PCE Working Group Y. Lee
D. Dhody
Internet-Draft Huawei Technologies
Intended Status: Standards track D. Ceccarelli
Ericsson
Expires: August 2016
February 25, 2016
PCEP Extensions for Establishing Relationships Between Sets of LSPs
and Virtual Networks
draft-leedhody-pce-vn-association-00.txt
Abstract
This document describes how to extend PCE association mechanism
introduced by [PCE-Association] to further associate sets of LSPs
with a higher-level structure such as a virtual network requested by
clients or applications. This extended association mechanism can be
used to facilitate virtual network control using PCE architecture.
Status of this Memo
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Table of Contents
1. Introduction...................................................2
1.1. Requirements Language.....................................3
2. Terminology....................................................4
3. Operation Overview.............................................4
4. Extensions to PCEP.............................................4
5. Applicability to H-PCE architecture............................6
6. Security Considerations........................................7
7. IANA Considerations............................................7
7.1. Association Object Type Indicator.........................7
7.2. PCEP TLV Type Indicator...................................8
7.3. PCEP Error................................................8
8. References.....................................................8
8.1. Normative References......................................8
8.2. Informative References....................................9
Author's Addresses................................................9
1. Introduction
The Path Computation Element communication Protocol (PCEP) provides
mechanisms for Path Computation Elements (PCEs) to perform path
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computations in response to Path Computation Clients' (PCCs)
requests.
[I-D.ietf-pce-stateful-pce-app] describes general considerations for
a stateful PCE deployment and examines its applicability and
benefits, as well as its challenges and limitations through a number
of use cases. [I-D.ietf-pce-stateful-pce] describes a set of
extensions to PCEP to provide stateful control. A stateful PCE has
access to not only the information carried by the network's Interior
Gateway Protocol (IGP), but also the set of active paths and their
reserved resources for its computations. The additional state
allows the PCE to compute constrained paths while considering
individual LSPs and their interactions.
[I-D.ietf-pce-pce-initiated-lsp] describes the setup, maintenance
and teardown of PCE-initiated LSPs under the stateful PCE model.
Within the hierarchical PCE architecture, a PCE is used to initiate
or delete LSPs to a PCC.
[I-D.ietf-pce-association-group] introduces a generic mechanism to
create a grouping of LSPs. This grouping can then be used to define
association between sets of LSPs or between a set of LSPs and a set
of attributes.
[ACTN-REQ] describes various Virtual Network (VN) operations
initiated by a customer/application. In this context, there is a
need for associating a set of LSPs with a VN "construct" to
facilitate VN operations in PCE architecture. This association
allows the PCEs to identify which LSPs belong to a certain VN.
This document specifies a PCEP extension to associate a set of LSPs
based on Virtual Network or customer.
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].
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2. Terminology
The terminology is as per [RFC4655], [RFC5440], [RFC6805], and [I-
D.ietf-pce-stateful-pce].
3. Operation 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. In this draft, this grouping is used to define
associationsbetween a set of LSPs and a virtual network.
One new optional Association Object-type is defined based on the
generic Association object -
o VN Association Group (VNAG)
Thus this document define one new association type called "VN
Association Type" of value TBD1. The scope and handling of VNAG
identifier is similar to the generic association identifier defined
in [I-D.ietf-pce-association-group].
4. Extensions to PCEP
[I-D.ietf-pce-association-group] introduces the ASSOCIATION object,
the format of VNAG is as follows:
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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 VNAG Object formats
Please refer to [I-D.ietf-pce-association-group] for the definition
of each field in Figure 1. This document defines one mandatory TLV.
o VIRTUAL-NETWORK-TLV: Used to communicate the VN Identifier.
The format of VIRTUAL-NETWORK-TLV is as follows.
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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 (variable) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
// Virtual Network Name //
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2: The VIRTUAL-NETWORK-TLV formats
Type: TBD2 (to be allocated by IANA)
Length: Variable Length
Virtual Network Name(variable): symbolic name for the VN.
The VIRTUAL-NETWORK-TLV MUST be included in VNAG object.If a PCEP
speaker receives the VNAG object without the VIRTUAL-NETWORK-TLV, it
MUST send a PCErr message with Error-Type= 6 (mandatory object
missing) and Error-Value=TBD3 (VIRTUAL-NETWORK-TLV missing) and
close the session.
5. Applicability to H-PCE architecture
The ability to compute shortest constrained TE LSPs in Multiprotocol
Label Switching (MPLS) and Generalized MPLS (GMPLS) networks across
multiple domains has been identified as a key motivation for PCE
development. [RFC6805] describes a Hierarchical PCE (H-PCE)
architecture which can be used for computing end-to-end paths for
inter-domain MPLS Traffic Engineering (TE) and GMPLS Label Switched
Paths (LSPs). Within the hierarchical PCE architecture, the parent
PCE is used to compute a multi-domain path based on the domain
connectivity information. A child PCE may be responsible for a
single domain or multiple domains, it is used to compute the intra-
domain path based on its domain topology information.
[I-D.ietf-dhodylee-stateful-HPCE] introduces general considerations
for stateful PCE(s) in hierarchical PCE architecture. In
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particular, the behavior changes and additions to the existing
stateful PCE mechanisms in the context of a H-PCE architecture.
In Stateful H-PCE architecture, the Parent PCE receives a virtual
network creation request by its client over its Northbound API. This
VN is uniquely identified by an Association ID in VNAG as well as
the VIRTUAL-NETWORK name. This VN may comprise multiple LSPs in the
network in a single domain or across multiple domains.
As the Parent PCE computes the optimum E2E paths for each tunnel in
VN, it MUST associate each LSP with the VN to which it belongs.
Parent PCE sends a PCInitiate Message with this association
information in the VNAG Object (See Section 4 for details). This in
effect binds an LSP that is to be instantiated at the child PCE with
the VN.
Whenever changes occur with the instantiated LSP in a domain
network, the domain child PCE reports the changes using a PCRpt
Message in which the VNAG Object indicates the relationship between
the LSP and the VN.
Whenever an update occurs with VNs in the Parent PCE (via the
client's request), the parent PCE sends an PCUpd Message to inform
each affected child PCE of this change.
6. Security Considerations
TDB
7. IANA Considerations
7.1. Association Object Type Indicator
This document defines the following new association type originally
defined in [I-D.ietf-pce-association-group].
Value Name Reference
TBD1 VN Association Type [This I.D.]
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7.2. PCEP TLV Type Indicator
This document defines the following new PCEP TLV; IANA is requested
to make the following allocations from this registry at
http://www.iana.org/assignments/pcep/pcep.xhtml; see PCEP TLV Type
Indicators.
Value Name Reference
TBD2 VIRTUAL-NETWORK-TLV [This I.D.]
7.3. PCEP Error
IANA is requested to make the following allocations from this
registry at http://www.iana.org/assignments/pcep/pcep.xhtml; see
PCEP-ERROR Object Error Types and Values.
This document defines new Error-Type and Error-Value for the
following new error conditions:
Error-Type Meaning
6 Mandatory Object missing
Error-value=TBD3: VIRTUAL-NETWORK TLV missing
8. References
8.1. Normative References
[I-D.ietf-pce-stateful-pce] E. Crabbe, I. Minei, J. Medved, and R.
Varga, "PCEP Extensions for Stateful PCE", draft-ietf-pce-
stateful-pce, work in progress.
[I-D.ietf-pce-pce-initiated-lsp] E. Crabbe, et. al., "PCEP
Extensions for PCE-initiated LSP Setup in a Stateful PCE
Model", draft-ietf-pce-pce-initiated-lsp, work in
progress.
[I-D.ietf-pce-association-group] I, Minei, Ed., "PCEP Extensions for
Establishing Relationships Between Sets of LSPs", draft-
ietf-pce-association-group, work in progress.
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[I-D.ietf-dhodylee-stateful-HPCE] Dhody, D. and Lee, Y.,
"Hierarchical Stateful Path Computation Element (PCE)",
draft-dhodylee-pce-stateful-hpce, work in progress.
8.2. Informative References
[RFC4655] Farrel, A., Vasseur, J.-P., and J. Ash, "A Path
Computation Element (PCE)-Based Architecture", RFC 4655,
August 2006.
[RFC5440] Vasseur, JP., Ed. and JL. Le Roux, Ed., "Path Computation
Element (PCE) Communication Protocol (PCEP)", RFC 5440,
March 2009.
[RFC4655] Farrel, A., Vasseur, J., and J. Ash, "A Path Computation
Element (PCE)-Based Architecture", RFC 4655, August 2006.
[RFC6805] A. Farrel and D. King, "The Application of the Path
Computation Element Architecture to the Determination of a
Sequence of Domains in MPLS and GMPLS", RFC 6805, November
2012.
[I-D.ietf-pce-stateful-pce-app] Zhang, X., ED, and Minei, I., ED,
"Applicability of a Stateful Path Computation Element
(PCE)", draft-ietf-pce-stateful-pce-app, work-in-progress.
[ACTN-REQ] Y. Lee, D. Dhody, S. Belotti, K. Pithewan, and D.
Ceccarelli, "Requirements for Abstraction and Control of
TE Networks", draft-ietf-teas-actn-requirements, work in
progress.
Author's Addresses
Young Lee (Editor)
Huawei Technologies
5340 Legacy Drive, Building 3
Plano, TX 75023, USA
Email: leeyoung@huawei.com
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Dhruv Dhody (Editor)
Huawei Technologies
Divyashree Technopark, Whitefield
Bangalore, Karnataka 560037
India
EMail: dhruv.ietf@gmail.com
Daniele Ceccarelli
Ericsson
Torshamnsgatan,48
Stockholm, Sweden
EMail: daniele.ceccarelli@ericsson.com
Xian Zhang
Huawei Technologies
Email: zhang.xian@huawei.com
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