[Docs] [txt|pdf] [Tracker] [WG] [Email] [Diff1] [Diff2] [Nits]
Versions: (draft-vasseur-pce-monitoring) 00
01 02 03 04 05 06 07 08 09 RFC 5886
Networking Working Group JP. Vasseur, Ed.
Internet-Draft Cisco Systems, Inc
Intended status: Standards Track JL. Le Roux
Expires: August 9, 2008 France Telecom
Y. Ikejiri
NTT Communications Corporation
February 6, 2008
A set of monitoring tools for Path Computation Element based
Architecture
draft-ietf-pce-monitoring-01.txt
Status of this Memo
By submitting this Internet-Draft, each author represents that any
applicable patent or other IPR claims of which he or she is aware
have been or will be disclosed, and any of which he or she becomes
aware will be disclosed, in accordance with Section 6 of BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as Internet-
Drafts.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt.
The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html.
This Internet-Draft will expire on August 9, 2008.
Copyright Notice
Copyright (C) The IETF Trust (2008).
Abstract
A Path Computation Element (PCE) based architecture has been
specified for the computation of Traffic Engineering (TE) Label
Switched Paths (LSPs) in Multiprotocol Label Switching (MPLS) and
Generalized MPLS (GMPLS) networks in the context of single or
Vasseur, et al. Expires August 9, 2008 [Page 1]
Internet-Draft draft-ietf-pce-monitoring-01.txt February 2008
multiple domains (where a domain is referred to as a collection of
network elements within a common sphere of address management or path
computational responsibility such as IGP areas and Autonomous
Systems). In PCE-based environments it is thus critical to monitor
the state of the path computation chain for troubleshooting and
performance monitoring purposes: liveness of each element (PCE)
involved in the PCE chain, detection of potential resource contention
states, 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) in order
to gather such information.
Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].
Vasseur, et al. Expires August 9, 2008 [Page 2]
Internet-Draft draft-ietf-pce-monitoring-01.txt February 2008
Table of Contents
1. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Path Computation Monitoring messages . . . . . . . . . . . . . 5
3.1. Path Computation Monitoring Request message (PCMonReq) . . 6
3.2. Path Monitoring Reply message (PCMonRep) . . . . . . . . . 8
4. Path Computation Monitoring Objects . . . . . . . . . . . . . 9
4.1. MONITORING Object . . . . . . . . . . . . . . . . . . . . 9
4.2. PCE-ID Object . . . . . . . . . . . . . . . . . . . . . . 11
4.3. PROC-TIME Object . . . . . . . . . . . . . . . . . . . . . 12
4.4. CONGESTION Object . . . . . . . . . . . . . . . . . . . . 14
4.5. TIMESTAMP Object . . . . . . . . . . . . . . . . . . . . . 15
5. Multi-destination monitoring . . . . . . . . . . . . . . . . . 15
6. Policy . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
7. Elements of procedure . . . . . . . . . . . . . . . . . . . . 15
8. Manageability Considerations . . . . . . . . . . . . . . . . . 16
9. To be considered in a further revision of this document . . . 16
10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 16
11. Security Considerations . . . . . . . . . . . . . . . . . . . 17
12. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 18
13. References . . . . . . . . . . . . . . . . . . . . . . . . . . 18
13.1. Normative References . . . . . . . . . . . . . . . . . . . 18
13.2. Informative References . . . . . . . . . . . . . . . . . . 18
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 19
Intellectual Property and Copyright Statements . . . . . . . . . . 20
Vasseur, et al. Expires August 9, 2008 [Page 3]
Internet-Draft draft-ietf-pce-monitoring-01.txt February 2008
1. Terminology
AS: Autonomous System.
LSR: Label Switching Router.
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.
TE LSP: Traffic Engineering Label Switched Path.
TED: Traffic Engineering Database.
2. Introduction
The Path Computation Element (PCE) based architecture has been
specified in [RFC4655] for the computation of Traffic Engineering
(TE) Label Switched Paths (LSPs) in Multiprotocol Label Switching
(MPLS) and Generalized MPLS (GMPLS) networks in the context of single
or multiple domains where a domain is referred to as a collection of
network elements within a common sphere of address management or path
computational responsibility such as IGP areas and Autonomous
Systems.
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, 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
(referred to as single PCE path computation) or several PCEs
(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 PCE (see [RFC5088] and [RFC5089]) or PCEP using Keepalive
messages. In contrast, when multiple PCEs are involved in the path
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
first PCE involved in the path computation chain. Thus, it is
Vasseur, et al. Expires August 9, 2008 [Page 4]
Internet-Draft draft-ietf-pce-monitoring-01.txt February 2008
critical to define mechanisms in order to monitor the state of the
path computation chain.
The aim of this document is to specify PCEP extensions in order to
gather various state metrics along the path computation chain. In
this document we call a "state metric" a metric that characterizes a
PCE state. For example, such metric can have a form of a bolean (PCE
is alive or not, PCE is congested or not) or a performance metric
(path computation time at each PCE).
PCE state metrics collection can be gathered in two different
contexts: in band or out of band. By "In band" we refer to the
situation whereby a PCC requests to gather metrics in the context of
a path computation request. For example, a PCC may send a path
computation request to a PCE and may want to know the processing time
of that request in addition to the computed path. Conversely, if the
request is "out of band", PCE state metric collection is performed as
a standalone request (e.g. check the liveness of a specific PCE
chain, collect the average processing time computed over the last 5mn
period on one or more PCE(s)").
In this document we define two monitoring request types: general and
specific. A general monitoring request relates to the collection of
a PCE state metric(s) that is not coupled to a particular path
computation request (e.g. average CPU load on a PCE). Conversely, a
specific monitoring request relates to a particular path computation
request (processing time to complete the path computation for a TE
LSP).
3. Path Computation Monitoring messages
As defined in [I-D.ietf-pce-pcep], a PCEP message consists of a
common header followed by a variable length body made of a set of
objects that can either be mandatory or optional. As a reminder, an
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
(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 enforce a PCE to
take into account the related information during the path
computation. Because the P flag exclusively relates to a path
computation request, it MUST be cleared in the two PCEP messages
(PCEMonReq and PCMonRep message) defined in this document.
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
Form (BNF) to specify such rules. Square brackets refer to optional
sub-sequences. An implementation MUST form the PCEP messages using
Vasseur, et al. Expires August 9, 2008 [Page 5]
Internet-Draft draft-ietf-pce-monitoring-01.txt February 2008
the object ordering specified in this document.
In this document we define two PCEP messages referred to as the Path
Computation Monitoring request (PCMonReq) and Path Computation
Monitoring Reply (PCMonRep) messages so as to handle "out of band"
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
involved in a path computation chain. The PCMonRep message sent by a
PCE to a PCC is used to provide such data.
3.1. Path Computation Monitoring Request message (PCMonReq)
The Message-Type field of the PCEP common header for the PCMonReq
message is set to 8 (To be confirmed by IANA).
There is one mandatory object that MUST be included within a PCMonReq
message: the Monitoring object (see section Section 4.1). If the
Monitoring object is missing, the receiving PCE MUST send an error
message to the sender. Other objects are optional.
Vasseur, et al. Expires August 9, 2008 [Page 6]
Internet-Draft draft-ietf-pce-monitoring-01.txt February 2008
The format of a PCMonReq message is as follows:
<PCMonReq Message>::= <Common Header>
<MONITORING>
[<pce-list>]
[<svec-list>]
[<request-list>]
where:
<svec-list>::=<SVEC>
[<OF>]
[<svec-list>]
<request-list>::=<request>[<request-list>]
<request>::= <RP>
<END-POINTS>
[<LSPA>]
[<BANDWIDTH>]
[<metric-list>]
[<RRO>]
[<IRO>]
[<LOAD-BALANCING>]
[<XRO>]
<metric-list>::=<METRIC>[<metric-list>]
<pce-list>::=<PCE-ID>[<pce-list>]
The SVEC, RP, END-POINTS, LSPA, BANDWIDTH, METRIC, ERO, IRO and LOAD-
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
[I-D.ietf-pce-of].
The PCMonReq message is used to gather various PCE state metrics
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
objects defined in Section 4.2.) or may alternatively be determined
by the path computation procedure. For example, if the BRPC
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
PCC sends a PCMonReq message that contains the PCEP objects that
charaterize the TE LSP attributes along with the monitoring objects
(see Section 4.1) that list the set of metric(s) of interest.
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
is by all means not limitative and may be extended in further
revision of this document.
Vasseur, et al. Expires August 9, 2008 [Page 7]
Internet-Draft draft-ietf-pce-monitoring-01.txt February 2008
For the sake of illustraion, consider the three following examples:
Example 1: PCC1 requests to check the path computation chain should a
path computation be requested 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: 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
metric of interest. The PCRep message also comprises 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
specific path computation chain <pce1, pce2, pce3, pce7>. A PCMonreq
message is sent to PCE1 that contains a set of PCE-ID objects that
identify PCE1, PCE2, PCE3 and PCE7 respectively.
3.2. Path Monitoring Reply message (PCMonRep)
The PCMonRep message is used to provide PCE state metrics back to the
requester for "out of band" monitoring requests. The Message-Type
field of the PCEP common header for the PCMonRep message is set to 9
(To be confirmed by IANA).
There is one mandatory object that MUST be included within a PCMonRep
message: the Monitoring object (see Section 4.1). If the Monitoring
object is missing, the receiving PCE MUST send an error message to
the requesting PCC. Other objects are optional.
Vasseur, et al. Expires August 9, 2008 [Page 8]
Internet-Draft draft-ietf-pce-monitoring-01.txt February 2008
The format of a PCReq message is as follows:
<PCMonRep Message>::= <Common Header>
<MONITORING>
[<RP>]
[<metric-pce-list>]
where:
<metric-pce-list>::=<metric-pce>[<metric-pce-list>]
<metric-pce>::=[<PCE-ID>]
[<PROC-TIME>]
[<TIME-STAMP>]
[<CONGESTION>]
4. Path Computation Monitoring Objects
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
I flag cleared since these flags are exclusively related to path
computation request.
Several objects are defined in this section that can be carried
within the PCEP PCReq or PCRep messages defined in
[I-D.ietf-pce-pcep] in case of "in band" monitoring requests. In
case of "out of band" monitoring requests, the objects defined in
this section are carried within PCMonReq and PCMonRep messages.
Conversely, if the PCC requests the computation of the TE LSP in
addition to gathering PCE state metrics (i.e. "In band" requests),
these objects are carried within PCReq and PCRep messages.
4.1. MONITORING Object
The MONITORING object MUST be present within PCMonReq and PCMonRep
messages ("out of band" monitoring requests) and MAY be carried
within PCERep and PCReq messages ("in band" monitoring requests).
There MUST be exactly once instance of the MONITORING object: if more
than one instance of the MONITORING object is present, the recipient
MUST only process the first instance and ignore other instances. The
MONITORING object is used to specify the set of requested PCE state
metrics.
The MONITORING Object-Class is to be assigned by IANA (recommended
value=19)
The MONITORING Object-Type is to be assigned by IANA (recommended
value=1)
Vasseur, et al. Expires August 9, 2008 [Page 9]
Internet-Draft draft-ietf-pce-monitoring-01.txt February 2008
The format of the MONITORING object body is as follows:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved | Flags |I|C|P|G|L|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| monitoring-id-number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
// Optional TLV(s) //
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Flags: 18 bits
The following flags are currently defined:
L (Liveness) - 1 bit: when set, this indicates that the state metric
of interest is the PCE's liveness and thus the PCE MUST include a
PCE-ID object in the corresponding reply.
G (General) - 1 bit: when set, this indicates that the monitoring
request is a general monitoring request. When the requested
performance metric is specific, the G bit MUST be cleared.
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
processing times is a metric of interest, in which case a PROC-TIME
object MUST be inserted in the corresponding PCMonRep or PCRep
message. The P bit MUST always be set in a PCMonRep message if also
set in the corresponding PCMonReq message.
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
status is a metric of interest, in which case a CONGESTION object
MUST be inserted in the corresponding PCMonRep or PCRep message. The
C bit MUST always be set in a PCMonRep message if also set in the
corresponding PCMonReq message.
I (Incomplete) - 1 bit: the I bit MUST be set by a PCE that supports
the PCMonReq message, which does not trigger any policy violation but
that cannot provide the set of requested performance metrics for
unspecified reasons.
Monitoring-id-number (32 bits). The monitoring-id-number value
combined with the source IP address of the PCC and the PCE address
uniquely identify the monitoring request context. The monitoring-id-
Vasseur, et al. Expires August 9, 2008 [Page 10]
Internet-Draft draft-ietf-pce-monitoring-01.txt February 2008
number MUST be incremented each time a new monitoring is sent to a
PCE. The value 0x0000000 is considered as invalid. If no reply to a
monitoring request is received from the PCE, and the PCC wishes to
resend its path computation monitoring request, the same monitoring-
id-number MUST be used. Conversely, different monitoring-id-number
MUST be used for different requests sent to a PCE. The same
monitoring-id-number may be used for path computation monitoring
requests sent to different PCEs. The path computation monitoring
reply is unambiguously identified by the IP source address of the
replying PCE.
Unassigned bits are considered as reserved and MUST be set to zero on
transmission.
No optional TLVs are currently defined.
4.2. PCE-ID Object
The PCE-ID Object is used to specify a PCE's IP address.
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
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
computation chain.
Two PCE-ID objects (for IPv4 and IPv6) are defined. PCE-ID Object-
Class is to be assigned by IANA (recommended value=20) PCE-ID Object-
Type is to be assigned by IANA (recommended value=1 for IPv4 and 2
for IPv6)
The format of the PCE-ID Object is as follows:
Vasseur, et al. Expires August 9, 2008 [Page 11]
Internet-Draft draft-ietf-pce-monitoring-01.txt February 2008
The format of the PCE-ID object body for IPv4 and IPv6 are as
follows:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv4 Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| IPv6 Address |
| |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The PCE-ID object body has a fixed length of 4 octets for IPv4 and 16
octets for IPv6.
A PCE MUST use the same IP address as the address used in the PCE-
ADDRESS sub-TLV defined in [RFC5088] and [RFC5089] should a dynamic
discovery mechanism be used for PCE discovery.
4.3. PROC-TIME Object
The PROC-TIME object MUST be present within a PCMonRep or a PCRep
message if the P bit of the MONITORING object carried within the
corresponding PCMonReq or PCReq message is set. The PROC-TIME object
is used to report various processing time related metrics.
1) Case of general monitoring requests
A PCC may request processing time metrics for general monitoring
requests (e.g. the PCC may want to know the minimum, maximum and
average processing times on a particular PCE). In this case, general
requests can only be made by using PCMonReq/PCMonRep messages. The
processing-time field (as explained below) is exclusively used for
specific monitoring requests and MUST be cleared for general
monitoring requests. The algorithm(s) used by a PCE to compute 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
processing time over a period of times, for the last N path
computation requests, ...).
2) Case of specific monitoring requests
In the case of a specific request, the algorithm(s) used by a PCE to
Vasseur, et al. Expires August 9, 2008 [Page 12]
Internet-Draft draft-ietf-pce-monitoring-01.txt February 2008
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
requester whether the processing time value was estimated or
computed. The PCE may either (1) estimate the processing time
without performing an actual path computation or (2) effectively
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
be cleared and the Min-processing-time, Max-processing-time, Average-
processing-time and Variance-processing-time MUST be set to
0x00000000.
When the processing time is requested in addition to a path
computation (case where the MONITORING object is carried within a
PCReq message), the PROC-TIME object always report the actual
processing time for that request and thus the E bits MUST be cleared.
The PROC-TIME Object-Class is to be assigned by IANA (recommended
value=21)
The PROC-TIME Object-Type is to be assigned by IANA (recommended
value=1)
The format of the PROC-TIME object body is as follows:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved | Flags |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Processing-time |E|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Min-processing-time |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Max-processing-time |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Average-processing time |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Variance-processing-time |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Flags: 18 bits - No Flags are currently defined:
E (Estimated) - 1 bit: when set, this indicates that the reported
metric value is based on estimated processing time as opposed to
actual computation(s).
Current-processing-time: This field indicates in milliseconds the
processing time for the path computation of interest characterized in
Vasseur, et al. Expires August 9, 2008 [Page 13]
Internet-Draft draft-ietf-pce-monitoring-01.txt February 2008
the corresponding PCMonReq message.
Min-processing-time: This field indicates in milliseconds the minimum
processing time.
Max-processing-time: This field indicates in milliseconds the maximum
processing time.
Average-processing-time: This field indicates in milliseconds the
average processing time.
Variance-processing-time: This field indicates in milliseconds the
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
The CONGESTIION object MUST be present within a PCMonRep or a PCRep
message if the C bit of the MONITORING object carried within the
corresponding PCMonReq or PCReq message is set. The CONGESTION
object is used to report a PCE processing congestion state. The
CONGESTION Object-Class is to be assigned by IANA (recommended
value=22) The CONGESTION Object-Type is to be assigned by IANA
(recommended value=1)
The format of the CONGESTION object body is as follows:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|C| Reserved | Congestion Duration |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
C (Congestion) - 1 bit: when set, this indicates that PCE is
congested, in which case the congestion duration may be non nul.
When cleared this indicates that the PCE is not congested.
Congestion duration - 16 bits: This field indicates in seconds the
estimated congestion duration.
Vasseur, et al. Expires August 9, 2008 [Page 14]
Internet-Draft draft-ietf-pce-monitoring-01.txt February 2008
4.5. TIMESTAMP Object
A TIMESTAMP object will be specified in a further revision of this
document that could be used to indicate when a PCMonReq message has
been received by a PCE and when the PCMonReq message has been relayed
to the next-hop PCE or the time at which a PCMonRep message has been
sent to the requester.
5. Multi-destination monitoring
In a further revision of this document, a new object will be
specified allowing a PCC or a user to gather PCE state metrics for a
set of destinations using a single PCMonReq message. For example,
using a single PCMonreq message originated by a PCC, PCE state
metrics for the set of path computation chains involved in the
computation of a set of TE LSPs will be gathered. Such set of
destinations could be specified in the form of a subnets.
6. Policy
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-
Type=5 and Error-value=3 (To be Confirmed by IANA).
7. Elements of procedure
I bit processing: as indicated in section Section 4.1, the I bit MUST
be set by a PCE that supports the PCMonReq message, which does not
trigger any policy violation but that cannot provide the set of
required performance metrics for unspecified reasons. Once set, the
I bit MUST NOT be changed by a receiving PCE.
Reception of a PCMonReq message: upon receiving a PCMonReq message:
1) If the PCE does not support the PCMonReq message, the PCE MUST
send a PCErr message with Error-type=14 and Error-value=1.
2) If the PCE supports the PCMonReq message but the request is
prohibited by policy, the PCE MUST send a PCErr message with Error-
Type=5 and Error-value=3.
3) If the PCE supports the PCMonReq and the monitoring 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 PCMonReq message
Vasseur, et al. Expires August 9, 2008 [Page 15]
Internet-Draft draft-ietf-pce-monitoring-01.txt February 2008
is relayed to the next hop PCE: such next-hop may either be specified
by means of a PCE-ID object present in the PCMonReq 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 PCMonRep message that
contains the requested objects according to the set of requested PCE
states metrics listed in the MONITORING object carried in the
corresponding PCMonReq message.
Reception of a PCMonRep message: upon receiving a PCMonRep message,
the PCE processes the request, adds the relevant objects to the
PCMonRep message and forwards the PCMonRep message to the upstream
requesting PCE or PCC.
Special case of Multi-destination monitoring: monitoring request
related to more than one destinations may involve a set of path
computation chains. In that case, a PCE sends each copy of the
PCMonReq message to each downstream PCE of each path computation
chain.
8. Manageability Considerations
To be addressed in a further revision of this document.
9. To be considered in a further revision of this document
It might be desirable to modify the format of the PCMonReq and
PCMonRep messages to support the bundling of multiple performance
metrics collection for a set of TE LSPs.
10. IANA Considerations
Two new PCEP (specified in [I-D.ietf-pce-pcep]) messages are defined
in this document:
Value Meaning
8 Path Computation Monitoring Request (PCMonReq)
9 Path Computation Monitoring Reply (PCMonRep)
The following new PCEP objects are defined in this document.
Vasseur, et al. Expires August 9, 2008 [Page 16]
Internet-Draft draft-ietf-pce-monitoring-01.txt February 2008
Object-Class Name
19 MONITORING
Object-Type
1
20 PCE-ID
Object-Type
1: IPv4 addresses
2: IPv6 addresses
21 PROC-TIME
Object-Type
1
22 CONGESTION
Object-Type
1
A new Error type for the PCErr message (see [I-D.ietf-pce-pcep]) is
defined in this document (Error-Type and Error-value to be assigned
by IANA).
Error-type Meaning
14 Performance Monitoring not supported
Error-value
1: Monitoring message not supported by one
of PCEs along the domain path
2: MONITORING object missing in a PCMonReq
message
A new Error-value for the PCErr message Error-types=4 (see
[I-D.ietf-pce-pcep]) is defined in this document (Error-Type and
Error-value to be assigned by IANA).
Error-type Meaning
5 Performance Monitoring Policy violation
3: Monitoring message supported but rejected
due to policy violation
11. Security Considerations
To be addressed in a further revision of this document.
Vasseur, et al. Expires August 9, 2008 [Page 17]
Internet-Draft draft-ietf-pce-monitoring-01.txt February 2008
12. Acknowledgements
The authors would like to thank Eiji Oki, Mach Chen and Dimitri
Papadimitriou for their useful comments.
13. References
13.1. Normative References
[I-D.ietf-pce-pcep]
Ayyangar, A., Oki, E., Atlas, A., Dolganow, A., Ikejiri,
Y., Kumaki, K., Vasseur, J., and J. Roux, "Path
Computation Element (PCE) communication Protocol (PCEP)",
draft-ietf-pce-pcep-09 (work in progress), November 2007.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
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.
13.2. Informative References
[I-D.ietf-pce-brpc]
Vasseur, J., "A Backward Recursive PCE-based Computation
(BRPC) procedure to compute shortest inter-domain Traffic
Engineering Label Switched Paths", draft-ietf-pce-brpc-06
(work in progress), September 2007.
[I-D.ietf-pce-disco-proto-isis]
Roux, J., "IS-IS Protocol Extensions for Path Computation
Element (PCE) Discovery",
draft-ietf-pce-disco-proto-isis-08 (work in progress),
September 2007.
[I-D.ietf-pce-of]
Roux, J., "Encoding of Objective Functions in Path
Computation Element communication Protocol (PCEP)",
draft-ietf-pce-of-01 (work in progress), November 2007.
[I-D.ietf-pce-pcep-xro]
Oki, E. and A. Farrel, "Extensions to the Path Computation
Element Communication Protocol (PCEP) for Route
Exclusions", draft-ietf-pce-pcep-xro-02 (work in
progress), September 2007.
[RFC5088] Le Roux, JL., Vasseur, JP., Ikejiri, Y., and R. Zhang,
Vasseur, et al. Expires August 9, 2008 [Page 18]
Internet-Draft draft-ietf-pce-monitoring-01.txt February 2008
"OSPF Protocol Extensions for Path Computation Element
(PCE) Discovery", RFC 5088, January 2008.
[RFC5089] Le Roux, JL., Vasseur, JP., Ikejiri, Y., and R. Zhang,
"IS-IS Protocol Extensions for Path Computation Element
(PCE) Discovery", RFC 5089, January 2008.
Authors' Addresses
JP Vasseur (editor)
Cisco Systems, Inc
1414 Massachusetts Avenue
Boxborough, MA 01719
USA
Email: jpv@cisco.com
JL Le Roux
France Telecom
2, Avenue Pierre-Marzin
Lannion, 22307
FRANCE
Email: jeanlouis.leroux@orange-ftgroup.com
Yuichi Ikejiri
NTT Communications Corporation
1-1-6, Uchisaiwai-cho, Chiyoda-ku
Tokyo, 100-8019
Japan
Email: : y.ikejiri@ntt.com
Vasseur, et al. Expires August 9, 2008 [Page 19]
Internet-Draft draft-ietf-pce-monitoring-01.txt February 2008
Full Copyright Statement
Copyright (C) The IETF Trust (2008).
This document is subject to the rights, licenses and restrictions
contained in BCP 78, and except as set forth therein, the authors
retain all their rights.
This document and the information contained herein are provided on an
"AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND
THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS
OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF
THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
Intellectual Property
The IETF takes no position regarding the validity or scope of any
Intellectual Property Rights or other rights that might be claimed to
pertain to the implementation or use of the technology described in
this document or the extent to which any license under such rights
might or might not be available; nor does it represent that it has
made any independent effort to identify any such rights. Information
on the procedures with respect to rights in RFC documents can be
found in BCP 78 and BCP 79.
Copies of IPR disclosures made to the IETF Secretariat and any
assurances of licenses to be made available, or the result of an
attempt made to obtain a general license or permission for the use of
such proprietary rights by implementers or users of this
specification can be obtained from the IETF on-line IPR repository at
http://www.ietf.org/ipr.
The IETF invites any interested party to bring to its attention any
copyrights, patents or patent applications, or other proprietary
rights that may cover technology that may be required to implement
this standard. Please address the information to the IETF at
ietf-ipr@ietf.org.
Acknowledgment
Funding for the RFC Editor function is provided by the IETF
Administrative Support Activity (IASA).
Vasseur, et al. Expires August 9, 2008 [Page 20]
Html markup produced by rfcmarkup 1.129b, available from
https://tools.ietf.org/tools/rfcmarkup/