traceroute Echo Requests................... 20
3.3.7 Use of Downstream Detailed Mapping TLV in Echo Request...... 20
4. Non-compliant Routers.......................................... 20
5. OAM Considerations............................................. 20
6. IANA Considerations............................................ 21
6.1. New Sub-TLV Types............................................ 21
6.2. New TLVs..................................................... 21
7. Security Considerations........................................ 22
8. Acknowledgements............................................... 22
9. References..................................................... 23
9.1 Normative References.......................................... 23
9.2 Informative References........................................ 23
10. Authors' Addresses............................................ 24
11. Full Copyright Statement...................................... 25
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0. Change Log
This section to be removed before publication as an RFC.
0.1 Changes from 00 to 01
- Update references.
- Fix boilerplate.
0.2 Changes from 01 to 02
- Update entire document so that it is not specific to MPLS-TE, but
also includes multicast LDP LSPs.
- Move the egress identifier sub-TLVs from the FEC Stack TLV to a new
egress identifier TLV.
- Include Multicast LDP FEC Stack sub-TLV definition from [MCAST-CV].
- Add brief section on use of LSP Ping for bootstrapping.
- Add new references to References section.
- Add details of two new authors.
0.3 Changes from 02 to 03
- Update references.
- Update boilerplate.
- Fix typos.
- Clarify in 3.2.2 that a recipient of an echo request must reply
only once it has applied incoming rate limiting.
- Tidy references to bootstrapping for [MCAST-CV] in 1.1.
- Allow multiple sub-TLVs in the P2MP Egress Identifier TLV in
sections 3.2.1, 3.2.2, 3.2.4, 3.3.1, and 3.3.4.
- Clarify how to handle a P2MP Egress Identifier TLV with no sub-TLVs
in sections 3.2.1 and 3.2.2.
0.4 Changes from 03 to 04
- Revert to previous text in sections 3.2.1, 3.2.2, 3.2.4, 3.3.1, and
3.3.4 with respect to multiple sub-TLVs in the P2MP Egress
Identifier TLV.
0.5 Changes from 04 to 05
- Change coordinates for Tom Nadeau. Section 13.
- Fix typos.
- Update references.
- Resolve all acronym expansions.
0.6 Changes from 05 to 06
- New section, 3.2.6, to explain echo response reporting in the Ping
case.
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- New section, 3.3.7, to explain echo response reporting in the
Traceroute case.
- Sections 3.3.2, 3.3.5, and 5. Retire the E-flag for identification
of bud nodes. Use the B-flag in a Downstream Mapping TLV with a
zero address to provide the necessary indication.
- Section 3.3.4. Note the use of ALLROUTERS address as per RFC 4379
- Section 7. Suggest values for IANA assignment.
- Rename "P2MP Responder Identifier TLV" to "P2MP Responder
Identifier TLV", "Egress Identifier sub-TLV" to "Responder
Identifier sub-TLV", and "P2MP egresses" multipath type to "P2MP
responder". This allows any LSR on the P2MP LSP to be the target
of, or responder to, an echo request.
0.7 Changes from 06 to 07
- Sections 3.3.2 and 3.3.3. Delete section 3.3.5. New sections
3.3.2.1 through 3.3.2.3: Retire B-flag from Downstream Mapping TLV.
Introduce new Node Properties TLV with Branching Properties and
Egress Address sub-TLVs.
- Section 3.3.2.4: Clarify rules on presence of Multipath Information
in Downstream Mapping TLVs.
- Section 3.3.5: Clarify padding rules.
- Section 3.3.6: Updated to use Downstream Detailed Mapping TLVs for
multiple return conditions reported by a single echo response.
- Section 7: Update IANA values and add new sub-sections.
- Section 11: Add reference draft-ietf-mpls-lsp-ping-enhanced-dsmap.
- Section 13: Update Bill Fenner's coordinates.
0.8 Changes from 07 to 08
- Removed the Node Properties TLV (Section 3.3.2.1 of version 07).
- Removed the New Multipath Type from Multipath Sub-TLV (Section
3.3.5 of version 07).
- Removed the Return Code Sub-TLV from Downstream Detailed TLV
(Section 3.3.6.1 of version 07), as it is already included in
draft-ietf-mpls-lsp-ping-enhanced-dsmap-02.
- Clarified the behavior of Responder Identifier TLV (Section
3.2.4 of version 07). Two new Sub-TLVs are introduced.
- Downstream Detailed Mapping TLV is now mandatory for implementing
P2MP OAM functionality.
- Split Multicast LDP TLV into two TLVs, one for P2MP and other for
MP2MP. Also added description to allow MP2MP ping by using this
draft.
- Removed Section 4. as it was a duplicate of Section 2.3.
1. Introduction
Simple and efficient mechanisms that can be used to detect data plane
failures in point-to-point (P2P) Multiprotocol Label Switching (MPLS)
Label Switched Paths (LSP) are described in [RFC4379]. The techniques
involve information carried in an MPLS "echo request" and "echo
reply", and mechanisms for transporting the echo reply. The echo
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request and reply messages provide sufficient information to check
correct operation of the data plane, as well as a mechanism to verify
the data plane against the control plane, and thereby localize
faults. The use of reliable channels for echo reply messages as
described in [RFC4379] enables more robust fault isolation. This
collection of mechanisms is commonly referred to as "LSP Ping".
The requirements for point-to-multipoint (P2MP) MPLS traffic
engineered (TE) LSPs are stated in [RFC4461]. [RFC4875] specifies a
signaling solution for establishing P2MP MPLS TE LSPs.
The requirements for point-to-multipoint extensions to the Label
Distribution Protocol (LDP) are stated in [P2MP-LDP-REQ]. [P2MP-LDP]
specifies extensions to LDP for P2MP MPLS.
P2MP MPLS LSPs are at least as vulnerable to data plane faults or to
discrepancies between the control and data planes as their P2P
counterparts. Mechanisms are, therefore, desirable to detect such
data plane faults in P2MP MPLS LSPs as described in [RFC4687].
This document extends the techniques described in [RFC4379] such
that they may be applied to P2MP MPLS LSPs and so that they can be
used to bootstrap other Operations and Management (OAM) procedures
such as [MCAST-CV]. This document stresses the reuse of existing LSP
Ping mechanisms used for P2P LSPs, and applies them to P2MP MPLS LSPs
in order to simplify implementation and network operation.
1.1 Design Considerations
An important consideration for designing LSP Ping for P2MP MPLS LSPs
is that every attempt is made to use or extend existing mechanisms
rather than invent new mechanisms.
As for P2P LSPs, a critical requirement is that the echo request
messages follow the same data path that normal MPLS packets traverse.
However, it can be seen this notion needs to be extended for P2MP
MPLS LSPs, as in this case an MPLS packet is replicated so that it
arrives at each egress (or leaf) of the P2MP tree.
MPLS echo requests are meant primarily to validate the data plane,
and they can then be used to validate data plane state against the
control plane. They may also be used to bootstrap other OAM
procedures such as [MPLS-BFD] and [MCAST-CV]. As pointed out in
[RFC4379], mechanisms to check the liveness, function, and
consistency of the control plane are valuable, but such mechanisms
are not a feature of LSP Ping and are not covered in this document.
As is described in [RFC4379], to avoid potential Denial of Service
attacks, it is RECOMMENDED to regulate the LSP Ping traffic passed to
the control plane. A rate limiter should be applied to the well-known
UDP port defined for use by LSP Ping traffic.
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2. Notes on Motivation
2.1. Basic Motivations for LSP Ping
The motivations listed in [RFC4379] are reproduced here for
completeness.
When an LSP fails to deliver user traffic, the failure cannot always
be detected by the MPLS control plane. There is a need to provide a
tool that enables users to detect such traffic "black holes" or
misrouting within a reasonable period of time. A mechanism to isolate
faults is also required.
[RFC4379] describes a mechanism that accomplishes these goals. This
mechanism is modeled after the ping/traceroute paradigm: ping (ICMP
echo request [RFC792]) is used for connectivity checks, and
traceroute is used for hop-by-hop fault localization as well as path
tracing. [RFC4379] specifies a "ping mode" and a "traceroute" mode
for testing MPLS LSPs.
The basic idea as expressed in [RFC4379] is to test that the packets
that belong to a particular Forwarding Equivalence Class (FEC)
actually end their MPLS path on an LSR that is an egress for that
FEC. [RFC4379] achieves this test by sending a packet (called an
"MPLS echo request") along the same data path as other packets
belonging to this FEC. An MPLS echo request also carries information
about the FEC whose MPLS path is being verified. This echo request is
forwarded just like any other packet belonging to that FEC. In "ping"
mode (basic connectivity check), the packet should reach the end of
the path, at which point it is sent to the control plane of the
egress LSR, which then verifies that it is indeed an egress for the
FEC. In "traceroute" mode (fault isolation), the packet is sent to
the control plane of each transit LSR, which performs various checks
that it is indeed a transit LSR for this path; this LSR also returns
further information that helps to check the control plane against the
data plane, i.e., that forwarding matches what the routing protocols
determined as the path.
One way these tools can be used is to periodically ping a FEC to
ensure connectivity. If the ping fails, one can then initiate a
traceroute to determine where the fault lies. One can also
periodically traceroute FECs to verify that forwarding matches the
control plane; however, this places a greater burden on transit LSRs
and should be used with caution.
2.2. Motivations for LSP Ping for P2MP LSPs
As stated in [RFC4687], MPLS has been extended to encompass P2MP
LSPs. As with P2P MPLS LSPs, the requirement to detect, handle, and
diagnose control and data plane defects is critical. For operators
deploying services based on P2MP MPLS LSPs, the detection and
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specification of how to handle those defects is important because
such defects may affect the fundamentals of an MPLS network, but also
because they may impact service level specification commitments for
customers of their network.
P2MP LDP [P2MP-LDP] uses the Label Distribution Protocol to establish
multicast LSPs. These LSPs distribute data from a single source to
one or more destinations across the network according to the next
hops indicated by the routing protocols. Each LSP is identified by an
MPLS multicast FEC.
P2MP MPLS TE LSPs [RFC4875] may be viewed as MPLS tunnels with a
single ingress and multiple egresses. The tunnels, built on P2MP
LSPs, are explicitly routed through the network. There is no concept
or applicability of a FEC in the context of a P2MP MPLS TE LSP.
MPLS packets inserted at the ingress of a P2MP LSP are delivered
equally (barring faults) to all egresses. In consequence, the basic
idea of LSP Ping for P2MP MPLS TE LSPs may be expressed as an
intention to test that packets that enter (at the ingress) a
particular P2MP LSP actually end their MPLS path on the LSRs that are
the (intended) egresses for that LSP. The idea may be extended to
check selectively that such packets reach specific egresses.
The technique in this document makes this test by sending an LSP Ping
echo request message along the same data path as the MPLS packets. An
echo request also carries the identification of the P2MP MPLS LSP
(multicast LSP or P2MP TE LSP) that it is testing. The echo request
is forwarded just as any other packet using that LSP, and so is
replicated at branch points of the LSP and should be delivered to all
egresses. In "ping" mode (basic connectivity check), the echo request
should reach the end of the path, at which point it is sent to the
control plane of the egress LSRs, which verify that they are indeed
an egress (leaf) of the P2MP LSP. An echo response message is sent by
an egress to the ingress to confirm the successful receipt (or
announce the erroneous arrival) of the echo request.
In "traceroute" mode (fault isolation), the echo request is sent to
the control plane at each transit LSR, and the control plane checks
that it is indeed a transit LSR for this P2MP MPLS LSP. The transit
LSR also returns information on an echo response that helps verify
the control plane against the data plane. That is, the information
is used by the ingress to check that the data plane forwarding
matches what is signaled by the control plane.
P2MP MPLS LSPs may have many egresses, and it is not necessarily the
intention of the initiator of the ping or traceroute operation to
collect information about the connectivity or path to all egresses.
Indeed, in the event of pinging all egresses of a large P2MP MPLS
LSP, it might be expected that a large number of echo responses would
arrive at the ingress independently but at approximately the same
time. Under some circumstances this might cause congestion at or
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around the ingress LSR. Therefore, the procedures described in this
document provide a mechanism that allows the responders to randomly
delay (or jitter) their responses so that the chances of swamping the
ingress are reduced.
Further, the procedures in this document allow the initiator to limit
the scope of an LSP Ping echo request (ping or traceroute mode) to
one specific intended egress.
The scalability issues surrounding LSP Ping for P2MP MPLS LSPs may be
addressed by other mechanisms such as [MCAST-CV] that utilize the LSP
Ping procedures in this document to provide bootstrapping mechanisms
as described in Section 2.3.
LSP Ping can be used to periodically ping a P2MP MPLS LSP to ensure
connectivity to any or all of the egresses. If the ping fails,
the operator or an automated process can then initiate a traceroute
to determine where the fault is located within the network. A
traceroute may also be used periodically to verify that data plane
forwarding matches the control plane state; however, this places an
increased burden on transit LSRs and should be used infrequently and
with caution.
2.3 Bootstrapping Other OAM Procedures Using LSP Ping
[MPLS-BFD] describes a process where LSP Ping [RFC4379] is used to
bootstrap the Bidirectional Forwarding Detection (BFD) mechanism
[BFD] for use to track the liveliness of an MPLS LSP. In particular
BFD can be used to detect a data plane failure in the forwarding
path of an MPLS LSP.
Requirements for MPLS P2MP LSPs extend to hundreds or even thousands
of endpoints. If a protocol required explicit acknowledgments to
each probe for connectivity verification, the response load at the
root would be overwhelming.
A more scalable approach to monitoring P2MP LSP connectivity is
described in [MCAST-CV]. It relies on using the MPLS echo request and
echo response messages of LSP Ping [RFC4379] to bootstrap the
monitoring mechanism in a manner similar to [MPLS-BFD]. The actual
monitoring is done using a separate process defined in [MCAST-CV].
Note that while the approach described in [MCAST-CV] was developed in
response to the multicast scalability problem, it can be applied to
P2P LSPs as well.
3. Operation of LSP Ping for a P2MP LSP
This section describes how LSP Ping is applied to P2MP MPLS LSPs.
It covers the mechanisms and protocol fields applicable to both ping
mode and traceroute mode. It explains the responsibilities of the
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initiator (ingress), transit nodes, and receivers (egresses).
3.1. Identifying the LSP Under Test
3.1.1. Identifying a P2MP MPLS TE LSP
[RFC4379] defines how an MPLS TE LSP under test may be identified in
an echo request. A Target FEC Stack TLV is used to carry either an
RSVP IPv4 Session or an RSVP IPv6 Session sub-TLV.
In order to identify the P2MP MPLS TE LSP under test, the echo
request message MUST carry a Target FEC Stack TLV, and this MUST
carry exactly one of two new sub-TLVs: either an RSVP P2MP IPv4
Session sub-TLV or an RSVP P2MP IPv6 Session sub-TLV. These sub-TLVs
carry fields from the RSVP-TE P2MP Session and Sender-Template
objects [RFC4875] and so provide sufficient information to uniquely
identify the LSP.
The new sub-TLVs are assigned sub-type identifiers as follows, and
are described in the following sections.
Sub-Type # Length Value Field
---------- ------ -----------
TBD 20 RSVP P2MP IPv4 Session
TBD 56 RSVP P2MP IPv6 Session
3.1.1.1. RSVP P2MP IPv4 Session Sub-TLV
The format of the RSVP P2MP IPv4 Session sub-TLV value field is
specified in the following figure. The value fields are taken from
the definitions of the P2MP IPv4 LSP Session Object and the P2MP
IPv4 Sender-Template Object in [RFC4875]. Note that the Sub-Group
ID of the Sender-Template is not required.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| P2MP ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Must Be Zero | Tunnel ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Extended Tunnel ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv4 tunnel sender address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Must Be Zero | LSP ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3.1.1.2. RSVP P2MP IPv6 Session Sub-TLV
The format of the RSVP P2MP IPv6 Session sub-TLV value field is
specified in the following figure. The value fields are taken from
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the definitions of the P2MP IPv6 LSP Session Object, and the
P2MP IPv6 Sender-Template Object in [RFC4875]. Note that the
Sub-Group ID of the Sender-Template is not required.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| P2MP ID |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Must Be Zero | Tunnel ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| Extended Tunnel ID |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| IPv6 tunnel sender address |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Must Be Zero | LSP ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3.1.2. Identifying a Multicast LDP LSP
[RFC4379] defines how a P2P LDP LSP under test may be identified in
an echo request. A Target FEC Stack TLV is used to carry one or more
sub-TLVs (for example, an IPv4 Prefix FEC sub-TLV) that identify the
LSP.
In order to identify a multicast LDP LSP under test, the echo request
message MUST carry a Target FEC Stack TLV, and this MUST carry
exactly one new sub-TLV: the Multicast LDP FEC Stack sub-TLV. This
sub-TLV uses fields from the multicast LDP messages [P2MP-LDP] and so
provides sufficient information to uniquely identify the LSP.
The new sub-TLV is assigned a sub-type identifier as follows, and
is described in the following section.
Sub-Type # Length Value Field
---------- ------ -----------
TBD Variable Multicast P2MP LDP FEC Stack
TBD Variable Multicast MP2MP LDP FEC Stack
3.1.2.1. Multicast LDP FEC Stack Sub-TLVs
Both Multicast P2MP and MP2MP LDP FEC Stack have the same format, as
specified in the following figure.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Address Family | Address Length| Root LSR Addr |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ Root LSR Address (Cont.) ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Opaque Length | Opaque Value ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
~ ~
| |
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Address Family
Two octet quantity containing a value from ADDRESS FAMILY NUMBERS
in [IANA-PORT] that encodes the address family for the Root LSR
Address.
Address Length
Length of the Root LSR Address in octets.
Root LSR Address
Address of the LSR at the root of the P2MP LSP encoded according
to the Address Family field.
Opaque Length
The length of the Opaque Value, in octets.
Opaque Value
An opaque value element which uniquely identifies the P2MP LSP in
the context of the Root LSR.
If the Address Family is IPv4, the Address Length MUST be 4. If the
Address Family is IPv6, the Address Length MUST be 16. No other
Address Family values are defined at present.
3.1.2.2. Applicability to Multipoint-to-Multipoint LSPs
The mechanisms defined in this document can be extended to include
Multipoint-to-Multipoint (MP2MP) Multicast LSPs. In an MP2MP LSP
tree, any leaf node can be treated like a head node of a P2MP
tree. In other words, for MPLS OAM purposes, the MP2MP tree can be
treated like a collection of P2MP trees, with each MP2MP leaf node
acting like a P2MP head-end node. When a leaf node is acting like a
P2MP head-end node, the remaining leaf nodes act like egress nodes.
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3.2. Ping Mode Operation
3.2.1. Controlling Responses to LSP Pings
As described in Section 2.2, it may be desirable to restrict the
operation of LSP Ping to a single egress. Since echo requests are
forwarded through the data plane without interception by the control
plane (compare with traceroute mode), there is no facility to limit
the propagation of echo requests, and they will automatically be
forwarded to all (reachable) egresses.
However, the intended egress under test can be identified by the
inclusion of a P2MP Responder Identifier TLV. The details of this TLV
and its Sub-TLVs are in section 3.2.4. The initiator may choose
whether only the node identified in the TLV responds or any node on
the path to the node identified in the TLV may respond.
An initiator may indicate that it wishes all egresses to respond to
an echo request by omitting the P2MP Responder Identifier TLV.
Note that the ingress of a multicast LDP LSP will not know the
identities of the egresses of the LSP except by some external means
such as running P2MP LSP Ping to all egresses.
3.2.2. Ping Mode Egress Procedures
An egress node is RECOMMENDED to rate limit its receipt of echo
request messages as described in [RFC4379]. After rate limiting, an
egress node that receives an echo request carrying an RSVP P2MP IPv4
Session sub-TLV, an RSVP P2MP IPv6 Session sub-TLV, or a Multicast
LDP FEC Stack sub-TLV MUST determine whether it is an egress of the
P2MP LSP in question by checking with the control plane.
- If the node is not an egress, it MUST respond according to the
setting of the Response Type field in the echo message following
the rules defined in [RFC4379].
- If the node is an egress of the P2MP LSP, the node must
check whether it is a receipient of the echo request.
- If a P2MP Responder Identifier TLV is present, then the node
must follow the procedures defined in section 3.2.4 to determine
whether it should respond to the reqeust or not.
- If the P2MP Responder Identifier TLV is not present (or, in the
error case, is present, but does not contain any sub-TLVs), and
the egress node that received the echo request is an intended
egress of the LSP, the node MUST respond according to the setting
of the Response Type field in the echo message following the
rules defined in [RFC4379].
3.2.3. Jittered Responses
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The initiator (ingress) of a ping request MAY request the responding
egress to introduce a random delay (or jitter) before sending the
response. The randomness of the delay allows the responses from
multiple egresses to be spread over a time period. Thus this
technique is particularly relevant when the entire LSP tree is being
pinged since it helps prevent the ingress (or nearby routers) from
being swamped by responses, or from discarding responses due to rate
limits that have been applied.
It is desirable for the ingress to be able to control the bounds
within which the egress delays the response. If the tree size is
small, only a small amount of jitter is required, but if the tree is
large, greater jitter is needed. The ingress informs the egresses of
the jitter bound by supplying a value in a new TLV (the Echo Jitter
TLV) carried on the echo request message. If this TLV is present, the
responding egress MUST delay sending a response for a random amount
of time between zero milliseconds and the value indicated in the
TLV. If the TLV is absent, the responding egress SHOULD NOT introduce
any additional delay in responding to the echo request.
LSP ping SHOULD NOT be used to attempt to measure the round-trip
time for data delivery. This is because the LSPs are unidirectional,
and the echo response is often sent back through the control plane.
The timestamp fields in the echo request/response MAY be used to
deduce some information about delivery times and particularly the
variance in delivery times.
The use of echo jittering does not change the processes for gaining
information, but note that the responding egress MUST set the value
in the Timestamp Received fields before applying any delay.
It is RECOMMENDED that echo response jittering is not used except in
the case of P2MP LSPs. If the Echo Jitter TLV is present in an echo
request for any other type of TLV, the responding egress MAY apply
the jitter behavior described here.
3.2.4. P2MP Responder Identifier TLV and Sub-TLVs
A new TLV is defined for inclusion in the Echo request message.
The P2MP Responder Identifier TLV is assigned the TLV type value TBD
and is encoded as follows.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Type=TBD(P2MP Responder ID TLV)| Length = Variable |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ Sub-TLVs ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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Sub-TLVs:
Zero, one or more sub-TLVs as defined below.
If no sub-TLVs are present, the TLV MUST be processed as if it
were absent. If more than one sub-TLV is present the first MUST
be processed as described in this document, and subsequent
sub-TLVs SHOULD be ignored.
The P2MP Responder Identifier TLV only has meaning on an echo request
message. If present on an echo response message, it SHOULD be
ignored.
Four sub-TLVs are defined for inclusion in the P2MP Responder
Identifier TLV carried on the echo request message. These are:
Sub-Type # Length Value Field
---------- ------ -----------
1 4 IPv4 Egress Address P2MP Responder Identifier
2 16 IPv6 Egress Address P2MP Responder Identifier
3 4 IPv4 Node Address P2MP Responder Identifier
4 16 IPv6 Node Address P2MP Responder Identifier
The content of these Sub-TLVs are defined in the following
sections. Also defined is the intended behavior of the responding
node upon receiving any of these Sub-TLVs. Please note that the echo
response is always controlled by Response Type field in the echo
message as defined in [RFC4379] and whether or not the responding
node is part for the P2MP tree being identified in the Target FEC
Stack TLV. The Sub-TLVs defined in this section provide additional
constraints to those requirements and are not a replacement for those
requirements.
3.2.4.1. Egress Address P2MP Responder Identifier Sub-TLVs
The IPv4 or IPv6 Egress Address P2MP Responder Identifier Sub-TLVs
MAY be used in an echo request carrying RSVP P2MP Session
Sub-TLV. They SHOULD NOT be used with an echo request carrying
Multicast LDP FEC Stack Sub-TLV.
A node that receives an echo request with this Sub-TLV present MUST
respond only if the node lies on the path to the address in the
Sub-TLV.
The address in this Sub-TLV SHOULD be of an egress or bud node and
SHOULD NOT be of a transit or branch node. This address MUST be known
to the nodes upstream of the target node, possibly via control plane
signaling, such as RSVP. This Sub-TLV may be used to trace a specific
egress or bud node in the P2MP tree.
3.2.4.2. Node Address P2MP Responder Identifier Sub-TLVs
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The IPv4 or IPv6 Node Address P2MP Responder Identifier Sub-TLVs MAY
be used in an echo request carrying either RSVP P2MP Session or
Multicast LDP FEC Stack Sub-TLV.
A node that receives an echo request with this Sub-TLV present MUST
respond only if the address in the Sub-TLV corresponds to any address
that is local to the node. This address in the Sub-TLV may be of any
physical interface or may be the router id of the node itself.
The address in this Sub-TLV SHOULD be of any transit, branch, bud or
egress node for that P2MP tree. This Sub-TLV may be used to ping any
specific node in the P2MP tree.
3.2.5. Echo Jitter TLV
A new TLV is defined for inclusion in the Echo request message.
The Echo Jitter TLV is assigned the TLV type value TBD and is encoded
as follows.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type = TBD (Jitter TLV) | Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Jitter time |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Jitter time:
This field specifies the upper bound of the jitter period that
should be applied by a responding node to determine how long to
wait before sending an echo response. A responding node SHOULD
wait a random amount of time between zero milliseconds and the
value specified in this field.
Jitter time is specified in milliseconds.
The Echo Jitter TLV only has meaning on an echo request message. If
present on an echo response message, it SHOULD be ignored.
3.2.6. Echo Response Reporting
Echo response messages carry return codes and subcodes to indicate
the result of the LSP Ping (when the ping mode is being used) as
described in [RFC4379].
When the responding node reports that it is an egress, it is clear
that the echo response applies only to the reporting node. Similarly,
when a node reports that it does not form part of the LSP described
by the FEC (i.e. there is a misconnection) then the echo response
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applies to the reporting node.
However, it should be noted that an echo response message that
reports an error from a transit node may apply to multiple egress
nodes (i.e. leaves) downstream of the reporting node. In the case of
the Ping mode of operation, it is not possible to correlate the
reporting node to the affected egresses unless the shape of the P2MP
tree is already known, and it may be necessary to use the Traceroute
mode of operation (see Section 3.3) to further diagnose the LSP.
Note also that a transit node may discover an error but also
determine that while it does lie on the path of the LSP under test,
it does not lie on the path to the specific egress being tested. In
this case, the node SHOULD NOT generate an echo response.
3.2.6.1 Ping Responses at Transit and Branch Nodes
If the TTL of the MPLS packet carrying an echo request expires at a
transit or branch node, the packet MUST be passed to the control
plane as specified in [RFC4379].
If the P2MP Responder Identifier is not present or does not contain
any Sub-TLV, then the node MUST respond. If the P2MP Responder
Identifier Sub-TLV is present, then the node MUST respond as per
section 3.2.4.
If the echo response being sent is not indicating an error condition,
such as Malformed request, then the Return Code in the echo response
header may be set to value 8 ('Label switched at stack-depth <RSC>')
or any other error value as needed.
3.2.6.2 Ping Responses at Egress and Bud Nodes
The echo request packet MUST be sent to the control plane at egress
and bud nodes.
If the P2MP Responder Identifier is not present or does not contain
any Sub-TLV, then the node MUST respond. If the P2MP Responder
Identifier Sub-TLV is present, then the node MUST respond as per
section 3.2.4.
If the echo response being sent is not indicating an error condition,
such as Malformed request, then the Return Code in the echo response
header may be set to value 3 ('Replying router is an egress for the
FEC at stack-depth <RSC>') or any other error value as needed.
3.3. Traceroute Mode Operation
The traceroute mode of operation is described in [RFC4379]. Like
other traceroute operations, it relies on the expiration of the TTL
of the packet that carries the echo request. When the TTL expires the
echo request is passed to the control plane on the transit node which
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responds according to the Response Type in the message (and any
Responder Identifier TLV that may be present).
Echo requests MAY include a Downstream Detailed Mapping TLV, and a
responding node fills in the fields of the Downstream Detailed
Mapping TLV to indicate the downstream interfaces and labels used by
the reported LSP from the responding node. In this way, by
successively sending out echo requests with increasing TTLs, the
ingress may gain a picture of the path and resources used by an
LSP. This process continues either to the point of failure when no
response is received, or an error response is generated by a node
where the control plane does not expect to be handling the LSP.
For P2MP Traceroute, a node MUST support Downstream Detailed Mapping
TLV [DDMT]. Downstream Mapping TLV [RFC4379] SHOULD NOT be used for
P2MP traceroute functionality. As per Section 4.3 of [DDMT],
Downstream Mapping TLV is being deprecated. A node MUST ignore any
Downstream Mapping TLV it receives in the echo request.
If there are nodes in the P2MP tree that do not support Downstream
Detailed Mapping TLV, they will send an echo reply with Return Code
set to 2. The ingress node upon receiving such a value SHOULD send
subsequent echo requests with a larger TTL.
The traceroute mode of operation is equally applicable to P2MP MPLS
TE LSP and P2MP Multicast LDP LSP and is described in the following
sections.
The traceroute mode can be applied to all destinations of the P2MP
tree just as in the ping mode. In the case of P2MP MPLS TE LSPs, the
traceroute mode can also be applied to individual traceroute targets
identified by the presence of a P2MP Responder Identifier TLV. In
this case, the responding node must follow the behavior specified in
3.2.4. These targets SHOULD be egresses or bud nodes. However, since
a transit node of a multicast LDP LSP is unable to determine whether
it lies on the path to any one destination or any other transit node,
the traceroute mode limited to specific nodes of such an LSP MUST NOT
be used.
In the absence of a P2MP Responder Identifier TLV, the echo request
is asking for traceroute information applicable to all egresses.
The echo response jitter technique described for the ping mode is
equally applicable to the traceroute mode and is not additionally
described in the procedures below.
3.3.1. Correlating Traceroute Responses
When traceroute is simultaneously applied to multiple responders
(e.g. egresses), it is important that the ingress is able to
correlate the echo responses with the nodes in the P2MP tree. Without
this information the ingress will be unable to determine the correct
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ordering of transit nodes. One possibility is for the ingress to poll
the path to each responder in turn, but this may be inefficient,
undesirable, or (in the case of multicast LDP LSPs) illegal.
The Downstream Detailed Mapping TLV MUST be included in the echo
response from transit, bud, or branch nodes. The information from
Downstream Detailed Mapping TLV can be pieced together by the ingress
to reconstruct the P2MP tree although it may be necessary to refer to
the routing information distributed by the IGP to correlate next hop
addresses and node reporting addresses in subsequent echo responses.
The following sections describe the Return Code used in the echo
response header and in the Downstream Detailed Mapping TLV. It is
possible to identify the type of node (transit, branch, bud and
egress) by using various values in the Return Code and presence of
Downstream Detailed Mapping TLV.
3.3.2. Traceroute Responses at Transit Nodes
When the TTL of the MPLS packet carrying an echo request expires the
packet MUST be passed to the control plane as specified in [RFC4379].
If the echo request packet contains an IPv4 or IPv6 Egress Address
P2MP Responder Identifier TLV, and the FEC is IPv4 or IPv6 P2MP TE
LSP, then the node MUST respond only if the node lies on the path to
the egress specified in the Sub-TLV.
If the LSP under test is a multicast LDP LSP and echo request has an
IPv4 or IPv6 Egress Address P2MP Responder Identifier TLV, then the
node MUST treat the echo request as malformed and MUST process it
according to the rules specified in [RFC4379].
If the echo response being sent is not indicating an error condition,
such as Malformed request, it MUST identify the next hop of the path
of the LSP in the data plane by including a Downstream Detailed
Mapping TLV as described in [DDMT].
The Return Code in echo response header will be value TBD ('See DDM
TLV for Return Code and Return SubCode') as defined in [DDMT]. The
Return Code for the Downstream Detailed Mapping TLV will depend on
the state of the output interface.
3.3.3. Traceroute Responses at Branch Nodes
A branch node MUST follow the procedures described in Section 3.3.2
to determine whether it should respond to an echo request.
If the P2MP Responder Identifier is not present or does not contain
any Sub-TLV (that is, if all egresses are being traced), then the
branch node MUST add a Downstream Detailed Mapping TLV to the echo
response for each outgoing branch that it reports.
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If an IPv4 or IPv6 Egress Address P2MP Responder Identifier is
present, it MUST report only the branch that is on the path to the
specified egress node and it MUST NOT report the other branches.
The Return Code in echo response header will be value TBD ('See DDM
TLV for Return Code and Return SubCode') as defined in [DDMT]. The
Return Code for each of the Downstream Detailed Mapping TLV will
depend on the state of the output interface being reported in this
TLV.
3.3.4. Traceroute Responses at Egress Nodes
If P2MP Responder Identifier is not present or does not contain any
Sub-TLV (that is, if all egresses are being traced), then the egress
node MUST respond to the echo request.
If an IPv4 or IPv6 Egress Address P2MP Responder Identifier is
present, it MUST respond only if the specified address belongs the
egress node.
Egress node MUST NOT return a Downstream Detailed Mapping TLV.
The Return Code in the echo response header will be value 3 ('Replying
router is an egress for the FEC at stack-depth <RSC>') as defined in
[RFC4379].
3.3.5. Traceroute Responses at Bud Nodes
Some nodes on a P2MP MPLS LSP may be an egress as well as a branch
(i.e. have one or more downstream nodes). Such nodes are known as bud
nodes [RFC4461]. A bud node's response is a combination of branch
node and egress node behavior.
If P2MP Responder Identifier is not present or does not contain any
Sub-TLV (that is, if all egresses are being traced), then the bud
node MUST respond to the echo request. It MUST add a Downstream
Detailed Mapping TLV to the echo response for each outgoing branch
that it reports. The Return Code in the echo response header will be
value 3 ('Replying router is an egress for the FEC at stack-depth
<RSC>') as defined in [RFC4379]. The Return Code for each of the
Downstream Detailed Mapping TLV will depend on the state of the
output interface being reported in this TLV.
If an IPv4 or IPv6 Egress Address P2MP Responder Identifier is
present, and the specified address belongs the bud node, then it MUST
respond as if it were an egress node. The Return Code in the echo
response header will be value 3 ('Replying router is an egress for
the FEC at stack-depth <RSC>') as defined in [RFC4379]. It MUST NOT
report any Downstream Detailed Mapping TLV.
If an IPv4 or IPv6 Egress Address P2MP Responder Identifier is
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present, and the bud node lies on the path to the specified egress
address, then it MUST respond as if it was a branch node. The Return
Code in the echo response header will be value TBD ('See DDM TLV for
Return Code and Return SubCode') as defined in [DDMT]. The Return
Code for each of the Downstream Detailed Mapping TLV will depend on
the state of the output interface being reported in this TLV.
3.3.6. Non-Response to Traceroute Echo Requests
There are multiple reasons for which an ingress node may not receive
a response to its echo request. For example, perhaps because the
transit node has failed, or perhaps because the transit node does not
support LSP Ping, or the Responder Identifier TLV failed to match a
valid node.
When no response to an echo request is received by the ingress, then
as per [RFC4379] the subsequent echo request with a larger TTL SHOULD
be sent.
3.3.7 Use of Downstream Detailed Mapping TLV in Echo Request
If no Responder Identifier TLV is being used, then in the Echo
Request packet, the "Downstream IP Address" field, of the Downstream
Detailed Mapping TLV, MUST be set to the ALLROUTERs multicast
address.
If a Responder Identifier TLV is being used, then the Echo Request
packet MAY reuse a received Downstream Detailed Mapping TLV.
4. Non-compliant Routers
If an egress for a P2MP LSP does not support MPLS LSP ping, then no
reply will be sent, resulting in a "false negative" result. There is
no protection for this situation, and operators may wish to ensure
that end points for P2MP LSPs are all equally capable of supporting
this function. Alternatively, the traceroute option can be used to
verify the LSP nearly all the way to the egress, leaving the final
hop to be verified manually.
If, in "traceroute" mode, a transit node does not support LSP ping,
then no reply will be forthcoming from that node for some TTL, say n.
The node originating the echo request SHOULD continue to send echo
request with TTL=n+1, n+2, ..., n+k to probe nodes further down the
path. In such a case, the echo request for TTL > n SHOULD be sent
with Downstream Detailed Mapping TLV "Downstream IP Address" field
set to the ALLROUTERs multicast address as described in Section 3.3.4
until a reply is received with a Downstream Detailed Mapping TLV.
5. OAM Considerations
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The procedures in this document provide OAM functions for P2MP MPLS
LSPs and may be used to enable bootstrapping of other OAM procedures.
In order to be fully operational several considerations must be made.
- Scaling concerns dictate that only cautious use of LSP Ping should
be made. In particular, sending an LSP Ping to all egresses of a
P2MP MPLS LSP could result in congestion at or near the ingress
when the responses arrive.
Further, incautious use of timers to generate LSP Ping echo
requests either in ping mode or especially in traceroute may lead
to significant degradation of network performance.
- Management interfaces should allow an operator full control over
the operation of LSP Ping. In particular, it SHOULD provide the
ability to limit the scope of an LSP Ping echo request for a P2MP
MPLS LSP to a single egress.
Such an interface SHOULD also provide the ability to disable all
active LSP Ping operations to provide a quick escape if the network
becomes congested.
- A MIB module is required for the control and management of LSP Ping
operations, and to enable the reported information to be inspected.
There is no reason to believe this should not be a simple extension
of the LSP Ping MIB module used for P2P LSPs.
6. IANA Considerations
6.1. New Sub-TLV Types
Three new sub-TLV types are defined for inclusion within the LSP Ping
[RFC4379] Target FEC Stack TLV (TLV type 1).
IANA is requested to assign sub-type values to the following
sub-TLVs from the "Multiprotocol Label Switching Architecture (MPLS)
Label Switched Paths (LSPs) Parameters - TLVs" registry, "TLVs and
sub-TLVs" sub-registry.
RSVP P2MP IPv4 Session (see Section 3.1.1). Suggested value 17.
RSVP P2MP IPv6 Session (see Section 3.1.1). Suggested value 18.
Multicast P2MP LDP FEC Stack (see Section 3.1.2). Suggested value 19.
Multicast MP2MP LDP FEC Stack (see Section 3.1.2). Suggested value 20.
6.2. New TLVs
Two new LSP Ping TLV types are defined for inclusion in LSP Ping
messages.
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IANA is requested to assign a new value from the "Multi-Protocol
Label Switching Architecture (MPLS) Label Switched Paths (LSPs)
Parameters - TLVs" registry, "TLVs and sub-TLVs" sub-registry as
follows using a Standards Action value.
P2MP Responder Identifier TLV (see Section 3.2.4) is a mandatory
TLV. Suggested value 11. Four sub-TLVs are defined.
- Type 1: IPv4 Egress Address P2MP Responder Identifier
- Type 2: IPv6 Egress Address P2MP Responder Identifier
- Type 3: IPv4 Node Address P2MP Responder Identifier
- Type 4: IPv6 Node Address P2MP Responder Identifier
Echo Jitter TLV (see Section 3.2.5) is a mandatory TLV. Suggested
value 12.
7. Security Considerations
This document does not introduce security concerns over and above
those described in [RFC4379]. Note that because of the scalability
implications of many egresses to P2MP MPLS LSPs, there is a
stronger concern to regulate the LSP Ping traffic passed to the
control plane by the use of a rate limiter applied to the LSP Ping
well-known UDP port. Note that this rate limiting might lead to
false positives.
8. Acknowledgements
The authors would like to acknowledge the authors of [RFC4379] for
their work which is substantially re-used in this document. Also
thanks to the members of the MBONED working group for their review
of this material, to Daniel King and Mustapha Aissaoui for their
review, and to Yakov Rekhter for useful discussions.
The authors would like to thank Vanson Lim, Danny Prairie, Reshad
Rahman, Ben Niven-Jenkins, Hannes Gredler, Nitin Bahadur, Tetsuya
Murakami, Michael Hua, Michael Wildt, Dipa Thakkar and IJsbrand
Wijnands for their comments and suggestions.
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9. References
9.1 Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC4379] Kompella, K., and Swallow, G., "Detecting Multi-Protocol
Label Switched (MPLS) Data Plane Failures", RFC 4379,
February 2006.
[DDMT] Bahadur, N., Kompella, K., and Swallow, G., "Mechanism
for Performing LSP-Ping over MPLS Tunnels", draft-ietf-
mpls-lsp-ping-enhanced-dsmap, work in progress.
9.2 Informative References
[RFC792] Postel, J., "Internet Control Message Protocol", RFC 792.
[RFC4461] Yasukawa, S., "Signaling Requirements for Point to
Multipoint Traffic Engineered Multiprotocol Label
Switching (MPLS) Label Switched Paths (LSPs)",
RFC 4461, April 2006.
[RFC4687] Yasukawa, S., Farrel, A., King, D., and Nadeau, T.,
"Operations and Management (OAM) Requirements for
Point-to-Multipoint MPLS Networks", RFC 4687, September
2006.
[RFC4875] Aggarwal, R., Papadimitriou, D., and Yasukawa, S.,
"Extensions to Resource Reservation Protocol - Traffic
Engineering (RSVP-TE) for Point-to-Multipoint TE Label
Switched Paths (LSPs)", RFC 4875, May 2007.
[P2MP-LDP-REQ] J.-L. Le Roux, et al., "Requirements for
point-to-multipoint extensions to the Label Distribution
Protocol", draft-ietf-mpls-mp-ldp-reqs, work in progress.
[P2MP-LDP] Minei, I., and Wijnands, I., "Label Distribution Protocol
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Extensions for Point-to-Multipoint and
Multipoint-to-Multipoint Label Switched Paths",
draft-ietf-mpls-ldp-p2mp, work in progress.
[MCAST-CV] Swallow, G., and Nadeau, T., "Connectivity Verification
for Multicast Label Switched Paths",
draft-swallow-mpls-mcast-cv, work in progress.
[BFD] Katz, D., and Ward, D., "Bidirectional Forwarding
Detection", draft-ietf-bfd-base, work in progress.
[MPLS-BFD] Aggarwal, R., Kompella, K., Nadeau, T., and Swallow, G.,
"BFD For MPLS LSPs", draft-ietf-bfd-mpls, work in
progress.
[IANA-PORT] IANA Assigned Port Numbers, http://www.iana.org
10. Authors' Addresses
Seisho Yasukawa
NTT Corporation
(R&D Strategy Department)
3-1, Otemachi 2-Chome Chiyodaku, Tokyo 100-8116 Japan
Phone: +81 3 5205 5341
Email: s.yasukawa@hco.ntt.co.jp
Adrian Farrel
Old Dog Consulting
EMail: adrian@olddog.co.uk
Zafar Ali
Cisco Systems Inc.
2000 Innovation Drive
Kanata, ON, K2K 3E8, Canada.
Phone: 613-889-6158
Email: zali@cisco.com
Bill Fenner
Arastra, Inc.
275 Middlefield Rd.
Suite 50
Menlo Park, CA 94025
Email: fenner@fenron.com
George Swallow
Cisco Systems, Inc.
1414 Massachusetts Ave
Boxborough, MA 01719
Email: swallow@cisco.com
Thomas D. Nadeau
Yasukawa and Farrel [Page 24]
Internet Draft draft-ietf-mpls-p2mp-lsp-ping-08.txt August 2009
British Telecom
BT Centre
81 Newgate Street
EC1A 7AJ
London
Email: tom.nadeau@bt.com
Shaleen Saxena
Cisco Systems, Inc.
1414 Massachusetts Ave
Boxborough, MA 01719
Email: ssaxena@cisco.com
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Please review these documents carefully, as they describe your rights
and restrictions with respect to this document.
Yasukawa and Farrel [Page 25]
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