Internet DRAFT - draft-dhody-pce-association-attr
draft-dhody-pce-association-attr
PCE Working Group D. Dhody
Internet-Draft Q. Wu
Intended status: Standards Track Huawei Technologies
Expires: September 13, 2017 March 12, 2017
Path Computation Element communication Protocol extension for
relationship between LSPs and Attributes
draft-dhody-pce-association-attr-06
Abstract
The Path Computation Element (PCE) provides functions of path
computation in support of traffic engineering in networks controlled
by Multi-Protocol Label Switching (MPLS) and Generalized MPLS
(GMPLS).
This document defines a mechanism to create associations between a
set of LSPs and a set of attributes (such as configuration
parameters).
Status of This Memo
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This Internet-Draft will expire on September 13, 2017.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Motivation . . . . . . . . . . . . . . . . . . . . . . . . . 3
3.1. Opaque Identifier . . . . . . . . . . . . . . . . . . . . 4
3.2. Bundled requests . . . . . . . . . . . . . . . . . . . . 4
4. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . 4
5. Attribute Association Group . . . . . . . . . . . . . . . . . 5
5.1. ATTRIBUTE-OBJECT-TLV . . . . . . . . . . . . . . . . . . 6
6. Security Considerations . . . . . . . . . . . . . . . . . . . 7
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8
7.1. Association object Type Indicators . . . . . . . . . . . 8
7.2. PCEP TLV Type Indicators . . . . . . . . . . . . . . . . 8
7.3. Flag field in ATTRIBUTE-OBJECT-TLV . . . . . . . . . . . 8
8. Manageability Considerations . . . . . . . . . . . . . . . . 8
8.1. Control of Function and Policy . . . . . . . . . . . . . 9
8.2. Information and Data Models . . . . . . . . . . . . . . . 9
8.3. Liveness Detection and Monitoring . . . . . . . . . . . . 9
8.4. Verify Correct Operations . . . . . . . . . . . . . . . . 9
8.5. Requirements On Other Protocols . . . . . . . . . . . . . 9
8.6. Impact On Network Operations . . . . . . . . . . . . . . 9
9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 9
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 9
10.1. Normative References . . . . . . . . . . . . . . . . . . 9
10.2. Informative References . . . . . . . . . . . . . . . . . 10
Appendix A. Policy . . . . . . . . . . . . . . . . . . . . . . . 12
Appendix B. Contributor Addresses . . . . . . . . . . . . . . . 12
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 12
1. Introduction
[RFC5440] describes the Path Computation Element communication
Protocol (PCEP) which enables the communication between a Path
Computation Client (PCC) and a Path Control Element (PCE), or between
two PCEs based on the PCE architecture [RFC4655].
[I-D.ietf-pce-association-group] introduces a generic mechanism to
create a grouping of LSPs which can then be used to define
associations between a set of LSPs and a set of attributes (such as
configuration parameters) and is equally applicable to the active and
passive modes of a stateful PCE and a stateless PCE.
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This document specifies a PCEP extension to associate one or more
LSPs with a set of attributes.
PCEP Extensions for Stateful PCE Model [I-D.ietf-pce-stateful-pce]
describes a set of extensions to PCEP to enable active control of
MPLS-TE and GMPLS tunnels. [I-D.ietf-pce-pce-initiated-lsp]
describes the setup and teardown of PCE-initiated LSPs under the
active stateful PCE model, without the need for local configuration
on the PCC, thus allowing for a dynamic network. The mechanism
described in this document is equally applicable to these deployment
models.
1.1. 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].
2. Terminology
The following terminology is used in this document.
AAG: Attribute Association Group.
LSR: Label Switch Router.
MPLS: Multi-protocol Label Switching.
PAG: Policy Association Group.
PCC: Path Computation Client. Any client application requesting a
path computation to be performed by a Path Computation Element.
PCE: Path Computation Element. An entity (component, application,
or network node) that is capable of computing a network path or
route based on a network graph and applying computational
constraints.
PCEP: Path Computation Element Communication Protocol.
3. Motivation
This section discusses in more detail the motivation and use cases
for such an association including but not limited to -
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3.1. Opaque Identifier
An opaque identifier may represent attributes such as configured
parameters or constraints that a PCEP speaker may invoke on a peer.
Thus a PCEP speaker may only need an opaque identifier to invoke
these attributes (parameters or constraints) rather than encoding
them explicitly in each PCEP message.
This can also be used for tagging bunch of LSP to a particular
customer or for creation of virtual network like in case of
Abstraction and Control of TE Networks (ACTN)
[I-D.ietf-teas-actn-requirements]. (See
[I-D.leedhody-pce-vn-association])
3.2. Bundled requests
In some scenarios(e.g.,the topology example described in Section 4.6
of [RFC6805]), there is a need to send multiple requests with the
same constraints and attributes to the PCE. Currently these requests
are either sent in a separate path computation request (PCReq)
messages or bundled together in one (or more) PCReq messages. In
either case, the constraints and attributes need to be encoded
separately for each request even though they are exactly identical.
If a association is used to identify these constraints and attributes
shared by multiple requests and grouped together via association
mechanism, thus simplifying the path computation message exchanges.
4. Overview
As per [I-D.ietf-pce-association-group], LSPs are associated with
other LSPs with which they interact by adding them to a common
association group. This grouping can then be used to define
associations between sets of LSPs or between a set of LSPs and a set
of attributes (such as configuration parameters). A new optional
Association Object-type is defined based on the generic Association
object -
o Attribute Association Group (AAG)
Thus this document defines a new association type called "Attribute
Association Type" of value TBD1. An AAG can have one or more LSPs
and its associated attributes. The scope and handling of AAG
identifier is similar to the generic association identifier defined
in [I-D.ietf-pce-association-group].
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One or more LSP are grouped via a single group identifier as defined
in [I-D.ietf-pce-association-group]. The attributes that may be
associated with this set of LSPs may either are -
o known to the PCEP peers via some external means like
configuration, policy enforcement etc (can be considered as 'out-
of-band'). PCEP speaker simply use the AAG identifier in the PCEP
message and the peer is supposed to be aware of the associated
attributes. This is suitable for stateless PCE where the PCEP
peers should be aware of the association and its significance
outside of the protocol.
o or communicated to the PCEP peer via PCEP itself on first use (can
be considered as 'in-band'). PCEP speaker creates a new AAG by
using a new identifier and the associated attributes are
communicated via TLVs in association object. This is applicable
for stateful PCE only.
Error handling would be taken up in future revision.
5. Attribute Association Group
The format of the generic Association object used for AAG is shown in
Figure 1:
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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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved | Flags |R|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Association type (TBD1) | Association ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv4 Association Source |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// Optional TLVs //
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved | Flags |R|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Association type (TBD1) | Association ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| IPv6 Association Source |
| |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// Optional TLVs //
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: The AAG Object formats
Type = TBD1 for the Attribute Association Type.
AAG may carry optional TLVs including but not limited to -
o ATTRIBUTE-OBJECT-TLV: Used to communicate associated attributes in
form of PCEP objects, described in this document.
o VENDOR-INFORMATION-TLV: Used to communicate arbitrary behavioral
information, described in [RFC7470].
5.1. ATTRIBUTE-OBJECT-TLV
The ATTRIBUTE-OBJECT-TLV(s) maybe included in AAG object to associate
attributes encoded in PCEP objects.
The format of the ATTRIBUTE-OBJECT-TLV is shown in the following
figure:
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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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type (TBD2) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flags |M|R|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Object-Class | OT |Res|P|I| Object Length (bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
// (Object body) //
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2: ATTRIBUTE-OBJECT-TLV format
The type of the TLV is TBD2 and it has a variable length. The value
part consist of a 32-bit Flag filed followed by a PCEP object
(including common header [RFC5440] identifying the object) that is
associated with this AAG.
Following Flags are defined:
R (Remove - 1 bit): This is set to indicate that the attribute is
being removed from the attribute-list.
M (Modify - 1 bit): This is set to indicate that a previous
attribute is being modified, and the peer should overwrite the
attribute with the new value as per the object-body.
This TLV identifies the attributes associated with this group. For
each attribute a separate TLV is used. Future PCEP message exchanges
may only carry the AAG with no ATTRIBUTE-OBJECT-TLV.
6. Security Considerations
This document defines a new types for association and a new
ATTRIBUTE-OBJECT-TLV which do not add any new security concerns
beyond those discussed in [RFC5440], [I-D.ietf-pce-stateful-pce] and
[I-D.ietf-pce-association-group] in itself.
Some deployments may find the associations and their implications as
extra sensitive and thus should employ suitable PCEP security
mechanisms like TCP-AO or [I-D.ietf-pce-pceps].
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7. IANA Considerations
7.1. Association object Type Indicators
This document defines the following new association type originally
defined in [I-D.ietf-pce-association-group].
Value Name Reference
TBD1 Attribute Association Type [This I.D.]
7.2. PCEP TLV Type Indicators
This document defines the following new PCEP TLV; IANA is requested
to make the following allocations from this registry.
http://www.iana.org/assignments/pcep/pcep.xhtml#pcep-tlv-type-
indicators
Value Name Reference
TBD2 ATTRIBUTE-OBJECT-TLV [This I.D.]
7.3. Flag field in ATTRIBUTE-OBJECT-TLV
This document requests that a new sub-registry, named "ATTRIBUTE-
OBJECT-TLV Flag Field", is created within the "Path Computation
Element Protocol (PCEP) Numbers" registry to manage the Flag field of
the ATTRIBUTE-OBJECT-TLV. New values are to be assigned by Standards
Action [RFC5226]. Each bit should be tracked with the following
qualities:
o Bit number (counting from bit 0 as the most significant bit)
o Capability description
o Defining RFC
The following values are defined in this document:
Bit Description Reference
31 Remove [This I.D.]
30 Modify [This I.D.]
8. Manageability Considerations
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8.1. Control of Function and Policy
An operator MUST BE allowed to configure the attribute associations
at PCEP peers and associate it with the LSPs.
8.2. Information and Data Models
[RFC7420] describes the PCEP MIB, there are no new MIB Objects for
this document.
8.3. Liveness Detection and Monitoring
Mechanisms defined in this document do not imply any new liveness
detection and monitoring requirements in addition to those already
listed in [RFC5440].
8.4. Verify Correct Operations
Mechanisms defined in this document do not imply any new operation
verification requirements in addition to those already listed in
[RFC5440].
8.5. Requirements On Other Protocols
Mechanisms defined in this document do not imply any new requirements
on other protocols.
8.6. Impact On Network Operations
Mechanisms defined in this document do not have any impact on network
operations in addition to those already listed in [RFC5440].
9. Acknowledgments
A special thanks to author of [I-D.ietf-pce-association-group], this
document borrow some of the text from it.
10. References
10.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>.
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[RFC5440] Vasseur, JP., Ed. and JL. Le Roux, Ed., "Path Computation
Element (PCE) Communication Protocol (PCEP)", RFC 5440,
DOI 10.17487/RFC5440, March 2009,
<http://www.rfc-editor.org/info/rfc5440>.
[RFC7470] Zhang, F. and A. Farrel, "Conveying Vendor-Specific
Constraints in the Path Computation Element Communication
Protocol", RFC 7470, DOI 10.17487/RFC7470, March 2015,
<http://www.rfc-editor.org/info/rfc7470>.
[I-D.ietf-pce-association-group]
Minei, I., Crabbe, E., Sivabalan, S., Ananthakrishnan, H.,
Zhang, X., and Y. Tanaka, "PCEP Extensions for
Establishing Relationships Between Sets of LSPs", draft-
ietf-pce-association-group-02 (work in progress), January
2017.
[I-D.ietf-pce-stateful-pce]
Crabbe, E., Minei, I., Medved, J., and R. Varga, "PCEP
Extensions for Stateful PCE", draft-ietf-pce-stateful-
pce-18 (work in progress), December 2016.
10.2. Informative References
[RFC4655] Farrel, A., Vasseur, J., and J. Ash, "A Path Computation
Element (PCE)-Based Architecture", RFC 4655,
DOI 10.17487/RFC4655, August 2006,
<http://www.rfc-editor.org/info/rfc4655>.
[RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", BCP 26, RFC 5226,
DOI 10.17487/RFC5226, May 2008,
<http://www.rfc-editor.org/info/rfc5226>.
[RFC6805] King, D., Ed. and A. Farrel, Ed., "The Application of the
Path Computation Element Architecture to the Determination
of a Sequence of Domains in MPLS and GMPLS", RFC 6805,
DOI 10.17487/RFC6805, November 2012,
<http://www.rfc-editor.org/info/rfc6805>.
[RFC7420] Koushik, A., Stephan, E., Zhao, Q., King, D., and J.
Hardwick, "Path Computation Element Communication Protocol
(PCEP) Management Information Base (MIB) Module",
RFC 7420, DOI 10.17487/RFC7420, December 2014,
<http://www.rfc-editor.org/info/rfc7420>.
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[I-D.ietf-pce-pceps]
Lopez, D., Dios, O., Wu, W., and D. Dhody, "Secure
Transport for PCEP", draft-ietf-pce-pceps-11 (work in
progress), January 2017.
[I-D.ietf-pce-pce-initiated-lsp]
Crabbe, E., Minei, I., Sivabalan, S., and R. Varga, "PCEP
Extensions for PCE-initiated LSP Setup in a Stateful PCE
Model", draft-ietf-pce-pce-initiated-lsp-09 (work in
progress), March 2017.
[I-D.ietf-teas-actn-requirements]
Lee, Y., Dhody, D., Belotti, S., Pithewan, K., and D.
Ceccarelli, "Requirements for Abstraction and Control of
TE Networks", draft-ietf-teas-actn-requirements-04 (work
in progress), January 2017.
[I-D.ietf-pce-association-policy]
Dhody, D., Sivabalan, S., Litkowski, S., Tantsura, J., and
J. Hardwick, "Path Computation Element communication
Protocol extension for associating Policies and LSPs",
draft-ietf-pce-association-policy-00 (work in progress),
December 2016.
[I-D.leedhody-pce-vn-association]
Lee, Y., Dhody, D., Zhang, X., and D. Ceccarelli, "PCEP
Extensions for Establishing Relationships Between Sets of
LSPs and Virtual Networks", draft-leedhody-pce-vn-
association-01 (work in progress), October 2016.
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Appendix A. Policy
An earlier version of this document also had details about Policy
association group. This has been moved to an independent document -
[I-D.ietf-pce-association-policy].
Appendix B. Contributor Addresses
Xian Zhang
Huawei Technologies
Bantian, Longgang District
Shenzhen 518129
P.R.China
EMail: zhang.xian@huawei.com
Udayasree Palle
Huawei Technologies
Divyashree Techno Park, Whitefield
Bangalore, Karnataka 560066
India
EMail: udayasree.palle@huawei.com
Authors' Addresses
Dhruv Dhody
Huawei Technologies
Divyashree Techno Park, Whitefield
Bangalore, Karnataka 560066
India
EMail: dhruv.ietf@gmail.com
Qin Wu
Huawei Technologies
101 Software Avenue, Yuhua District
Nanjing, Jiangsu 210012
China
EMail: sunseawq@huawei.com
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