draft-ietf-pce-monitoring-03.txt   draft-ietf-pce-monitoring-04.txt 
Networking Working Group JP. Vasseur, Ed. Networking Working Group JP. Vasseur, Ed.
Internet-Draft Cisco Systems, Inc Internet-Draft Cisco Systems, Inc
Intended status: Standards Track JL. Le Roux Intended status: Standards Track JL. Le Roux
Expires: May 6, 2009 France Telecom Expires: July 24, 2009 France Telecom
Y. Ikejiri Y. Ikejiri
NTT Communications Corporation NTT Communications Corporation
November 2, 2008 January 20, 2009
A set of monitoring tools for Path Computation Element based A set of monitoring tools for Path Computation Element based
Architecture Architecture
draft-ietf-pce-monitoring-03.txt draft-ietf-pce-monitoring-04.txt
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Abstract Abstract
A Path Computation Element (PCE) based architecture has been A Path Computation Element (PCE) based architecture has been
specified for the computation of Traffic Engineering (TE) Label specified for the computation of Traffic Engineering (TE) Label
Switched Paths (LSPs) in Multiprotocol Label Switching (MPLS) and Switched Paths (LSPs) in Multiprotocol Label Switching (MPLS) and
Generalized MPLS (GMPLS) networks in the context of single or Generalized MPLS (GMPLS) networks in the context of single or
multiple domains (where a domain refers to a collection of network multiple domains (where a domain refers to a collection of network
elements within a common sphere of address management or path elements within a common sphere of address management or path
computational responsibility such as IGP areas and Autonomous computational responsibility such as IGP areas and Autonomous
Systems). In PCE-based environments, it is thus critical to monitor Systems). Path Computation Clients (PCCs) send computation requests
the state of the path computation chain for troubleshooting and to PCEs, and these may forward the requests to and cooperate with
performance monitoring purposes: liveness of each element (PCE) other PCEs forming a "path computation chain". In PCE-based
involved in the PCE chain, detection of potential resource contention environments, it is thus critical to monitor the state of the path
states and statistics in term of path computation times are examples computation chain for troubleshooting and performance monitoring
of such metrics of interest. This document specifies procedures and purposes: liveness of each element (PCE) involved in the PCE chain,
extensions to the Path Computation Element Protocol (PCEP) in order detection of potential resource contention states and statistics in
to gather such information. term of path computation times are examples of such metrics of
interest. This document specifies procedures and extensions to the
Path Computation Element Protocol (PCEP) in order to gather such
information.
Requirements Language Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119]. document are to be interpreted as described in RFC 2119 [RFC2119].
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5
3. Path Computation Monitoring messages . . . . . . . . . . . . . 4 3. Path Computation Monitoring messages . . . . . . . . . . . . . 5
3.1. Path Computation Monitoring Request message (PCMonReq) . . 5 3.1. Path Computation Monitoring Request message (PCMonReq) . . 6
3.2. Path Monitoring Reply message (PCMonRep) . . . . . . . . . 7 3.2. Path Monitoring Reply message (PCMonRep) . . . . . . . . . 9
4. Path Computation Monitoring Objects . . . . . . . . . . . . . 8 4. Path Computation Monitoring Objects . . . . . . . . . . . . . 11
4.1. MONITORING Object . . . . . . . . . . . . . . . . . . . . 8 4.1. MONITORING Object . . . . . . . . . . . . . . . . . . . . 12
4.2. PCEP-ID Object . . . . . . . . . . . . . . . . . . . . . . 10 4.2. PCE-ID Object . . . . . . . . . . . . . . . . . . . . . . 14
4.3. PROC-TIME Object . . . . . . . . . . . . . . . . . . . . . 11 4.3. PROC-TIME Object . . . . . . . . . . . . . . . . . . . . . 14
4.4. CONGESTION Object . . . . . . . . . . . . . . . . . . . . 13 4.4. CONGESTION Object . . . . . . . . . . . . . . . . . . . . 16
5. Policy . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 5. Policy . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
6. Elements of Procedure . . . . . . . . . . . . . . . . . . . . 14 6. Elements of Procedure . . . . . . . . . . . . . . . . . . . . 17
7. Manageability Considerations . . . . . . . . . . . . . . . . . 15 7. Manageability Considerations . . . . . . . . . . . . . . . . . 19
7.1. Control of Function and Policy . . . . . . . . . . . . . . 15 7.1. Control of Function and Policy . . . . . . . . . . . . . . 19
7.2. Information and Data Models . . . . . . . . . . . . . . . 15 7.2. Information and Data Models . . . . . . . . . . . . . . . 19
7.3. Liveness Detection and Monitoring . . . . . . . . . . . . 15 7.3. Liveness Detection and Monitoring . . . . . . . . . . . . 20
7.4. Verify Correct Operations . . . . . . . . . . . . . . . . 15 7.4. Verify Correct Operations . . . . . . . . . . . . . . . . 20
7.5. Requirements On Other Protocols . . . . . . . . . . . . . 15 7.5. Requirements On Other Protocols . . . . . . . . . . . . . 20
7.6. Impact On Network Operations . . . . . . . . . . . . . . . 15 7.6. Impact On Network Operations . . . . . . . . . . . . . . . 20
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 16 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 20
9. Security Considerations . . . . . . . . . . . . . . . . . . . 17 8.1. New PCEP Message . . . . . . . . . . . . . . . . . . . . . 20
10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 17 8.2. New PCEP Objects . . . . . . . . . . . . . . . . . . . . . 20
11. References . . . . . . . . . . . . . . . . . . . . . . . . . . 17 8.3. New Error-Type and Error-Values . . . . . . . . . . . . . 21
11.1. Normative References . . . . . . . . . . . . . . . . . . . 17 8.4. MONITORING Object Flag Field . . . . . . . . . . . . . . . 21
11.2. Informative References . . . . . . . . . . . . . . . . . . 18 8.5. PROC-TIME Object Flag Field . . . . . . . . . . . . . . . 22
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 18 8.6. CONGESTION Object Flag field . . . . . . . . . . . . . . . 22
Intellectual Property and Copyright Statements . . . . . . . . . . 20 9. Security Considerations . . . . . . . . . . . . . . . . . . . 23
10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 23
11. References . . . . . . . . . . . . . . . . . . . . . . . . . . 23
11.1. Normative References . . . . . . . . . . . . . . . . . . . 23
11.2. Informative References . . . . . . . . . . . . . . . . . . 24
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 24
1. Introduction 1. Introduction
The Path Computation Element (PCE) based architecture has been The Path Computation Element (PCE) based architecture has been
specified in [RFC4655] for the computation of Traffic Engineering specified in [RFC4655] for the computation of Traffic Engineering
(TE) Label Switched Paths (LSPs) in Multiprotocol Label Switching (TE) Label Switched Paths (LSPs) in Multiprotocol Label Switching
(MPLS) and Generalized MPLS (GMPLS) networks in the context of single (MPLS) and Generalized MPLS (GMPLS) networks in the context of single
or multiple domains where a domain refers to a collection of network or multiple domains where a domain refers to a collection of network
elements within a common sphere of address management or path elements within a common sphere of address management or path
computational responsibility such as IGP areas and Autonomous computational responsibility such as IGP areas and Autonomous
Systems. Systems.
Path Computation Clients (PCCs) send computation requests to PCEs,
and these may forward the requests to and cooperate with other PCEs
forming a "path computation chain". In PCE-based environments, it is
critical to monitor the state of the path computation chain for
troubeshooting and performance monitoring purposes: liveness of each
element (PCE) involved in the PCE chain, detection of potential
resource contention states and statistics in term of path computation
times are examples of such metrics of interest. This document
specifies procedures and extensions to the Path Computation Element
Protocol (PCEP) ([I-D.ietf-pce-pcep]) in order to monitor the path
computation chain and gather various performance metrics.
As defined in [RFC4655], there are circumstances where more than one As defined in [RFC4655], there are circumstances where more than one
PCE is involved in the computation of a TE LSP. A typical example is PCE is involved in the computation of a TE LSP. A typical example is
when the PCC requires the computation of a TE LSP where the head-end when the PCC requires the computation of a TE LSP where the head-end
and the tail-end of the TE LSP do not reside in adjacent domains and and the tail-end of the TE LSP do not reside in adjacent domains and
there is no single PCE with the visibility of both the head-end and there is no single PCE with the visibility of both the head-end and
tail-end domain. We call the set of PCEs involved in the computation tail-end domain. We call the set of PCEs involved in the computation
of a TE LSP a "path computation chain". As further discussed in of a TE LSP a "path computation chain". As further discussed in
Section 3.1, the PCE chain may either be static (pre-configured) or Section 3.1, the PCE chain may either be static (pre-configured) or
dynamically determined during the path computation process. dynamically determined during the path computation process.
In PCE-based environments, it is critical to monitor the state of the
path computation chain for troubeshooting and performance monitoring
purposes: liveness of each element (PCE) involved in the PCE chain,
detection of potential resource contention states and statistics in
term of path computation times are examples of such metrics of
interest. This document specifies procedures and extensions to the
Path Computation Element Protocol (PCEP) ([I-D.ietf-pce-pcep]) in
order to monitor the path computation chain and gather various
performance metrics.
As discussed in [RFC4655], a TE LSP may be computed by one PCE As discussed in [RFC4655], a TE LSP may be computed by one PCE
(referred to as single PCE path computation) or several PCEs (referred to as single PCE path computation) or several PCEs
(referred to as multiple PCE path computation). In the former case, (referred to as multiple PCE path computation). In the former case,
the PCC may be able to use IGP extensions to check the liveness of the PCC may be able to use IGP extensions to check the liveness of
the PCE (see [RFC5088] and [RFC5089]) or PCEP using Keepalive the PCE (see [RFC5088] and [RFC5089]) or PCEP using Keepalive
messages. In contrast, when multiple PCEs are involved in the path messages. In contrast, when multiple PCEs are involved in the path
computation chain an example of which is the BRPC procedure defined computation chain an example of which is the BRPC procedure defined
in [I-D.ietf-pce-brpc], the PCC's visibility may be limited to the in [I-D.ietf-pce-brpc], the PCC's visibility may be limited to the
first PCE involved in the path computation chain. Thus, it is first PCE involved in the path computation chain. Thus, it is
critical to define mechanisms in order to monitor the state of the critical to define mechanisms in order to monitor the state of the
skipping to change at page 4, line 25 skipping to change at page 5, line 27
more PCEs"). more PCEs").
In this document we define two monitoring request types: general and In this document we define two monitoring request types: general and
specific. A general monitoring request relates to the collection of specific. A general monitoring request relates to the collection of
a PCE state metrics that is not coupled to a particular path a PCE state metrics that is not coupled to a particular path
computation request (e.g. average CPU load on a PCE). Conversely, a computation request (e.g. average CPU load on a PCE). Conversely, a
specific monitoring request relates to a particular path computation specific monitoring request relates to a particular path computation
request (processing time to complete the path computation for a TE request (processing time to complete the path computation for a TE
LSP). LSP).
The message formats in this document are specified using Backus Naur
Format (BNF) encoding as specified in [I-D.farrel-rtg-common-bnf].
2. Terminology 2. Terminology
PCC (Path Computation Client): any client application requesting a PCC (Path Computation Client): any client application requesting a
path computation to be performed by a Path Computation Element. path computation to be performed by a Path Computation Element.
PCE (Path Computation Element): an entity (component, application or PCE (Path Computation Element): an entity (component, application or
network node) that is capable of computing a network path or route network node) that is capable of computing a network path or route
based on a network graph and applying computational constraints. based on a network graph and applying computational constraints.
TE LSP: Traffic Engineering Label Switched Path. TE LSP: Traffic Engineering Label Switched Path.
skipping to change at page 5, line 6 skipping to change at page 6, line 10
object is said to be mandatory in a PCEP message when the object must object is said to be mandatory in a PCEP message when the object must
be included for the message to be considered as valid. The P flag be included for the message to be considered as valid. The P flag
(defined in [I-D.ietf-pce-pcep]) is located in the common header of (defined in [I-D.ietf-pce-pcep]) is located in the common header of
each PCEP object and can be set by a PCEP peer to require a PCE to each PCEP object and can be set by a PCEP peer to require a PCE to
take into account the related information during the path take into account the related information during the path
computation. Because the P flag exclusively relates to a path computation. Because the P flag exclusively relates to a path
computation request, it MUST be cleared in the two PCEP messages computation request, it MUST be cleared in the two PCEP messages
(PCEMonReq and PCMonRep message) defined in this document. (PCEMonReq and PCMonRep message) defined in this document.
For each PCEP message type a set of rules is defined that specify the For each PCEP message type a set of rules is defined that specify the
set of objects that the message can carry. We use the Backus-Naur set of objects that the message can carry. An implementation MUST
Form (BNF) to specify such rules. Square brackets refer to optional form the PCEP messages using the object ordering specified in this
sub-sequences. An implementation MUST form the PCEP messages using document.
the object ordering specified in this document.
In this document we define two PCEP messages referred to as the Path In this document we define two PCEP messages referred to as the Path
Computation Monitoring request (PCMonReq) and Path Computation Computation Monitoring Request (PCMonReq) and Path Computation
Monitoring Reply (PCMonRep) messages so as to handle "out of band" Monitoring Reply (PCMonRep) messages so as to handle "out of band"
monitoring request. The aim of the PCMonReq message sent by a PCC to monitoring request. The aim of the PCMonReq message sent by a PCC to
a PCE is to gather one or more PCE state metrics on a set of PCEs a PCE is to gather one or more PCE state metrics on a set of PCEs
involved in a path computation chain. The PCMonRep message sent by a involved in a path computation chain. The PCMonRep message sent by a
PCE to a PCC is used to provide such data. PCE to a PCC is used to provide such data.
3.1. Path Computation Monitoring Request message (PCMonReq) 3.1. Path Computation Monitoring Request message (PCMonReq)
The Message-Type field of the PCEP common header for the PCMonReq The Message-Type field of the PCEP common header for the PCMonReq
message is set to 8 (To be confirmed by IANA). message is set to 8 (To be confirmed by IANA).
There is one mandatory object that MUST be included within a PCMonReq There is one mandatory object that MUST be included within a PCMonReq
message: the Monitoring object (see section Section 4.1). If the message: the MONITORING object (see section Section 4.1). If the
Monitoring object is missing, the receiving PCE MUST send a PCErr MONITORING object is missing, the receiving PCE MUST send a PCErr
message with Error-type=6 (Mandatory Object missing) and Error- message with Error-type=6 (Mandatory Object missing) and Error-
value=4 (MONITORING Object missing). Other objects are optional. value=4 (MONITORING Object missing). Other objects are optional.
The format of a PCMonReq message is as follows: Format of a PCMonReq message (out of band request):
<PCMonReq Message>::= <Common Header> <PCMonReq Message>::= <Common Header>
<MONITORING> <MONITORING>
[<pce-list>] [<pce-list>]
[<svec-list>] [<svec-list>]
[<request-list>] [<request-list>]
where: where:
<svec-list>::=<SVEC> <svec-list>::=<SVEC>
[<OF>] [<OF>]
[<svec-list>] [<svec-list>]
skipping to change at page 6, line 32 skipping to change at page 8, line 4
[<BANDWIDTH>] [<BANDWIDTH>]
[<metric-list>] [<metric-list>]
[<RRO>] [<RRO>]
[<IRO>] [<IRO>]
[<LOAD-BALANCING>] [<LOAD-BALANCING>]
[<XRO>] [<XRO>]
<metric-list>::=<METRIC>[<metric-list>] <metric-list>::=<METRIC>[<metric-list>]
<pce-list>::=<PCE-ID>[<pce-list>] <pce-list>::=<PCE-ID>[<pce-list>]
Format of a PCReq message with monitoring data requested (in band
request):
<PCReq Message>::= <Common Header>
<MONITORING>
[<pce-list>]
[<svec-list>]
<request-list>
The SVEC, RP, END-POINTS, LSPA, BANDWIDTH, METRIC, ERO, IRO and LOAD- where:
<svec-list>::=<SVEC>[<svec-list>]
<request-list>::=<request>[<request-list>]
<request>::= <RP>
<END-POINTS>
[<LSPA>]
[<BANDWIDTH>]
[<metric-list>]
[<RRO>[<BANDWIDTH>]]
[<IRO>]
[<LOAD-BALANCING>]
where:
<metric-list>::=<METRIC>[<metric-list>]
<pce-list>::=<PCE-ID>[<pce-list>]
The SVEC, RP, END-POINTS, LSPA, BANDWIDTH, METRIC, RRO, IRO and LOAD-
BALANCING objects are defined in [I-D.ietf-pce-pcep]. The XRO object BALANCING objects are defined in [I-D.ietf-pce-pcep]. The XRO object
is defined in [I-D.ietf-pce-pcep-xro] and the OF object is defined in is defined in [I-D.ietf-pce-pcep-xro] and the OF object is defined in
[I-D.ietf-pce-of]. [I-D.ietf-pce-of].
The PCMonReq message is used to gather various PCE state metrics The PCMonReq message is used to gather various PCE state metrics
along a path computation chain. The path computation chain may be along a path computation chain. The path computation chain may be
determined by the PCC (in the form of a series of a series of PCE-ID determined by the PCC (in the form of a series of a series of PCE-ID
objects defined in Section 4.2.) or may alternatively be determined objects defined in Section 4.2.) or may alternatively be determined
by the path computation procedure. For example, if the BRPC by the path computation procedure. For example, if the BRPC
procedure ([I-D.ietf-pce-brpc]) is used to compute an inter-domain TE procedure ([I-D.ietf-pce-brpc]) is used to compute an inter-domain TE
LSP, the PCE chain may be determined dynamically. In that case, the LSP, the PCE chain may be determined dynamically. In that case, the
PCC sends a PCMonReq message that contains the PCEP objects that PCC sends a PCMonReq message that contains the PCEP objects that
charaterize the TE LSP attributes along with the monitoring objects charaterize the TE LSP attributes along with the MONITORING object
(see Section 4.1) that list the set of metric(s) of interest. (see Section 4.1) that lists the set of metrics of interest.
Several PCE state metrics may be requested that are specified by a Several PCE state metrics may be requested that are specified by a
set of objects defined in Section 4. Note that this set of objects set of objects defined in Section 4. Note that this set of objects
may be extended in the future. may be extended in the future.
For the sake of illustraion, consider the three following examples: As pointed out in [I-D.ietf-pce-pcep] several situations can arise:
Example 1: PCC1 requests to check the path computation chain that o Bundle of a set of independent and non-synchronized path
would be used should it request a path computation for a specific TE computation requests,
LSP named T1. A PCMonReq message is sent that contains a MONITORING
object specifying a path computation check, along with the
appropriate set of objects (e.g. RP, END-POINTS, ...) that would be
included in a PCReq message for T1.
Example 2: PCC1 requests a path computation for a TE LSP and also o Bundle of a set of independent and synchronized path computation
request to gather the processing time along the path computation requests (SVEC object defined below required),
chain selected for the computation of T1. A PCReq message is sent
that also contains a MONITORING object that specifies the performance
metric of interest. The PCRep message also carries a PROC-TIME
object defined in section Section 4.1 that reports the computed
metrics.
Example 3: PCC2 requests to gather performance metrics along the o Bundle of a set of dependent and synchronized path computation
specific path computation chain <pce1, pce2, pce3, pce7>. A PCMonreq requests (SVEC object defined below required).
message is sent to PCE1 that contains a sequence of PCE-ID objects
that identify PCE1, PCE2, PCE3 and PCE7 respectively. In the case of a bundle of a set of request, the MONITORING object
SHOULD only be present in the first PCReq or PCMonReq message and the
monitoring request applies to all the requests of the bundle, even in
the case of dependent and/or synchronized requests sent using more
than one PCReq or PCMonReq message.
Examples of requests. For the sake of illustration, consider the
three following examples:
Example 1 (out of band request): PCC1 requests to check the path
computation chain that would be used should it request a path
computation for a specific TE LSP named T1. A PCMonReq message is
sent that contains a MONITORING object specifying a path computation
check, along with the appropriate set of objects (e.g. RP, END-
POINTS, ...) that would be included in a PCReq message for T1.
Example 2 (in band request): PCC1 requests a path computation for a
TE LSP and also request to gather the processing time along the path
computation chain selected for the computation of T1. A PCReq
message is sent that also contains a MONITORING object that specifies
the performance metrics of interest.
Example 3 (out of band request): PCC2 requests to gather performance
metrics along the specific path computation chain <pce1, pce2, pce3,
pce7>. A PCMonreq message is sent to PCE1 that contains a MONITORING
object and a sequence of PCE-ID objects that identify PCE1, PCE2,
PCE3 and PCE7 respectively.
In all of the examples above, a PCRep message (in-band request) or
PCMonReq message (out of band request) is sent in response to the
request that reports the computed metrics.
3.2. Path Monitoring Reply message (PCMonRep) 3.2. Path Monitoring Reply message (PCMonRep)
The PCMonRep message is used to provide PCE state metrics back to the The PCMonRep message is used to provide PCE state metrics back to the
requester for "out of band" monitoring requests. The Message-Type requester for "out of band" monitoring requests. The Message-Type
field of the PCEP common header for the PCMonRep message is set to 9 field of the PCEP common header for the PCMonRep message is set to 9
(To be confirmed by IANA). (To be confirmed by IANA).
There is one mandatory object that MUST be included within a PCMonRep There is one mandatory object that MUST be included within a PCMonRep
message: the Monitoring object (see Section 4.1). If the Monitoring message: the MONITORING object (see Section 4.1). If the MONITORING
object is missing, the receiving PCE MUST send a PCErr message with object is missing, the receiving PCE MUST send a PCErr message with
Error-type=6 (Mandatory Object missing) and Error-value=4 (MONITORING Error-type=6 (Mandatory Object missing) and Error-value=4 (MONITORING
Object missing). Object missing).
Other objects are optional. Other objects are optional.
The format of a PCReq message is as follows: Format of a PCMonRep (out of band request):
<PCMonRep Message>::= <Common Header> <PCMonRep Message>::= <Common Header>
<MONITORING> <MONITORING>
[<RP>] [<RP>]
[<metric-pce-list>] [<metric-pce-list>]
where: where:
<metric-pce-list>::=<metric-pce>[<metric-pce-list>] <metric-pce-list>::=<metric-pce>[<metric-pce-list>]
<metric-pce>::=[<PCE-ID>] <metric-pce>::=<PCE-ID>
[<PROC-TIME>] [<PROC-TIME>]
[<CONGESTION>] [<CONGESTION>]
Format of a PCRep message with monitoring data (in band):
<PCRep Message> ::= <Common Header>
<response-list>
where:
<response-list>::=<response>[<response-list>]
<response>::=<RP>
<MONITORING>
[<NO-PATH>]
[<attribute-list>]
[<path-list>]
[<metric-pce-list>]
<path-list>::=<path>[<path-list>]
<path>::= <ERO><attribute-list>
where:
<attribute-list>::=[<LSPA>]
[<BANDWIDTH>]
[<metric-list>]
[<IRO>]
<metric-list>::=<METRIC>[<metric-list>]
<metric-pce-list>::=<metric-pce>[<metric-pce-list>]
<metric-pce>::=<PCE-ID>
[<PROC-TIME>]
[<CONGESTION>]
The RP object is defined in [I-D.ietf-pce-pcep].
4. Path Computation Monitoring Objects 4. Path Computation Monitoring Objects
The PCEP objects defined in the document are compliant with the PCEP The PCEP objects defined in the document are compliant with the PCEP
object format defined in [I-D.ietf-pce-pcep], with the P flag and the object format defined in [I-D.ietf-pce-pcep]. The P flag and the I
I flag cleared since these flags are exclusively related to path flag of the PCEP objects defined in this document SHOULD always be
computation requests. set to 0 on transmission and MUST be ignored on receipt since these
flags are exclusively related to path computation requests.
Several objects are defined in this section that can be carried Several objects are defined in this section that can be carried
within the PCEP PCReq or PCRep messages defined in within the PCEP PCReq or PCRep messages defined in
[I-D.ietf-pce-pcep] in case of "in band" monitoring requests. In [I-D.ietf-pce-pcep] in case of "in band" monitoring requests (the PCC
case of "out of band" monitoring requests, the objects defined in requests the computation of the TE LSP in addition to gathering PCE
this section are carried within PCMonReq and PCMonRep messages. state metrics). In case of "out of band" monitoring requests, the
Conversely, if the PCC requests the computation of the TE LSP in objects defined in this section are carried within PCMonReq and
addition to gathering PCE state metrics (i.e. "In band" requests), PCMonRep messages.
these objects are carried within PCReq and PCRep messages.
4.1. MONITORING Object 4.1. MONITORING Object
The MONITORING object MUST be present within PCMonReq and PCMonRep The MONITORING object MUST be present within PCMonReq and PCMonRep
messages ("out of band" monitoring requests) and MAY be carried messages ("out of band" monitoring requests) and MAY be carried
within PCERep and PCReq messages ("in band" monitoring requests). within PCRep and PCReq messages ("in band" monitoring requests).
There SHOULD NOT be more than one instance of the MONITORING object: There SHOULD NOT be more than one instance of the MONITORING object:
if more than one instance of the MONITORING object is present, the if more than one instance of the MONITORING object is present, the
recipient MUST process the first instance and MUST ignore other recipient MUST process the first instance and MUST ignore other
instances. instances.
The MONITORING object is used to specify the set of requested PCE The MONITORING object is used to specify the set of requested PCE
state metrics. state metrics.
The MONITORING Object-Class is to be assigned by IANA (recommended The MONITORING Object-Class is to be assigned by IANA (recommended
value=19) value=19)
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PCE-ID object in the corresponding reply. The L bit MUST always be PCE-ID object in the corresponding reply. The L bit MUST always be
ignored in a PCMonRep or PCRep message. ignored in a PCMonRep or PCRep message.
G (General) - 1 bit: when set, this indicates that the monitoring G (General) - 1 bit: when set, this indicates that the monitoring
request is a general monitoring request. When the requested request is a general monitoring request. When the requested
performance metric is specific, the G bit MUST be cleared. The G bit performance metric is specific, the G bit MUST be cleared. The G bit
MUST always be ignored in a PCMonRep or PCRep message. MUST always be ignored in a PCMonRep or PCRep message.
P (Processing Time) - 1 bit: the P bit of the MONITORING object P (Processing Time) - 1 bit: the P bit of the MONITORING object
carried in a PCMonReq or a PCReq message is set to indicate that the carried in a PCMonReq or a PCReq message is set to indicate that the
processing times is a metric of interest, in which case a PROC-TIME processing times is a metric of interest. If allowed by policy, a
object MUST be inserted in the corresponding PCMonRep or PCRep PROC-TIME object MUST be inserted in the corresponding PCMonRep or
message. The P bit MUST always be ignored in a PCMonRep or PCRep PCRep message. The P bit MUST always be ignored in a PCMonRep or
message. PCRep message.
C (Congestion) - 1 bit: The C bit of the MONITORING object carried in C (Congestion) - 1 bit: The C bit of the MONITORING object carried in
a PCMonReq or a PCReq message is set to indicate that the congestion a PCMonReq or a PCReq message is set to indicate that the congestion
status is a metric of interest, in which case a CONGESTION object status is a metric of interest, in which case a CONGESTION object
MUST be inserted in the corresponding PCMonRep or PCRep message. The MUST be inserted in the corresponding PCMonRep or PCRep message. The
C bit MUST always be ignored in a PCMonRep or PCRep message. C bit MUST always be ignored in a PCMonRep or PCRep message.
I (Incomplete) - 1 bit: If a PCE supports a received PCMonReq message I (Incomplete) - 1 bit: If a PCE supports a received PCMonReq message
and that message does not trigger any policy violation, but the PCE and that message does not trigger any policy violation, but the PCE
cannot provide any of the set of requested performance metrics for cannot provide any of the set of requested performance metrics for
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PCEP-ID of the replying PCE. A PCEP implementation SHOULD checkpoint PCEP-ID of the replying PCE. A PCEP implementation SHOULD checkpoint
the Monitoring-id-number of pending monitoring requests in case of the Monitoring-id-number of pending monitoring requests in case of
restart thus avoiding the re-use of a Monitoring-id-number of an in- restart thus avoiding the re-use of a Monitoring-id-number of an in-
process monitoring request. process monitoring request.
Unassigned bits are considered as reserved and MUST be set to zero on Unassigned bits are considered as reserved and MUST be set to zero on
transmission and ignored on reception. transmission and ignored on reception.
No optional TLVs are currently defined. No optional TLVs are currently defined.
4.2. PCEP-ID Object 4.2. PCE-ID Object
The PCEP-ID Object is used to specify a PCE's IP address. The PCE-ID Object is used to specify a PCE's IP address.
A set of PCEP-ID objects may be inserted within a PCReq or a PCMonReq A set of PCE-ID objects may be inserted within a PCReq or a PCMonReq
message to specify the PCE for which PCE state metrics are requested message to specify the PCE for which PCE state metrics are requested
and in a PCMonRep or a PCRep message to record the IP address of the and in a PCMonRep or a PCRep message to record the IP address of the
PCE reporting PCE state metrics or that was involved in the path PCE reporting PCE state metrics or that was involved in the path
computation chain. computation chain.
Two PCEP-ID objects (for IPv4 and IPv6) are defined. PCEP-ID Object- Two PCE-ID objects (for IPv4 and IPv6) are defined. PCE-ID Object-
Class is to be assigned by IANA (recommended value=20) PCEP-ID Class is to be assigned by IANA (recommended value=20) PCE-ID Object-
Object-Type is to be assigned by IANA (recommended value=1 for IPv4 Type is to be assigned by IANA (recommended value=1 for IPv4 and 2
and 2 for IPv6) for IPv6)
The format of the PCEP-ID Object is as follows: The format of the PCE-ID Object is as follows:
The format of the PCEP-ID object body for IPv4 and IPv6 are as The format of the PCE-ID object body for IPv4 and IPv6 are as
follows: follows:
0 1 2 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 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv4 Address | | IPv4 Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
0 1 2 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 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | |
| IPv6 Address | | IPv6 Address |
| | | |
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The PCEP-ID object body has a fixed length of 4 octets for IPv4 and The PCE-ID object body has a fixed length of 4 octets for IPv4 and 16
16 octets for IPv6. octets for IPv6.
When a dynamic discovery mechanism is used for PCE discovery, a PCE When a dynamic discovery mechanism is used for PCE discovery, a PCE
advertises its PCE address in the PCE-ADDRESS sub-TLV defined in advertises its PCE address in the PCE-ADDRESS sub-TLV defined in
[RFC5088] and [RFC5089]. A PCC MUST use this address in PCReq and [RFC5088] and [RFC5089]. A PCC MUST use this address in PCReq and
PCMonReq messages and a PCE MUST also use this address in PCRep and PCMonReq messages and a PCE MUST also use this address in PCRep and
PCMonRep messages. PCMonRep messages.
4.3. PROC-TIME Object 4.3. PROC-TIME Object
If allowed by policy, the PCE includes a PROC-TIME object within a If allowed by policy, the PCE includes a PROC-TIME object within a
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related metrics. related metrics.
1) Case of general monitoring requests 1) Case of general monitoring requests
A PCC may request processing time metrics for general monitoring A PCC may request processing time metrics for general monitoring
requests (e.g. the PCC may want to know the minimum, maximum and requests (e.g. the PCC may want to know the minimum, maximum and
average processing times on a particular PCE). In this case, general average processing times on a particular PCE). In this case, general
requests can only be made by using PCMonReq/PCMonRep messages. The requests can only be made by using PCMonReq/PCMonRep messages. The
Current-processing-time field (as explained below) is exclusively Current-processing-time field (as explained below) is exclusively
used for specific monitoring requests and MUST be cleared for general used for specific monitoring requests and MUST be cleared for general
monitoring requests. The algorithm(s) used by a PCE to compute the monitoring requests. The algorithms used by a PCE to compute the
Min, Average, Max and Variance of the processing times are out of the Min, Average, Max and Variance of the processing times are out of the
scope of this document (A PCE may decide to compute the minimum scope of this document (A PCE may decide to compute the minimum
processing time over a period of times, for the last N path processing time over a period of times, for the last N path
computation requests, ...). computation requests, ...).
2) Case of specific monitoring requests 2) Case of specific monitoring requests
In the case of a specific request, the algorithm(s) used by a PCE to In the case of a specific request, the algorithms used by a PCE to
compute the Procesing-time metrics are out of the scope of this compute the Procesing-time metrics are out of the scope of this
document but a flag is specified that is used to indicate to the document but a flag is specified that is used to indicate to the
requester whether the processing time value was estimated or requester whether the processing time value was estimated or
computed. The PCE may either (1) estimate the processing time computed. The PCE may either (1) estimate the processing time
without performing an actual path computation or (2) effectively without performing an actual path computation or (2) effectively
perform the computation to report the processing time. In the former perform the computation to report the processing time. In the former
case, the E bit of the PROC-TIME object MUST be set. The G bit MUST case, the E bit of the PROC-TIME object MUST be set. The G bit MUST
be cleared and the Min-processing-time, Max-processing-time, Average- be cleared and the Min-processing-time, Max-processing-time, Average-
processing-time and Variance-processing-time MUST be set to processing-time and Variance-processing-time MUST be set to
0x00000000. 0x00000000.
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Min-processing-time | | Min-processing-time |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Max-processing-time | | Max-processing-time |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Average-processing time | | Average-processing time |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Variance-processing-time | | Variance-processing-time |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Flags: 18 bits - No Flags are currently defined: Flags: 16 bits - one flag is currently defined:
E (Estimated) - 1 bit: when set, this indicates that the reported E (Estimated) - 1 bit: when set, this indicates that the reported
metric value is based on estimated processing time as opposed to metric value is based on estimated processing time as opposed to
actual computation(s). actual computations.
Unassigned bits are considered as reserved and MUST be set to zero on
transmission.
Current-processing-time: This field indicates in milliseconds the Current-processing-time: This field indicates in milliseconds the
processing time for the path computation of interest characterized in processing time for the path computation of interest characterized in
the corresponding PCMonReq message. the corresponding PCMonReq message.
Min-processing-time: This field indicates in milliseconds the minimum Min-processing-time: This field indicates in milliseconds the minimum
processing time. processing time.
Max-processing-time: This field indicates in milliseconds the maximum Max-processing-time: This field indicates in milliseconds the maximum
processing time. processing time.
Average-processing-time: This field indicates in milliseconds the Average-processing-time: This field indicates in milliseconds the
average processing time. average processing time.
Variance-processing-time: This field indicates in milliseconds the Variance-processing-time: This field indicates in milliseconds the
variance of the processing times. variance of the processing times.
Unassigned bits are considered as reserved and MUST be set to zero on
transmission.
More granularity may be introduced in further revision of this
document to get a monitoring metric for a general request of a
particular class (e.g. all PCReq of priority X).
4.4. CONGESTION Object 4.4. CONGESTION Object
The CONGESTION object MUST be present within a PCMonRep or a PCRep The CONGESTION object is used to report a PCE processing congestion
message if the C bit of the MONITORING object carried within the state. The CONGESTION object MUST be present within a PCMonRep or a
corresponding PCMonReq or PCReq message is set. The CONGESTION PCRep message if the C bit of the MONITORING object carried within
object is used to report a PCE processing congestion state. The the corresponding PCMonReq or PCReq message is set and the PCE is
CONGESTION Object-Class is to be assigned by IANA (recommended experiencing a congested state. The CONGESTION Object-Class is to be
value=22) The CONGESTION Object-Type is to be assigned by IANA assigned by IANA (recommended value=22) The CONGESTION Object-Type is
(recommended value=1) to be assigned by IANA (recommended value=1)
The format of the CONGESTION object body is as follows: The format of the CONGESTION object body is as follows:
0 1 2 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 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|C| Reserved | Congestion Duration | | Flags | Reserved | Congestion Duration |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
C (Congestion) - 1 bit: when set, this indicates that PCE is Flags: 8 bits - No flag is currently defined:
congested, in which case the congestion duration may be non nul.
When cleared this indicates that the PCE is not congested and the
"Congestion Duration" field MUST be set to 0x0000.
Congestion duration - 16 bits: This field indicates in seconds the Congestion duration - 16 bits: This field indicates in the amount of
estimated congestion duration. time in seconds that the responding PCE expects that it may continue
to be congested from the time that the response message was
generated. The receiver MAY use this value to decide whether or not
so send further requests to the same PCE.
It is worth noting that a PCE along a PCE chain involved in the
monitoring request may decide to learn from the congestion
information received by one of downstream PCE in the chain.
5. Policy 5. Policy
The receipt of a PCMonReq message may trigger a policy violation on The receipt of a PCMonReq message may trigger a policy violation on
some PCE in which case the PCE MUST send a PCErr message with Error- some PCE in which case the PCE MUST send a PCErr message with Error-
Type=5 and Error-value=3 (To be Confirmed by IANA). Type=5 and Error-value=3 (To be Confirmed by IANA).
6. Elements of Procedure 6. Elements of Procedure
I bit processing: as indicated in section Section 4.1, if a PCE I bit processing: as indicated in section Section 4.1, if a PCE
supports a received PCMonReq message and that message does not supports a received PCMonReq message and that message does not
trigger any policy violation, but the PCE cannot provide any of the trigger any policy violation, but the PCE cannot provide any of the
set of requested performance metrics for unspecified reasons, the PCE set of requested performance metrics for unspecified reasons, the PCE
MUST set the I bit. Once set, the I bit MUST NOT be changed by a MUST set the I bit. Once set, the I bit MUST NOT be changed by a
receiving PCE. receiving PCE.
Reception of a PCMonReq message: upon receiving a PCMonReq message: Upon receiving a PCMonReq message:
1) As specified in [I-D.ietf-pce-pcep], if the PCE does not support 1) As specified in [I-D.ietf-pce-pcep], if the PCE does not support
the PCMonReq message, the PCE peer must send a PCErr message with the PCMonReq message, the PCE peer MUST send a PCErr message with
Error-value=2 (capability not supported). Error-value=2 (capability not supported). According to the procedure
defined in section 6.9 of [I-D.ietf-pce-pcep], if a PCC/PCE receives
unrecognized messages at a rate equal of greater than specified rate,
the PCC/PCE must send a PCEP CLOSE message with close
value="Reception of an unacceptable number of unknown PCEP message.
In this case, the PCC/PCE must also close the TCP session and must
not send any further PCEP messages on the PCEP session.
2) If the PCE supports the PCMonReq message but the request is 2) If the PCE supports the PCMonReq message but the monitoring
prohibited by policy, the PCE MUST send a PCErr message with Error- request is prohibited by policy, the PCE must follow the procedure
Type=5 and Error-value=3. specified in section 5. As pointed out in section 4.3, a PCE may
still partially satisfy a request, leaving out some of the required
data if not allowed by policy.
3) If the PCE supports the PCMonReq and the monitoring request is not 3) If the PCE supports the PCMonReq and the monitoring request is not
prohibited by policy, the receiving PCE MUST first determine whether prohibited by policy, the receiving PCE MUST first determine whether
it is the last PCE of the path computation chain. If the PCE is not it is the last PCE of the path computation chain. If the PCE is not
the last element of the path computation chain, the PCMonReq message the last element of the path computation chain, the PCMonReq message
is relayed to the next hop PCE: such next-hop may either be specified is relayed to the next hop PCE: such next-hop may either be specified
by means of a PCEP-ID object present in the PCMonReq message or by means of a PCE-ID object present in the PCMonReq message or
dynamically determined by means of a procedure outside of the scope dynamically determined by means of a procedure outside of the scope
of this document. Conversely, if the PCE is the last PCE of the path of this document. Conversely, if the PCE is the last PCE of the path
computation chain, the PCE originates a PCMonRep message that computation chain, the PCE originates a PCMonRep message that
contains the requested objects according to the set of requested PCE contains the requested objects according to the set of requested PCE
states metrics listed in the MONITORING object carried in the states metrics listed in the MONITORING object carried in the
corresponding PCMonReq message. corresponding PCMonReq message.
Upon receiving a PCReq message that carries a MONITORING and
potentially other monitoring objects (e.g. PCE-ID object):
1) As specified in [I-D.ietf-pce-pcep], if the PCE does not support
(in band) monitoring, the PCE peer MUST send a PCErr message with
Error-value=2 (capability not supported). According to the procedure
defined in section 6.9 of [I-D.ietf-pce-pcep], if a PCC/PCE receives
unrecognized messages at a rate equal of greater than specified rate,
the PCC/PCE must send a PCEP CLOSE message with close
value="Reception of an unacceptable number of unknown PCEP message.
In this case, the PCC/PCE must also close the TCP session and must
not send any further PCEP messages on the PCEP session.
2) If the PCE supports the monitoring request but the monitoring
request is prohibited by policy, the PCE must follow the procedure
specified in section 5. As pointed out in section 4.3, a PCE may
still partially satisfy a request, leaving out some of the required
data if not allowed by policy.
3) If the PCE supports the monitoring request and that request is not
prohibited by policy, the receiving PCE MUST first determine whether
it is the last PCE of the path computation chain. If the PCE is not
the last element of the path computation chain, the PCReq message
(with the MONITORING object and potentially other monitoring objects
such as the PCE-ID) is relayed to the next hop PCE: such next-hop may
either be specified by means of a PCE-ID object present in the PCReq
message or dynamically determined by means of a procedure outside of
the scope of this document. Conversely, if the PCE is the last PCE
of the path computation chain, the PCE originates a PCRep message
that contains the requested objects according to the set of requested
PCE states metrics listed in the MONITORING and potentially other
monitoring objects carried in the corresponding PCReq message.
Upon receiving a PCMonRep message: upon receiving a PCMonRep message, Upon receiving a PCMonRep message: upon receiving a PCMonRep message,
the PCE processes the request, adds the relevant objects to the the PCE processes the request, adds the relevant objects to the
PCMonRep message and forwards the PCMonRep message to the upstream PCMonRep message and forwards the PCMonRep message to the upstream
requesting PCE or PCC. requesting PCE or PCC.
Upon receiving a PCRep message that carrries monitoring data, the
message is processed, additional monitoring data is added according
to this specification and the message is forwarded upstream to the
requesting PCE or PCC.
Special case of Multi-destination monitoring: monitoring request Special case of Multi-destination monitoring: monitoring request
related to more than one destinations may involve a set of path related to more than one destinations may involve a set of path
computation chains. In that case, a PCE sends each copy of the computation chains. In that case, a PCE sends each copy of the
PCMonReq message to each downstream PCE of each path computation PCMonReq message to each downstream PCE of each path computation
chain. chain.
7. Manageability Considerations 7. Manageability Considerations
7.1. Control of Function and Policy 7.1. Control of Function and Policy
It MUST be possible to configure the activation/deactivation of PCEP It MUST be possible to configure the activation/deactivation of PCEP
monitoring on a PCEP speaker. In addition to the parameters already monitoring on a PCEP speaker. In addition to the parameters already
listed in section 8.1 of [I-D.ietf-pce-pcep], a PCEP implementation listed in section 8.1 of [I-D.ietf-pce-pcep], a PCEP implementation
SHOULD allow configuring on a PCE whether specific, generic, in-band SHOULD allow configuring on a PCE whether specific, generic, in band
and out-of-band monitoring requests are allowed or not. Also a PCEP and out of band monitoring requests are allowed or not. Also a PCEP
implementation SHOULD allow configuring on a PCE a list of authorized implementation SHOULD allow configuring on a PCE a list of authorized
state metrics (aliveness, congestion, processing time, etc). This state metrics (aliveness, congestion, processing time, etc). This
may apply to any session the PCEP speaker participates in, to a 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 specific session with a given PCEP peer or to a specific group of
sessions with a specific group of PCEP peers, for instance the PCEP sessions with a specific group of PCEP peers, for instance the PCEP
peers of a neighbor AS. peers of a neighbor AS.
7.2. Information and Data Models 7.2. Information and Data Models
A new MIB Module MAY be defined that provides local PCE state A new MIB Module may be defined that provides local PCE state
metrics, as well as state metrics of other PCEs gathered using metrics, as well as state metrics of other PCEs gathered using
mechanisms defined in this document. mechanisms defined in this document.
7.3. Liveness Detection and Monitoring 7.3. Liveness Detection and Monitoring
This document provides mechanisms to monitor the liveliness and This document provides mechanisms to monitor the liveliness and
performances of a given PCE chain. performances of a given PCE chain.
7.4. Verify Correct Operations 7.4. Verify Correct Operations
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other protocols in addition to those already listed in other protocols in addition to those already listed in
[I-D.ietf-pce-pcep]. [I-D.ietf-pce-pcep].
7.6. Impact On Network Operations 7.6. Impact On Network Operations
The frequency of PCMonReq messages may impact the operations of PCEs. The frequency of PCMonReq messages may impact the operations of PCEs.
An implementation SHOULD allow a limit to be placed on the rate of An implementation SHOULD allow a limit to be placed on the rate of
PCMonReq messages sent by a PCEP speaker and processed from a peer. PCMonReq messages sent by a PCEP speaker and processed from a peer.
It SHOULD also allow sending a notification when a rate threshold is It SHOULD also allow sending a notification when a rate threshold is
reached. An implementation SHOULD allow handling PCReq messages with reached. An implementation SHOULD allow handling PCReq messages with
a higher priority than PCMonReq messages. a higher priority than PCMonReq messages. An implementation SHOULD
allow the configuration of a second limit for the PCReq message
requesting monitoring data.
8. IANA Considerations 8. IANA Considerations
8.1. New PCEP Message
Each PCEP message has a message type value. Each PCEP message has a message type value.
Two new PCEP (specified in [I-D.ietf-pce-pcep]) messages are defined Two new PCEP (specified in [I-D.ietf-pce-pcep]) messages are defined
in this document: in this document:
Value Meaning Value Description Reference
8 Path Computation Monitoring Request (PCMonReq) 8 Path Computation Monitoring Request (PCMonReq) This document
9 Path Computation Monitoring Reply (PCMonRep) 9 Path Computation Monitoring Reply (PCMonRep) This document
8.2. New PCEP Objects
Each PCEP object has an Object-Class and an Object-Type. The Each PCEP object has an Object-Class and an Object-Type. The
following new PCEP objects are defined in this document. following new PCEP objects are defined in this document.
Object-Class Name Object-Class Value Name Object-Type Reference
19 MONITORING 19 MONITORING 1 This document
Object-Type
1
20 PCEP-ID 20 PCE-ID 1: IPv4 addresses This document
Object-Type 2: IPv6 addresses This document
1: IPv4 addresses
2: IPv6 addresses
21 PROC-TIME 21 PROC-TIME 1 This document
Object-Type
1
22 CONGESTION 22 CONGESTION 1 This document
Object-Type
1 8.3. New Error-Type and Error-Values
A registry has been created for the Error-type and Error-value of the A registry has been created for the Error-type and Error-value of the
PCEP Error Object. PCEP Error Object.
A new Error-value for the PCErr message Error-types=5 (Policy A new Error-value for the PCErr message Error-types=5 (Policy
Violation) (see [I-D.ietf-pce-pcep]) is defined in this document Violation) (see [I-D.ietf-pce-pcep]) is defined in this document
(Error-Type and Error-value to be assigned by IANA). (Error-value to be assigned by IANA).
Error-type Meaning Error-Type Meaning Error-value Reference
5 Policy violation 5 Policy violation 3 This document
Error-value=3 [This document] Monitoring message supported
Monitoring message supported but rejected but rejected due to
due to policy violation policy violation
A new Error-value for the PCErr message Error-types=6 (Mandatory A new Error-value for the PCErr message Error-types=6 (Mandatory
Object missing) (see [I-D.ietf-pce-pcep]) is defined in this document Object missing) (see [I-D.ietf-pce-pcep]) is defined in this document
(Error-Type and Error-value to be assigned by IANA). (Error-Type and Error-value to be assigned by IANA).
Error-type Meaning Error-type Meaning Error-value Reference
6 Mandatory Object missing 6 Mandatory Object missing 4 This document
Error-value=4 [This document]
MONITORING Object missing MONITORING Object missing
8.4. MONITORING Object Flag Field
IANA is requested to create a registry to manage the Flag field of
the MONITORING object.
New bit numbers may be allocated only by an IETF Consensus action.
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
Several bits are defined for the MONITORING Object flag field in this
document:
Codespace of the Flag field (MONITORING Object)
Bit Description Reference
0-18 Unassigned
19 Incomplete This document
20 Congestion This document
21 Processing Time This document
22 General This document
23 Liveness This document
8.5. PROC-TIME Object Flag Field
IANA is requested to create a registry to manage the Flag field of
the PROC-TIME object.
New bit numbers may be allocated only by an IETF Consensus action.
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
One bit is defined for the PROC-TIME Object flag field in this
document:
Codespace of the Flag field (PROC-TIME Object)
Bit Description Reference
0-14 Unassigned
15 Estimated This document
8.6. CONGESTION Object Flag field
IANA is requested to create a registry to manage the Flag field of
the CONGESTION object.
New bit numbers may be allocated only by an IETF Consensus action.
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
One bit is defined for the CONGESTION Object flag field in this
document:
Codespace of the Flag field (CONGESTION Object)
Bit Description Reference
0-6 Unassigned
7 Congestion This document
9. Security Considerations 9. Security Considerations
Mechanisms discussed in [I-D.ietf-pce-pcep] to secure a PCEP session The use of monitoring data can be used for various attacks such as
(authenticity, integrity, privacy, DoS protection, etc) can be used denail of service attacks (for example by setting the C bit and
to secure the PCMonReq, PCMonRep messages and PCE state metric congestion during field of the CONGESTION object to stop PCCs from
objects defined in this document as well. A PCE may face a denial of using a PCE). Thus it is recommended to make use of the security
service attack with PCMonReq messages. An implementation SHOULD mechanisms discussed in [I-D.ietf-pce-pcep] to secure a PCEP session
allow limiting the rate at which PCMonReq messages received from a (authenticity, integrity, privacy, DoS protection, etc) to secure the
specific peer are processed (input shapping), or from another domain PCMonReq, PCMonRep messages and PCE state metric objects defined in
(see also section 7.6). this document. An implementation SHOULD allow limiting the rate at
which PCMonReq or PCReq messages carrying monitoring requests
received from a specific peer are processed (input shapping), or from
another domain (see also section 7.6).
10. Acknowledgements 10. Acknowledgements
The authors would like to thank Eiji Oki, Mach Chen and Dimitri The authors would like to thank Eiji Oki, Mach Chen, Fabien Verhaeghe
Papadimitriou for their useful comments. Special thank to Adrian and Dimitri Papadimitriou for their useful comments. Special thank
Farrel for his detailed review. to Adrian Farrel for his detailed review.
11. References 11. References
11.1. Normative References 11.1. Normative References
[I-D.farrel-rtg-common-bnf]
Farrel, A., "Reduced Backus-Naur Form (RBNF) A Syntax Used
in Various Protocol Specifications",
draft-farrel-rtg-common-bnf-07 (work in progress),
November 2008.
[I-D.ietf-pce-of]
Roux, J., Vasseur, J., and Y. Lee, "Encoding of Objective
Functions in the Path Computation Element Communication
Protocol (PCEP)", draft-ietf-pce-of-06 (work in progress),
December 2008.
[I-D.ietf-pce-pcep] [I-D.ietf-pce-pcep]
Ayyangar, A., Farrel, A., Oki, E., Atlas, A., Dolganow, Ayyangar, A., Farrel, A., Oki, E., Atlas, A., Dolganow,
A., Ikejiri, Y., Kumaki, K., Vasseur, J., and J. Roux, A., Ikejiri, Y., Kumaki, K., Vasseur, J., and J. Roux,
"Path Computation Element (PCE) Communication Protocol "Path Computation Element (PCE) Communication Protocol
(PCEP)", draft-ietf-pce-pcep-18 (work in progress), (PCEP)", draft-ietf-pce-pcep-19 (work in progress),
November 2008. November 2008.
[I-D.ietf-pce-pcep-xro]
Takeda, T., Oki, E., and A. Farrel, "Extensions to the
Path Computation Element Communication Protocol (PCEP) for
Route Exclusions", draft-ietf-pce-pcep-xro-06 (work in
progress), July 2008.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997. Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC4655] Farrel, A., Vasseur, J., and J. Ash, "A Path Computation
Element (PCE)-Based Architecture", RFC 4655, August 2006.
11.2. Informative References 11.2. Informative References
[I-D.ietf-pce-brpc] [I-D.ietf-pce-brpc]
Vasseur, J., Zhang, R., Bitar, N., and J. Roux, "A Vasseur, J., Zhang, R., Bitar, N., and J. Roux, "A
Backward Recursive PCE-based Computation (BRPC) Procedure Backward Recursive PCE-based Computation (BRPC) Procedure
To Compute Shortest Constrained Inter-domain Traffic To Compute Shortest Constrained Inter-domain Traffic
Engineering Label Switched Paths", draft-ietf-pce-brpc-09 Engineering Label Switched Paths", draft-ietf-pce-brpc-09
(work in progress), April 2008. (work in progress), April 2008.
[I-D.ietf-pce-disco-proto-isis] [RFC4655] Farrel, A., Vasseur, J., and J. Ash, "A Path Computation
Roux, J., "IS-IS Protocol Extensions for Path Computation Element (PCE)-Based Architecture", RFC 4655, August 2006.
Element (PCE) Discovery",
draft-ietf-pce-disco-proto-isis-08 (work in progress),
September 2007.
[I-D.ietf-pce-of]
Roux, J., Vasseur, J., and Y. Lee, "Encoding of Objective
Functions in the Path Computation Element Communication
Protocol (PCEP)", draft-ietf-pce-of-05 (work in progress),
September 2008.
[I-D.ietf-pce-pcep-xro]
Takeda, T., Oki, E., and A. Farrel, "Extensions to the
Path Computation Element Communication Protocol (PCEP) for
Route Exclusions", draft-ietf-pce-pcep-xro-06 (work in
progress), July 2008.
[RFC5088] Le Roux, JL., Vasseur, JP., Ikejiri, Y., and R. Zhang, [RFC5088] Le Roux, JL., Vasseur, JP., Ikejiri, Y., and R. Zhang,
"OSPF Protocol Extensions for Path Computation Element "OSPF Protocol Extensions for Path Computation Element
(PCE) Discovery", RFC 5088, January 2008. (PCE) Discovery", RFC 5088, January 2008.
[RFC5089] Le Roux, JL., Vasseur, JP., Ikejiri, Y., and R. Zhang, [RFC5089] Le Roux, JL., Vasseur, JP., Ikejiri, Y., and R. Zhang,
"IS-IS Protocol Extensions for Path Computation Element "IS-IS Protocol Extensions for Path Computation Element
(PCE) Discovery", RFC 5089, January 2008. (PCE) Discovery", RFC 5089, January 2008.
Authors' Addresses Authors' Addresses
skipping to change at page 20, line 4 skipping to change at line 1038
Email: jeanlouis.leroux@orange-ftgroup.com Email: jeanlouis.leroux@orange-ftgroup.com
Yuichi Ikejiri Yuichi Ikejiri
NTT Communications Corporation NTT Communications Corporation
1-1-6, Uchisaiwai-cho, Chiyoda-ku 1-1-6, Uchisaiwai-cho, Chiyoda-ku
Tokyo, 100-8019 Tokyo, 100-8019
Japan Japan
Email: : y.ikejiri@ntt.com Email: : y.ikejiri@ntt.com
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