Internet Engineering Task Force (IETF) M. Chen

Internet Engineering Task Force (IETF) M. Chen
Request for Comments: 6829 Huawei Technologies Co., Ltd
Updates: 4379 P. Pan
Category: Standards Track Infinera
ISSN: 2070-1721 C. Pignataro
R. Asati
Cisco
January 2013

Label Switched Path (LSP) Ping for
Pseudowire Forwarding Equivalence Classes (FECs) Advertised over IPv6

Abstract

The Multiprotocol Label Switching (MPLS) Label Switched Path (LSP)
Ping and traceroute mechanisms are commonly used to detect and
isolate data-plane failures in all MPLS LSPs, including LSPs used for
each direction of an MPLS Pseudowire (PW). However, the LSP Ping and
traceroute elements used for PWs are not specified for IPv6 address
usage.

This document extends the PW LSP Ping and traceroute mechanisms so
they can be used with PWs that are set up and maintained using IPv6
LDP sessions. This document updates RFC 4379.

Status of This Memo

This is an Internet Standards Track document.

This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 5741.

Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc6829.

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RFC 6829 PW LSP Ping for IPv6 January 2013

Copyright Notice

Copyright (c) 2013 IETF Trust and the persons identified as the
document authors. All rights reserved.

This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.

Table of Contents

1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Pseudowire IPv4 Target FEC Stack Sub-TLVs . . . . . . . . . . . 3
3. Pseudowire IPv6 Target FEC Stack Sub-TLVs . . . . . . . . . . . 4
3.1. FEC 128 Pseudowire . . . . . . . . . . . . . . . . . . . . 4
3.2. FEC 129 Pseudowire . . . . . . . . . . . . . . . . . . . . 5
4. Summary of Changes . . . . . . . . . . . . . . . . . . . . . . 6
5. Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 6
7. Security Considerations . . . . . . . . . . . . . . . . . . . . 7
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 7
9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 7
9.1. Normative References . . . . . . . . . . . . . . . . . . . 7
9.2. Informative References . . . . . . . . . . . . . . . . . . 7

1. Introduction

Multiprotocol Label Switching (MPLS) Label Switched Path (LSP) Ping
and traceroute are defined in [RFC4379]. These mechanisms can be
used to detect data-plane failures in all MPLS LSPs, including
Pseudowires (PWs). However, the PW LSP Ping and traceroute elements
are not specified for IPv6 address usage.

Specifically, the PW Forwarding Equivalence Class (FEC) sub-TLVs for
the Target FEC Stack in the LSP Ping and traceroute mechanism are
defined only for IPv4 Provider Edge (PE) routers and are not
applicable for the case where PEs use IPv6 addresses. Three PW-
related Target FEC sub-TLVs are currently defined (FEC 128
Pseudowire-Deprecated, FEC 128 Pseudowire-Current, and FEC 129
Pseudowire, see Sections 3.2.8 through 3.2.10 of [RFC4379]). These
sub-TLVs contain the source and destination addresses of the LDP
session, and currently only an IPv4 LDP session is covered. Despite

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the fact that the PE IP address family is not explicit in the sub-TLV
definition, this can be inferred indirectly by examining the lengths
of the Sender's/Remote PE Address fields or calculating the length of
the sub-TLVs (see Section 3.2 of [RFC4379]). When an IPv6 LDP
session is used, these existing sub-TLVs cannot be used since the
addresses will not fit. Additionally, all other sub-TLVs are defined
in pairs, one for IPv4 and another for IPv6, but not the PW sub-TLVs.

This document updates [RFC4379] to explicitly constrain the existing
PW FEC sub-TLVs for IPv4 LDP sessions and extends the PW LSP Ping to
IPv6 LDP sessions (i.e., when IPv6 LDP sessions are used to signal
the PW, the Sender's and Receiver's IP addresses are IPv6 addresses).
This is done by renaming the existing PW sub-TLVs to indicate "IPv4"
and also by defining two new Target FEC sub-TLVs (FEC 128 Pseudowire
IPv6 sub-TLV and FEC 129 Pseudowire IPv6 sub-TLV) to extend the
application of PW LSP Ping and traceroute to IPv6 usage when an IPv6
LDP session [MPLS-LDP] is used to signal the Pseudowire. Note that
FEC 128 Pseudowire (Deprecated) is not defined for IPv6 in this
document.

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].

2. Pseudowire IPv4 Target FEC Stack Sub-TLVs

This document updates Section 3.2 and Sections 3.2.8 through 3.2.10
of [RFC4379] as follows and as indicated in Sections 4 and 6. This
is done to avoid any potential ambiguity and confusion and to clarify
that these TLVs carry only IPv4 addresses. Note that the changes are
limited to the names of fields; there are no semantic changes.

Sections 3.2.8 through 3.2.10 of [RFC4379] list the PW sub-TLVs and
state:

"FEC 128" Pseudowire (Deprecated)

"FEC 128" Pseudowire

"FEC 129" Pseudowire

These names and titles are now changed to:

"FEC 128" Pseudowire - IPv4 (Deprecated)

"FEC 128" Pseudowire - IPv4

"FEC 129" Pseudowire - IPv4

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Additionally, when referring to the PE addresses, Sections 3.2.8
through 3.2.10 of [RFC4379] state:

Sender's PE Address

Remote PE Address

These are now updated to say:

Sender's PE IPv4 Address

Remote PE IPv4 Address

3. Pseudowire IPv6 Target FEC Stack Sub-TLVs

3.1. FEC 128 Pseudowire

The FEC 128 Pseudowire IPv6 sub-TLV has a structure consistent with
the FEC 128 Pseudowire sub-TLV as described in Section 3.2.9 of
[RFC4379]. The encoding of the FEC 128 Pseudowire IPv6 sub-TLV is 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| FEC 128 PW IPv6 Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ Sender's PE IPv6 Address ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ Remote PE IPv6 Address ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| PW ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| PW Type | Must Be Zero |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Figure 1: FEC 128 Pseudowire - IPv6

FEC 128 PW IPv6 Type: 24. 2 octets.

Length: Defines the length in octets of the value field of the sub-
TLV and its value is 38. 2 octets.

Sender's PE IPv6 Address: The source IP address of the target IPv6
LDP session. 16 octets.

Remote PE IPv6 Address: The destination IP address of the target IPv6
LDP session. 16 octets.

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RFC 6829 PW LSP Ping for IPv6 January 2013

PW ID: Same as FEC 128 Pseudowire IPv4 [RFC4379].

PW Type: Same as FEC 128 Pseudowire IPv4 [RFC4379].

3.2. FEC 129 Pseudowire

The FEC 129 Pseudowire IPv6 sub-TLV has a structure consistent with
the FEC 129 Pseudowire sub-TLV as described in Section 3.2.10 of
[RFC4379]. The encoding of FEC 129 Pseudowire IPv6 is 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| FEC 129 PW IPv6 Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ Sender's PE IPv6 Address ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ Remote PE IPv6 Address ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| PW Type | AGI Type | AGI Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ AGI Value ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AII Type | SAII Length | SAII Value |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ SAII Value (continued) ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AII Type | TAII Length | TAII Value |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ TAII Value (continued) ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TAII (cont.) | 0-3 octets of zero padding |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Figure 2: FEC 129 Pseudowire - IPv6

FEC 129 PW IPv6 Type: 25. 2 octets.

Length: Defines the length in octets of the value field of the sub-
TLV. 2 octets

The length of this TLV is 40 + AGI (Attachment Group Identifier)
length + SAII (Source Attachment Individual Identifier) length + TAII
(Target Attachment Individual Identifier) 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.

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Sender's PE IPv6 Address: The source IP address of the target IPv6
LDP session. 16 octets.

Remote PE IPv6 Address: The destination IP address of the target IPv6
LDP session. 16 octets.

The other fields are the same as FEC 129 Pseudowire IPv4 [RFC4379].

4. Summary of Changes

Section 3.2 of [RFC4379] tabulates all the sub-TLVs for the Target
FEC Stack. Per the change described in Sections 2 and 3, the table
would show the following:

Sub-Type Length Value Field
-------- ------ -----------
...
9 10 "FEC 128" Pseudowire - IPv4 (Deprecated)
10 14 "FEC 128" Pseudowire - IPv4
11 16+ "FEC 129" Pseudowire - IPv4
...
24 38 "FEC 128" Pseudowire - IPv6
25 40+ "FEC 129" Pseudowire - IPv6

5. Operation

This document does not define any new procedures. The process
described in [RFC4379] MUST be used.

6. IANA Considerations

IANA has made the following assignments in the "Multi-Protocol Label
Switching (MPLS) Label Switched Paths (LSPs) Ping Parameters"
registry.

The following sub-TLV changes, which comprise three updates and two
additions, are made for the TLV Type 1 "Target FEC Stack" in the
"TLVs and sub-TLVs" sub-registry.

The names of the Value fields of these three Sub-TLVs have been
updated to include the "IPv4" qualifier (see Section 2), and the
Reference has been updated to point to this document:

Type Sub-Type Value Field
---- -------- -----------
1 9 "FEC 128" Pseudowire - IPv4 (Deprecated)
1 10 "FEC 128" Pseudowire - IPv4
1 11 "FEC 129" Pseudowire - IPv4

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Two new entries for the Sub-Type field of the Target FEC TLV (see
Section 3) have been created:

Type Sub-Type Value Field
---- -------- -----------
1 24 "FEC 128" Pseudowire - IPv6
1 25 "FEC 129" Pseudowire - IPv6

7. Security Considerations

This document does not introduce any new security issues; the
security mechanisms defined in [RFC4379] apply here.

8. Acknowledgements

The authors gratefully acknowledge the review and comments of Vanson
Lim, Tom Petch, Spike Curtis, Loa Andersson, and Kireeti Kompella.

9. References

9.1. Normative References

[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.

[RFC4379] Kompella, K. and G. Swallow, "Detecting Multi-Protocol
Label Switched (MPLS) Data Plane Failures", RFC 4379,
February 2006.

9.2. Informative References

[MPLS-LDP] Asati, R., Manral, V., Papneja, R., and C. Pignataro,
"Updates to LDP for IPv6", Work in Progress, June 2012.

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Authors' Addresses

Mach(Guoyi) Chen
Huawei Technologies Co., Ltd
No. 3 Xinxi Road, Shang-di, Hai-dian District
Beijing 100085
China

EMail: [email protected]

Ping Pan
Infinera
US

EMail: [email protected]

Carlos Pignataro
Cisco Systems
7200-12 Kit Creek Road
Research Triangle Park, NC 27709
US

EMail: [email protected]

Rajiv Asati
Cisco Systems
7025-6 Kit Creek Road
Research Triangle Park, NC 27709
US

EMail: [email protected]

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