draft-ietf-mpls-lsp-ping-05.txt   draft-ietf-mpls-lsp-ping-06.txt 
Network Working Group K. Kompella (Juniper)
Internet Draft P. Pan (Ciena)
draft-ietf-mpls-lsp-ping-05.txt N. Sheth (Juniper)
Category: Standards Track D. Cooper (Global Crossing)
Expires: August 2004 G. Swallow (Cisco)
S. Wadhwa (Juniper)
R. Bonica (WorldCom)
February 2004
Detecting MPLS Data Plane Failures Network Working Group K. Kompella
Internet Draft Juniper Networks
Category: Standards Track G. Swallow
Expires: January 2005 Cisco Systems
July 2004
<draft-ietf-mpls-lsp-ping-05.txt> Detecting MPLS Data Plane Failures
draft-ietf-mpls-lsp-ping-06.txt
*** DRAFT ***
Status of this Memo Status of this Memo
This document is an Internet-Draft and is in full conformance with By submitting this Internet-Draft, I certify that any applicable
all provisions of Section 10 of RFC2026. patent or other IPR claims of which I am aware have been disclosed,
and any of which I become aware will be disclosed, in accordance with
RFC 3668.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that Task Force (IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as Internet- other groups may also distribute working documents as Internet-
Drafts. Drafts.
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The list of current Internet-Drafts can be accessed at The list of current Internet-Drafts can be accessed at
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Copyright Notice Copyright Notice
Copyright (C) The Internet Society (2004). All Rights Reserved. Copyright (C) The Internet Society (2004). All Rights Reserved.
Abstract Abstract
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used to detect data plane failures in Multi-Protocol Label Switching used to detect data plane failures in Multi-Protocol Label Switching
(MPLS) Label Switched Paths (LSPs). There are two parts to this (MPLS) Label Switched Paths (LSPs). There are two parts to this
document: information carried in an MPLS "echo request" and "echo document: information carried in an MPLS "echo request" and "echo
reply" for the purposes of fault detection and isolation; and reply" for the purposes of fault detection and isolation; and
mechanisms for reliably sending the echo reply. mechanisms for reliably sending the echo reply.
Changes since last revision Changes since last revision
(This section to be removed before publication.) (This section to be removed before publication.)
*** Changed the format of an L2 circuit ID FEC. Added a sender's PE *** Changed the format of an L2 circuit ID FEC back to what it was,
address field to uniquely identify the VC ID *** on demand. Added a new FEC with sender's PE address field to
uniquely identify the VC ID ***
Further clarified that an MPLS echo request/reply can be either an
IPv4 or an IPv6 packet.
Added format pictures for LDP IPv4/IPv6 prefixes.
Clarified the section on Receiving an MPLS Echo Request. *** Added a FEC TLV for "Labeled BGP IPv4" ***
Issues Reformatted section on Downstream Mapping
(This section to be removed before publication.) Described issue with (and solution to) problem with VPN IPv4/6
Need to address issues with pinging L3VPN FECs. Rephrased section on receiving an LSP ping
Need to add new FEC type for "type 129" L2 circuits. Clarified "Expert Review" allocation policy.
1. Introduction 1. Introduction
This document describes a simple and efficient mechanism that can be This document describes a simple and efficient mechanism that can be
used to detect data plane failures in MPLS LSPs. There are two parts used to detect data plane failures in MPLS LSPs. There are two parts
to this document: information carried in an MPLS "echo request" and to this document: information carried in an MPLS "echo request" and
"echo reply"; and mechanisms for transporting the echo reply. The "echo reply"; and mechanisms for transporting the echo reply. The
first part aims at providing enough information to check correct first part aims at providing enough information to check correct
operation of the data plane, as well as a mechanism to verify the operation of the data plane, as well as a mechanism to verify the
data plane against the control plane, and thereby localize faults. data plane against the control plane, and thereby localize faults.
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to this document: information carried in an MPLS "echo request" and to this document: information carried in an MPLS "echo request" and
"echo reply"; and mechanisms for transporting the echo reply. The "echo reply"; and mechanisms for transporting the echo reply. The
first part aims at providing enough information to check correct first part aims at providing enough information to check correct
operation of the data plane, as well as a mechanism to verify the operation of the data plane, as well as a mechanism to verify the
data plane against the control plane, and thereby localize faults. data plane against the control plane, and thereby localize faults.
The second part suggests two methods of reliable reply channels for The second part suggests two methods of reliable reply channels for
the echo request message, for more robust fault isolation. the echo request message, for more robust fault isolation.
An important consideration in this design is that MPLS echo requests An important consideration in this design is that MPLS echo requests
follow the same data path that normal MPLS packets would traverse. follow the same data path that normal MPLS packets would traverse.
MPLS echo requests are meant primarily to validate the data plane, MPLS echo requests are meant primarily to validate the data plane,
and secondarily to verify the data plane against the control plane. and secondarily to verify the data plane against the control plane.
Mechanisms to check the control plane are valuable, but are not Mechanisms to check the control plane are valuable, but are not
covered in this document. covered in this document.
To avoid potential Denial of Service attacks, it is recommended to To avoid potential Denial of Service attacks, it is recommended to
regulate the MPLS ping traffic going to the control plane. A rate regulate the LSP ping traffic going to the control plane. A rate
limiter should be applied to the well-known UDP port defined below. limiter should be applied to the well-known UDP port defined below.
1.1. Conventions 1.1. Conventions
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [KEYWORDS]. document are to be interpreted as described in RFC 2119 [KEYWORDS].
1.2. Structure of this document 1.2. Structure of this document
The body of this memo contains four main parts: motivation, MPLS echo The body of this memo contains four main parts: motivation, MPLS echo
request/reply packet format, MPLS ping operation, and a reliable request/reply packet format, LSP ping operation, and a reliable
return path. It is suggested that first-time readers skip the actual return path. It is suggested that first-time readers skip the actual
packet formats and read the Theory of Operation first; the document packet formats and read the Theory of Operation first; the document
is structured the way it is to avoid forward references. is structured the way it is to avoid forward references.
The last section (reliable return path for RSVP LSPs) may be removed 1.3. Contributors
in a future revision.
The following made vital contributions to all aspects of this
document, and much of the material came out of debate and discussion
among this group.
Ronald P. Bonica, MCI
Dave Cooper, Global Crossing
Ping Pan, Ciena
Nischal Sheth, Juniper Networks, Inc.
Sanjay Wadhwa, Juniper Networks
2. Motivation 2. Motivation
When an LSP fails to deliver user traffic, the failure cannot always 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 be detected by the MPLS control plane. There is a need to provide a
tool that would enable users to detect such traffic "black holes" or tool that would enable users to detect such traffic "black holes" or
misrouting within a reasonable period of time; and a mechanism to misrouting within a reasonable period of time; and a mechanism to
isolate faults. isolate faults.
In this document, we describe a mechanism that accomplishes these In this document, we describe a mechanism that accomplishes these
goals. This mechanism is modeled after the ping/traceroute paradigm: goals. This mechanism is modeled after the ping/traceroute paradigm:
ping (ICMP echo request [ICMP]) is used for connectivity checks, and ping (ICMP echo request [ICMP]) is used for connectivity checks, and
traceroute is used for hop-by-hop fault localization as well as path traceroute is used for hop-by-hop fault localization as well as path
tracing. This document specifies a "ping mode" and a "traceroute" tracing. This document specifies a "ping mode" and a "traceroute"
mode for testing MPLS LSPs. mode for testing MPLS LSPs.
The basic idea is to test that packets that belong to a particular The basic idea is to verify that packets that belong to a particular
Forwarding Equivalence Class (FEC) actually end their MPLS path on an Forwarding Equivalence Class (FEC) actually end their MPLS path on an
LSR that is an egress for that FEC. This document proposes that this LSR that is an egress for that FEC. This document proposes that this
test be carried out by sending a packet (called an "MPLS echo test be carried out by sending a packet (called an "MPLS echo
request") along the same data path as other packets belonging to this request") along the same data path as other packets belonging to this
FEC. An MPLS echo request also carries information about the FEC FEC. An MPLS echo request also carries information about the FEC
whose MPLS path is being verified. This echo request is forwarded whose MPLS path is being verified. This echo request is forwarded
just like any other packet belonging to that FEC. In "ping" mode just like any other packet belonging to that FEC. In "ping" mode
(basic connectivity check), the packet should reach the end of the (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 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 LSR, which then verifies whether it is indeed an egress for the FEC.
"traceroute" mode (fault isolation), the packet is sent to the In "traceroute" mode (fault isolation), the packet is sent to the
control plane of each transit LSR, which performs various checks that control plane of each transit LSR, which performs various checks that
it is indeed a transit LSR for this path; this LSR also returns it is indeed a transit LSR for this path; this LSR also returns
further information that helps check the control plane against the further information that helps check the control plane against the
data plane, i.e., that forwarding matches what the routing protocols data plane, i.e., that forwarding matches what the routing protocols
determined as the path. determined as the path.
One way these tools can be used is to periodically ping a FEC to 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 ensure connectivity. If the ping fails, one can then initiate a
traceroute to determine where the fault lies. One can also traceroute to determine where the fault lies. One can also
periodically traceroute FECs to verify that forwarding matches the periodically traceroute FECs to verify that forwarding matches the
skipping to change at page 7, line 36 skipping to change at page 8, line 15
<RSC> <RSC>
10 Mapping for this FEC is not the given label at stack 10 Mapping for this FEC is not the given label at stack
depth <RSC> depth <RSC>
11 No label entry at stack-depth <RSC> 11 No label entry at stack-depth <RSC>
12 Protocol not associated with interface at FEC stack 12 Protocol not associated with interface at FEC stack
depth <RSC> depth <RSC>
13 Premature termination of ping due to label stack
shrinking to a single label
3.2. Target FEC Stack 3.2. Target FEC Stack
A Target FEC Stack is a list of sub-TLVs. The number of elements is A Target FEC Stack is a list of sub-TLVs. The number of elements is
determined by the looking at the sub-TLV length fields. determined by the looking at the sub-TLV length fields.
Sub-Type # Length Value Field Sub-Type # Length Value Field
---------- ------ ----------- ---------- ------ -----------
1 5 LDP IPv4 prefix 1 5 LDP IPv4 prefix
2 17 LDP IPv6 prefix 2 17 LDP IPv6 prefix
3 20 RSVP IPv4 Session Query 3 20 RSVP IPv4 Session Query
4 56 RSVP IPv6 Session Query 4 56 RSVP IPv6 Session Query
5 Reserved; see Appendix 5 Reserved; see Appendix
6 13 VPN IPv4 prefix 6 13 VPN IPv4 prefix
7 25 VPN IPv6 prefix 7 25 VPN IPv6 prefix
8 14 L2 VPN endpoint 8 14 L2 VPN endpoint
9 10 L2 circuit ID 9 10 "FEC 128" Pseudowire (old)
10 14 "FEC 128" Pseudowire (new)
11 13+ "FEC 129" Pseudowire
12 10 BGP labeled IPv4 prefix
Other FEC Types will be defined as needed. Other FEC Types will be defined as needed.
Note that this TLV defines a stack of FECs, the first FEC element Note that this TLV defines a stack of FECs, the first FEC element
corresponding to the top of the label stack, etc. corresponding to the top of the label stack, etc.
An MPLS echo request MUST have a Target FEC Stack that describes the An MPLS echo request MUST have a Target FEC Stack that describes the
FEC stack being tested. For example, if an LSR X has an LDP mapping FEC stack being tested. For example, if an LSR X has an LDP mapping
for 192.168.1.1 (say label 1001), then to verify that label 1001 does for 192.168.1.1 (say label 1001), then to verify that label 1001 does
indeed reach an egress LSR that announced this prefix via LDP, X can indeed reach an egress LSR that announced this prefix via LDP, X can
send an MPLS echo request with a FEC Stack TLV with one FEC in it, send an MPLS echo request with a FEC Stack TLV with one FEC in it,
skipping to change at page 10, line 25 skipping to change at page 11, line 9
| | | |
| | | |
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Must Be Zero | LSP ID | | Must Be Zero | LSP ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3.2.5. VPN IPv4 Prefix 3.2.5. VPN IPv4 Prefix
The value field consists of the Route Distinguisher advertised with The value field consists of the Route Distinguisher advertised with
the VPN IPv4 prefix, the IPv4 prefix and a prefix length, as follows: the VPN IPv4 prefix, the IPv4 prefix (with trailing 0 bits to make 32
bits in all) and a prefix length, as follows:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Route Distinguisher | | Route Distinguisher |
| (8 octets) | | (8 octets) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv4 prefix | | IPv4 prefix |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Prefix Length | Must Be Zero | | Prefix Length | Must Be Zero |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3.2.6. VPN IPv6 Prefix 3.2.6. VPN IPv6 Prefix
The value field consists of the Route Distinguisher advertised with The value field consists of the Route Distinguisher advertised with
the VPN IPv6 prefix, the IPv6 prefix and a prefix length, as follows: the VPN IPv6 prefix, the IPv6 prefix (with trailing 0 bits to make
128 bits in all) and a prefix length, as follows:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Route Distinguisher | | Route Distinguisher |
| (8 octets) | | (8 octets) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv6 prefix | | IPv6 prefix |
| | | |
| | | |
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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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Route Distinguisher | | Route Distinguisher |
| (8 octets) | | (8 octets) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sender's CE ID | Receiver's CE ID | | Sender's CE ID | Receiver's CE ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Encapsulation Type | Must Be Zero | | Encapsulation Type | Must Be Zero |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3.2.8. L2 Circuit ID 3.2.8. FEC 128 Pseudowire (Deprecated)
The value field consists of the remote PE address (the destination
address of the targetted LDP session), a VC ID and an encapsulation
type, 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Remote PE Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| VC ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Encapsulation Type | Must Be Zero |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
This FEC will be deprecated, and is retained only for backward
compatibility. Implementations of LSP ping SHOULD accept and process
this TLV, but SHOULD send LSP ping echo requests with the new TLV
(see next section), unless explicitly asked by configuration to use
the old TLV.
An LSR receiving this TLV SHOULD use the source IP address of the LSP
echo request to infer the Sender's PE Address.
3.2.9. FEC 128 Pseudowire (Current)
The value field consists of the sender's PE address (the source The value field consists of the sender's PE address (the source
address of the targetted LDP session), the remote PE address (the address of the targetted LDP session), the remote PE address (the
destination address of the targetted LDP session), a VC ID and an destination address of the targetted LDP session), a VC ID and an
encapsulation type, as follows: encapsulation type, as follows:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sender's PE Address | | Sender's PE Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Remote PE Address | | Remote PE Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| VC ID | | VC ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Encapsulation Type | Must Be Zero | | Encapsulation Type | Must Be Zero |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3.2.10. FEC 129 Pseudowire
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sender's PE Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Remote PE Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| PW Type | AGI Length | SAII Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TAII Length | AGI Value ... SAII Value ... TAII Value ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
. ... .
. .
. .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
... | 0-3 octets of zero padding |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The Length of this TLV is 13 + AGI length + SAII length + TAII
length. Padding is used to make the total length a multiple of 4;
the length of the padding is not included in the Length field.
3.2.11. BGP Labeled IPv4 Prefix
The value field consists of the BGP Next Hop associated with the NLRI
advertising the prefix and label, the IPv4 prefix (with trailing 0
bits to make 32 bits in all), and the prefix length, 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| BGP Next Hop |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv4 Prefix |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Prefix Length | Must Be Zero |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3.3. Downstream Mapping 3.3. Downstream Mapping
The Downstream Mapping object is an optional TLV. Only one The Downstream Mapping object is an optional TLV. Only one
Downstream Mapping request may appear in and echo request. The Downstream Mapping request may appear in and echo request. The
presence of a Downstream Mapping object is a request that Downstream presence of a Downstream Mapping object is a request that Downstream
Mapping objects be included in the echo reply. If the replying Mapping objects be included in the echo reply. If the replying
router is the destination of the FEC, then a Downstream Mapping TLV router is the destination of the FEC, then a Downstream Mapping TLV
SHOULD NOT be included in the echo reply. Otherwise Downstream SHOULD NOT be included in the echo reply. Otherwise Downstream
Mapping objects SHOULD include a Downstream Mapping object for each Mapping objects SHOULD include a Downstream Mapping object for each
interface over which this FEC could be forwarded. interface over which this FEC could be forwarded. For a more precise
definition of the notion of "downstream", see the section named
"Downstream".
The Length is 16 + M + 4*N octets, where M is the Multipath Length, The Length is 16 + M + 4*N octets, where M is the Multipath Length,
and N is the number of Downstream Labels. The Value field of a and N is the number of Downstream Labels. The Value field of a
Downstream Mapping has the following format: Downstream Mapping has the 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MTU | Address Type | Resvd (SBZ) | | MTU | Address Type | Resvd (SBZ) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Downstream Label | Protocol | | Downstream Label | Protocol |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Maximum Transmission Unit (MTU) Maximum Transmission Unit (MTU)
The MTU is the largest MPLS frame (including label stack) that The MTU is the largest MPLS frame (including label stack) that
fits on the interface to the Downstream LSR. fits on the interface to the Downstream LSR.
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 and is set to one of the following values: unnumbered and is set to one of the following values:
Type # Address Type Type # Address Type
------ ------------ ------ ------------
1 IPv4 1 IPv4
2 Unnumbered 2 Unnumbered
3 IPv6 3 IPv6
Reserved
The field marked SBZ SHOULD be set to zero when sending and The field marked SBZ SHOULD be set to zero when sending and
SHOULD be ignored on receipt. SHOULD be ignored on receipt.
Downstream IP Address and Downstream Interface Address Downstream IP Address and Downstream Interface Address
If the interface to the downstream LSR is numbered, then the If the interface to the downstream LSR is numbered, then the
Address Type MUST be set to IPv4 or IPv6, the Downstream IP Address Type MUST be set to IPv4 or IPv6, the Downstream IP
Address MUST be set to either the downstream LSR's Router ID or Address MUST be set to either the downstream LSR's Router ID or
the interface address of the downstream LSR, and the Downstream the interface address of the downstream LSR, and the Downstream
Interface Address MUST be set to the downstream LSR's interface Interface Address MUST be set to the downstream LSR's interface
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The length in octets of the Multipath Information. The length in octets of the Multipath Information.
Downstream Label(s) Downstream Label(s)
The set of labels in the label stack as it would have appeared if The set of labels in the label stack as it would have appeared if
this router were forwarding the packet through this interface. this router were forwarding the packet through this interface.
Any Implicit Null labels are explicitly inluded. Labels are Any Implicit Null labels are explicitly inluded. Labels are
treated as numbers, i.e. they are right justified in the field. treated as numbers, i.e. they are right justified in the field.
Protocol A Downstream Label is 24 bits, in the same format as an MPLS
label minus the TTL field, i.e., the MSBit of the label is bit 0,
the LSbit is bit 19, the EXP bits are bits 20-22, and bit 23 is
the S bit. The replying router SHOULD fill in the EXP and S
bits; the LSR receiving the echo reply MAY choose to ignore these
bits.
Protocol
The Protocol is taken from the following table: The Protocol is taken from the following table:
Protocol # Signaling Protocol Protocol # Signaling Protocol
---------- ------------------ ---------- ------------------
0 Unknown 0 Unknown
1 Static 1 Static
2 BGP 2 BGP
3 LDP 3 LDP
4 RSVP-TE 4 RSVP-TE
5 Reserved; see Appendix 5 Reserved; see Appendix
The notion of "downstream router" and "downstream interface"
should be explained. Consider an LSR X. If a packet that was
originated with TTL n>1 arrived with outermost label L at LSR X,
X must be able to compute which LSRs could receive the packet if
it was originated with TTL=n+1, over which interface the request
would arrive and what label stack those LSRs would see. (It is
outside the scope of this document to specify how this
computation is done.) The set of these LSRs/interfaces are the
downstream routers/interfaces (and their corresponding labels)
for X with respect to L. Each pair of downstream router and
interface requires a separate Downstream Mapping to be added to
the reply. (Note that there are multiple Downstream Label fields
in each TLV as the incoming label L may be swapped with a label
stack.)
The case where X is the LSR originating the echo request is a
special case. X needs to figure out what LSRs would receive the
MPLS echo request for a given FEC Stack that X originates with
TTL=1.
The set of downstream routers at X may be alternative paths (see
the discussion below on ECMP) or simultaneous paths (e.g., for
MPLS multicast). In the former case, the Multipath sub-field is
used as a hint to the sender as to how it may influence the
choice of these alternatives. The "No of Multipaths" is the
number of IP Address/Next Label fields. The Hash Key Type is
taken from the following table:
Key Type Multipath Information
--- ---------------- ---------------------
0 no multipath (empty; M = 0)
1 label labels
2 IP address IP addresses
3 label range low/high label pairs
4 IP address range low/high address pairs
5 no more labels (empty; M = 0)
6 All IP addresses (empty; M = 0)
7 no match (empty; M = 0)
8 Bit-masked IPv4 IP address prefix and bit mask
address set
9 Bit-masked label set Label prefix and bit mask
Type 0 indicates that all packets will be forwarded out this one
interface.
Types 1, 2, 3, 4, 8 and 9 specify that the supplied Multipath
Information will serve to execise this path.
Types 5 and 6 are TBD.
Type 7 indicates that no matches are possible given the Multipath
Information in the received DS mapping information.
Depth Limit Depth Limit
The Depth Limit is applicable only to a label stack, and is the The Depth Limit is applicable only to a label stack, and is the
maximum number of labels considered in the hash; this SHOULD be maximum number of labels considered in the hash; this SHOULD be
set to zero if unspecified or unlimited. set to zero if unspecified or unlimited.
Multipath Information Multipath Information
The multipath information encodes labels or addresses which will The multipath information encodes labels or addresses which will
exercise this path. The multipath informaiton depends on the exercise this path. The multipath informaiton depends on the
hash key type. The contents of the field are shown in the table hash key type. The contents of the field are shown in the table
above. IP addresses are drawn from the range 127/8. Labels are above. IP addresses are drawn from the range 127/8. Labels are
skipping to change at page 15, line 36 skipping to change at page 16, line 49
Hash key 9 allows a denser encoding of Labels. The label prefix Hash key 9 allows a denser encoding of Labels. The label prefix
is formatted as a base label value with the non-prefix low order is formatted as a base label value with the non-prefix low order
bits set to zero. The maximum prefix (including leading zeros bits set to zero. The maximum prefix (including leading zeros
due to encoding) length is 27. Following the prefix is a mask of due to encoding) length is 27. Following the prefix is a mask of
length 2^(32-prefix length) bits. Each bit set to one represents length 2^(32-prefix length) bits. Each bit set to one represents
a valid Label. The label is the base label plus the position of a valid Label. The label is the base label plus the position of
the bit in the mask where the bits are numbered left to right the bit in the mask where the bits are numbered left to right
begining with zero. begining with zero.
If the received DS mapping information is non-null the labels and If the received multipath information is non-null, the labels and
IP addresses MUST be picked from the set provided or the Hash Key IP addresses MUST be picked from the set provided or the Hash Key
Type MUST be set to 7. Type MUST be set to 7. If the received multipath information is
null, the receiver simply returns null.
For example, suppose LSR X at hop 10 has two downstream LSRs Y For example, suppose LSR X at hop 10 has two downstream LSRs Y
and Z for the FEC in question. X could return Hash Key Type 4, and Z for the FEC in question. X could return Hash Key Type 4,
with low/high IP addresses of 1.1.1.1->1.1.1.255 for downstream with low/high IP addresses of 1.1.1.1->1.1.1.255 for downstream
LSR Y and 2.1.1.1->2.1.1.255 for downstream LSR Z. The head end LSR Y and 2.1.1.1->2.1.1.255 for downstream LSR Z. The head end
reflects this information to LSR Y. Y, which has three reflects this information to LSR Y. Y, which has three
downstream LSRs U, V and W, computes that 1.1.1.1->1.1.1.127 downstream LSRs U, V and W, computes that 1.1.1.1->1.1.1.127
would go to U and 1.1.1.128-> 1.1.1.255 would go to V. Y would would go to U and 1.1.1.128-> 1.1.1.255 would go to V. Y would
then respond with 3 Downstream Mappings: to U, with Hash Key Type then respond with 3 Downstream Mappings: to U, with Hash Key Type
4 (1.1.1.1->1.1.1.127); to V, with Hash Key Type 4 4 (1.1.1.1->1.1.1.127); to V, with Hash Key Type 4
(1.1.1.127->1.1.1.255); and to W, with Hash Key Type 7. (1.1.1.127->1.1.1.255); and to W, with Hash Key Type 7.
3.3.1. "Downstream"
The notion of "downstream router" and "downstream interface" should
be explained. Consider an LSR X. If a packet that was originated
with TTL n>1 arrived with outermost label L at LSR X, X must be able
to compute which LSRs could receive the packet if it was originated
with TTL=n+1, over which interface the request would arrive and what
label stack those LSRs would see. (It is outside the scope of this
document to specify how this computation is done.) The set of these
LSRs/interfaces are the downstream routers/interfaces (and their
corresponding labels) for X with respect to L. Each pair of
downstream router and interface requires a separate Downstream
Mapping to be added to the reply. (Note that there are multiple
Downstream Label fields in each TLV as the incoming label L may be
swapped with a label stack.)
The case where X is the LSR originating the echo request is a special
case. X needs to figure out what LSRs would receive the MPLS echo
request for a given FEC Stack that X originates with TTL=1.
The set of downstream routers at X may be alternative paths (see the
discussion below on ECMP) or simultaneous paths (e.g., for MPLS
multicast). In the former case, the Multipath sub-field is used as a
hint to the sender as to how it may influence the choice of these
alternatives. The "No of Multipaths" is the number of IP
Address/Next Label fields. The Hash Key Type is taken from the
following table:
Key Type Multipath Information
--- ---------------- ---------------------
0 no multipath (empty; M = 0)
1 label labels
2 IP address IP addresses
3 label range low/high label pairs
4 IP address range low/high address pairs
5 no more labels (empty; M = 0)
6 All IP addresses (empty; M = 0)
7 no match (empty; M = 0)
8 Bit-masked IPv4 IP address prefix and bit mask
address set
9 Bit-masked label set Label prefix and bit mask
Type 0 indicates that all packets will be forwarded out this one
interface.
Types 1, 2, 3, 4, 8 and 9 specify that the supplied Multipath
Information will serve to execise this path.
Types 5 and 6 are TBD.
Type 7 indicates that no matches are possible given the Multipath
Information in the received DS mapping information.
3.4. Pad TLV 3.4. Pad TLV
The value part of the Pad TLV contains a variable number (>= 1) of The value part of the Pad TLV contains a variable number (>= 1) of
octets. The first octet takes values from the following table; all octets. The first octet takes values from the following table; all
the other octets (if any) are ignored. The receiver SHOULD verify the other octets (if any) are ignored. The receiver SHOULD verify
that the TLV is received in its entirety, but otherwise ignores the that the TLV is received in its entirety, but otherwise ignores the
contents of this TLV, apart from the first octet. contents of this TLV, apart from the first octet.
Value Meaning Value Meaning
----- ------- ----- -------
skipping to change at page 18, line 9 skipping to change at page 20, line 28
header is set as follows: the source IP address is a routable address header is set as follows: the source IP address is a routable address
of the sender; the destination IP address is a (randomly chosen) of the sender; the destination IP address is a (randomly chosen)
address from 127/8; the IP TTL is set to 1. The source UDP port is address from 127/8; the IP TTL is set to 1. The source UDP port is
chosen by the sender; the destination UDP port is set to 3503 chosen by the sender; the destination UDP port is set to 3503
(assigned by IANA for MPLS echo requests). The Router Alert option (assigned by IANA for MPLS echo requests). The Router Alert option
is set in the IP header. is set in the IP header.
If the echo request is labelled, one may (depending on what is being If the echo request is labelled, one may (depending on what is being
pinged) set the TTL of the innermost label to 1, to prevent the ping pinged) set the TTL of the innermost label to 1, to prevent the ping
request going farther than it should. Examples of this include request going farther than it should. Examples of this include
pinging a VPN IPv4 or IPv6 prefix, an L2 VPN end point or an L2 pinging a VPN IPv4 or IPv6 prefix, an L2 VPN end point or a
circuit ID. This can also be accomplished by inserting a router pseudowire. This can also be accomplished by inserting a router
alert label above this label; however, this may lead to the undesired alert label above this label; however, this may lead to the undesired
side effect that MPLS echo requests take a different data path than side effect that MPLS echo requests take a different data path than
actual data. actual data.
In "ping" mode (end-to-end connectivity check), the TTL in the In "ping" mode (end-to-end connectivity check), the TTL in the
outermost label is set to 255. In "traceroute" mode (fault isolation outermost label is set to 255. In "traceroute" mode (fault isolation
mode), the TTL is set successively to 1, 2, .... mode), the TTL is set successively to 1, 2, ....
The sender chooses a Sender's Handle, and a Sequence Number. When The sender chooses a Sender's Handle, and a Sequence Number. When
sending subsequent MPLS echo requests, the sender SHOULD increment sending subsequent MPLS echo requests, the sender SHOULD increment
skipping to change at page 19, line 16 skipping to change at page 21, line 36
echo was received, and the label stack with which it came. echo was received, and the label stack with which it came.
X matches up the labels in the received label stack with the FECs X matches up the labels in the received label stack with the FECs
contained in the FEC stack. The matching is done beginning at the contained in the FEC stack. The matching is done beginning at the
bottom of both stacks, and working up. For reporting purposes the bottom of both stacks, and working up. For reporting purposes the
bottom of stack is consided to be stack-depth of 1. This is to bottom of stack is consided to be stack-depth of 1. This is to
establish an absolute reference for the case where the stack may have establish an absolute reference for the case where the stack may have
more labels than are in the FEC stack. more labels than are in the FEC stack.
If there are more FECs than labels, the extra FECs are assumed to If there are more FECs than labels, the extra FECs are assumed to
correspond to Implicit Null Labels. Thus for the processing below, correspond to Implicit Null Labels. That is, extra Implicit Null
there is never the case where there is a FEC with no corresponding Labels are added to the top of the received label stack and the stack
label. Further the label operation associated with an assumed Null depth is set to the depth of the FEC stack. Thus for the processing
Label is 'pop and continue processing'. below, there is never the case where there is a FEC with no
corresponding label. Further, the label operation associated with an
assumed Null Label is 'pop and continue processing'.
Note: in all the error codes listed in this draft a stack-depth of 0 Note: in all the error codes listed in this draft a stack-depth of 0
means "no value specified". This allows compatibility with existing means "no value specified". This allows compatibility with existing
implementations which do not use the Return Subcode field. implementations which do not use the Return Subcode field.
X sets a variable, call it current-stack-depth, to the number of X sets a variable, call it current-stack-depth, to the number of
labels in the received label stack. Processing now continues with labels in the received label stack. Processing now continues with
the following steps: the following steps:
1. Check if there is a FEC corresponding to the current-stack- 1. Check if there is a FEC corresponding to the current-stack-
skipping to change at page 20, line 38 skipping to change at page 23, line 12
MPLS echo reply has either a Return Code of 8, or a Return Code of 9 MPLS echo reply has either a Return Code of 8, or a Return Code of 9
with a Return Subcode of 1 then Downstream mapping TLVs SHOULD be with a Return Subcode of 1 then Downstream mapping TLVs SHOULD be
included for each multipath. included for each multipath.
X uses the procedure in the next subsection to send the echo reply. X uses the procedure in the next subsection to send the echo reply.
4.4. Sending an MPLS Echo Reply 4.4. Sending an MPLS Echo Reply
An MPLS echo reply is a UDP packet. It MUST ONLY be sent in response An MPLS echo reply is a UDP packet. It MUST ONLY be sent in response
to an MPLS echo request. The source IP address is a routable address to an MPLS echo request. The source IP address is a routable address
of the replier; the source port is the well-known UDP port for MPLS of the replier; the source port is the well-known UDP port for LSP
ping. The destination IP address and UDP port are copied from the ping. The destination IP address and UDP port are copied from the
source IP address and UDP port of the echo request. The IP TTL is source IP address and UDP port of the echo request. The IP TTL is
set to 255. If the Reply Mode in the echo request is "Reply via an set to 255. If the Reply Mode in the echo request is "Reply via an
IPv4 UDP packet with Router Alert", then the IP header MUST contain IPv4 UDP packet with Router Alert", then the IP header MUST contain
the Router Alert IP option. If the reply is sent over an LSP, the the Router Alert IP option. If the reply is sent over an LSP, the
topmost label MUST in this case be the Router Alert label (1) (see topmost label MUST in this case be the Router Alert label (1) (see
[LABEL-STACK]). [LABEL-STACK]).
The format of the echo reply is the same as the echo request. The The format of the echo reply is the same as the echo request. The
Sender's Handle, the Sequence Number and TimeStamp Sent are copied Sender's Handle, the Sequence Number and TimeStamp Sent are copied
skipping to change at page 21, line 36 skipping to change at page 24, line 10
otherwise, it checks the Sequence Number to see if it matches. Gaps otherwise, it checks the Sequence Number to see if it matches. Gaps
in the Sequence Number MAY be logged and SHOULD be counted. Once an in the Sequence Number MAY be logged and SHOULD be counted. Once an
Echo Reply is received for a given Sequence Number (for a given UDP Echo Reply is received for a given Sequence Number (for a given UDP
port and Handle), the Sequence Number for subsequent Echo Requests port and Handle), the Sequence Number for subsequent Echo Requests
for that UDP port and Handle SHOULD be incremented. for that UDP port and Handle SHOULD be incremented.
If the Echo Reply contains Downstream Mappings, and X wishes to If the Echo Reply contains Downstream Mappings, and X wishes to
traceroute further, it SHOULD copy the Downstream Mappings into its traceroute further, it SHOULD copy the Downstream Mappings into its
next Echo Request (with TTL incremented by one). next Echo Request (with TTL incremented by one).
4.6. Non-compliant Routers 4.6. Issue with VPN IPv4 and IPv6 Prefixes
Typically, a LSP ping for a VPN IPv4 or IPv6 prefix is sent with a
label stack of depth greater than 1, with the innermost label having
a TTL of 1. This is to terminate the ping at the egress PE, before
it gets sent to the customer device. However, under certain
circumstances, the label stack can shrink to a single label before
the ping hits the egress PE; this will result in the ping terminating
prematurely. One such scenario is a multi-AS Carrier's Carrier VPN.
To get around this problem, one approach is for the LSR that receives
such a ping to realize that the ping terminated prematurely, and send
back error code 13. In that case, the initiating LSR can retry the
ping after incrementing the TTL on the VPN label. In this fashion,
the ingress LSR will sequentially try TTL values until it finds one
that allows the VPN ping to reach the egress PE.
4.7. Non-compliant Routers
If the egress for the FEC Stack being pinged does not support MPLS If the egress for the FEC Stack being pinged does not support MPLS
ping, then no reply will be sent, resulting in possible "false ping, then no reply will be sent, resulting in possible "false
negatives". If in "traceroute" mode, a transit LSR does not support negatives". If in "traceroute" mode, a transit LSR does not support
MPLS ping, then no reply will be forthcoming from that LSR for some LSP ping, then no reply will be forthcoming from that LSR for some
TTL, say n. The LSR originating the echo request SHOULD try sending TTL, say n. The LSR originating the echo request SHOULD try sending
the echo request with TTL=n+1, n+2, ..., n+k in the hope that some the echo request with TTL=n+1, n+2, ..., n+k in the hope that some
transit LSR further downstream may support MPLS echo requests and transit LSR further downstream may support MPLS echo requests and
reply. In such a case, the echo request for TTL>n MUST NOT have reply. In such a case, the echo request for TTL>n MUST NOT have
Downstream Mapping TLVs, until a reply is received with a Downstream Downstream Mapping TLVs, until a reply is received with a Downstream
Mapping. Mapping.
Normative References Normative References
[IANA] Narten, T. and H. Alvestrand, "Guidelines for IANA
Considerations", BCP 26, RFC 2434, October 1998.
[KEYWORDS] Bradner, S., "Key words for use in RFCs to Indicate [KEYWORDS] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997. Requirement Levels", BCP 14, RFC 2119, March 1997.
[LABEL-STACK] Rosen, E., et al, "MPLS Label Stack Encoding", RFC [LABEL-STACK] Rosen, E., et al, "MPLS Label Stack Encoding", RFC
3032, January 2001. 3032, January 2001.
[RSVP] Braden, R. (Editor), et al, "Resource ReSerVation protocol [RSVP] Braden, R. (Editor), et al, "Resource ReSerVation protocol
(RSVP) -- Version 1 Functional Specification," RFC 2205, (RSVP) -- Version 1 Functional Specification," RFC 2205,
September 1997. September 1997.
skipping to change at page 22, line 47 skipping to change at page 25, line 50
tampering with MPLS echo requests and replies. tampering with MPLS echo requests and replies.
Authentication will help reduce the number of seemingly valid MPLS Authentication will help reduce the number of seemingly valid MPLS
echo requests, and thus cut down the Denial of Service attacks; echo requests, and thus cut down the Denial of Service attacks;
beyond that, each LSR must protect itself. beyond that, each LSR must protect itself.
Authentication sufficiently addresses spoofing, replay and most Authentication sufficiently addresses spoofing, replay and most
tampering attacks; one hopes to use some mechanism devised or tampering attacks; one hopes to use some mechanism devised or
suggested by the RPSec WG. It is not clear how to prevent hijacking suggested by the RPSec WG. It is not clear how to prevent hijacking
(non-delivery) of echo requests or replies; however, if these (non-delivery) of echo requests or replies; however, if these
messages are indeed hijacked, MPLS ping will report that the data messages are indeed hijacked, LSP ping will report that the data
plane isn't working as it should. plane isn't working as it should.
It doesn't seem vital (at this point) to secure the data carried in It doesn't seem vital (at this point) to secure the data carried in
MPLS echo requests and replies, although knowledge of the state of MPLS echo requests and replies, although knowledge of the state of
the MPLS data plane may be considered confidential by some. the MPLS data plane may be considered confidential by some.
5. IANA Considerations 5. IANA Considerations
The TCP and UDP port number 3503 has been allocated by IANA for LSP The TCP and UDP port number 3503 has been allocated by IANA for LSP
echo requests and replies. echo requests and replies.
The following sections detail the new name spaces to be managed by The following sections detail the new name spaces to be managed by
IANA. For each of these name spaces, the space is divided into IANA. For each of these name spaces, the space is divided into
assignment ranges; the following terms are used in describing the assignment ranges; the following terms are used in describing the
procedures by which IANA allocates values: "Standards Action" (as procedures by which IANA allocates values: "Standards Action" (as
defined in [IANA]); "Expert Review" and "Vendor Private Use". defined in [IANA]); "Expert Review" and "Vendor Private Use".
Values from "Expert Review" ranges MUST be registered with IANA, and Values from "Expert Review" ranges MUST be registered with IANA, and
MUST be accompanied by an Experimental RFC that describes the format MUST be accompanied by an Experimental RFC that describes the format
and procedures for using the code point. and procedures for using the code point; the actual assignment is
made during the IANA actions for the RFC.
Values from "Vendor Private" ranges MUST NOT be registered with IANA; Values from "Vendor Private" ranges MUST NOT be registered with IANA;
however, the message MUST contain an enterprise code as registered however, the message MUST contain an enterprise code as registered
with the IANA SMI Network Management Private Enterprise Codes. For with the IANA SMI Network Management Private Enterprise Codes. For
each name space that has a Vendor Private range, it must be specified each name space that has a Vendor Private range, it must be specified
where exactly the SMI Enterprise Code resides; see below for where exactly the SMI Enterprise Code resides; see below for
examples. In this way, several enterprises (vendors) can use the examples. In this way, several enterprises (vendors) can use the
same code point without fear of collision. same code point without fear of collision.
5.1. Message Types, Reply Modes, Return Codes 5.1. Message Types, Reply Modes, Return Codes
skipping to change at page 23, line 47 skipping to change at page 27, line 10
Use, and MUST NOT be allocated. Use, and MUST NOT be allocated.
If any of these fields fall in the Vendor Private range, a top-level If any of these fields fall in the Vendor Private range, a top-level
Vendor Enterprise Code TLV MUST be present in the message. Vendor Enterprise Code TLV MUST be present in the message.
5.2. TLVs 5.2. TLVs
It is requested that IANA maintain registries for the Type field of It is requested that IANA maintain registries for the Type field of
top-level TLVs as well as for sub-TLVs. The valid range for each of top-level TLVs as well as for sub-TLVs. The valid range for each of
these is 0-65535. Assignments in the range 0-32767 are made via these is 0-65535. Assignments in the range 0-32767 are made via
Standards Action; assignments in the range 32768-64511 are made via Standards Action as defined in {IANA]; assignments in the range
Expert Review; values in the range 64512-65535 are for Vendor Private 32768-64511 are made via Expert Review (see below); values in the
Use, and MUST NOT be allocated. range 64512-65535 are for Vendor Private Use, and MUST NOT be
allocated.
If a TLV or sub-TLV has a Type that falls in the range for Vendor If a TLV or sub-TLV has a Type that falls in the range for Vendor
Private Use, the Length MUST be at least 4, and the first four octets Private Use, the Length MUST be at least 4, and the first four octets
MUST be that vendor's SMI Enterprise Code, in network octet order. MUST be that vendor's SMI Enterprise Code, in network octet order.
The rest of the Value field is private to the vendor. The rest of the Value field is private to the vendor.
Acknowledgments Acknowledgments
This document is the outcome of many discussions among many people, This document is the outcome of many discussions among many people,
that include Manoj Leelanivas, Paul Traina, Yakov Rekhter, Der-Hwa that include Manoj Leelanivas, Paul Traina, Yakov Rekhter, Der-Hwa
Gan, Brook Bailey, Eric Rosen and Ina Minei. Gan, Brook Bailey, Eric Rosen, Ina Minei and Shivani Aggarwal.
The description of the Multipath Information sub-field of the The description of the Multipath Information sub-field of the
Downstream Mapping TLV was adapted from text suggested by Curtis Downstream Mapping TLV was adapted from text suggested by Curtis
Villamizar. Villamizar.
Appendix Appendix
This appendix specifies non-normative aspects of detecting MPLS data This appendix specifies non-normative aspects of detecting MPLS data
plane liveness. plane liveness.
skipping to change at page 25, line 14 skipping to change at page 28, line 19
5.2. Downstream Mapping for CR-LDP 5.2. Downstream Mapping for CR-LDP
If a label in a Downstream Mapping was learned via CR-LDP, the If a label in a Downstream Mapping was learned via CR-LDP, the
Protocol field in the Mapping TLV can use the following entry: Protocol field in the Mapping TLV can use the following entry:
Protocol # Signaling Protocol Protocol # Signaling Protocol
---------- ------------------ ---------- ------------------
5 CR-LDP 5 CR-LDP
Authors' Addresses Authors' Address
Kireeti Kompella Kireeti Kompella
Nischal Sheth
Juniper Networks Juniper Networks
1194 N.Mathilda Ave 1194 N.Mathilda Ave
Sunnyvale, CA 94089 Sunnyvale, CA 94089
e-mail: kireeti@juniper.net Email: kireeti@juniper.net
e-mail: nsheth@juniper.net
Ping Pan
Ciena
10480 Ridgeview Court
Cupertino, CA 95014
e-mail: ppan@ciena.com
phone: +1 408.366.4700
Dave Cooper
Global Crossing
960 Hamlin Court
Sunnyvale, CA 94089
email: dcooper@gblx.net
phone: +1 916.415.0437
George Swallow George Swallow
Cisco Systems, Inc. Cisco Systems
250 Apollo Drive 1414 Massachusetts Ave,
Chelmsford, MA 01824 Boxborough, MA 01719
e-mail: swallow@cisco.com Phone: +1 978 936 1398
phone: +1 978.497.8143 Email: swallow@cisco.com
Sanjay Wadhwa
Juniper Networks
10 Technology Park Drive
Westford, MA 01886-3146
email: swadhwa@unispherenetworks.com
phone: +1 978.589.0697
Ronald P. Bonica
WorldCom
22001 Loudoun County Pkwy
Ashburn, Virginia, 20147
email: ronald.p.bonica@wcom.com
phone: +1 703.886.1681
Intellectual Property Rights Notices Intellectual Property Rights Notices
The IETF takes no position regarding the validity or scope of any The IETF takes no position regarding the validity or scope of any
intellectual property or other rights that might be claimed to intellectual property or other rights that might be claimed to
pertain to the implementation or use of the technology described in pertain to the implementation or use of the technology described in
this document or the extent to which any license under such rights this document or the extent to which any license under such rights
might or might not be available; neither does it represent that it might or might not be available; neither does it represent that it
has made any effort to identify any such rights. Information on the has made any effort to identify any such rights. Information on the
IETF's procedures with respect to rights in standards-track and IETF's procedures with respect to rights in standards-track and
skipping to change at page 26, line 33 skipping to change at page 29, line 11
obtain a general license or permission for the use of such obtain a general license or permission for the use of such
proprietary rights by implementors or users of this specification can proprietary rights by implementors or users of this specification can
be obtained from the IETF Secretariat. be obtained from the IETF Secretariat.
The IETF invites any interested party to bring to its attention any The IETF invites any interested party to bring to its attention any
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rights which may cover technology that may be required to practice rights which may cover technology that may be required to practice
this standard. Please address the information to the IETF Executive this standard. Please address the information to the IETF Executive
Director. Director.
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Copyright (C) The Internet Society (2004). All Rights Reserved.
This document and translations of it may be copied and furnished to This document and the information contained herein are provided on an
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distributed, in whole or in part, without restriction of any kind, ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED,
provided that the above copyright notice and this paragraph are INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE
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The limited permissions granted above are perpetual and will not be Copyright Statement
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