MPLS S. Boutros
Internet-Draft S. Bryant, Ed.
Intended status: Standards Track S. Sivabalan
Expires: September 10, 2009 G . Swallow
D. Ward
Cisco Systems
March 9, 2009
Definition of ACH TLV Structure
draft-bryant-mpls-tp-ach-tlv-01
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Abstract
In some application of the associated channel header (ACH), it is
necessary to have the ability to include a set of TLVs to provide
additional context information for the ACH payload. This document
defines a number of TLV types.
NOTE the family of Address Types is known to be incomplete. The
authors request that members of the MPLS-TP community provide details
of their required address formats in the form of text for the
creation of an additional sections similar to Section 3.1.
NOTE other TLV types will be added in further revisions of this
document. The authors request that members if the MPLS-TP community
requiring new TLVs to complete there MPLS-TP specifications provide
details of their required TLV in the form of text for the creation of
additional sections similar to Section 2.2.
Requirements Language
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 RFC2119 [1].
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
2. ACH TLV Object Definitions . . . . . . . . . . . . . . . . . . 4
2.1. The Null TLV Object . . . . . . . . . . . . . . . . . . . 4
2.2. Source Address . . . . . . . . . . . . . . . . . . . . . . 5
2.3. Destination Address . . . . . . . . . . . . . . . . . . . 5
2.4. Label Switched Path Identifier (LSPI) . . . . . . . . . . 6
2.5. Pseudowire Identifier (PWI) . . . . . . . . . . . . . . . 6
3. ACH Addresses . . . . . . . . . . . . . . . . . . . . . . . . 7
3.1. IPv4 Address . . . . . . . . . . . . . . . . . . . . . . . 7
3.2. IPv6 Address . . . . . . . . . . . . . . . . . . . . . . . 8
4. Security Considerations . . . . . . . . . . . . . . . . . . . 8
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8
6. References . . . . . . . . . . . . . . . . . . . . . . . . . . 9
6.1. Normative References . . . . . . . . . . . . . . . . . . . 9
6.2. Informative References . . . . . . . . . . . . . . . . . . 9
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 10
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1. Introduction
The MPLS generic associated channel header specification [9] (GACH)
describes a TLV structure that is used to provide additional context
information for the ACH payload. This document defines a number of
TLVs that are required by the MPLS-TP design [10], [11]. One use of
these TLVs to identify the source and/or intended destination of the
ACH payload for use in transport networks. However the use of this
construct is not limited to providing addressing information nor is
the applicability restricted to transport network applications.
Additionally TLVs from defined in this document may be used as sub-
TLVs in the construction of compound TLV structures.
2. ACH TLV Object Definitions
This section provides the definition for a number of ACH TLV objects.
In each case the length in the TLV header is the length of just the
value component.
2.1. The Null TLV Object
The Null TLV provides an OPTIONAL mechanism of restoring 32bit
alignment of the following element in the packet and also provides an
OPTIONAL mechanism to reserve space in the packet to be used by TLV
objects that will be written by LSR that perform some operation on
the packet at a later time. For security reasons the value must be
zero.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AchTlvType = 0 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ Value = 0 ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: Null TLV Object
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2.2. Source Address
This TLV specifies the source address (SA) of an ACH packet.
Where the packet is associated with a maintenance request/response
operation it refers to the requester of the operation, i.e. It is
the address of the Maintenance End Point that initiated the operation
being either requested, or being responded to.
The address is an ACH address as described in Section 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AchTlvType = 1 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ Address |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2: Source Address
2.3. Destination Address
This TLV specifies the destination address (DA) of an ACH packet.
Where the packet is associated with a maintenance request/response
operation it refers to the target of the operation, i.e. It is the
address of the Maintenance End Point or Maintenance Intermediate
Point that has been requested to execute the operation being either
requested, or being responded to.
The address is an ACH address as described in Section 3.
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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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AchTlvType = 2 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ Address |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 3: Destination Address
2.4. Label Switched Path Identifier (LSPI)
This TLV is used to identify a Label Switched Path (LSP).
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AchTlvType = 3 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ TBD |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 4: Label Switched Path Identifier
This will draw on the contents of [2]. Further material will be
added in a future version of this document.
2.5. Pseudowire Identifier (PWI)
This TLV is used to identify a pseudowire.
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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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AchTlvType = 4 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ TBD |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 5: Pseudowire Identifier
This will draw on the contents of [2]. Further material will be
added in a future version of this document.
3. ACH Addresses
This section is incomplete. Definitions of other address types will
be provided in a future version of this document. The authors would
like to take input from other members of the MPLS-TP design community
as to the required additional addressing types and the correct way to
represent them in this framework.
Addresses are expressed in the following TLV format. This
representation allows ACH TLVs to be specified in a format that is
independent of the address that are to be used in the TV instance.
Although many address types are of fixed length, and some which are
not incorporate a length indicator, this may not always be the case
and hence a length field is incorporated in the address TLV.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AddType | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ Address |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3.1. IPv4 Address
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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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AddType = 1 | Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv4 Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
This address TLV contains an IPv4 address as defined in [3].
3.2. IPv6 Address
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AddType = 2 | Length = 16 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ IPv6 Address |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
This address TLV contains an IPv6 address as defined in [4]
4. Security Considerations
This specification defines a mechanism to identify a set of protocol
parameters. The necessary security considerations will be described
in the definition of the protocols that uses these parameters.
5. IANA Considerations
IANA is requested to create two new registries in the pseudowire name
spaces: the ACH TLV Registry and the ACH Address Type Registry.
The ACH TLV Registry should be initialized with the following
entries. The allocation policy for this registry is IETF consensus.
Name Type Length Description Reference
(octets)
Null 0 3 Null TLV This Draft
SA 1 var Source Addr This Draft
DA 2 var Dest Addr This Draft
LSPI 3 var LSP Identifier This Draft
PWI 4 var PW Identifier This Draft
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The ACH Address Type Registry should be initialized with the
following entries. The allocation policy for this registry is IETF
consensus.
Name Type Length Description Reference
(octets)
Null 0 Reserved
IPv4 1 4 IPv4 Address This Draft
IPv6 2 16 IPv6 Address This Draft
6. References
6.1. Normative References
[1] Bradner, S., "Key words for use in RFCs to Indicate Requirement
Levels", BCP 14, RFC 2119, March 1997.
[2] Kompella, K. and G. Swallow, "Detecting Multi-Protocol Label
Switched (MPLS) Data Plane Failures", RFC 4379, February 2006.
[3] Postel, J., "Internet Protocol", STD 5, RFC 791,
September 1981.
[4] Deering, S. and R. Hinden, "Internet Protocol, Version 6 (IPv6)
Specification", RFC 1883, December 1995.
[5] Martini, L., Rosen, E., El-Aawar, N., Smith, T., and G. Heron,
"Pseudowire Setup and Maintenance Using the Label Distribution
Protocol (LDP)", RFC 4447, April 2006.
[6] Bryant, S., Swallow, G., Martini, L., and D. McPherson,
"Pseudowire Emulation Edge-to-Edge (PWE3) Control Word for Use
over an MPLS PSN", RFC 4385, February 2006.
[7] Allan, D. and T. Nadeau, "A Framework for Multi-Protocol Label
Switching (MPLS) Operations and Management (OAM)", RFC 4378,
February 2006.
[8] Rosen, E., Tappan, D., Fedorkow, G., Rekhter, Y., Farinacci,
D., Li, T., and A. Conta, "MPLS Label Stack Encoding",
RFC 3032, January 2001.
6.2. Informative References
[9] Bocci, M., Vigoureux, M., Swallow, G., Ward, D., Bryant, S.,
and R. Aggarwal, "MPLS Generic Associated Channel header",
draft-ietf-mpls-tp-gach-gal-02 (work in progress),
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February 2009.
[10] Niven-Jenkins, B., Brungard, D., Betts, M., Sprecher, N., and
S. Ueno, "MPLS-TP Requirements",
draft-ietf-mpls-tp-requirements-04 (work in progress),
February 2009.
[11] Bocci, M., Bryant, S., and L. Levrau, "A Framework for MPLS in
Transport Networks", draft-ietf-mpls-tp-framework-00 (work in
progress), November 2008.
Authors' Addresses
Sami Boutros
Cisco Systems
Phone:
Fax:
Email: sboutros@cisco.com
URI:
Stewart Bryant (editor)
Cisco Systems
Phone:
Fax:
Email: stbryant@cisco.com
URI:
Siva Sivabalan
Cisco Systems
Phone:
Fax:
Email: msiva@cisco.com
URI:
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George Swallow
Cisco Systems
Phone:
Fax:
Email: swallow@cisco.com
URI:
David Ward
Cisco Systems
Phone:
Fax:
Email: dward@cisco.com
URI:
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