One document matched: draft-ietf-pce-of-01.txt
Differences from draft-ietf-pce-of-00.txt
Network Working Group J.L. Le Roux
Internet Draft France Telecom
Category: Standard Track
Expires: May 2008 J.P. Vasseur
Cisco System Inc.
Y. Lee
Huawei
November 2007
Encoding of Objective Functions in Path Computation Element
communication Protocol (PCEP)
draft-ietf-pce-of-01.txt
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Le Roux, Vasseur, Lee Encoding of Objective Functions in PCEP [Page 1]
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Abstract
The computation of one or a series of Traffic Engineering Label
Switched Paths (TE LSPs) in MultiProtocol Label Switching (MPLS) and
Generalized MPLS (GMPLS) networks, is subject to a set of one or more
specific optimization criteria(s), referred to as an objective
function (e.g. minimum cost path, widest path, etc.). A Path
Computation Element (PCE) may support one or multiple objective
functions, and it is desired for a Path Computation Client (PCC) to
automatically discover the set of objective functions supported by a
PCE. Furthermore, it may be useful for a PCC to specify in a path
computation request the required objective function to be used by the
PCE to compute a TE LSP or a set of TE LSPs. Thus the aim of this
document is to define extensions to the PCE communication Protocol
(PCEP) in order to allow a PCC to discover the set of objective
functions supported by a PCE as well as to allow a PCC to indicate in
a path computation request the required objective function and a PCE
to indicate in a path computation reply the objective function that
was used for path computation.
Conventions used 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.
Table of Contents
1. Terminology.................................................3
2. Introduction................................................3
3. Discovery of PCE Objective Functions........................5
3.1. OF-List TLV.................................................5
3.2. Elements of procedure.......................................6
4. Objective Function in PCEP Path Computation request and
reply messages..............................................6
4.1. OF Object...................................................6
4.1.1. Elements of Procedure.......................................7
4.2. Carrying the OF object in a PCEP message....................8
4.3. New RP object flag.........................................10
4.3.1. Elements of procedure......................................10
5. Objective Functions definition.............................10
6. IANA Considerations........................................12
6.1. PCE Objective Function registry............................12
6.2. PCEP code points...........................................13
6.2.1. OF Object..................................................13
6.2.2. OF-List TLV................................................13
6.2.3. PCEP Error values..........................................13
6.2.4. RP Object flag.............................................14
7. Security Considerations....................................14
8. Manageability Considerations...............................14
8.1. Control of Function and Policy.............................14
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8.2. Information and Data Models................................14
8.3. Liveness Detection and Monitoring..........................15
8.4. Verify Correct Operations..................................15
8.5. Requirements on other protocols............................15
8.6. Impact on network operations...............................15
9. Acknowledgments............................................15
10. References.................................................15
10.1. Normative references.......................................15
10.2. Informative references.....................................16
11. Author's Addresses:........................................16
12. Intellectual Property Statement............................17
1. Terminology
Terminology used in this document
LSR: Label Switching Router.
OF: Objective Function: A set of one or more optimization
criteria(s) used for the computation of a single path (e.g. path
cost minimization), or the synchronized computation of a set of
paths (e.g. aggregate bandwidth consumption minimization, etc.).
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.
TE LSP: Traffic Engineered Label Switched Path.
2. Introduction
The PCE-based network architecture [RFC4655] defines a Path
Computation Element (PCE) as an entity capable of computing TE LSP
paths based on a network graph, and applying computational
constraints. A PCE serves path computation requests sent by Path
Computation Clients (PCC).
The PCE communication Protocol (PCEP), defined in [PCEP], allows for
communication between a PCC and a PCE or between two PCEs, in
compliance with requirements and guidelines set forth in [RFC4657].
Such interactions include path computation requests and path
computation replies.
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The computation of one or a set of TE LSPs is subject to a set of one
or more optimization criteria(s), called an objective function. An
objective function is used by the PCE, when it computes a path or a
set of paths, in order to select the "best" candidate path(s). There
is a variety of objective functions: an objective function could
apply either to a set of non synchronized path computation requests,
or to a set of synchronized path computation requests. In the former
case, the objective function refers to an individual path computation
request (e.g. computation of the shortest constrained path where the
metric is the IGP metric, computation of the least loaded constrained
path, etc.). Conversely in the latter case, the objective function
refers to a set of path computation requests the computation of which
is synchronized (e.g. minimize the aggregate bandwidth consumption of
all LSPs, minimize the sum of the delays for two diverse paths, or
the delta between those delays, etc.). Moreover, some objective
functions relate to the optimization of a single metric and others to
the optimization of a set of metrics (organized in a hierarchical
manner, using a weighted function, etc.).
As spelled out in [RFC4674], it may be useful for a PCC to discover
the set of objective functions supported by a PCE. Furthermore,
[RFC4657] requires the ability for a PCC to indicate in a path
computation request a required/desired objective function, as well as
optional function parameters.
For these purposes, this document extends the PCE communication
Protocol (PCEP). It defines PCEP extensions allowing a PCE
advertising a list of supported objective functions, as well as
extensions so as to carry the objective function in PCEP request and
reply messages. It thus complements the PCEP base specification
[PCEP].
Note that IS-IS and OSPF based PCE Discovery mechanisms are defined
in ([ISIS-PCED], [OSPF-PCED]). These mechanisms are dedicated to the
discovery of a few generic parameters while more detailed PCE
parameters should rather be discovered using the PCE communication
Protocol. Objective functions pertain to this second category; thus
the Objective Function discovery procedure is handled by PCEP.
A new PCEP TLV, named the OF-List TLV is defined in section 3. The
OF-List TLV is carried in the PCEP OPEN object and allows a PCE
advertising to a PCEP peer, during PCEP session setup phase, the list
of objective functions that it supports.
A new PCEP object, the OF object, is defined in section 4. The OF
object is carried within a PCReq message to indicate the
required/desired objective function to be applied by a PCE or in a
PCRep message to indicate the objective function that was used for
path computation.
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Six mandatory objective functions that must be supported by PCEP are
listed in [RFC4657]. This document provides a definition of these six
mandatory objective functions. Additional objective functions may be
defined in other documents. Note that additional objective functions
are defined for PCE Global Concurrent Optimization (GCO) application,
in [PCE-GCO].
3. Discovery of PCE Objective Functions
This section defines PCEP extensions (see [PCEP]) so as to support
the advertisement of the objective functions supported by a PCE.
A new PCEP OF-List (Objective Function list) TLV is defined. The PCEP
OF-List TLV is carried within an OPEN object, in order for a PCE to
advertise to a PCEP peer the list of objective functions it supports,
during PCEP session setup phase.
3.1. OF-List TLV
The PCEP OF-List TLV is optional. It MAY be carried within an OPEN
object sent by a PCE in an Open message to a PCEP peer, so as to
indicate the list of supported objective functions.
The OF-List TLV format is compliant with the PCEP TLV format defined
in [PCEP]. That is, the TLV is composed of 2 octets for the type, 2
octets specifying the TLV length, and a value field. The Length field
defines the length of the value portion in octets. The TLV is padded
to four-octet alignment and padding is not included in the Length
field (e.g. a three octet value would have a length of three, but the
total size of the TLV would be eight octets).
The OSPF OF-List TLV has the following format:
TYPE: To be assigned by IANA (suggested value = 4 )
LENGTH: N * 2 (where N is the number of objective functions)
VALUE: list of 2-bytes objective function code points,
identifying the objective functions supported by the
sender of the Open message.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| OF Code #1 | OF Code #2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// //
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| OF Code #N | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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OF Code (2 bytes): Objective Function code point identifier.
IANA is requested to manage the PCE objective function code point
registry (see IANA section).
3.2. Elements of procedure
A PCE MAY include and OF-List TLV within an OPEN object in an Open
message sent to a PCEP peer, to advertise a set of one or more
objective functions. The OF-List TLV MUST NOT appear more than once
in an OPEN object. The absence of the OF-List TLV in an OPEN object
must be interpreted as an absence of information on the list of
supported objective functions by the PCE.
As specified in [PCEP], a PCEP peer that does not recognize the OF-
List TLV will silently ignore it.
4. Objective Function in PCEP Path Computation request and reply
messages
This section defines PCEP extensions ([PCEP]) so as to support the
communication of objective functions in PCEP path computation request
and reply messages. A new PCEP OF (Objective Function) object is
defined, to be carried within a PCReq message in order for the PCC to
indicate the required/desired objective function.
The PCEP OF Object may also be carried within a PCRep message in
order for the PCE to indicate the objective function that was used by
the PCE.
A new flag is defined in the RP object, so as to indicate in a PCReq
message that the PCE MUST provide in the PCRep message the objective
function that was used during path computation.
Also new PCEP error type and value are defined.
4.1. OF Object
The PCEP OF (Objective Function) object is optional. It MAY be
carried within a PCReq message so as to indicate the desired/required
objective function to be applied by the PCE during path computation,
or within a PCRep message so as to indicate the objective function
that was used by the PCE during path computation.
The OF object format is compliant with the PCEP object format defined
in [PCEP].
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The OF Object-Class is to be assigned by IANA (recommended value=21).
The OF Object-Types is to be assigned by IANA (recommended value=1).
The format of the OF object body is:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Objective Function Code(IANA) | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
// Optional TLV(s) //
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Objective Function Code (2 bytes): The identifier of the Objective
Function. The IANA is requested to manage the PCE objective function
code point registry (see IANA section).
Reserved (2 bytes): This field MUST be set to zero on transmission
and MUST be ignored on receipt.
Optional TLVs may be defined so as to encode objective function
parameters.
4.1.1. Elements of Procedure
To request the use of a specific objective function to be used by the
PCE a PCC MUST include an OF object in the PCReq message.
[PCEP] specifies a bit flag referred to as the P bit in a PCEP
common header that can be set by a PCC to enforce a PCE to take into
account the related information during the path computation. If the
objective function is mandatory (required objective function), the P
bit in the OF object MUST be set, else if it is optional (desired
objective function) the P bit MUST be cleared.
On receipt of a PCReq message with an OF object, a PCE MUST proceed
as follows:
- If the OF object is unknown/unsupported, the PCE MUST follow
procedures defined in [PCEP], that is if the P bit is set, it
sends a PCErr message with error type unknown/unsupported
object (type 3 and 4) and the related path computation request
MUST be discarded. If the P bit is cleared it is free
to ignore the object.
- If the objective function is unknown / unsupported and the P
bit is set, the PCE MUST send a PCErr message with a new PCEP
error type "objective function error" and error value
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"unknown/unsupported objective function" (defined in this
document), and the related path computation request MUST be
discarded.
- If the objective function is unknown / unsupported and the P
bit is cleared, the PCE SHOULD apply another (default)
objective function.
- If the objective function is supported but policy does not
permit applying it, and the P bit is set, the PCE MUST send a
PCErr message with the PCEP error type "policy-violation"
(type 5) and a new error value "objective function not
allowed" (defined in this document).
- If the objective function is supported but policy does not
allow applying it, and the P bit is cleared, the PCE SHOULD
apply another (default) objective function.
- If the objective function is supported and policy allows
applying it, then if the P bit is set the PCE MUST apply the
requested objective function, else if the P bit is cleared the
PCE is free to apply any other objective function.
The default objective function may be locally configured.
4.2. Carrying the OF object in a PCEP message
The OF object MAY be carried within a PCReq message. An OF object
specifying an objective function that applies to a set of
synchronized path computation requests MUST be carried just after the
corresponding SVEC object, and MUST NOT be repeated for each
elementary request.
An OF object specifying an objective function that applies to an
individual path computation request (non synchronized case) MUST
follow the RP object for which it applies.
The format of the PCReq message is updated as follows:
<PCReq Message>::= <Common Header>
[<SVEC-list>]
<request-list>
where:
<svec-list>::=<SVEC>
[<OF>]
[<svec-list>]
<request-list>::=<request>[<request-list>]
<request>::= <RP>
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<END-POINTS>
[<OF>]
[<LSPA>]
[<BANDWIDTH>]
[<metric-list>]
[<RRO>]
[<IRO>]
[<LOAD-BALANCING>]
where:
<metric-list>::=<METRIC>[<metric-list>]
The OF object MAY be carried within a PCRep message to indicate the
objective function used by the PCE during path computation.
When the PCE wants to indicate to the PCC the objective function that
was used for the synchronized computation of a set of paths, the
PCRep message MUST include the corresponding SVEC object directly
followed by the OF object, which MUST NOT be repeated for each
elementary request.
An OF object specifying an objective function used for an individual
path computation (non synchronized case) MUST follow the RP object
for which it applies.
The format of the PCRep message is updated as follows:
<PCRep Message> ::= <Common Header>
[<SVEC-list>]
<response-list>
where:
<svec-list> ::=<SVEC>
[<OF>]
[<svec-list>]
<response-list>::=<response>[<response-list>]
<response>::=<RP>
[<NO-PATH>]
[<path-list>]
<path-list>::=<path>[<path-list>]
<path>::= <ERO>
[<OF>]
[<LSPA>]
[<BANDWIDTH>]
[<metric-list>]
[<IRO>]
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where:
<metric-list>::=<METRIC>[<metric-list>]
4.3. New RP object flag
In some cases, where no objective function is specified in the
request, or an optional objective function is desired (P flag cleared
in the OF object common header) but the PCE does not follow the
recommendation, the PCC may desire to know the objective function
that was used by the PCE during path computation. To that end, a new
flag is defined in the RP object, named the OF flag, allowing a PCC
to request for the inclusion in the path computation reply of the
objective function that was used by the PCE during path computation.
The following new bit flag of the RP object is defined:
Objective Function (OF) flag (1 bit): 0x200 (bit number 16)
(suggested value, to be assigned by IANA). When set in a PCReq
message, this indicates that the PCE has to provide the applied
objective function (should a path satisfying the constraints be found)
in the PCRep message. When set in a PCRep message this indicates that
the Objective Function that was used during path computation is
included.
4.3.1. Elements of procedure
If the PCC wants to know the objective function used by the PCE
during path computation for a given request, it MUST set the OF flag
in the RP object.
On receipt of a PCReq message with the OF flag in the RP object set,
the PCE has to proceed as follows:
- If policy permits it MUST include in the PCRep message an OF
object indicating the objective function it used during path
computation.
- If policy does not permit, it MUST send a PCErr message with
the PCEP error code "policy-violation" (type 5) and a new
error value "objective function indication not allowed"
(defined in this document).
5. Objective Functions definition
Six objective functions that must be supported by PCEP are listed in
[RFC4657]. Objective function codes should be assigned by IANA and
are suggested below.
Objective functions are formulated using the following terminology:
- a network comprises a set of N links {Li, (i=1...N)}
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- a path P is a list of K links {Lpi,(i=1...K)}
- metric of link L is noted M(L), this can be the IGP metric the
TE metric or any other metric.
- the cost of a path P is noted C(P),
C(P) = sum {M(Lpi), (i=1...K)}.
- residual bandwidth on link L is noted r(L)
- maximum reservable bandwidth on link L is noted R(L).
There are three objective functions that apply to the computation of
a single path:
Objective Function Code: 1 (suggested value, to be assigned by IANA)
Name: Minimum Cost Path (MCP)
Description: Find a path P such that C(P) is minimized.
Objective Function Code: 2 (suggested value, to be assigned by IANA)
Name: Minimum Load Path (MLP)
Description: Find a path P such that ( Max {(R(Lpi) - r(Lpi)) /
R(Lpi), i=1...K } ) is minimized
Objective Function Code: 3 (suggested value, to be assigned by IANA)
Name: Maximum residual Bandwidth Path (MBP)
Description: Find a path P such that ( Min { r(Lpi)), i=1...K } ) is
maximized.
There are three objective functions that apply to a set of path
computation requests the computation of which is synchronized:
Objective Function Code: 4 (suggested value, to be assigned by IANA)
Name: Minimize aggregate Bandwidth Consumption (MBC)
Description: Find a set of paths such that ( Sum {R(Li) - r(Li),
i=1...N} ) is minimized.
Objective Function Code: 5 (suggested value, to be assigned by IANA)
Name: Minimize the Load of the most loaded Link (MLL)
Description: Find a set of paths such that ( Max { (R(Li) - r(Li)) /
R(Li), i=1...N}) is minimized.
Objective Function Code: 6 (suggested value, to be assigned by IANA)
Name: Minimize the Cumulative Cost of a set of paths (MCC)
Description: Find a set of paths {P1...Pm} such that (Sum { C(Pi),
i=1...m}) is minimized.
Other objective functions may be defined in separate documents.
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6. IANA Considerations
6.1. PCE Objective Function registry
This document defines a 16-bit PCE Objective Function identifier to
be carried within the PCEP OF object, as well as the PCEP OF-List TLV.
IANA is requested to create and manage the 16-bit "PCE Objective
Function" code point registry, starting from 1 and continuing through
32767, as follows:
- Objective Function code point value
- Objective Function name
- Defining RFC
The same registry is applicable to the OF object and the OF-List TLV
defined in this document.
The guidelines (using terms defined in [RFC2434]) for the
assignment of objective function code point values are as follows:
- Function code value 0 is reserved.
- Function code value in the range 1-32767 are to be assigned as
follows:
- Function code values 1 through 1023 are to be assigned by
IANA using the "IETF Consensus" policy.
- Function code values 1024 through 32767 are to be
assigned by IANA, using the "First Come First Served"
policy.
- Function code values in the range 32768-65535 are for
"Private Use".
Six objective functions are defined in section 5 of this document and
should be assigned by IANA:
Code Point Name Defining RFC
1 MCP this doc
2 MLP this doc
3 MBP this doc
4 MBC this doc
5 MLL this doc
6 MCC this doc
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6.2. PCEP code points
6.2.1. OF Object
The IANA has been requested to manage the PCEP Objects code point
registry (see [PCEP]).
This document defines a new PCEP object, the OF object, to be
carried in PCReq and PCRep messages. The IANA is requested to make
the following allocation (suggested value):
Object Name Object Name Reference
Class Type
21 OF 1 Objective (this document)
Function
6.2.2. OF-List TLV
IANA is requested to manage the PCEP TLV code point registry (see
[PCEP]).
This document defines a new PCEP TLV, the OF-List TLV, to be carried
in the OPEN object. The IANA is requested to make the following
allocation (suggested value):
Type TLV name References
----- -------- ----------
4 OF-List (This document)
6.2.3. PCEP Error values
A new PCEP Error-Type is defined in this document, with two error
values (Error-Type and Error-value to be assigned by IANA):
Error-type Meaning and error values Reference
14 Objective Function Error (this doc)
Error-value=1: unknown objective function
(request rejected)
Error-value=2: unsupported objective function
(request rejected)
Two new error values are defined for the error type "policy
violation" (type 5):
Error-type Meaning and error values Reference
5 Policy violation
Error-value=3: objective function not allowed (this doc)
(request rejected)
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Error-value=4: OF bit of the RP object set (this doc)
(request rejected)
6.2.4. RP Object flag
A new flag of the RP object (specified in [PCEP]) is defined in this
document. The IANA is requested to make the following allocation
(suggested value):
Bit Hex Name Reference
Number
16 0x200 OF (this document)
7. Security Considerations
Mechanisms discussed in [PCEP] to secure a PCEP session can be used
to secure the PCEP OF object and OF list TLV as well.
8. Manageability Considerations
8.1. Control of Function and Policy
It MUST be possible to configure the activation/deactivation of
Objective Function Discovery in PCEP.
In addition to the parameters already listed in section 8.1 of [PCEP],
a PCEP implementation SHOULD allow configuring on a PCE a list of
authorized objective functions. This may apply to any session the
PCEP speaker participates in, to a specific session with a given PCEP
peer or to a specific group of sessions with a specific group of PCEP
peers.
Note that it is not mandatory for an implementation to support all
objective functions defined in section 5.
It MUST be possible to configure a default objective function used
for path computation when a path request is received that requests to
use an optional objective function.
8.2. Information and Data Models
The PCEP MIB Module defined in [PCEP-MIB] MUST be extended to include
Objective Functions.
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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 [PCEP].
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
[PCEP].
8.5. Requirements on other protocols
Mechanisms defined in this document do not imply any requirements on
other protocols in addition to those already listed in [PCEP].
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 [PCEP].
9. Acknowledgments
The authors would like to thank Jerry Ash for his useful comments.
10. References
10.1. Normative references
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2740] Coltun, R., Ferguson, D., and J. Moy, "OSPF for IPv6",
RFC 2740, December 1999.
[RFC3630] Katz, D., Yeung, D., Kompella, K., "Traffic Engineering
Extensions to OSPF Version 2", RFC 3630, September 2003.
[RFC3784] Li, T., Smit, H., "IS-IS extensions for Traffic
Engineering", RFC 3784, June 2004.
[RFC4655] Farrel, A., Vasseur, J.P., Ash, J., "Path Computation
Element (PCE)-based Architecture", RFC4655, august 2006.
[PCEP] Vasseur, Le Roux, et al., "Path Computation Element (PCE)
communication Protocol (PCEP)", draft-ietf-pce-pcep, work in
progress.
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Internet Draft draft-ietf-pce-of-01.txt December 2007
10.2. Informative references
[RFC4657] Ash, J., Le Roux, J.L., " PCE Communication Protocol
Generic Requirements", RFC4657, September 2006.
[RFC4674] Le Roux, J.L., et al. "Requirements for PCE discovery",
RFC4674, October 2006.
[ISIS-PCED] Le Roux, Vasseur, et al. "IS-IS protocol extensions for
Path Computation Element (PCE) Discovery", draft-ietf-pce-disco-
proto-isis, work in progress.
[OSPF-PCED] Le Roux, Vasseur, et al. "OSPF protocol extensions for
Path Computation Element (PCE) Discovery", draft-ietf-pce-disco-
proto-ospf, work in progress.
[PCE-GCO] Y. Lee, J.L. Le Roux, D. King, and E. Oki, "Path
Computation Element Communication Protocol (PCECP) Requirements and
Protocol Extensions In Support of Global Concurrent Optimization",
draft-ietf-pce-global-concurrent-optimization-01.txt, work in
progress
11. Author's Addresses:
Jean-Louis Le Roux
France Telecom
2, avenue Pierre-Marzin
22307 Lannion Cedex
FRANCE
Email: jeanlouis.leroux@orange-ftgroup.com
Jean-Philippe Vasseur
Cisco Systems, Inc.
1414 Massachusetts avenue
Boxborough , MA - 01719
USA
Email: jpv@cisco.com
Young Lee
Huawei Technologies, LTD.
1700 Alma Drive, Suite 100
Plano, TX 75075
USA
Email: ylee@huawei.com
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Internet Draft draft-ietf-pce-of-01.txt December 2007
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