draft-ietf-pce-stateful-pce-auto-bandwidth-00.txt   draft-ietf-pce-stateful-pce-auto-bandwidth-01.txt 
PCE Working Group D. Dhody PCE Working Group D. Dhody
Internet-Draft U. Palle Internet-Draft U. Palle
Intended status: Standards Track Huawei Technologies Intended status: Standards Track Huawei Technologies
Expires: July 24, 2017 R. Singh Expires: August 2, 2017 R. Singh
Juniper Networks Juniper Networks
R. Gandhi R. Gandhi
Individual Contributor Individual Contributor
L. Fang L. Fang
eBay eBay
January 24, 2017 January 29, 2017
PCEP Extensions for MPLS-TE LSP Automatic Bandwidth Adjustment with PCEP Extensions for MPLS-TE LSP Automatic Bandwidth Adjustment with
Stateful PCE Stateful PCE
draft-ietf-pce-stateful-pce-auto-bandwidth-00 draft-ietf-pce-stateful-pce-auto-bandwidth-01
Abstract Abstract
The Path Computation Element Communication Protocol (PCEP) provides The Path Computation Element Communication Protocol (PCEP) provides
mechanisms for Path Computation Elements (PCEs) to perform path mechanisms for Path Computation Elements (PCEs) to perform path
computations in response to Path Computation Clients (PCCs) requests. computations in response to Path Computation Clients (PCCs) requests.
The stateful PCE extensions allow stateful control of Multi-Protocol The stateful PCE extensions allow stateful control of Multi-Protocol
Label Switching (MPLS) Traffic Engineering Label Switched Paths (TE Label Switching (MPLS) Traffic Engineering Label Switched Paths (TE
LSPs) using PCEP. LSPs) using PCEP.
This document describes PCEP extensions for automatic bandwidth Automatic bandwidth adjustment allows automatic and dynamic
adjustment when employing an Active Stateful PCE for both PCE- adjustment of the reserved bandwidth allocation of an TE LSP based on
initiated and PCC-initiated LSPs. the volume of traffic flowing through it. This document describes
PCEP extensions for automatic bandwidth adjustment when employing an
Active Stateful PCE for both PCE-initiated and PCC-initiated LSPs.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/. Drafts is at http://datatracker.ietf.org/drafts/current/.
skipping to change at page 2, line 48 skipping to change at page 3, line 4
5.2.4.2. Maximum-Bandwidth sub-TLV . . . . . . . . . . . . 14 5.2.4.2. Maximum-Bandwidth sub-TLV . . . . . . . . . . . . 14
5.2.5. Overflow and Underflow Conditions . . . . . . . . . . 14 5.2.5. Overflow and Underflow Conditions . . . . . . . . . . 14
5.2.5.1. Overflow-Threshold sub-TLV . . . . . . . . . . . . 14 5.2.5.1. Overflow-Threshold sub-TLV . . . . . . . . . . . . 14
5.2.5.2. Overflow-Threshold-Percentage sub-TLV . . . . . . 15 5.2.5.2. Overflow-Threshold-Percentage sub-TLV . . . . . . 15
5.2.5.3. Underflow-Threshold sub-TLV . . . . . . . . . . . 16 5.2.5.3. Underflow-Threshold sub-TLV . . . . . . . . . . . 16
5.2.5.4. Underflow-Threshold-Percentage sub-TLV . . . . . . 17 5.2.5.4. Underflow-Threshold-Percentage sub-TLV . . . . . . 17
5.3. BANDWIDTH Object . . . . . . . . . . . . . . . . . . . . . 17 5.3. BANDWIDTH Object . . . . . . . . . . . . . . . . . . . . . 17
5.4. The PCInitiate Message . . . . . . . . . . . . . . . . . . 18 5.4. The PCInitiate Message . . . . . . . . . . . . . . . . . . 18
5.5. The PCRpt Message . . . . . . . . . . . . . . . . . . . . 18 5.5. The PCRpt Message . . . . . . . . . . . . . . . . . . . . 18
5.6. The PCNtf Message . . . . . . . . . . . . . . . . . . . . 18 5.6. The PCNtf Message . . . . . . . . . . . . . . . . . . . . 18
5.7. The PCUpd Message . . . . . . . . . . . . . . . . . . . . 19
6. Security Considerations . . . . . . . . . . . . . . . . . . . 19 6. Security Considerations . . . . . . . . . . . . . . . . . . . 19
7. Manageability Considerations . . . . . . . . . . . . . . . . . 19 7. Manageability Considerations . . . . . . . . . . . . . . . . . 19
7.1. Control of Function and Policy . . . . . . . . . . . . . . 19 7.1. Control of Function and Policy . . . . . . . . . . . . . . 19
7.2. Information and Data Models . . . . . . . . . . . . . . . 19 7.2. Information and Data Models . . . . . . . . . . . . . . . 20
7.3. Liveness Detection and Monitoring . . . . . . . . . . . . 19 7.3. Liveness Detection and Monitoring . . . . . . . . . . . . 20
7.4. Verify Correct Operations . . . . . . . . . . . . . . . . 20 7.4. Verify Correct Operations . . . . . . . . . . . . . . . . 20
7.5. Requirements On Other Protocols . . . . . . . . . . . . . 20 7.5. Requirements On Other Protocols . . . . . . . . . . . . . 20
7.6. Impact On Network Operations . . . . . . . . . . . . . . . 20 7.6. Impact On Network Operations . . . . . . . . . . . . . . . 20
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 21 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 21
8.1. PCEP TLV Type Indicators . . . . . . . . . . . . . . . . . 21 8.1. PCEP TLV Type Indicators . . . . . . . . . . . . . . . . . 21
8.2. AUTO-BANDWIDTH-CAPABILITY TLV Flag Field . . . . . . . . . 21 8.2. AUTO-BANDWIDTH-CAPABILITY TLV Flag Field . . . . . . . . . 21
8.3. AUTO-BANDWIDTH-ATTRIBUTE Sub-TLV . . . . . . . . . . . . . 21 8.3. AUTO-BANDWIDTH-ATTRIBUTE Sub-TLV . . . . . . . . . . . . . 21
8.4. Error Object . . . . . . . . . . . . . . . . . . . . . . . 22 8.4. Error Object . . . . . . . . . . . . . . . . . . . . . . . 22
8.5. Notification Object . . . . . . . . . . . . . . . . . . . 22 8.5. Notification Object . . . . . . . . . . . . . . . . . . . 22
9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 22 9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 22
9.1. Normative References . . . . . . . . . . . . . . . . . . . 22 9.1. Normative References . . . . . . . . . . . . . . . . . . . 22
9.2. Informative References . . . . . . . . . . . . . . . . . . 23 9.2. Informative References . . . . . . . . . . . . . . . . . . 23
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 24 Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 25
Contributors' Addresses . . . . . . . . . . . . . . . . . . . . . 24 Contributors' Addresses . . . . . . . . . . . . . . . . . . . . . 25
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 25 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 26
1. Introduction 1. Introduction
[RFC5440] describes the Path Computation Element Protocol (PCEP) as a [RFC5440] describes the Path Computation Element Protocol (PCEP) as a
communication mechanism between a Path Computation Client (PCC) and a communication mechanism between a Path Computation Client (PCC) and a
Path Control Element (PCE), or between PCE and PCE, that enables Path Control Element (PCE), or between PCE and PCE, that enables
computation of Multi-Protocol Label Switching (MPLS) Traffic computation of Multi-Protocol Label Switching (MPLS) Traffic
Engineering Label Switched Paths (TE LSPs). Engineering Label Switched Paths (TE LSPs).
[I-D.ietf-pce-stateful-pce] specifies extensions to PCEP to enable [I-D.ietf-pce-stateful-pce] specifies extensions to PCEP to enable
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Enabling Auto-Bandwidth feature on an LSP results in the LSP Enabling Auto-Bandwidth feature on an LSP results in the LSP
automatically adjusting its bandwidth reservation based on the actual automatically adjusting its bandwidth reservation based on the actual
traffic flowing through the LSP. The initial LSP bandwidth can be traffic flowing through the LSP. The initial LSP bandwidth can be
set to an arbitrary value (including zero), in practice, it 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 operator expected value based on design and planning. Once the LSP
is set-up, the LSP monitors the traffic flow and adjusts its is set-up, the LSP monitors the traffic flow and adjusts its
bandwidth every adjustment-interval period. The bandwidth adjustment bandwidth every adjustment-interval period. The bandwidth adjustment
uses the make-before-break signaling method so that there is no uses the make-before-break signaling method so that there is no
interruption to the traffic flow. The Auto-Bandwidth is described in 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 detail in Section 4.1. [RFC8051] describes the use-case for Auto-
use-case for Auto-Bandwidth adjustment for passive and active Bandwidth adjustment for passive and active stateful PCE.
stateful PCE.
o 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.
o 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.
o For PCE-initiated LSP, the PCC is requested during the LSP The PCC (head-end of the LSP) monitors the traffic flowing through
initiation to monitor and calculate the new adjusted bandwidth. the LSP and calculates the new adjusted bandwidth. The PCC reports
the calculated bandwidth to be adjusted to the PCE. This is similar
to a 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. In case of PCE-
initiated LSP, the PCC is requested during the LSP initiation to
monitor and calculate the new adjusted bandwidth.
This document defines extensions needed to support Auto-Bandwidth This document defines extensions needed to support Auto-Bandwidth
feature on the LSPs in a active stateful PCE model using PCEP. feature on the LSPs in a active stateful PCE model using PCEP.
Note that, another document [I-D.gandhi-pce-pm], describes the PCEP
extensions to report the performance measurements to the PCE, this
includes the bandwidth usage information of a TE LSP and can be used
at the PCE to calculate the new bandwidth to be adjusted.
2. Conventions Used in This Document 2. Conventions Used in This Document
2.1. Requirements Language 2.1. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119]. document are to be interpreted as described in [RFC2119].
2.2. Terminology 2.2. Terminology
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+---------------------------------+---------------------------------+ +---------------------------------+---------------------------------+
| PCC Initiated | PCE Initiated | | PCC Initiated | PCE Initiated |
+---------------------------------+---------------------------------+ +---------------------------------+---------------------------------+
| | | | | |
| PCC monitors the traffic | At the time of initiation, | | PCC monitors the traffic | At the time of initiation, |
| and reports the calculated | PCE request PCC to monitor | | and reports the calculated | PCE request PCC to monitor |
| bandwidth to be adjusted | the traffic and report the | | bandwidth to be adjusted | the traffic and report the |
| to the PCE. | calculated bandwidth to be | | to the PCE. | calculated bandwidth to be |
| | adjusted to the PCE. | | | adjusted to the PCE. |
| | | | | |
| No new extensions are needed. | Extension is needed for PCE | | Extension is needed for PCC | Extension is needed for PCE |
| | to pass on the adjustment | | to pass on the adjustment | to pass on the adjustment |
| | parameters at the time of | | parameters at the time of | parameters at the time of |
| | Initiation. | | Delegation. | Initiation. |
| | | | | |
+---------------------------------+---------------------------------+ +---------------------------------+---------------------------------+
Table 1: Auto-Bandwidth PCEP extensions Table 1: Auto-Bandwidth PCEP extensions
Further Auto-Bandwidth deployment considerations are summarized Further Auto-Bandwidth deployment considerations are summarized
below: below:
o It is required to identify and inform the PCEP peer, the LSP that 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 are enabled with Auto-Bandwidth feature. Not all LSPs in some
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o Further for the LSP with Auto-Bandwidth feature enabled, an o Further for the LSP with Auto-Bandwidth feature enabled, an
operator should be able to specify the adjustment parameters (i.e. operator should be able to specify the adjustment parameters (i.e.
configuration knobs) to control this feature (e.g. minimum/ configuration knobs) to control this feature (e.g. minimum/
maximum bandwidth range) and PCEP peer should be informed. maximum bandwidth range) and PCEP peer should be informed.
4. Architectural Overview 4. Architectural Overview
4.1. Auto-Bandwidth Overview 4.1. Auto-Bandwidth Overview
Auto-Bandwidth feature allows an LSP to automatically and dynamically Auto-Bandwidth feature allows automatic and dynamic adjustment of the
adjust its reserved bandwidth over time, i.e. without network reserved bandwidth of an LSP over time, i.e. without network operator
operator intervention. The bandwidth adjustment uses the intervention. The bandwidth adjustment uses the make-before-break
make-before-break signaling method so that there is no interruption signaling method so that there is no interruption to the traffic
to the traffic flow. flow.
The new bandwidth reservation is determined by sampling the actual The new bandwidth reservation is determined by sampling the actual
traffic flowing through the LSP. If the traffic flowing through the traffic flowing through the LSP. If the traffic flowing through the
LSP is lower than the configured or current bandwidth of the LSP, the LSP is lower than the configured or current bandwidth of the LSP, the
extra bandwidth is being reserved needlessly and being wasted. extra bandwidth is being reserved needlessly and being wasted.
Conversely, if the actual traffic flowing through the LSP is higher Conversely, if the actual traffic flowing through the LSP is higher
than the configured or current bandwidth of the LSP, it can than the configured or current bandwidth of the LSP, it can
potentially cause congestion or packet loss in the network. With potentially cause congestion or packet loss in the network. With
Auto-Bandwidth feature, the LSP bandwidth can be set to some Auto-Bandwidth feature, the LSP bandwidth can be set to some
arbitrary value (including zero) during initial setup time, and it arbitrary value (including zero) during initial setup time, and it
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current MaxAvgBw and the current bandwidth reservation is greater current MaxAvgBw and the current bandwidth reservation is greater
than or equal to the threshold value, the underflow-condition is than or equal to the threshold value, the underflow-condition is
set to be met. The LSP bandwidth is adjusted to the current set to be met. The LSP bandwidth is adjusted to the current
bandwidth demand bypassing the adjustment-interval if the bandwidth demand bypassing the adjustment-interval if the
underflow-condition is met consecutively for the Underflow-Count. underflow-condition is met consecutively for the Underflow-Count.
4.2. Auto-bandwidth Theory of Operation 4.2. Auto-bandwidth Theory of Operation
The traffic rate is periodically sampled at each sample-interval The traffic rate is periodically sampled at each sample-interval
(which can be configured by the user and the default value as 5 (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 minutes) by the PCC which is the head-end node of the LSP. The
are accumulated over the adjustment-interval period (which can be sampled traffic rates are accumulated over the adjustment-interval
configured by the user and the default value as 24 hours). The PCEP period (which can be configured by the user and the default value as
peer which is in-charge of calculating the bandwidth to be adjusted, 24 hours). The PCC is in-charge of calculating the bandwidth to be
will adjust the bandwidth of the LSP to the highest sampled traffic adjusted, will adjust the bandwidth of the LSP to the highest sampled
rate (MaxAvgBw) amongst the set of bandwidth samples collected over traffic rate (MaxAvgBw) amongst the set of bandwidth samples
the adjustment-interval. collected over the adjustment-interval.
Note that the highest sampled traffic rate could be higher or lower Note that the highest sampled traffic rate could be higher or lower
than the current LSP bandwidth. Only if the difference between the than the current LSP bandwidth. Only if the difference between the
current bandwidth demand (MaxAvgBw) and the current bandwidth current bandwidth demand (MaxAvgBw) and the current bandwidth
reservation is greater than or equal to the Adjustment-Threshold reservation is greater than or equal to the Adjustment-Threshold
(percentage or absolute value), the LSP bandwidth is adjusted to the (percentage or absolute value), the LSP bandwidth is adjusted to the
current bandwidth demand (MaxAvgBw). Some LSPs are less eventful current bandwidth demand (MaxAvgBw). Some LSPs are less eventful
while other LSPs may encounter a lot of changes in the traffic while other LSPs may encounter a lot of changes in the traffic
pattern. PCE sets the intervals for adjustment based on the traffic pattern. The intervals for adjustment is based on the traffic
pattern of the LSP. pattern of the LSP.
In order to avoid frequent re-signaling, an operator may set a longer In order to avoid frequent re-signaling, an operator may set a longer
adjustment-interval value. However, longer adjustment-interval can adjustment-interval value. However, longer adjustment-interval can
result in an undesirable effect of masking sudden changes in traffic result in an undesirable effect of masking sudden changes in traffic
demands of an LSP. To avoid this, the Auto-Bandwidth feature may demands of an LSP. To avoid this, the Auto-Bandwidth feature may
pre-maturely expire the adjustment-interval and adjust the LSP pre-maturely expire the adjustment-interval and adjust the LSP
bandwidth to accommodate the sudden bursts of increase in traffic bandwidth to accommodate the sudden bursts of increase in traffic
demand as an overflow condition or decrease in traffic demand as an demand as an overflow condition or decrease in traffic demand as an
underflow condition. underflow condition.
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It should be noted that any bandwidth change would require re- It should be noted that any bandwidth change would require re-
signaling of an LSP in a make-before-break fashion, which can further signaling of an LSP in a make-before-break fashion, which can further
trigger preemption of lower priority LSPs in the network. When trigger preemption of lower priority LSPs in the network. When
deployed under scale, this can lead to a signaling churn in the deployed under scale, this can lead to a signaling churn in the
network. The Auto-bandwidth application algorithm is thus advised to network. The Auto-bandwidth application algorithm is thus advised to
take this into consideration before adjusting the LSP bandwidth. take this into consideration before adjusting the LSP bandwidth.
Operators are advised to set the values of various auto-bandwidth Operators are advised to set the values of various auto-bandwidth
adjustment parameters appropriate for the deployed LSP scale. adjustment parameters appropriate for the deployed LSP scale.
If a PCE gets overwhelmed, it can notify the PCC to temporarily If a PCE gets overwhelmed, it can notify the PCC to temporarily
suspend its auto-bandwidth reporting (see Section 5.6). Similarly if suspend the reporting of the new bandwidth to be adjusted (see
a PCC gets overwhelmed due to signaling churn, it can notify the PCE Section 5.6). Similarly if a PCC gets overwhelmed due to signaling
to temporarily suspend the LSP bandwidth adjustment. churn, it can notify the PCE to temporarily suspend the LSP bandwidth
adjustment.
5. Extensions to the PCEP 5. Extensions to the PCEP
5.1. Capability Advertisement 5.1. Capability Advertisement
During PCEP Initialization Phase, PCEP Speakers (PCE or PCC) During PCEP Initialization Phase, PCEP Speakers (PCE or PCC)
advertise their support of Automatic Bandwidth Adjustment. A PCEP advertise their support of Automatic Bandwidth Adjustment. A PCEP
Speaker includes the "Auto-Bandwidth Capability" TLV, in the OPEN Speaker includes the "Auto-Bandwidth Capability" TLV, in the OPEN
Object to advertise its support for PCEP Auto-Bandwidth extensions. Object to advertise its support for PCEP Auto-Bandwidth extensions.
The presence of the "Auto-Bandwidth Capability" TLV in the OPEN The presence of the "Auto-Bandwidth Capability" TLV in the OPEN
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5.1.1 AUTO-BANDWIDTH-CAPABILITY TLV 5.1.1 AUTO-BANDWIDTH-CAPABILITY TLV
The AUTO-BANDWIDTH-CAPABILITY TLV is an optional TLV for use in the The AUTO-BANDWIDTH-CAPABILITY TLV is an optional TLV for use in the
OPEN Object for Automatic Bandwidth Adjustment via PCEP capability OPEN Object for Automatic Bandwidth Adjustment via PCEP capability
advertisement. Its format is shown in the following figure: advertisement. Its format is shown in the following figure:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type=[TBD5] | Length=4 | | Type=TBD2 | Length=4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flags | | Flags |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
AUTO-BANDWIDTH-CAPABILITY TLV format AUTO-BANDWIDTH-CAPABILITY TLV format
The type of the TLV is (TBD5) and it has a fixed length of 4 octets. The type of the TLV is (TBD2) and it has a fixed length of 4 octets.
The value comprises a single field - Flags (32 bits). Currently no The value comprises a single field - Flags (32 bits). Currently no
flags are defined for this TLV. flags are defined for this TLV.
Unassigned bits are considered reserved. They MUST be set to 0 on Unassigned bits are considered reserved. They MUST be set to 0 on
transmission and MUST be ignored on receipt. transmission and MUST be ignored on receipt.
Advertisement of the Auto-Bandwidth capability TLV implies support of Advertisement of the Auto-Bandwidth capability TLV implies support of
auto-bandwidth adjustment, as well as the objects, TLVs and auto-bandwidth adjustment, as well as the objects, TLVs and
procedures defined in this document. procedures defined in this document.
5.2. AUTO-BANDWIDTH-ATTRIBUTE TLV 5.2. AUTO-BANDWIDTH-ATTRIBUTE TLV
The AUTO-BANDWIDTH-ATTRIBUTE TLV provides the 'configurable knobs' of The AUTO-BANDWIDTH-ATTRIBUTE TLV provides the 'configurable knobs' of
the feature and it can be included as an optional TLV in the LSPA the feature and it can be included as an optional TLV in the LSPA
Object (as described in [RFC5440]). Object (as described in [RFC5440]).
For PCE-Initiated LSP ([I-D.ietf-pce-pce-initiated-lsp]), this TLV is For PCE-Initiated LSP ([I-D.ietf-pce-pce-initiated-lsp]), this TLV is
included in the LSPA Object with PCInitiate message. For delegated included in the LSPA Object with the PCInitiate message. For
LSPs, this TLV is carried in PCRpt message in LSPA Object. delegated LSPs, this TLV is carried in the PCRpt message in LSPA
Object. This TLV is also included in the LSPA object with the PCUpd
message to direct the PCE to use different parameters with the LSP.
The TLV is encoded in all PCEP messages for the LSP till the auto The TLV is encoded in all PCEP messages for the LSP while the auto
bandwidth adjustment feature is enabled, the absence of the TLV bandwidth adjustment feature is enabled, the absence of the TLV
indicate the PCEP speaker wish to disable the feature. indicate the PCEP speaker wish to disable the feature.
The format of the AUTO-BANDWIDTH-ATTRIBUTE TLV is shown in the The format of the AUTO-BANDWIDTH-ATTRIBUTE TLV is shown in the
following figure: following figure:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type=[TBD1] | Length | | Type=TBD1 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | |
// sub-TLVs // // sub-TLVs //
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
AUTO-BANDWIDTH-ATTRIBUTE TLV format AUTO-BANDWIDTH-ATTRIBUTE TLV format
Type: TBD1 Type: TBD1
Length: Variable Length: The Length field defines the length of the value portion in
bytes as per [RFC5440].
Value: This comprises one or more sub-TLVs. Value: This comprises one or more sub-TLVs.
Following sub-TLVs are defined in this document: Following sub-TLVs are defined in this document:
Type Len Name Type Len Name
------------------------------------------------------------------- -------------------------------------------------------------------
1 4 Sample-Interval sub-TLV 1 4 Sample-Interval sub-TLV
2 4 Adjustment-Interval sub-TLV 2 4 Adjustment-Interval sub-TLV
3 4 Adjustment-Threshold sub-TLV 3 4 Adjustment-Threshold sub-TLV
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As per [RFC5440], the PCEP Notification message (PCNtf) can be sent As per [RFC5440], the PCEP Notification message (PCNtf) can be sent
by a PCEP speaker to notify its peer of a specific event. As by a PCEP speaker to notify its peer of a specific event. As
described in Section 4.3 of this document, a PCEP speaker SHOULD described in Section 4.3 of this document, a PCEP speaker SHOULD
notify its PCEP peer that it is overwhelmed, and on receipt of such notify its PCEP peer that it is overwhelmed, and on receipt of such
notification the peer SHOULD NOT send any PCEP messages related to notification the peer SHOULD NOT send any PCEP messages related to
auto-bandwidth adjustment. If a PCEP message related to auto- auto-bandwidth adjustment. If a PCEP message related to auto-
bandwidth adjustment is received, it MUST be silently ignored. bandwidth adjustment is received, it MUST be silently ignored.
When a PCEP speaker is overwhelmed, it SHOULD notify its peer by When a PCEP speaker is overwhelmed, it SHOULD notify its peer by
sending a PCNtf message with Notification Type = TBD6 (Auto-bandwidth sending a PCNtf message with Notification Type = TBD3 (Auto-bandwidth
Overwhelm State) and Notification Value = 1 (Entering auto-bandwidth Overwhelm State) and Notification Value = 1 (Entering auto-bandwidth
overwhelm state). Optionally, OVERLOADED-DURATION TLV [RFC5440] MAY overwhelm state). Optionally, OVERLOADED-DURATION TLV [RFC5440] MAY
be included that specifies the time period during which no further be included that specifies the time period during which no further
PCEP messages related to auto-bandwidth adjustment should be sent. PCEP messages related to auto-bandwidth adjustment should be sent.
When the PCEP speaker is no longer in the overwhelm state and is When the PCEP speaker is no longer in the overwhelm state and is
available to process the auto-bandwidth adjustment, it SHOULD notify available to process the auto-bandwidth adjustment, it SHOULD notify
its peer by sending a PCNtf message with Notification Type = TBD6 its peer by sending a PCNtf message with Notification Type = TBD3
(Auto-bandwidth Overwhelm State) and Notification Value = 2 (Clearing (Auto-bandwidth Overwhelm State) and Notification Value = 2 (Clearing
auto-bandwidth overwhelm state). auto-bandwidth overwhelm state).
When Auto-Bandwidth feature is deployed, a PCE can send this When Auto-Bandwidth feature is deployed, a PCE can send this
notification to PCC when a PCC is reporting frequent auto-bandwidth notification to PCC when a PCC is reporting frequent auto-bandwidth
adjustments. If a PCC is overwhelmed with re-signaling/re-routing, adjustments. If a PCC is overwhelmed with re-signaling/re-routing,
it can also notify the PCE to not adjust the LSP bandwidth while in it can also notify the PCE to not adjust the LSP bandwidth while in
overwhelm state. overwhelm state.
5.7. The PCUpd Message
A PCUpd message is a PCEP message sent by a PCE to a PCC to update
the LSP parameters [I-D.ietf-pce-stateful-pce].
For the LSPs with Auto-Bandwidth feature enabled, AUTO-BANDWIDTH-
ATTRIBUTE TLV MUST be included in the LSPA object with the PCUpd
message. The PCE can use this TLV to direct the PCC to change the
auto bandwidth parameters. The rest of the processing remains
unchanged.
The definition of the PCUpd message (see [I-D.ietf-pce-stateful-pce])
is unchanged by this document.
6. Security Considerations 6. Security Considerations
This document defines AUTO-BANDWIDTH-CAPABILITY TLV, This document defines AUTO-BANDWIDTH-CAPABILITY TLV,
AUTO-BANDWIDTH-ATTRIBUTE TLV which do not add any new security AUTO-BANDWIDTH-ATTRIBUTE TLV which does not add any new security
concerns beyond those discussed in [RFC5440] and concerns beyond those discussed in [RFC5440] and
[I-D.ietf-pce-stateful-pce]. [I-D.ietf-pce-stateful-pce] in itself. Some deployments may find the
auto-bandwidth information as extra sensitive and could be used to
Some deployments may find the reporting of the auto-bandwidth influence path computation and setup with adverse effect.
information as extra sensitive and thus SHOULD employ suitable PCEP Additionally snooping of PCEP messages with such data or using PCEP
security mechanisms like TCP-AO or [I-D.ietf-pce-pceps]. messages for network reconnaissance, may give an attacker sensitive
information about the operations of the network. Thus, such
deployment should employ suitable PCEP security mechanisms like TCP
Authentication Option (TCP-AO) [RFC5925] or [I-D.ietf-pce-pceps].
7. Manageability Considerations 7. Manageability Considerations
7.1. Control of Function and Policy 7.1. Control of Function and Policy
The Auto-Bandwidth feature SHOULD be controlled per tunnel (at The Auto-Bandwidth feature SHOULD be controlled per tunnel (at
ingress (PCC) or PCE), the values for parameters like sample- ingress (PCC) or PCE), the values for parameters like sample-
interval, adjustment-interval, minimum-bandwidth, maximum-bandwidth, interval, adjustment-interval, minimum-bandwidth, maximum-bandwidth,
adjustment-threshold SHOULD be configurable by an operator. adjustment-threshold SHOULD be configurable by an operator.
7.2. Information and Data Models 7.2. Information and Data Models
[RFC7420] describes the PCEP MIB, there are no new MIB Objects A Management Information Base (MIB) module for modeling PCEP is
defined in this document. described in [RFC7420]. However, the preferred mechanism for
configuration is through a YANG model [I-D.ietf-pce-pcep-yang]. This
SHOULD be enhanced to provide controls and indicators for support of
auto-bandwidth feature. Support for various configuration knobs as
well as counters of messages sent/received containing the TLVs
(defined in this document) should be added.
7.3. Liveness Detection and Monitoring 7.3. Liveness Detection and Monitoring
Mechanisms defined in this document do not imply any new liveness Mechanisms defined in this document do not imply any new liveness
detection and monitoring requirements in addition to those already detection and monitoring requirements in addition to those already
listed in [RFC5440]. listed in [RFC5440].
7.4. Verify Correct Operations 7.4. Verify Correct Operations
Mechanisms defined in this document do not imply any new operation Mechanisms defined in this document do not imply any new operation
verification requirements in addition to those already listed in verification requirements in addition to those already listed in
[RFC5440]. [RFC5440].
7.5. Requirements On Other Protocols 7.5. Requirements On Other Protocols
Mechanisms defined in this document do not add any new requirements Mechanisms defined in this document do not add any new requirements
on other protocols. on other protocols.
7.6. Impact On Network Operations 7.6. Impact On Network Operations
Mechanisms defined in this document do not have any impact on network In order to avoid any unacceptable impact on network operations, an
operations in addition to those already listed in [RFC5440]. implementation SHOULD allow a limit to be placed on the number of
LSPs that can be enabled with auto-bandwidth feature, and MAY allow a
limit to be placed on the rate of messages sent by a PCEP speaker and
received from a peer related to auto-bandwidth. It MAY also allow
sending a notification when the PCEP speaker is overwhelmed or a rate
threshold is reached.
8. IANA Considerations 8. IANA Considerations
8.1. PCEP TLV Type Indicators 8.1. PCEP TLV Type Indicators
This document defines the following new PCEP TLVs; IANA is requested This document defines the following new PCEP TLVs; IANA is requested
to make the following allocations from this registry. to make the following allocations from this registry.
<http://www.iana.org/assignments/pcep/pcep.xhtml#pcep-tlv-type- <http://www.iana.org/assignments/pcep/pcep.xhtml#pcep-tlv-type-
indicators>. indicators>.
Value Name Reference Value Name Reference
-------------------------------------------------------------- --------------------------------------------------------------
TBD5 AUTO-BANDWIDTH-CAPABILITY [This I.D.] TBD2 AUTO-BANDWIDTH-CAPABILITY [This I.D.]
TBD1 AUTO-BANDWIDTH-ATTRIBUTE [This I.D.] TBD1 AUTO-BANDWIDTH-ATTRIBUTE [This I.D.]
8.2. AUTO-BANDWIDTH-CAPABILITY TLV Flag Field 8.2. AUTO-BANDWIDTH-CAPABILITY TLV Flag Field
IANA is requested to create a registry to manage the Flag field of IANA is requested to create a registry to manage the Flag field of
the AUTO-BANDWIDTH-CAPABILITY TLV. the AUTO-BANDWIDTH-CAPABILITY TLV.
New bit numbers may be allocated only by an IETF Consensus action. New bit numbers are allocated only by an IETF Review action
Each bit should be tracked with the following qualities: [RFC5226]. Each bit should be tracked with the following qualities:
o Bit number (counting from bit 0 as the most significant bit) o Bit number (counting from bit 0 as the most significant bit)
o Capability description o Capability description
o Defining RFC o Defining RFC
No bit is defined for the AUTO-BANDWIDTH-CAPABILITY TLV Object flag No bit is defined for the AUTO-BANDWIDTH-CAPABILITY TLV Object flag
field in this document. field in this document.
8.3. AUTO-BANDWIDTH-ATTRIBUTE Sub-TLV 8.3. AUTO-BANDWIDTH-ATTRIBUTE Sub-TLV
This document specifies the AUTO-BANDWIDTH-ATTRIBUTE Sub-TLVs. IANA This document specifies the AUTO-BANDWIDTH-ATTRIBUTE Sub-TLVs. IANA
is requested to create an "AUTO-BANDWIDTH-ATTRIBUTE Sub-TLV Types" is requested to create an "AUTO-BANDWIDTH-ATTRIBUTE Sub-TLV Types"
sub-registry in the "PCEP TLV Type Indicators" for the sub-TLVs sub-registry in the "PCEP TLV Type Indicators" for the sub-TLVs
carried in the AUTO-BANDWIDTH-ATTRIBUTE TLV. This document defines carried in the AUTO-BANDWIDTH-ATTRIBUTE TLV. New sub-TLV are
the following types: allocated only by an IETF Review action [RFC5226].
This document defines the following types:
Type Name Reference Type Name Reference
-------------------------------------------------------------- --------------------------------------------------------------
0 Reserved [This I.D.] 0 Reserved [This I.D.]
1 Sample-Interval sub-TLV [This I.D.] 1 Sample-Interval sub-TLV [This I.D.]
2 Adjustment-Interval sub-TLV [This I.D.] 2 Adjustment-Interval sub-TLV [This I.D.]
3 Adjustment-Threshold sub-TLV [This I.D.] 3 Adjustment-Threshold sub-TLV [This I.D.]
4 Adjustment-Threshold-Percentage sub-TLV [This I.D.] 4 Adjustment-Threshold-Percentage sub-TLV [This I.D.]
5 Minimum-Bandwidth sub-TLV [This I.D.] 5 Minimum-Bandwidth sub-TLV [This I.D.]
6 Maximum-Bandwidth sub-TLV [This I.D.] 6 Maximum-Bandwidth sub-TLV [This I.D.]
skipping to change at page 22, line 33 skipping to change at page 22, line 35
was not Advertised was not Advertised
8.5. Notification Object 8.5. Notification Object
IANA is requested to allocate new Notification Types and Notification IANA is requested to allocate new Notification Types and Notification
Values within the "Notification Object" sub-registry of the PCEP Values within the "Notification Object" sub-registry of the PCEP
Numbers registry, as follows: Numbers registry, as follows:
Type Meaning Reference Type Meaning Reference
--------------------------------------------------------------- ---------------------------------------------------------------
TBD6 Auto-Bandwidth Overwhelm State [This I.D.] TBD3 Auto-Bandwidth Overwhelm State [This I.D.]
Notification-value=1: Entering Auto-Bandwidth Notification-value=1: Entering Auto-Bandwidth
overwhelm state overwhelm state
Notification-value=2: Clearing Auto-Bandwidth Notification-value=2: Clearing Auto-Bandwidth
overwhelm state overwhelm state
9. References 9. References
9.1. Normative References 9.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997. Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", BCP 26, RFC 5226,
May 2008.
[RFC5440] Vasseur, JP. and JL. Le Roux, "Path Computation Element [RFC5440] Vasseur, JP. and JL. Le Roux, "Path Computation Element
(PCE) Communication Protocol (PCEP)", RFC 5440, March (PCE) Communication Protocol (PCEP)", RFC 5440, March
2009. 2009.
[I-D.ietf-pce-stateful-pce] Crabbe, E., Minei, I., Medved, J., and [I-D.ietf-pce-stateful-pce] Crabbe, E., Minei, I., Medved, J., and
R. Varga, "PCEP Extensions for Stateful PCE", draft-ietf- R. Varga, "PCEP Extensions for Stateful PCE", draft-ietf-
pce-stateful-pce (work in progress). pce-stateful-pce (work in progress).
[I-D.ietf-pce-pce-initiated-lsp] Crabbe, E., Minei, I., Sivabalan, [I-D.ietf-pce-pce-initiated-lsp] Crabbe, E., Minei, I., Sivabalan,
S., and R. Varga, "PCEP Extensions for PCE-initiated LSP S., and R. Varga, "PCEP Extensions for PCE-initiated LSP
Setup in a Stateful PCE Model", draft-ietf-pce-pce- Setup in a Stateful PCE Model", draft-ietf-pce-pce-
initiated-lsp (work in progress). initiated-lsp (work in progress).
9.2. Informative References 9.2. Informative References
[RFC3471] Berger, L., "Generalized Multi-Protocol Label Switching [RFC3471] Berger, L., "Generalized Multi-Protocol Label Switching
(GMPLS) Signaling Functional Description", RFC 3471, (GMPLS) Signaling Functional Description", RFC 3471,
January 2003. January 2003.
[RFC5925] Touch, J., Mankin, A., and R. Bonica, "The TCP
Authentication Option", RFC 5925, June 2010.
[RFC7420] Koushik, A., Stephan, E., Zhao, Q., King, D., and J. [RFC7420] Koushik, A., Stephan, E., Zhao, Q., King, D., and J.
Hardwick, "Path Computation Element Communication Protocol Hardwick, "Path Computation Element Communication Protocol
(PCEP) Management Information Base (MIB) Module", RFC (PCEP) Management Information Base (MIB) Module", RFC
7420, December 2014. 7420, December 2014.
[I-D.ietf-pce-stateful-pce-app] Zhang, X. and I. Minei, [RFC8051] Zhang, X. and I. Minei, "Applicability of a Stateful Path
"Applicability of a Stateful Path Computation Element Computation Element (PCE)", RFC 8051, January 2017.
(PCE)", draft-ietf-pce-stateful-pce-app (work in
progress).
[I-D.ietf-pce-pceps] Lopez, D., Dios, O., Wu, W., and D. Dhody, [I-D.ietf-pce-pceps] Lopez, D., Dios, O., Wu, W., and D. Dhody,
"Secure Transport for PCEP", draft-ietf-pce-pceps (work in "Secure Transport for PCEP", draft-ietf-pce-pceps (work in
progress). progress).
[I-D.ietf-pce-pcep-yang] Dhody, D., Hardwick, J., Beeram, V., and J.
Tantsura, "A YANG Data Model for Path Computation Element
Communications Protocol (PCEP)", draft-ietf-pce-pcep-yang
(work in progress), October 2016.
[I-D.gandhi-pce-pm] Gandhi, R., Wen, B., Barth, C., and D. Dhody
"PCEP Extensions for Reporting MPLS-TE LSP Performance
Measurements", draft-gandhi-pce-pm (work in progress),
November 2016
[IEEE.754.1985] Institute of Electrical and Electronics Engineers, [IEEE.754.1985] Institute of Electrical and Electronics Engineers,
"Standard for Binary Floating-Point Arithmetic", IEEE "Standard for Binary Floating-Point Arithmetic", IEEE
Standard 754, August 1985. Standard 754, August 1985.
Acknowledgments Acknowledgments
Authors would like to thank Robert Varga, Venugopal Reddy, Reeja Authors would like to thank Robert Varga, Venugopal Reddy, Reeja
Paul, Sandeep Boina, Avantika, JP Vasseur and Himanshu Shah for their Paul, Sandeep Boina, Avantika, JP Vasseur, Himanshu Shah and Adrian
useful comments and suggestions. Farrel for their useful comments and suggestions.
Contributors' Addresses Contributors' Addresses
He Zekun He Zekun
Tencent Holdings Ltd, Tencent Holdings Ltd,
Shenzhen P.R.China Shenzhen P.R.China
EMail: kinghe@tencent.com EMail: kinghe@tencent.com
Xian Zhang Xian Zhang
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