draft-ietf-mpls-lsp-ping-00.txt   draft-ietf-mpls-lsp-ping-01.txt 
Network Working Group Kireeti Kompella (Juniper) Network Working Group K. Kompella (Juniper)
Internet Draft Ping Pan (Juniper) Internet Draft P. Pan (Ciena)
Expiration Date: September 2002 Nischal Sheth (Juniper) draft-ietf-mpls-lsp-ping-01.txt N. Sheth (Juniper)
Network Working Group Dave Cooper (Global Crossing) Category: Standards Track D. Cooper (Global Crossing)
George Swallow (Cisco) Expires: April 2003 G. Swallow (Cisco)
Sanjay Wadhwa (Unisphere) S. Wadhwa (Juniper)
Ron Bonica (Worldcom) R. Bonica (WorldCom)
October 2002
Detecting Data Plane Liveliness in MPLS Detecting MPLS Data Plane Liveness
draft-ietf-mpls-lsp-ping-00.txt *** DRAFT ***
Status of this Memo Status of this Memo
This document is an Internet-Draft and is in full conformance with all This document is an Internet-Draft and is in full conformance with
provisions of Section 10 of RFC2026. all provisions of Section 10 of RFC2026.
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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 (C) The Internet Society (2002). All Rights Reserved.
Abstract Abstract
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 to used to detect data plane failures in Multi-Protocol Label Switching
this document: information carried in an MPLS "echo request" and "echo (MPLS) Label Switched Paths (LSPs). There are two parts to this
reply" for the purposes of fault detection and isolation; and mechanisms document: information carried in an MPLS "echo request" and "echo
for transporting the echo reply. reply" for the purposes of fault detection and isolation; and
mechanisms for reliably sending the echo reply.
Sub-IP ID Summary Sub-IP ID Summary
(This section to be removed before publication.)
(See Abstract above.) (See Abstract above.)
RELATED DOCUMENTS RELATED DOCUMENTS
May be found in the "references" section. May be found in the "references" section.
WHERE DOES IT FIT IN THE PICTURE OF THE SUB-IP WORK WHERE DOES IT FIT IN THE PICTURE OF THE SUB-IP WORK
Fits in the MPLS box. Fits in the MPLS box.
WHY IS IT TARGETED AT THIS WG WHY IS IT TARGETED AT THIS WG
MPLS WG is currently looking at MPLS-specific error detection and MPLS WG is currently looking at MPLS-specific error detection and
recovery mechanisms. The mechanisms proposed here are for packet-based recovery mechanisms. The mechanisms proposed here are for packet-
MPLS LSPs, which is why the MPLS WG is targeted. based MPLS LSPs, which is why the MPLS WG is targeted.
JUSTIFICATION JUSTIFICATION
The WG should consider this document, as it allows network operators to The WG should consider this document, as it allows network operators
detect MPLS LSP data plane failures in the network. This type of to detect MPLS LSP data plane failures in the network. This type of
failures have occurred, and are a source of concern to operators failures have occurred, and are a source of concern to operators
implementing MPLS networks. implementing MPLS networks.
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
skipping to change at page 3, line 5 skipping to change at page 3, line 28
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 MPLS 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
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 [KEYWORDS].
1.2. Changes since last revision
(This section to be removed before publication.)
- Packet format changed; Version Number field added
- Reply modes: "don't reply" added
- Reply flags removed
- Return codes extended
- RSVP session formats modified
- VPN IPv4/v6 formats defined
- L2 VPN endpoint and L2 circuits defined
- Downstream mapping format changed
- Pad and Error Code TLVs introduced
- Aspects dealing with CR-LDP moved to non-normative appendix
- IPR notices and Full Copyright Statement (per 2026) added
- other nits to better conform to 2223bis
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, termed "MPLS ping", that In this document, we describe a mechanism that accomplishes these
accomplishes these goals. This mechanism is modeled after the ICMP goals. This mechanism is modeled after the ping/traceroute
echo request/reply, used by ping and traceroute to detect and philosophy: ping (ICMP echo request [ICMP]) is used for connectivity
localize faults in IP networks. This document also offers some checks, and traceroute is used for hop-by-hop fault localization as
alternative methods for replying to MPLS echo requests. well as path tracing. This document specifies a "ping mode" and a
"traceroute" mode for testing MPLS LSPs.
The basic idea is to test that packets that belong to a particular The basic idea is to test 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. Therefore, an MPLS echo request LSR that is an egress for that FEC. This document proposes that this
carries information about the FEC whose MPLS path is being verified. test be carried out by sending a packet (called an "MPLS echo
This echo request is forwarded just like any other packet belonging request") along the same data path as other packets belonging to this
to that FEC. In "ping" mode (basic connectivity check), the packet FEC. An MPLS echo request also carries information about the FEC
should reach the end of the path, at which point it is sent to the whose MPLS path is being verified. This echo request is forwarded
control plane of the egress LSR, which then verifies that it is just like any other packet belonging to that FEC. In "ping" mode
indeed an egress for the FEC. In "traceroute" mode (fault (basic connectivity check), the packet should reach the end of the
isolation), the packet is sent to the control plane of each transit path, at which point it is sent to the control plane of the egress
LSR, which performs various checks that it is indeed a transit LSR LSR, which then verifies that it is indeed an egress for the FEC. In
for this path; this LSR also returns further information that helps "traceroute" mode (fault isolation), the packet is sent to the
check the control plane against the data plane, i.e., that forwarding control plane of each transit LSR, which performs various checks that
matches what the routing protocols determined as the path. it is indeed a transit LSR for this path; this LSR also returns
further information that helps 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 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
control plane; however, this places a greater burden on transit LSRs control plane; however, this places a greater burden on transit LSRs
and thus should be used with caution. and thus should be used with caution.
3. Packet Format 3. Packet Format
An MPLS ping packet is a (possibly labelled) UDP packet with the An MPLS echo request is a (possibly labelled) UDP packet; the
following payload format: contents of the UDP packet have 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Version Number | Must Be Zero |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Message Type | Reply mode | Return Code | Return Subcode|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sender's Handle |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence Number | | Sequence Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TimeStamp (seconds) | | TimeStamp Sent (seconds) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TimeStamp (microseconds) | | TimeStamp Sent (microseconds) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reply mode | Reply flags | Return Code | Must be zero | | TimeStamp Received (seconds) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TimeStamp Received (microseconds) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TLVs ... | | TLVs ... |
. . . .
. . . .
. . . .
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The Sequence Number is assigned by the sender of the MPLS echo The Version Number is currently 1. (Note: the Version Number is to
request, and can be used to detect missed replies (for example). be incremented whenever a change is made that affects the ability of
an implementation to correctly parse or process an MPLS echo
The TimeStamp is set to the time of day (in seconds and microseconds) request/reply. These changes include any syntactic or semantic
when the MPLS echo request or reply is sent, and may be used to changes made to any of the fixed fields, or to any TLV or sub-TLV
compute delay or round trip time (for example). assignment or format that is defined at a certain version number.
The Version Number may not need to be changed if a TLV or sub-TLV is
added.)
The Reply Mode can take one of the following values: The Message Type is one of the following:
Value Meaning Value Meaning
----- ------- ----- -------
1 Reply via an IPv4 UDP packet 1 MPLS Echo Request
2 Reply via an IPv4 UDP packet with Router Alert 2 MPLS Echo Reply
3 Reply via the control plane
Reply Flags are a bit vector with bit 0x1 being the Least Significant
Bit and bit 0x80 being the Most Significant Bit; the following bits
are defined:
Bit Meaning when set The Reply Mode can take one of the following values:
--- ----------------
0x1 Downstream Mappings desired
0x2 Upstream direction pinged
Bit 0x2 is set when the reverse (upstream) direction of a bidirection Value Meaning
LSP is being tested. The details of the procedures in this case will ----- -------
be given in a later version. 1 Do not reply
2 Reply via an IPv4 UDP packet
3 Reply via an IPv4 UDP packet with Router Alert
4 Reply via the control plane
The rest of the bits are reserved and must be zero. An MPLS echo request with "Do not reply" may be used for one-way
connectivity tests; the receiving router may log gaps in the sequence
numbers and/or maintain delay/jitter statistics. An MPLS echo
request would normally have "Reply via an IPv4 UDP packet"; if the
normal IPv4 return path is deemed unreliable, one may use "Reply via
an IPv4 UDP packet with Router Alert" (note that this requires that
all intermediate routers understand and know how to forward MPLS echo
replies) or "Reply via the control plane" (this is currently only
defined for control plane that uses RSVP).
The Return code can take one of the following values: The Return Code is set to zero by the sender. The receiver can set
it to one of the following values:
Value Meaning Value Meaning
----- ------- ----- -------
1 Replying router is an egress for the FEC 0 The error code is contained in the Error Code TLV
2 Replying router has no mapping for the FEC 1 Malformed echo request received
3 Replying router is not one of the "Downstream Routers". 2 One or more of the TLVs was not understood
4 Replying router is one of the "Downstream Routers", 3 Replying router is an egress for the FEC
4 Replying router has no mapping for the FEC
5 Replying router is not one of the "Downstream Routers"
6 Replying router is one of the "Downstream Routers",
and its mapping for this FEC on the received interface and its mapping for this FEC on the received interface
is the given label is the given label
5 Replying router is one of the "Downstream Routers", 7 Replying router is one of the "Downstream Routers",
but its mapping for this FEC is not the given label but its mapping for this FEC is not the given label
The Return Subcode is unused at present and SHOULD be set to zero.
The Sender's Handle is filled in by the sender, and returned
unchanged by the receiver in the echo reply (if any). There are no
semantics associated with this handle, although a sender may find
this useful for matching up requests with replies.
The Sequence Number is assigned by the sender of the MPLS echo
request, and can be (for example) used to detect missed replies.
The TimeStamp Sent is the time-of-day (in seconds and microseconds,
wrt the sender's clock) when the MPLS echo request is sent. The
TimeStamp Received in an echo reply is the time-of-day (wrt the
receiver's clock) that the corresponding echo request was received.
TLVs (Type-Length-Value tuples) have the following format: TLVs (Type-Length-Value tuples) have 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | | Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Value | | Value |
. . . .
. . . .
skipping to change at page 5, line 44 skipping to change at page 7, line 27
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Types are defined below; Length is the length of the Value field in Types are defined below; Length is the length of the Value field in
octets. The Value field depends on the Type; it is zero padded to octets. The Value field depends on the Type; it is zero padded to
align to a four-octet boundary. align to a four-octet boundary.
Type # Value Field Type # Value Field
------ ----------- ------ -----------
1 Target FEC Stack 1 Target FEC Stack
2 Downstream Mapping 2 Downstream Mapping
3 Pad
4 Error Code
3.1. Target FEC Stack 3.1. 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.
Type # Length Value Field Sub-Type # Length Value Field
------ ------ ----------- ---------- ------ -----------
1 5 IPv4 prefix 1 5 LDP IPv4 prefix
2 17 IPv6 prefix 2 17 LDP IPv6 prefix
3 16 RSVP IPv4 Session 3 20 RSVP IPv4 Session Query
4 52 RSVP IPv6 Session 4 56 RSVP IPv6 Session Query
5 6 CR-LDP LSP ID 5 Reserved; see Appendix
6 13 VPN IPv4 prefix 6 13 VPN IPv4 prefix
7 25 VPN IPv4 prefix 7 25 VPN IPv6 prefix
8 ?? L2 VPN "prefix" 8 14 L2 VPN endpoint
9 10 L2 circuit ID
Other FEC Stack 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. However, we will corresponding to the top of the label stack, etc.
assume for now that the stack consists of just one element. Also,
only the formats for FEC Types 1-5 will be described in this version. 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
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
send an MPLS echo request with a FEC Stack TLV with one FEC in it,
namely of type LDP IPv4 prefix, with prefix 192.168.1.1/32, and send
the echo request with a label of 1001.
If LSR X wanted to verify that a label stack of <1001, 23456> is the
right label stack to use to reach an IP VPN prefix of 10/8 in VPN foo
on an egress LSR with loopback address 192.168.1.1 (learned via LDP),
X has two choices. X can send an MPLS echo request with a FEC Stack
TLV with a single FEC of type VPN IPv4 prefix with a prefix of 10/8
with the Route Distinguisher for VPN foo. Alternatively, X can send
a FEC Stack TLV with two FECs, the first of type LDP IPv4 with a
prefix of 192.168.1.1/32 and the second of type of IP VPN with a
prefix 10/8 in VPN foo. In either case, the MPLS echo request would
have a label stack of <1001, 23456>. (Note: in this example, 1001 is
the "outer" label and 23456 is the "inner" label.)
3.1.1. IPv4 Prefix 3.1.1. IPv4 Prefix
The value consists of four octets of an IPv4 prefix followed by one The value consists of four octets of an IPv4 prefix followed by one
octet of prefix length in bits. The IPv4 prefix is in network byte octet of prefix length in bits. The IPv4 prefix is in network byte
order. order. See [LDP] for an example of a Mapping for an IPv4 FEC.
3.1.2. IPv6 Prefix 3.1.2. IPv6 Prefix
The value consists of sixteen octets of an IPv6 prefix followed by The value consists of sixteen octets of an IPv6 prefix followed by
one octet of prefix length in bits. The IPv6 prefix is in network one octet of prefix length in bits. The IPv6 prefix is in network
byte order. byte order.
3.1.3. RSVP IPv4 Session 3.1.3. RSVP IPv4 Session
The value has the format below. The value fields are taken from The value has the format below. The value fields are taken from
[RFC3209, sections 4.6.1.1 and 4.6.2.1] [RFC3209, sections 4.6.1.1 and 4.6.2.1].
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv4 tunnel end point address | | IPv4 tunnel end point address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| LSP ID | Tunnel ID | | Must Be Zero | Tunnel ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Extended Tunnel ID | | Extended Tunnel ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv4 tunnel sender address | | IPv4 tunnel sender address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Must Be Zero | LSP ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3.1.4. RSVP IPv6 Session 3.1.4. RSVP IPv6 Session
The value has the format below. The value fields are taken from The value has the format below. The value fields are taken from
[RFC3209, sections 4.6.1.2 and 4.6.2.2] [RFC3209, sections 4.6.1.2 and 4.6.2.2].
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv6 tunnel end point address | | IPv6 tunnel end point address |
| | | |
| | | |
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| LSP ID | Tunnel ID | | Must Be Zero | Tunnel ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Extended Tunnel ID | | Extended Tunnel ID |
| | | |
| | | |
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv6 tunnel sender address | | IPv6 tunnel sender address |
| | | |
| | | |
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Must Be Zero | LSP ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3.1.5. CR-LDP LSP ID 3.1.5. VPN IPv4 Prefix
The value consists of the LSPID of the LSP being pinged. An LSPID is The value field consists of a Route Distinguisher, an IPv4 prefix and
a four octet IPv4 address (a local address on the head end LSR) plus a prefix length, as follows:
a two octet identifier that is unique for each LSP that starts on an
LSR. 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Route Distinguisher |
| (8 octets) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv4 prefix |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Prefix Length | Must Be Zero |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3.1.6. VPN IPv6 Prefix
The value field consists of a Route Distinguisher, an IPv6 prefix and
a 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Route Distinguisher |
| (8 octets) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv6 prefix |
| |
| |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Prefix Length | Must Be Zero |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3.1.7. L2 VPN Endpoint
The value field consists of a Route Distinguisher (8 octets), the
sender (of the ping)'s CE ID (2 octets), the receiver's CE ID (2
octets), and an encapsulation type (2 octets), formatted 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Route Distinguisher |
| (8 octets) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sender's CE ID | Receiver's CE ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Encapsulation Type | Must Be Zero |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3.1.8. L2 Circuit ID
The value field consists of a remote PE address (the 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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3.2. Downstream Mapping 3.2. Downstream Mapping
The Downstream Mapping is an optional TLV in an echo request. The The Downstream Mapping is an optional TLV in an echo request. The
Length is 4 + 4*N, where N is the number of Downstream Labels. The Length is 12 + 4*N octets, where N is the number of Downstream
Value of a Downstream Mapping has the following format: Labels. The Value of a 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Downstream IPv4 Router ID | | Downstream IPv4 Router ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MTU | Address Type | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Downstream Label | Protocol | | Downstream Label | Protocol |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
. . . .
. . . .
. . . .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Downstream Label | Protocol | | Downstream Label | Protocol |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The MTU is the largest MPLS frame (including label stack) that fits
on the interface to the Downstream LSR. The Address Type is one of:
Type # Address Type
------ ------------
1 IPv4
2 Unnumbered
'Protocol' is taken from the following table: '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 CR-LDP 5 Reserved; see Appendix
The notion of "downstream router" should be explained. Consider an The notion of "downstream router" should be explained. Consider an
LSR X. If a packet with outermost label L and TTL n>1 arrived at X LSR X. If a packet with outermost label L and TTL n>1 arrived at X
on interface I, X must be able to compute which LSRs could receive on interface I, X must be able to compute which LSRs could receive
the packet with TTL=n, and what label they would see. (It is outside the packet with TTL=n+1, and what label they would see. (It is
the scope of this document to specify how this computation may be outside the scope of this document to specify how this computation
done.) The set of these LSRs are the downstream routers (and their may be done.) The set of these LSRs are the downstream routers (and
corresponding labels) for X with respect to L. their corresponding labels) for X with respect to L.
The case where X is the LSR originating the echo request is a special The case where X is the LSR originating the echo request is a special
case. X needs to figure out what LSRs would receive a labelled case. X needs to figure out what LSRs would receive a labelled
packet with TTL=1 when X tries to send a packet to the FEC Stack that packet with TTL=1 when X tries to send a packet to the FEC Stack that
is being pinged. is being pinged.
4. Theory of Operation 3.3. Pad TLV
4.1. MPLS Echo Request The value part of the Pad TLV contains a variable number (>= 1) of
octets. The first octet takes values from the following table; all
the other octets (if any) are ignored. The receiver SHOULD verify
that the TLV is received in its entirety, but otherwise ignores the
contents of this TLV, apart from the first octet.
An MPLS echo request is a labeled UDP packet sent to the well-known Value Meaning
port for MPLS ping [UDP port # 3503 assigned by IANA], with ----- -------
destination IP address set to the ALL-ROUTERS multicast address 1 Drop Pad TLV from reply
(224.0.0.2). The source IP address is set to a routable address of 2 Copy Pad TLV to reply
the sender; the source port identifies the sending process. The IP 3-255 Reserved for future use
TTL in the UDP packet is set to 1.
An MPLS echo request MUST have a FEC Stack TLV. Also, the Reply Mode 3.4. Error Code
must be set to the desired reply mode; the Return Code is set to zero
and ignored on receipt. The Error Code TLV is currently not defined; its purpose is to
provide a mechanism for a more elaborate error reporting structure,
should the reason arise.
4. Theory of Operation
4.1. Sending an MPLS Echo Request
An MPLS echo request is a (possibly) labelled UDP packet. The IP
header is set as follows: the source IP address is a routable address
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
chosen by the sender; the destination UDP port is set to 3503
(assigned by IANA for MPLS echo requests). If the echo request is
labelled, the MPLS TTL on all the labels except the outermost should
be set to 1.
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. outermost label is set to 255. In "traceroute" mode (fault isolation
mode), the TTL is set successively to 1, 2, ....
In "traceroute" mode (fault isolation mode), the TTL is set The sender chooses a Sender's Handle, and a Sequence Number. When
successively to 1, 2, .... sending subsequent MPLS echo requests, the sender SHOULD increment
the sequence number by 1. However, a sender MAY choose to send a
group of echo requests with the same sequence number to improve the
chance of arrival of at least one packet with that sequence number.
The TimeStamp Sent is set to the time-of-day (in seconds and
microseconds) that the echo request is sent. The TimeStamp Received
is set to zero.
An MPLS echo request MUST have a FEC Stack TLV. Also, the Reply Mode
must be set to the desired reply mode; the Return Code and Subcode
are set to zero.
In the "traceroute" mode, the echo request SHOULD contain one or more In the "traceroute" mode, the echo request SHOULD contain one or more
Downstream Mapping TLVs. For TTL=1, all the downstream routers (and Downstream Mapping TLVs. For TTL=1, all the downstream routers (and
corresponding labels) for the sender with respect to the FEC Stack corresponding labels) for the sender with respect to the FEC Stack
being pinged SHOULD be sent in the echo request. For n>1, the being pinged SHOULD be sent in the echo request. For n>1, the
Downstream Mapping TLVs from the echo reply for TTL=(n-1) are copied Downstream Mapping TLVs from the echo reply for TTL=(n-1) are copied
to the echo request with TTL=n. to the echo request with TTL=n.
4.2. MPLS Echo Reply 4.2. Receiving an MPLS Echo Request
An LSR L that receives an MPLS echo request first parses the packet
to ensure that it is a well-formed packet, and that the TLVs are
understood. If not, L SHOULD send an MPLS echo reply with the
Return Code set to "Malformed echo request received" or "TLV not
understood" (as appropriate), and the Subcode set to the appropriate
value.
If the echo request is good, L then checks whether it is a valid
transit or egress LSR for the FEC in the echo request. If not, L MAY
log this fact.
If the echo request contains a Downstream Mapping TLV, L MUST further
check whether its Router ID matches one of the Downstream IPv4 Router
IDs; and if so, whether the given Downstream Label is in fact the
label that L sent as its mapping for the FEC. For an RSVP FEC, the
downstream label is the label that L sent in its Resv message. The
result of the checks in the previous and this paragraph are captured
in the Return Code/Subcode.
If the echo request has a Reply Mode that wants a reply, L uses the
procedure in the next subsection to send the echo reply.
4.3. 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 the Router ID of to an MPLS echo request. The source IP address is a routable address
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 MPLS
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. the Router Alert IP option.
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
Sequence Number is copied from the echo request; the TimeStamp is set Sender's Handle, the Sequence Number and TimeStamp Sent are copied
to the time-of-day that the echo request is received (note that this from the echo request; the TimeStamp Received is set to the time-of-
information is most useful if the time-of-day clocks on the requestor day that the echo request is received (note that this information is
and the replier are synchronized). The FEC Stack TLV from the echo most useful if the time-of-day clocks on the requestor and the
request is copied to the reply. replier are synchronized). The FEC Stack TLV from the echo request
MAY be copied to the reply.
The replier MUST fill in the Return Code. This is set based on The replier MUST fill in the Return Code and Subcode, as determined
whether the replier has a mapping for the FEC, and whether it is an in the previous subsection.
egress for that FEC. Note that 'having a mapping' for an RSVP FEC
means that the replier is a transit LSR for the RSVP LSP defined by If the echo request contains a Pad TLV, the replier MUST interpret
the FEC. the first octet for instructions regarding how to reply.
If the echo request contains a Downstream Mapping TLV, the replier If the echo request contains a Downstream Mapping TLV, the replier
MUST further check whether its Router ID matches one of the SHOULD compute its downstream routers and corresponding labels for
Downstream IPv4 Router IDs; and if so, whether the given Downstream the incoming label, and add Downstream Mapping TLVs for each one to
Label is in fact the label that the replier sent as its mapping for the echo reply it sends back.
the FEC. For an RSVP FEC, the downstream label is the label that the
replier sent in its Resv message. The result of these checks are
captured in the Return Code.
If the flag requesting Downstream Mapping TLVs is set in the Reply 4.4. Receiving an MPLS Echo Reply
Flags, the replier SHOULD compute its downstream routers and
corresponding labels for the incoming label, and add Downstream
Mapping TLVs for each one to the echo reply it sends back.
4.3. Non-compliant Routers An LSR X should only receive an MPLS Echo Reply in response to an
MPLS Echo Request that it sent. Thus, on receipt of an MPLS Echo
Reply, X should parse the packet to assure that it is well-formed,
then attempt to match up the Echo Reply with an Echo Request that it
had previously sent, using the destination UDP port and the Sender's
Handle. If no match is found, then X jettisons the Echo Reply;
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
Echo Reply is received for a given Sequence Number (for a given UDP
port and Handle), the Sequence Number for subsequent Echo Requests
for that UDP port and Handle SHOULD be incremented.
If the Echo Reply contains Downstream Mappings, and X wishes to
traceroute further, it SHOULD copy the Downstream Mappings into its
next Echo Request (with TTL incremented by one).
4.5. 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 MPLS 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
skipping to change at page 11, line 15 skipping to change at page 16, line 11
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence Number | | Sequence Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TimeStamp (seconds) | | TimeStamp (seconds) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TimeStamp (microseconds) | | TimeStamp (microseconds) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| UDP Source Port | Return Code | Must be zero | | UDP Source Port | Return Code | Return Subcode|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The Sequence Number is copied from the Sequence Number of the echo The Sequence Number is copied from the Sequence Number of the echo
request. The TimeStamp is set to the time the echo request is request. The TimeStamp is set to the time the echo request is
received. The UDP Source Port is copied from the UDP source port of received. The UDP Source Port is copied from the UDP source port of
the MPLS echo request. The FEC is implied by the Session and the the MPLS echo request. The FEC is implied by the Session and the
Sender Template Objects. Sender Template Objects.
5.2. Operation 5.2. Operation
skipping to change at page 11, line 37 skipping to change at page 16, line 33
control plane" we mean "the RSVP-TE component of the control plane". control plane" we mean "the RSVP-TE component of the control plane".
Consider an LSP between an ingress LSR and an egress LSR spanning Consider an LSP between an ingress LSR and an egress LSR spanning
multiple LSR hops. multiple LSR hops.
5.3. Procedures at the ingress LSR 5.3. Procedures at the ingress LSR
One must ensure before setting the Reply Mode to "reply via the One must ensure before setting the Reply Mode to "reply via the
control plane" that the egress LSR supports this feature. control plane" that the egress LSR supports this feature.
The ingress LSR, say X, selects a unique UDP source port for its MPLS The ingress LSR, say X, builds an MPLS echo request as in section
ping. X also sets the FEC Stack TLV Type to RSVP IPv4 (IPv6), and "Sending an MPLS Echo Request". The FEC Type must be an RVSP Session
copies the SESSION and SENDER_TEMPLATE into the appropriate fields of Query. X also sets the Reply Mode to "reply via the control plane".
the value field. Finally, X sets the Reply Mode to "reply via the
control plane".
If X does not receive an Resv message from the egress LSR that If X does not receive an Resv message from the egress LSR that
contains an LSP_ECHO object within some period of time, it declares contains an LSP_ECHO object within some period of time, it declares
the LSP as "down". At this point, the ingress LSR may apply the the LSP as "down". At this point, the ingress LSR may apply the
necessary procedures to fix the LSP. These may include generating a necessary procedures to fix the LSP. These may include generating a
message to network management, tearing-down and re-building the LSP, message to network management, tearing-down and re-building the LSP,
and/or rerouting user traffic to a backup LSP. and/or rerouting user traffic to a backup LSP.
To test an LSP that carries non-IP traffic, before injecting ICMP and To test an LSP that carries non-IP traffic, before injecting ICMP and
MPLS ping messages into the LSP, the IPv4 Explicit NULL label should MPLS ping messages into the LSP, the IPv4 Explicit NULL label should
skipping to change at page 12, line 33 skipping to change at page 17, line 28
At intermediate LSRs, normal RSVP processing procedures will cause At intermediate LSRs, normal RSVP processing procedures will cause
the LSP_ECHO object to be forwarded as RSVP messages are refreshed. the LSP_ECHO object to be forwarded as RSVP messages are refreshed.
At the LSR's that support MPLS ping the Resv messages that carry the At the LSR's that support MPLS ping the Resv messages that carry the
LSP_ECHO object MUST be delivered upstream immediately. LSP_ECHO object MUST be delivered upstream immediately.
Note that an intermediate LSR using RSVP refresh reduction [RSVP- Note that an intermediate LSR using RSVP refresh reduction [RSVP-
REFRESH], the new or changed LSP_ECHO object will cause the LSR to REFRESH], the new or changed LSP_ECHO object will cause the LSR to
classify the RSVP message as a trigger message. classify the RSVP message as a trigger message.
6. Security Considerations 6. Normative References
The security considerations pertaining to the original RSVP protocol [KEYWORDS] Bradner, S., "Key words for use in RFCs to Indicate
remain relevant. Requirement Levels", BCP 14, RFC 2119, March 1997.
7. Intellectual Property Considerations [LABEL-STACKING] Rosen, E., et al, "MPLS Label Stack Encoding", RFC
3032, January 2001.
Juniper Networks, Inc. is seeking patent protection on technology [RSVP] Braden, R. (Editor), et al, "Resource ReSerVation protocol
described in this Internet-Draft. If technology in this Internet- (RSVP) -- Version 1 Functional Specification," RFC 2205,
Draft is adopted as a standard, Juniper Networks agrees to license, September 1997.
on reasonable and non-discriminatory terms, any patent rights it
obtains covering such technology to the extent necessary to comply
with the standard.
8. Acknowledgments [RSVP-REFRESH] Berger, L., et al, "RSVP Refresh Overhead Reduction
Extensions", RFC 2961, April 2001.
This is the outcome of many discussions among many people, that also [RSVP-TE] Awduche, D., et al, "RSVP-TE: Extensions to RSVP for LSP
include Manoj Leelanivas, Paul Traina, Yakov Rekhter, Der-Hwa Gan, tunnels", RFC 3209, December 2001.
Brook Bailey and Eric Rosen.
9. References 7. Informative References
[ICMP] J. Postel, "Internet Control Message Protocol", RFC792. [ICMP] Postel, J., "Internet Control Message Protocol", RFC 792.
[RSVP] R. Braden, Ed., et al, "Resource ReSerVation protocol (RSVP) [LDP] Andersson, L., et al, "LDP Specification", RFC 3036, January
-- version 1 functional specification," RFC2205. 2001.
[RSVP-TE] D. Awduche, et al, "RSVP-TE: Extensions to RSVP for LSP 8. Security Considerations
tunnels" Internet Draft.
[LABEL-STACKING] E. Rosen, et al, "MPLS Label Stack Encoding", There are at least two approaches to attacking LSRs using the
RFC3032. mechanisms defined here. One is a Denial of Service attack, by
sending MPLS echo requests/replies to LSRs and thereby increasing
their workload. The other is obfuscating the state of the MPLS data
plane liveness by spoofing, hijacking, replaying or otherwise
tampering with MPLS echo requests and replies.
[RSVP-REFRESH] L. Berger, et al, "RSVP Refresh Overhead Reduction Authentication will help reduce the number of seemingly valid MPLS
Extensions", RFC2961. echo requests, and thus cut down the Denial of Service attacks;
beyond that, each LSR must protect itself.
[RFC-IANA] T. Narten and H. Alvestrand, "Guidelines for Writing an Authentication sufficiently addresses spoofing, replay and most
IANA Considerations Section in RFCs", RFC 2434. tampering attacks; one hopes to use some mechanism devised or
suggested by the RPSec WG. It is not clear how to prevent hijacking
(non-delivery) of echo requests or replies; however, if these
messages are indeed hijacked, MPLS ping will report that the data
plane isn't working as it should.
10. Author Information 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
the MPLS data plane may be considered confidential by some.
9. IANA Considerations
(To be filled in a later revision)
10. Acknowledgments
This document is the outcome of many discussions among many people,
that include Manoj Leelanivas, Paul Traina, Yakov Rekhter, Der-Hwa
Gan, Brook Bailey, Eric Rosen and Ina Minei.
11. Appendix
This appendix specifies non-normative aspects of detecting MPLS data
plane liveness.
11.1. CR-LDP FEC
This section describes how a CR-LDP FEC can be included in an Echo
Request using the following FEC subtype:
Sub-Type # Length Value Field
---------- ------ -----------
5 6 CR-LDP LSP ID
The value consists of the LSPID of the LSP being pinged. An LSPID is
a four octet IPv4 address (a local address on the ingress LSR, for
example, the Router ID) plus a two octet identifier that is unique
per LSP on a given ingress LSR.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Ingress LSR Router ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Must Be Zero | LSP ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
11.2. Downstream Mapping for CR-LDP
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 # Signaling Protocol
---------- ------------------
5 CR-LDP
12. Authors' Addresses
Kireeti Kompella Kireeti Kompella
Ping Pan
Nischal Sheth 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 e-mail: kireeti@juniper.net
e-mail: pingpan@juniper.net
e-mail: nsheth@juniper.net e-mail: nsheth@juniper.net
phone: 408.745.2000
Ping Pan
Ciena
10480 Ridgeview Court
Cupertino, CA 95014
e-mail: ppan@ciena.com
phone: +1 408.366.4700
Dave Cooper Dave Cooper
Global Crossing Global Crossing
960 Hamlin Court 960 Hamlin Court
Sunnyvale, CA 94089 Sunnyvale, CA 94089
email: dcooper@gblx.net email: dcooper@gblx.net
phone: 916.415.0437 phone: +1 916.415.0437
George Swallow George Swallow
Cisco Systems, Inc. Cisco Systems, Inc.
250 Apollo Drive 250 Apollo Drive
Chelmsford, MA 01824 Chelmsford, MA 01824
e-mail: swallow@cisco.com e-mail: swallow@cisco.com
phone: 978.244.8143 phone: +1 978.497.8143
Sanjay Wadhwa Sanjay Wadhwa
Unisphere Networks, Inc. Juniper Networks
10 Technology Park Drive 10 Technology Park Drive
Westford, MA 01886-3146 Westford, MA 01886-3146
email: swadhwa@unispherenetworks.com email: swadhwa@unispherenetworks.com
phone: 978.589.0697 phone: +1 978.589.0697
Ronald P. Bonica Ronald P. Bonica
WorldCom WorldCom
22001 Loudoun County Pkwy 22001 Loudoun County Pkwy
Ashburn, Virginia, 20147 Ashburn, Virginia, 20147
email: ronald.p.bonica@wcom.com email: ronald.p.bonica@wcom.com
phone: 703.886.1681 phone: +1 703.886.1681
13. Intellectual Property Rights Notices
The IETF takes no position regarding the validity or scope of any
intellectual property or other rights that might be claimed to
pertain to the implementation or use of the technology described in
this document or the extent to which any license under such rights
might or might not be available; neither does it represent that it
has made any effort to identify any such rights. Information on the
IETF's procedures with respect to rights in standards-track and
standards-related documentation can be found in BCP-11. Copies of
claims of rights made available for publication and any assurances of
licenses to be made available, or the result of an attempt made to
obtain a general license or permission for the use of such
proprietary rights by implementors or users of this specification can
be obtained from the IETF Secretariat.
The IETF invites any interested party to bring to its attention any
copyrights, patents or patent applications, or other proprietary
rights which may cover technology that may be required to practice
this standard. Please address the information to the IETF Executive
Director.
Full Copyright Statement
Copyright (C) The Internet Society (2002). All Rights Reserved.
This document and translations of it may be copied and furnished to
others, and derivative works that comment on or otherwise explain it
or assist in its implmentation may be prepared, copied, published and
distributed, in whole or in part, without restriction of any kind,
provided that the above copyright notice and this paragraph are
included on all such copies and derivative works. However, this
document itself may not be modified in any way, such as by removing
the copyright notice or references to the Internet Society or other
Internet organizations, except as needed for the purpose of
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copyrights defined in the Internet Standards process must be
followed, or as required to translate it into languages other than
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The limited permissions granted above are perpetual and will not be
revoked by the Internet Society or its successors or assigns.
This document and the information contained herein is provided on an
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HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
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