Internet DRAFT - draft-dhody-pce-stateful-pce-auto-bandwidth
draft-dhody-pce-stateful-pce-auto-bandwidth
PCE Working Group D. Dhody
Internet-Draft U. Palle
Intended status: Standards Track Huawei Technologies
Expires: August 30, 2016 R. Singh
Juniper Networks
R. Gandhi
Cisco Systems, Inc.
L. Fang
Microsoft
February 29, 2016
PCEP Extensions for MPLS-TE LSP Automatic Bandwidth Adjustment with
Stateful PCE
draft-dhody-pce-stateful-pce-auto-bandwidth-07
Abstract
The Path Computation Element Communication Protocol (PCEP) provides
mechanisms for Path Computation Elements (PCEs) to perform path
computations in response to Path Computation Clients (PCCs) requests.
The stateful PCE extensions allow stateful control of Multi-Protocol
Label Switching (MPLS) Traffic Engineering Label Switched Paths (TE
LSPs) using PCEP.
This document describes PCEP extensions for automatic bandwidth
adjustment when employing an Active Stateful PCE for both PCE-
initiated and PCC-initiated LSPs. In one of the models described,
PCC computes the bandwidth to be adjusted and informs the PCE whereas
in the second model, PCC reports the real-time bandwidth usage to a
PCE and the PCE computes the adjustment bandwidth.
Status of This Memo
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provisions of BCP 78 and BCP 79.
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material or to cite them other than as "work in progress."
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Copyright Notice
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Conventions Used in This Document . . . . . . . . . . . . . . 5
2.1. Requirements Language . . . . . . . . . . . . . . . . . . 5
2.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 5
3. Requirements for PCEP Extensions . . . . . . . . . . . . . . . 6
4. Architectural Overview . . . . . . . . . . . . . . . . . . . . 7
4.1. Auto-Bandwidth Overview . . . . . . . . . . . . . . . . . 7
4.2. Theory of Operation . . . . . . . . . . . . . . . . . . . 10
4.3. Scaling Considerations . . . . . . . . . . . . . . . . . . 11
5. Extensions to the PCEP . . . . . . . . . . . . . . . . . . . . 11
5.1. Capability Advertisement . . . . . . . . . . . . . . . . . 11
5.1.1 AUTO-BANDWIDTH-CAPABILITY TLV . . . . . . . . . . . . . 12
5.2. AUTO-BANDWIDTH-ATTRIBUTE TLV . . . . . . . . . . . . . . . 12
5.2.1. Sample-Interval sub-TLV . . . . . . . . . . . . . . . 14
5.2.2. Adjustment-Interval sub-TLV . . . . . . . . . . . . . 14
5.2.3. Adjustment Threshold . . . . . . . . . . . . . . . . . 15
5.2.3.1. Adjustment-Threshold sub-TLV . . . . . . . . . . . 15
5.2.3.2. Adjustment-Threshold-Percentage sub-TLV . . . . . 15
5.2.4. Minimum and Maximum Bandwidth Values . . . . . . . . . 16
5.2.4.1. Minimum-Bandwidth sub-TLV . . . . . . . . . . . . 16
5.2.4.2. Maximum-Bandwidth sub-TLV . . . . . . . . . . . . 16
5.2.5. Overflow and Underflow Condition . . . . . . . . . . . 17
5.2.5.1. Overflow-Threshold sub-TLV . . . . . . . . . . . . 17
5.2.5.2. Overflow-Threshold-Percentage sub-TLV . . . . . . 18
5.2.5.3. Underflow-Threshold sub-TLV . . . . . . . . . . . 18
5.2.5.4. Underflow-Threshold-Percentage sub-TLV . . . . . . 19
5.3. BANDWIDTH-USAGE-ATTRIBUTE TLV . . . . . . . . . . . . . . 20
5.3.1. Bandwidth-Usage-Report-Interval sub-TLV . . . . . . . 21
5.3.2. Bandwidth-Usage-Report-Threshold sub-TLV . . . . . . . 22
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5.3.3. Bandwidth-Usage-Report-Threshold-Percentage sub-TLV . 22
5.3.4. Bandwidth-Usage-Report-Flow-Threshold sub-TLV . . . . 23
5.3.5. Bandwidth-Usage-Report-Flow-Threshold-Percent
sub-TLV . . . . . . . . . . . . . . . . . . . . . . . 24
5.4. BANDWIDTH Object . . . . . . . . . . . . . . . . . . . . . 24
5.4.1. Auto-Bandwidth Adjusted Bandwidth Report . . . . . . . 24
5.4.2. Bandwidth-Usage Report . . . . . . . . . . . . . . . . 25
5.5. The PCInitiate Message . . . . . . . . . . . . . . . . . . 25
5.6. The PCRpt Message . . . . . . . . . . . . . . . . . . . . 26
6. Security Considerations . . . . . . . . . . . . . . . . . . . 26
7. Manageability Considerations . . . . . . . . . . . . . . . . . 26
7.1. Control of Function and Policy . . . . . . . . . . . . . . 26
7.2. Information and Data Models . . . . . . . . . . . . . . . 27
7.3. Liveness Detection and Monitoring . . . . . . . . . . . . 27
7.4. Verify Correct Operations . . . . . . . . . . . . . . . . 27
7.5. Requirements On Other Protocols . . . . . . . . . . . . . 27
7.6. Impact On Network Operations . . . . . . . . . . . . . . . 27
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 28
8.1. PCEP TLV Type Indicators . . . . . . . . . . . . . . . . . 28
8.2. AUTO-BANDWIDTH-ATTRIBUTE Sub-TLV . . . . . . . . . . . . . 28
8.3. BANDWIDTH-USAGE-ATTRIBUTE Sub-TLV . . . . . . . . . . . . 28
8.4. BANDWIDTH Object . . . . . . . . . . . . . . . . . . . . . 29
8.5. Error Object . . . . . . . . . . . . . . . . . . . . . . . 29
9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 29
9.1. Normative References . . . . . . . . . . . . . . . . . . . 29
9.2. Informative References . . . . . . . . . . . . . . . . . . 30
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 31
Contributors' Addresses . . . . . . . . . . . . . . . . . . . . . 31
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 32
1. Introduction
[RFC5440] describes the Path Computation Element Protocol (PCEP) as a
communication mechanism between a Path Computation Client (PCC) and a
Path Control Element (PCE), or between PCE and PCE, that enables
computation of Multi-Protocol Label Switching (MPLS) Traffic
Engineering Label Switched Paths (TE LSPs).
[I-D.ietf-pce-stateful-pce] specifies extensions to PCEP to enable
stateful control of MPLS TE LSPs. It describes two mode of
operations - Passive Stateful PCE and Active Stateful PCE. In this
document, the focus is on Active Stateful PCE where LSPs are
configured at the PCC and control over them is delegated to the PCE.
Further [I-D.ietf-pce-pce-initiated-lsp] describes the setup,
maintenance and teardown of PCE-initiated LSPs for the stateful PCE
model.
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Over time, based on the varying traffic pattern, an LSP established
with certain bandwidth may require to adjust the bandwidth, reserved
in the network automatically. Ingress Label Switch Router (LSR)
collects the traffic rate at each sample interval to determine the
bandwidth demand of the LSP. This bandwidth information is then used
to adjust the LSP bandwidth periodically. This feature is commonly
referred to as Auto-Bandwidth.
Enabling Auto-Bandwidth feature on an LSP results in the LSP
automatically adjusting its bandwidth reservation based on the actual
traffic flowing through the LSP. The initial LSP bandwidth can be
set to an arbitrary value (including zero), in practice, it can be
operator expected value based on design and planning. Once the LSP
is set-up, the LSP monitors the traffic flow and adjusts its
bandwidth every adjustment-interval period. The bandwidth adjustment
uses the make-before-break signaling method so that there is no
interruption to the traffic flow. The Auto-Bandwidth is described in
detail in Section 4.1. [I-D.ietf-pce-stateful-pce-app] describes the
use-case for Auto-Bandwidth adjustment for passive and active
stateful PCE.
In this document, following deployment models are considered for
employing Auto-Bandwidth feature with active stateful PCE.
o Deployment model 1: PCC to decide adjusted bandwidth:
* In this model, the PCC (head-end of the LSP) monitors and
calculates the new adjusted bandwidth. The PCC reports the
calculated bandwidth to be adjusted to the PCE.
* This approach would be similar to passive stateful PCE model,
while the passive stateful PCE uses path request/reply
mechanism, the active stateful PCE uses report/update mechanism
to adjust the LSP bandwidth.
* For PCE-initiated LSP, the PCC is requested during the LSP
initiation to monitor and calculate the new adjusted bandwidth.
o Deployment model 2: PCE to decide adjusted bandwidth:
* In this model, the PCE calculates the new adjusted bandwidth
for the LSP.
* Active stateful PCE can use information such as historical
trending data, application-specific information about expected
demands and central policy information along with real-time
bandwidth usage to make smarter bandwidth adjustment to the
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delegated LSPs. Since the LSP has delegated control to the
PCE, it is inherently suited that it should be the stateful PCE
that decides the bandwidth adjustments.
* For PCE-initiated LSP, the PCC is requested during initiation,
to monitor and report the real-time bandwidth usage.
* This model does not exclude use of any other mechanism employed
by stateful PCE to learn real-time bandwidth usage information.
But at the same time, using the same protocol (PCEP in this
case) for updating and reporting the adjustment parameters as
well as to learn real-time bandwidth usage is operationally
beneficial.
This document defines extensions needed to support Auto-Bandwidth
feature on the LSPs in a active stateful PCE model using PCEP.
2. Conventions Used in This Document
2.1. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119].
2.2. Terminology
The following terminology is used in this document.
Active Stateful PCE: PCE that uses tunnel state information learned
from PCCs to optimize path computations. Additionally, it
actively updates tunnel parameters in those PCCs that delegated
control over their tunnels to the PCE.
Delegation: An operation to grant a PCE temporary rights to modify a
subset of tunnel parameters on one or more PCC's tunnels. Tunnels
are delegated from a PCC to a PCE.
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.
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Note the Auto-Bandwidth feature specific terms defined in Section
4.1.
3. Requirements for PCEP Extensions
The PCEP speaker supporting this document MUST have a mechanism to
advertise the automatic bandwidth adjustment capability.
As discussed in Section 1, there are two deployment models considered
in this document for automatic bandwidth adjustments in case of
active stateful PCE. In the model 1, where PCC decides the adjusted
bandwidth, PCC reports the new adjusted bandwidth and an active
stateful PCE updates the bandwidth of a delegated LSP via existing
mechanisms defined in [I-D.ietf-pce-stateful-pce]. PCEP extensions
required for both models are summarized in the following table.
+-------------------------------------------------------------------+
| Model 1: PCC decides adjusted BW |
+---------------------------------+---------------------------------+
| PCC Initiated | PCE Initiated |
+---------------------------------+---------------------------------+
| | |
| PCC monitors the traffic | At the time of initiation, |
| and reports the calculated | PCE request PCC to monitor |
| bandwidth to be adjusted | the traffic and report the |
| to the PCE. | calculated bandwidth to be |
| | adjusted to the PCE. |
| | |
| No new extensions are needed. | Extension is needed for PCE |
| | to pass on the adjustment |
| | parameters at the time of |
| | Initiation. |
| | |
+---------------------------------+---------------------------------+
+-------------------------------------------------------------------+
| Model 2: PCC reports bandwidth-usage, PCE decides adjusted BW |
+---------------------------------+---------------------------------+
| PCC Initiated | PCE Initiated |
+---------------------------------+---------------------------------+
| | |
| PCC monitors bandwidth usage | At the time of initiation, |
| and reports the real-time | PCE request PCC to monitor |
| bandwidth usage to the PCE. | the traffic and reports the |
| It is PCE that decides the | real-time bandwidth usage to |
| calculated bandwidth to be | the PCE. It is PCE that decides|
| adjusted and updates the | the calculated bandwidth to |
| LSP accordingly. | be adjusted and updates the |
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| | LSP accordingly. |
| | |
| Extension is needed for | Extension is needed for PCE |
| PCC to pass on the auto-bw | to pass on the real-time |
| adjustment parameters at | bandwidth usage reporting |
| the time of delegation to | parameters at the time of |
| PCE. | Initiation. |
| | |
| Further extension to report | Further extension to report |
| the bandwidth-usage to | the bandwidth-usage to |
| PCE are also needed | PCE are also needed. |
| | |
+---------------------------------+---------------------------------+
Table 1: Auto-Bandwidth PCEP extensions
Further Auto-Bandwidth deployment considerations are summarized
below:
o It is required to identify and inform the PCEP peer, the LSP that
are enabled with Auto-Bandwidth feature. Not all LSPs in some
deployments would like their bandwidth to be dependent on the
real-time bandwidth usage but be constant as set by the operator.
o It is also required to identify and inform the PCEP peer the model
of operation i.e. if PCC decides the adjusted bandwidth, or PCC
reports the real-time bandwidth usage instead and the PCE decides
the adjusted bandwidth.
* Note that PCEP extension for reporting real-time bandwidth
usage, as specified in this document, is one of the ways for a
PCE to learn this information. But at the same time a stateful
PCE may choose to learn this information from other means like
management, performance tools, which are beyond the scope of
this document.
o Further for the LSP with Auto-Bandwidth feature enabled, an
operator should be able to specify the adjustment parameters (i.e.
configuration knobs) to control this feature (e.g. minimum/
maximum bandwidth range) and PCEP peer should be informed.
4. Architectural Overview
4.1. Auto-Bandwidth Overview
Auto-Bandwidth feature allows an LSP to automatically and dynamically
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adjust its reserved bandwidth over time, i.e. without network
operator intervention. The bandwidth adjustment uses the
make-before-break signaling method so that there is no interruption
to the traffic flow.
The new bandwidth reservation is determined by sampling the actual
traffic flowing through the LSP. If the traffic flowing through the
LSP is lower than the configured or current bandwidth of the LSP, the
extra bandwidth is being reserved needlessly and being wasted.
Conversely, if the actual traffic flowing through the LSP is higher
than the configured or current bandwidth of the LSP, it can
potentially cause congestion or packet loss in the network. With
Auto-Bandwidth feature, the LSP bandwidth can be set to some
arbitrary value (including zero) during initial setup time, and it
will be periodically adjusted over time based on the actual bandwidth
requirement.
Note the following definitions of the Auto-Bandwidth terms:
Maximum Average Bandwidth (MaxAvgBw): The maximum average bandwidth
represents the current traffic bandwidth demand during a time
interval. This is the maximum value of the averaged traffic
bandwidth rate in a given adjustment-interval.
Adjusted Bandwidth: This is the Auto-Bandwidth computed bandwidth
that needs to be adjusted for the LSP.
Sample-Interval: The periodic time interval at which the traffic
rate is collected as a sample.
Bandwidth-Sample (BwSample): The bandwidth sample collected at every
sample interval to measure the traffic rate.
Adjustment-Interval: The periodic time interval at which the
bandwidth adjustment should be made using the MaxAvgBw.
Maximum-Bandwidth: The maximum bandwidth that can be reserved for
the LSP.
Minimum-Bandwidth: The minimum bandwidth that can be reserved for
the LSP.
Adjustment-Threshold: This value is used to decide when the
bandwidth should be adjusted. If the percentage or absolute
difference between the current MaxAvgBw and the current bandwidth
reservation is greater than or equal to the threshold value, the
LSP bandwidth is adjusted to the current bandwidth demand
(Adjusted Bandwidth) at the adjustment-interval expiry.
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Overflow-Count: This value is used to decide when the bandwidth
should be adjusted when there is a sudden increase in traffic
demand. This value indicates how many times consecutively, the
percentage or absolute difference between the current MaxAvgBw and
the current bandwidth reservation is greater than or equal to the
Overflow-Threshold value.
Overflow-Threshold: This value is used to decide when the bandwidth
should be adjusted when there is a sudden increase in traffic
demand. If the percentage or absolute difference between the
current MaxAvgBw and the current bandwidth reservation is greater
than or equal to the threshold value, the overflow-condition is
set to be met. The LSP bandwidth is adjusted to the current
bandwidth demand bypassing the adjustment-interval if the
overflow-condition is met consecutively for the Overflow-Count.
Underflow-Count: This value is used to decide when the bandwidth
should be adjusted when there is a sudden decrease in traffic
demand. This value indicates how many times consecutively, the
percentage or absolute difference between the current MaxAvgBw and
the current bandwidth reservation is greater than or equal to the
Underflow-Threshold value.
Underflow-Threshold: This value is used to decide when the bandwidth
should be adjusted when there is a sudden decrease in traffic
demand. If the percentage or absolute difference between the
current MaxAvgBw and the current bandwidth reservation is greater
than or equal to the threshold value, the underflow-condition is
set to be met. The LSP bandwidth is adjusted to the current
bandwidth demand bypassing the adjustment-interval if the
underflow-condition is met consecutively for the Underflow-Count.
Report-Interval: This value indicates the periodic interval when the
collected real-time bandwidth-usage samples (BwSample) should be
reported to the stateful PCE via the PCRpt message.
Report-Threshold: This value is used to decide if the real-time
bandwidth-usage samples collected should be reported. Only if the
percentage or the absolute difference between at least one of the
bandwidth samples collected and the current bandwidth reservation
is greater than or equal to the threshold value, the bandwidth
samples collected during the Report-Interval are reported
otherwise the bandwidth sample(s) are skipped.
Report-Flow-Threshold: This value is used to decide when the real-
time traffic bandwidth samples should be reported immediately when
there is a sudden change in traffic demand. If the percentage or
absolute difference between the current bandwidth sample and the
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current bandwidth reservation is greater than or equal to the
flow-threshold value, the bandwidth usage report condition is said
to be met. The collected bandwidth usage information is reported
bypassing the report-interval if the bandwidth usage report
condition is met consecutively for the Report-Flow-Count.
Report-Flow-Count: This value is used to decide when the bandwidth
usage collected so far should be reported when there is a sudden
change in bandwidth usage. This value indicates how many times
consecutively, the percentage or absolute difference between the
current bandwidth sample and the current bandwidth reservation is
greater than or equal to the Report-Flow-Threshold value, all the
bandwidth samples collected so far are reported to the PCE
immediately.
4.2. Theory of Operation
The traffic rate is periodically sampled at each sample-interval
(which can be configured by the user and the default value as 5
minutes) by the head-end node of the LSP. The sampled traffic rates
are accumulated over the adjustment-interval period (which can be
configured by the user and the default value as 24 hours). The PCEP
peer which is in-charge of calculating the bandwidth to be adjusted,
will adjust the bandwidth of the LSP to the highest sampled traffic
rate (MaxAvgBw) amongst the set of bandwidth samples collected over
the adjustment-interval.
Note that the highest sampled traffic rate could be higher or lower
than the current LSP bandwidth. Only if the difference between the
current bandwidth demand (MaxAvgBw) and the current bandwidth
reservation is greater than or equal to the Adjustment-Threshold
(percentage or absolute value), the LSP bandwidth is adjusted to the
current bandwidth demand (MaxAvgBw). Some LSPs are less eventful
while other LSPs may encounter a lot of changes in the traffic
pattern. PCE sets the intervals for reporting and adjustment based
on the traffic pattern of the LSP.
In order to avoid frequent re-signaling, an operator may set a longer
adjustment-interval value. However, longer adjustment-interval can
result in an undesirable effect of masking sudden changes in traffic
demands of an LSP. To avoid this, the Auto-Bandwidth feature may
pre-maturely expire the adjustment-interval and adjust the LSP
bandwidth to accommodate the sudden bursts of increase in traffic
demand as an overflow condition or decrease in traffic demand as an
underflow condition.
In case of Deployment model 2, the PCC reports the real-time
bandwidth-usage information and the PCE decides the adjusted
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bandwidth. Multiple bandwidth samples are collected every report-
interval, and reported together to the PCE. To avoid reporting minor
changes in real-time bandwidth-usage, report-threshold is used, to
suppress the sending of the collected samples during the report-
interval. The collected samples are reported if at least one sample
crosses the Report-Threshold (percentage or absolute value). In
order to accommodate sudden changes in the bandwidth usage, report-
flow-threshold is employed by pre-maturely expiry of the report-
interval to report the unreported bandwidth samples collected so far.
All thresholds in this document could be represented in both absolute
value and percentage, and could be used together.
4.3. Scaling Considerations
There are potential scaling concerns for the model where PCC (ingress
LSR) reports real-time bandwidth usage information to the stateful
PCE for a large number of LSPs. It is recommended to combine
multiple bandwidth samples (BwSamples) using larger report-interval
and report them together to the PCE, thus reducing the number of
PCRpt messages. Further, Report-Threshold can be use to skip
reporting the bandwidth samples for small changes in the bandwidth.
The processing cost of monitoring a large number of LSPs at the PCC
and handling bandwidth change requests at PCE should be taken into
consideration. Note that, this will be implementation dependent.
5. Extensions to the PCEP
5.1. Capability Advertisement
During PCEP Initialization Phase, PCEP Speakers (PCE or PCC)
advertise their support of Automatic Bandwidth Adjustment. A PCEP
Speaker includes the "Auto-Bandwidth Capability" TLV, in the OPEN
Object to advertise its support for PCEP Auto-Bandwidth extensions.
The presence of the "Auto-Bandwidth Capability" TLV in the OPEN
Object indicates that the Automatic Bandwidth Adjustment is supported
as described in this document.
The PCEP protocol extensions for Auto-Bandwidth adjustments MUST NOT
be used if one or both PCEP Speakers have not included the "Auto-
Bandwidth Capability" TLV in their respective OPEN message. If the
PCEP speaker that supports the extensions of this draft but did not
advertise this capability, then upon receipt of AUTO-BANDWIDTH-
ATTRIBUTE TLV in LSPA object, it SHOULD generate a PCErr with error-
type 19 (Invalid Operation), error-value TBD4 (Auto-Bandwidth
capability was not advertised) and it will terminate the PCEP
session.
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5.1.1 AUTO-BANDWIDTH-CAPABILITY TLV
The AUTO-BANDWIDTH-CAPABILITY TLV is an optional TLV for use in the
OPEN Object for Automatic Bandwidth Adjustment via PCEP capability
advertisement. Its format is shown in the following figure:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type=[TBD5] | Length=4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flags |B|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
AUTO-BANDWIDTH-CAPABILITY TLV format
The type of the TLV is [TBD5] and it has a fixed length of 4 octets.
The value comprises a single field - Flags (32 bits):
o B (bandwidth usage - 1 bit): if set to 1 by a PCC, the B Flag
indicates that the PCC allows reporting of bandwidth usage
information; if set to 1 by a PCE, the B Flag indicates that the
PCE is capable of receiving bandwidth usage information from the
PCC. The BANDWIDTH-USAGE-ATTRIBUTE TLV MUST be encoded when both
PCEP speakers have the B Flag set.
Unassigned bits are considered reserved. They MUST be set to 0 on
transmission and MUST be ignored on receipt.
Advertisement of the Auto-Bandwidth capability TLV implies support of
auto-bandwidth adjustment, as well as the objects, TLVs and
procedures defined in this document.
5.2. AUTO-BANDWIDTH-ATTRIBUTE TLV
The AUTO-BANDWIDTH-ATTRIBUTE TLV provides the 'configurable knobs' of
the feature and it can be included as an optional TLV in the LSPA
Object (as described in [RFC5440]).
For PCE-Initiated LSP ([I-D.ietf-pce-pce-initiated-lsp]), this TLV is
included in the LSPA Object with PCInitiate message. For delegated
LSPs, this TLV is carried in PCRpt message in LSPA Object.
The TLV is encoded in all PCEP messages for the LSP till the auto
bandwidth adjustment feature is enabled, the absence of the TLV
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indicate the PCEP speaker wish to disable the feature.
The format of the AUTO-BANDWIDTH-ATTRIBUTE TLV is shown in the
following figure:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type=[TBD1] | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
// sub-TLVs //
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
AUTO-BANDWIDTH-ATTRIBUTE TLV format
Type: TBD1
Length: Variable
Value: This comprises one or more sub-TLVs.
Following sub-TLVs are defined in this document:
Type Len Name
-------------------------------------------------------------------
1 4 Sample-Interval sub-TLV
2 4 Adjustment-Interval sub-TLV
3 4 Adjustment-Threshold sub-TLV
4 4 Adjustment-Threshold-Percentage sub-TLV
5 4 Minimum-Bandwidth sub-TLV
6 4 Maximum-Bandwidth sub-TLV
7 8 Overflow-Threshold sub-TLV
8 4 Overflow-Threshold-Percentage sub-TLV
9 8 Underflow-Threshold sub-TLV
10 4 Underflow-Threshold-Percentage sub-TLV
Future specification can define additional sub-TLVs.
The presence of AUTO-BANDWIDTH-ATTRIBUTE TLV in LSPA Object means
that the automatic bandwidth adjustment feature is enabled. All
sub-TLVs are optional and any unrecognized sub-TLV MUST be silently
ignored. If a sub-TLV of same type appears more than once, only the
first occurrence is processed and all others MUST be ignored.
The AUTO-BANDWIDTH-ATTRIBUTE TLV can also be carried in PCUpd message
in LSPA Object in order to make updates to auto-bandwidth attributes
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such as Adjustment-Interval.
If sub-TLVs are not present, the default values based on the local
policy are assumed.
The sub-TLVs are encoded to inform the PCEP peer the various sampling
and adjustment parameters, and serves the following purpose -
o For PCE-Initiated LSPs, in the Deployment Model 1, inform the PCC
of the various sampling and adjustment parameters.
o For PCC-Initiated LSPs, in the Deployment Model 2, inform the PCE
of the various sampling and adjustment parameters.
The following sub-sections describe the sub-TLVs which are currently
defined to be carried within the AUTO-BANDWIDTH-ATTRIBUTE TLV.
5.2.1. Sample-Interval sub-TLV
The Sample-Interval sub-TLV specifies a time interval in seconds at
which traffic samples are collected at the PCC.
The Type is 1, Length is 4, and the value comprises of 4-octet time
interval, the valid range is from 1 to 604800, in seconds. The
default value is 300 seconds.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type=1 | Length=4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sample-Interval |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Sample-Interval sub-TLV format
5.2.2. Adjustment-Interval sub-TLV
The Adjustment-Interval sub-TLV specifies a time interval in seconds
at which bandwidth adjustment should be made.
The Type is 2, Length is 4, and the value comprises of 4-octet time
interval, the valid range is from 1 to 604800, in seconds. The
default value is 300 seconds.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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| Type=2 | Length=4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Adjustment-Interval |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Adjustment-Interval sub-TLV format
5.2.3. Adjustment Threshold
The sub-TLVs in this section are encoded to inform the PCEP peer the
adjustment threshold parameters. An implementation MAY include both
sub-TLVs for the absolute value and the percentage, in which case the
bandwidth is adjusted when either of the adjustment threshold
conditions are met.
5.2.3.1. Adjustment-Threshold sub-TLV
The Adjustment-Threshold sub-TLV is used to decide when the LSP
bandwidth should be adjusted.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type=3 | Length=4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Adjustment Threshold |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Adjustment-Threshold sub-TLV format
The Type is 3, Length is 4, and the value comprises of -
o Adjustment Threshold: The absolute Adjustment-Threshold bandwidth
value, encoded in IEEE floating point format (see
[IEEE.754.1985]), expressed in bytes per second. Refer to Section
3.1.2 of [RFC3471] for a table of commonly used values.
If the difference between the current MaxAvgBw and the current
bandwidth reservation is greater than or equal to the threshold
value, the LSP bandwidth is adjusted to the current bandwidth
demand.
5.2.3.2. Adjustment-Threshold-Percentage sub-TLV
The Adjustment-Threshold-Percentage sub-TLV is used to decide when
the LSP bandwidth should be adjusted.
0 1 2 3
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0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type=4 | Length=4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved | Percentage |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Adjustment-Threshold-Percentage sub-TLV format
The Type is 4, Length is 4, and the value comprises of -
o Reserved: SHOULD be set to zero on transmission and MUST be
ignored on receipt.
o Percentage: The Adjustment-Threshold value, encoded in percentage
(an integer from 0 to 100). If the percentage difference between
the current MaxAvgBw and the current bandwidth reservation is
greater than or equal to the threshold percentage, the LSP
bandwidth is adjusted to the current bandwidth demand.
5.2.4. Minimum and Maximum Bandwidth Values
5.2.4.1. Minimum-Bandwidth sub-TLV
The Minimum-Bandwidth sub-TLV specify the minimum bandwidth allowed
for the LSP, and is expressed in bytes per second. The LSP bandwidth
cannot be adjusted below the minimum bandwidth value.
The Type is 5, Length is 4, and the value comprises of 4-octet
bandwidth value encoded in IEEE floating point format (see
[IEEE.754.1985]), expressed in bytes per second. Refer to Section
3.1.2 of [RFC3471] for a table of commonly used values.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type=5 | Length=4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Minimum-Bandwidth |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Minimum-Bandwidth sub-TLV format
5.2.4.2. Maximum-Bandwidth sub-TLV
The Maximum-Bandwidth sub-TLV specify the maximum bandwidth allowed
for the LSP, and is expressed in bytes per second. The LSP bandwidth
cannot be adjusted above the maximum bandwidth value.
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The Type is 6, Length is 4, and the value comprises of 4-octet
bandwidth value encoded in IEEE floating point format (see
[IEEE.754.1985]), expressed in bytes per second. Refer to Section
3.1.2 of [RFC3471] for a table of commonly used values.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type=6 | Length=4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Maximum-Bandwidth |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Maximum-Bandwidth sub-TLV format
5.2.5. Overflow and Underflow Condition
The sub-TLVs in this section are encoded to inform the PCEP peer the
overflow and underflow threshold parameters. An implementation MAY
include sub-TLVs for the absolute value and the percentage for the
threshold, in which case the bandwidth is immediately adjusted when
either of the adjustment threshold conditions are met consecutively
for the given count.
5.2.5.1. Overflow-Threshold sub-TLV
The Overflow-Threshold sub-TLV is used to decide if the bandwidth
should be adjusted immediately.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type=7 | Length=8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved | Count |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Overflow Threshold |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Overflow-Threshold sub-TLV format
The Type is 7, Length is 8, and the value comprises of -
o Reserved: SHOULD be set to zero on transmission and MUST be
ignored on receipt.
o Count: The Overflow-Count value, encoded in integer. The value 0
is considered to be invalid. The number of consecutive samples
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for which the overflow condition MUST be met for the LSP bandwidth
to be immediately adjusted to the current bandwidth demand,
bypassing the adjustment-interval.
o Overflow Threshold: The absolute Overflow-Threshold bandwidth
value, encoded in IEEE floating point format (see
[IEEE.754.1985]), expressed in bytes per second. Refer to Section
3.1.2 of [RFC3471] for a table of commonly used values. If the
increase of the current MaxAvgBw from the current bandwidth
reservation is greater than or equal to the threshold value, the
overflow condition is met.
5.2.5.2. Overflow-Threshold-Percentage sub-TLV
The Overflow-Threshold-Percentage sub-TLV is used to decide if the
bandwidth should be adjusted immediately.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type=8 | Length=4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Percentage | Reserved | Count |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Overflow-Threshold-Percentage sub-TLV format
The Type is 8, Length is 4, and the value comprises of -
o Percentage: The Overflow-Threshold value, encoded in percentage
(an integer from 0 to 100). If the percentage increase of the
current MaxAvgBw from the current bandwidth reservation is greater
than or equal to the threshold percentage, the overflow condition
is met.
o Reserved: SHOULD be set to zero on transmission and MUST be
ignored on receipt.
o Count: The Overflow-Count value, encoded in integer. The value 0
is considered to be invalid. The number of consecutive samples
for which the overflow condition MUST be met for the LSP bandwidth
to be immediately adjusted to the current bandwidth demand,
bypassing the adjustment-interval.
5.2.5.3. Underflow-Threshold sub-TLV
The Underflow-Threshold sub-TLV is used to decide if the bandwidth
should be adjusted immediately.
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0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type=9 | Length=8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved | Count |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Underflow Threshold |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Underflow-Threshold sub-TLV format
The Type is 9, Length is 8, and the value comprises of -
o Reserved: SHOULD be set to zero on transmission and MUST be
ignored on receipt.
o Count: The Underflow-Count value, encoded in integer. The value 0
is considered to be invalid. The number of consecutive samples
for which the underflow condition MUST be met for the LSP
bandwidth to be immediately adjusted to the current bandwidth
demand, bypassing the adjustment-interval.
o Underflow Threshold: The absolute Underflow-Threshold bandwidth
value, encoded in IEEE floating point format (see
[IEEE.754.1985]), expressed in bytes per second. Refer to Section
3.1.2 of [RFC3471] for a table of commonly used values. If the
decrease of the current MaxAvgBw from the current bandwidth
reservation is greater than or equal to the threshold value, the
underflow condition is met.
5.2.5.4. Underflow-Threshold-Percentage sub-TLV
The Underflow-Threshold-Percentage sub-TLV is used to decide if the
bandwidth should be adjusted immediately.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type=10 | Length=4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Percentage | Reserved | Count |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Underflow-Threshold-Percentage sub-TLV format
The Type is 10, Length is 4, and the value comprises of -
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o Percentage: The Underflow-Threshold value, encoded in percentage
(an integer from 0 to 100). If the percentage decrease of the
current MaxAvgBw from the current bandwidth reservation is greater
than or equal to the threshold percentage, the underflow condition
is met.
o Reserved: SHOULD be set to zero on transmission and MUST be
ignored on receipt.
o Count: The Underflow-Count value, encoded in integer. The value 0
is considered to be invalid. The number of consecutive samples
for which the underflow condition MUST be met for the LSP
bandwidth to be immediately adjusted to the current bandwidth
demand, bypassing the adjustment-interval.
5.3. BANDWIDTH-USAGE-ATTRIBUTE TLV
The BANDWIDTH-USAGE-ATTRIBUTE TLV provides the 'configurable knobs'
of the feature and it can be included as an optional TLV in the LSPA
Object (as described in [RFC5440]).
For PCE-Initiated LSP ([I-D.ietf-pce-pce-initiated-lsp]), this TLV is
included in the LSPA Object with PCInitiate message.
The TLV is encoded in all PCEP messages for the LSP till the
bandwidth usage reporting feature is enabled, the absence of the TLV
indicate the PCEP speaker wish to disable this feature.
The format of the BANDWIDTH-USAGE-ATTRIBUTE TLV is shown in the
following figure:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type=[TBD2] | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
// sub-TLVs //
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
BANDWIDTH-USAGE-ATTRIBUTE TLV format
Type: TBD2
Length: Variable
Value: This comprises one or more sub-TLVs.
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Following sub-TLVs are defined in this document:
Type Len Name
-------------------------------------------------------------------
1 4 Bandwidth-Usage-Report-Interval sub-TLV
2 4 Bandwidth-Usage-Report-Threshold sub-TLV
3 4 Bandwidth-Usage-Report-Threshold-Percentage sub-TLV
4 4 Bandwidth-Usage-Report-Flow-Threshold sub-TLV
5 4 Bandwidth-Usage-Report-Flow-Threshold-Percentage sub-TLV
Future specification can define additional sub-TLVs.
The presence of BANDWIDTH-USAGE-ATTRIBUTE TLV in LSPA Object means
that the bandwidth usage reporting to PCE is enabled. All sub-TLVs
are optional and any unrecognized sub-TLV MUST be silently ignored.
If a sub-TLV of same type appears more than once, only the first
occurrence is processed and all others MUST be ignored.
The BANDWIDTH-USAGE-ATTRIBUTE TLV can also be carried in PCUpd
message in LSPA Object in order to make updates to the attributes
such as Bandwidth-Usage-Report-Interval.
If sub-TLVs are not present, the default values based on the local
policy are assumed.
The following sub-sections describe the sub-TLVs which are currently
defined to be carried within the BANDWIDTH-USAGE-ATTRIBUTE TLV, and
serves the following purpose -
o For PCE-Initiated LSPs, in the Deployment Model 2, inform the PCC
of the various sampling and reporting parameters.
5.3.1. Bandwidth-Usage-Report-Interval sub-TLV
The Bandwidth-Usage-Report-Interval sub-TLV specifies a time
interval in seconds in which collected bandwidth samples should be
reported to PCE.
The Type is 1, Length is 4, and the value comprises of 4-octet
time interval, the valid range is from 1 to 604800, in seconds.
Default value is 3600 seconds.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type=1 | Length=4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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| Bandwidth-Usage-Report-Interval |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Bandwidth-Usage-Report-Interval sub-TLV format
5.3.2. Bandwidth-Usage-Report-Threshold sub-TLV
The Bandwidth-Usage-Report-Threshold sub-TLV is used to decide
when the bandwidth samples collected so far should be reported
immediately, bypassing the report-interval.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type=2 | Length=4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Bandwidth-Usage-Report Threshold |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Bandwidth-Usage-Report-Threshold sub-TLV format
The Type is 2, Length is 4, and the value comprises of -
o Threshold: The absolute threshold bandwidth value, encoded in IEEE
floating point format (see [IEEE.754.1985]), expressed in bytes
per second. Refer to Section 3.1.2 of [RFC3471] for a table of
commonly used values. If the increase or the decrease of at least
one of the bandwidth samples (BwSamples) collected so far compared
to the current bandwidth reservation is greater than or equal to
the threshold value, the bandwidth samples collected so far are
reported.
5.3.3. Bandwidth-Usage-Report-Threshold-Percentage sub-TLV
The Bandwidth-Usage-Report-Threshold-Percentage sub-TLV is used to
decide when the bandwidth samples collected so far should be reported
immediately, bypassing the report-interval.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type=3 | Length=4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved | Percentage |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Bandwidth-Usage-Report-Threshold-Percentage sub-TLV format
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The Type is 3, Length is 4, and the value comprises of -
o Reserved: SHOULD be set to zero on transmission and MUST be
ignored on receipt.
o Percentage: The threshold value, encoded in percentage (an integer
from 0 to 100). If the percentage increase or the decrease of at
least one of the bandwidth sample (BwSample) compared to the
current bandwidth reservation is greater than or equal to the
threshold percentage, the bandwidth samples collected so far are
reported.
5.3.4. Bandwidth-Usage-Report-Flow-Threshold sub-TLV
The Bandwidth-Usage-Report-Flow-Threshold sub-TLV is used to decide
when the bandwidth samples collected should be reported immediately,
bypassing the report-interval.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type=4 | Length=8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved | Count |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Bandwidth-Usage-Report-Flow Threshold |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Bandwidth-Usage-Report-Flow-Threshold sub-TLV format
The Type is 4, Length is 8, and the value comprises of -
o Reserved: SHOULD be set to zero on transmission and MUST be
ignored on receipt.
o Count: The Report-Flow-Count value, encoded in integer. The value
0 is considered to be invalid. The number of consecutive samples
for which the bandwidth usage report condition MUST be met for the
the bandwidth samples collected so far are reported immediately,
bypassing the report-interval.
o Threshold: The absolute flow threshold bandwidth value, encoded in
IEEE floating point format (see [IEEE.754.1985]), expressed in
bytes per second. Refer to Section 3.1.2 of [RFC3471] for a table
of commonly used values. If the increase or the decrease of the
current bandwidth sample (BwSample) compared to the current
bandwidth reservation is greater than or equal to the flow
threshold value, bandwidth usage report condition is said to be
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met.
5.3.5. Bandwidth-Usage-Report-Flow-Threshold-Percent sub-TLV
The Bandwidth-Usage-Report-Flow-Threshold-Percent sub-TLV is used to
decide when the bandwidth samples collected should be reported
immediately, bypassing the report-interval.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type=5 | Length=4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Percentage | Reserved | Count |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Bandwidth-Usage-Report-Flow-Threshold-Percentage sub-TLV format
The Type is 5, Length is 4, and the value comprises of -
o Reserved: SHOULD be set to zero on transmission and MUST be
ignored on receipt.
o Percentage: The flow threshold value, encoded in percentage (an
integer from 0 to 100). If the percentage increase or the
decrease of the current bandwidth sample (BwSample) compared to
the current bandwidth reservation is greater than or equal to the
threshold percentage, bandwidth usage report condition is said to
be met.
o Count: The Report-Flow-Count value, encoded in integer. The value
0 is considered to be invalid. The number of consecutive samples
for which the bandwidth usage report condition MUST be met for the
the bandwidth samples collected so far are reported immediately,
bypassing the report-interval.
5.4. BANDWIDTH Object
5.4.1. Auto-Bandwidth Adjusted Bandwidth Report
As per [RFC5440], the BANDWIDTH object (Object-Class value 5) is
defined with two Object-Type values as following:
o Requested Bandwidth: BANDWIDTH Object-Type value is 1.
o Re-optimization Bandwidth: Bandwidth of an existing TE LSP for
which a re-optimization is requested. BANDWIDTH Object-Type value
is 2.
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In the first deployment model, where PCC calculates the adjusted
bandwidth, PCC reports the calculated bandwidth to be adjusted
(MaxAvgBw) to the PCE. This is done via the existing 'Requested
Bandwidth with BANDWIDTH Object-Type as 1.
5.4.2. Bandwidth-Usage Report
A new Object-type for BANDWIDTH object is defined to report the real-
time bandwidth usage of a TE LSP.
The Object-type is [TBD3], the object length is variable with
multiples of 4 bytes. The payload format 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| BwSample1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| BwSampleN |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Bandwidth-Usage format
o BwSample: The actual bandwidth usage, (the BwSample collected at
the end of each sample-interval) encoded in IEEE floating point
format (see [IEEE.754.1985]), expressed in bytes per second.
The Bandwidth-Usage object-type is used in the second deployment
model where PCC reports the TE LSP bandwidth usage and the PCE
decides the Auto-Bandwidth adjusted bandwidth.
The Bandwidth-Usage object-type can also be used for TE LSPs without
enabling the Auto-Bandwidth feature, to learn the actual bandwidth
usage of the LSPs for other applications at the stateful PCE, details
of which are beyond the scope of this document.
5.5. The PCInitiate Message
A PCInitiate message is a PCEP message sent by a PCE to a PCC to
trigger LSP instantiation or deletion [I.D.ietf-pce-pce-initiated-
lsp].
For the PCE-initiated LSP [I-D.ietf-pce-pce-initiated-lsp] with
Auto-Bandwidth feature enabled, AUTO-BANDWIDTH-ATTRIBUTE TLV or
BANDWIDTH-USAGE-ATTRIBUTE TLV MUST be included in the LSPA object
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with the PCInitiate message, depending on the deployment model being
used. The rest of the processing remains unchanged.
5.6. The PCRpt Message
As specified in [I.D.ietf-pce-pce-initiated-lsp], the PCC creates the
LSP using the attributes communicated by the PCE, and local values
for the unspecified parameters. After the successful instantiation
of the LSP, PCC automatically delegates the LSP to the PCE and
generates an LSP State Report (PCRpt) for the LSP.
When LSP is delegated to a PCE for the very first time, BANDWIDTH
object of type 1 is used to specify the requested bandwidth in the
PCRpt message.
When the LSP is enabled with the Auto-Bandwidth feature using
Deployment Model 1, PCC SHOULD include the BANDWIDTH object of type 1
to specify the calculated bandwidth to be adjusted to the PCE in the
PCRpt message.
When the LSP is enabled with the Auto-Bandwidth feature using
Deployment Model 2, PCC SHOULD include the BANDWIDTH object of type
[TBD3] to report the real-time bandwidth-usage to the PCE in the
PCRpt message.
The definition of the PCRpt message (see [I-D.ietf-pce-stateful-pce])
is unchanged by this document.
6. Security Considerations
This document defines a new BANDWIDTH object type,
AUTO-BANDWIDTH-CAPABILITY TLV, AUTO-BANDWIDTH-ATTRIBUTE TLV and
BANDWIDTH-USAGE-ATTRIBUTE TLV which do not add any new security
concerns beyond those discussed in [RFC5440] and
[I-D.ietf-pce-stateful-pce].
Some deployments may find the reporting of the real-time bandwidth-
usage information as extra sensitive and thus SHOULD employ suitable
PCEP security mechanisms like TCP-AO or [I-D.ietf-pce-pceps].
7. Manageability Considerations
7.1. Control of Function and Policy
The Auto-Bandwidth feature SHOULD be controlled per tunnel (at
ingress (PCC) or PCE), the values for parameters like sample-
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interval, adjustment-interval, minimum-bandwidth, maximum-bandwidth,
adjustment-threshold, report-interval, report-threshold SHOULD be
configurable by an operator.
7.2. Information and Data Models
[RFC7420] describes the PCEP MIB, there are no new MIB Objects
defined in this document.
7.3. Liveness Detection and Monitoring
Mechanisms defined in this document do not imply any new liveness
detection and monitoring requirements in addition to those already
listed in [RFC5440].
7.4. Verify Correct Operations
Mechanisms defined in this document do not imply any new operation
verification requirements in addition to those already listed in
[RFC5440].
7.5. Requirements On Other Protocols
Mechanisms defined in this document do not add any new requirements
on other protocols.
7.6. Impact On Network Operations
Mechanisms defined in this document do not have any impact on network
operations in addition to those already listed in [RFC5440].
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8. IANA Considerations
8.1. PCEP TLV Type Indicators
This document defines the following new PCEP TLVs; IANA is requested
to make the following allocations from this registry.
<http://www.iana.org/assignments/pcep/pcep.xhtml#pcep-tlv-type-
indicators>.
Value Name Reference
--------------------------------------------------------------
TBD5 AUTO-BANDWIDTH-CAPABILITY [This I.D.]
TBD1 AUTO-BANDWIDTH-ATTRIBUTE [This I.D.]
TBD2 BANDWIDTH-USAGE-ATTRIBUTE [This I.D.]
8.2. AUTO-BANDWIDTH-ATTRIBUTE Sub-TLV
This document specifies the AUTO-BANDWIDTH-ATTRIBUTE Sub-TLVs. IANA
is requested to create an "AUTO-BANDWIDTH-ATTRIBUTE Sub-TLV Types"
sub-registry in the "PCEP TLV Type Indicators" for the sub-TLVs
carried in the AUTO-BANDWIDTH-ATTRIBUTE TLV. This document defines
the following types:
Type Name Reference
--------------------------------------------------------------
0 Reserved [This I.D.]
1 Sample-Interval sub-TLV [This I.D.]
2 Adjustment-Interval sub-TLV [This I.D.]
3 Adjustment-Threshold sub-TLV [This I.D.]
4 Adjustment-Threshold-Percentage sub-TLV [This I.D.]
5 Minimum-Bandwidth sub-TLV [This I.D.]
6 Maximum-Bandwidth sub-TLV [This I.D.]
7 Overflow-Threshold sub-TLV [This I.D.]
8 Overflow-Threshold-Percentage sub-TLV [This I.D.]
9 Underflow-Threshold sub-TLV [This I.D.]
10 Underflow-Threshold-Percentage sub-TLV [This I.D.]
11- Unassigned [This I.D.]
65535
8.3. BANDWIDTH-USAGE-ATTRIBUTE Sub-TLV
This document specifies the BANDWIDTH-USAGE-ATTRIBUTE Sub-TLVs. IANA
is requested to create an "BANDWIDTH-USAGE-ATTRIBUTE Sub-TLV Types"
sub-registry in the "PCEP TLV Type Indicators" for the sub-TLVs
carried in the BANDWIDTH-USAGE-ATTRIBUTE TLV. This document defines
the following types:
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Type Name Reference
--------------------------------------------------------------
0 Reserved [This I.D.]
1 Bandwidth-Usage-Report-Interval sub-TLV [This I.D.]
2 Bandwidth-Usage-Report-Threshold sub-TLV [This I.D.]
3 Bandwidth-Usage-Report-Threshold-Percentage [This I.D.]
sub-TLV
4 Bandwidth-Usage-Report-Flow-Threshold [This I.D.]
sub-TLV
5 Bandwidth-Usage-Report-Flow-Threshold [This I.D.]
-Percentage sub-TLV
6- Unassigned [This I.D.]
65535
8.4. BANDWIDTH Object
This document defines new Object-Type for the BANDWIDTH object
(Object-Class 5, [RFC5440]); IANA is requested to make the following
allocation from this registry.
<http://www.iana.org/assignments/pcep/pcep.xhtml#pcep-objects>.
Object-Type Name Reference
--------------------------------------------------------------
TBD3 Bandwidth-Usage Report [This I.D.]
8.5. Error Object
This document defines a new Error-Value for PCErr message of type 19
(Invalid Operation) [I-D.ietf-pce-stateful-pce]); IANA is requested
to make the following allocation from this registry.
<http://www.iana.org/assignments/pcep/pcep.xhtml#pcep-error-object>
Error-Value Meaning Reference
--------------------------------------------------------------
TBD4 Auto-Bandwidth Capability [This I.D.]
was not Advertised
9. References
9.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
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[RFC5440] Vasseur, JP. and JL. Le Roux, "Path Computation Element
(PCE) Communication Protocol (PCEP)", RFC 5440, March
2009.
[I-D.ietf-pce-stateful-pce] Crabbe, E., Minei, I., Medved, J., and
R. Varga, "PCEP Extensions for Stateful PCE", draft-ietf-
pce-stateful-pce (work in progress).
[I-D.ietf-pce-pce-initiated-lsp] Crabbe, E., Minei, I., Sivabalan,
S., and R. Varga, "PCEP Extensions for PCE-initiated LSP
Setup in a Stateful PCE Model", draft-ietf-pce-pce-
initiated-lsp (work in progress).
[IEEE.754.1985] Institute of Electrical and Electronics Engineers,
"Standard for Binary Floating-Point Arithmetic", IEEE
Standard 754, August 1985.
9.2. Informative References
[RFC3471] Berger, L., "Generalized Multi-Protocol Label Switching
(GMPLS) Signaling Functional Description", RFC 3471,
January 2003.
[RFC7420] Koushik, A., Stephan, E., Zhao, Q., King, D., and J.
Hardwick, "Path Computation Element Communication Protocol
(PCEP) Management Information Base (MIB) Module", RFC
7420, December 2014.
[I-D.ietf-pce-stateful-pce-app] Zhang, X. and I. Minei,
"Applicability of a Stateful Path Computation Element
(PCE)", draft-ietf-pce-stateful-pce-app (work in
progress).
[I-D.ietf-pce-pceps] Lopez, D., Dios, O., Wu, W., and D. Dhody,
"Secure Transport for PCEP", draft-ietf-pce-pceps (work in
progress).
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Acknowledgments
Authors would like to thank Robert Varga, Venugopal Reddy, Reeja
Paul, Sandeep Boina and Avantika for their useful comments and
suggestions.
Contributors' Addresses
He Zekun
Tencent Holdings Ltd,
Shenzhen P.R.China
EMail: kinghe@tencent.com
Xian Zhang
Huawei Technologies
Research Area F3-1B,
Huawei Industrial Base,
Shenzhen, 518129
China
Phone: +86-755-28972645
EMail: zhang.xian@huawei.com
Young Lee
Huawei Technologies
1700 Alma Drive, Suite 100
Plano, TX 75075
USA
Phone: +1 972 509 5599 x2240
Fax: +1 469 229 5397
EMail: leeyoung@huawei.com
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Authors' Addresses
Dhruv Dhody
Huawei Technologies
Divyashree Techno Park, Whitefield
Bangalore, Karnataka 560066
India
EMail: dhruv.ietf@gmail.com
Udayasree Palle
Huawei Technologies
Divyashree Techno Park, Whitefield
Bangalore, Karnataka 560037
India
EMail: udayasree.palle@huawei.com
Ravi Singh
Juniper Networks
1194 N. Mathilda Ave.
Sunnyvale, CA 94089
USA
EMail: ravis@juniper.net
Rakesh Gandhi
Cisco Systems, Inc.
EMail: rgandhi.ietf@gmail.com
Luyuan Fang
Microsoft
15590 NE 31st St
Redmond, WA 98052
USA
EMail: lufang@microsoft.com
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