| PCE Working Group | D. Dhody |
| Internet-Draft | U. Palle |
| Intended status: Standards Track | Huawei Technologies |
| Expires: December 19, 2015 | R. Singh |
| Juniper Networks | |
| R. Gandhi | |
| Cisco Systems, Inc. | |
| June 17, 2015 |
PCEP Extensions for MPLS-TE LSP Automatic Bandwidth Adjustment with Stateful PCE
draft-dhody-pce-stateful-pce-auto-bandwidth-05
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 provide stateful control of Multi-Protocol Label Switching (MPLS) Traffic Engineering Label Switched Paths (TE LSPs) via PCEP, for the case where PCC delegates control over one or more locally configured LSPs to the PCE.
This document describes automatic bandwidth adjustment of such LSPs when employing an Active Stateful PCE. 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 traffic to a PCE and the PCE computes the adjustment bandwidth.
This document also describes automatic bandwidth adjustment for stateful PCE-initiated LSPs.
This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet-Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress."
This Internet-Draft will expire on December 19, 2015.
Copyright (c) 2015 IETF Trust and the persons identified as the document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License.
[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 under the stateful PCE model.
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 based on the actual traffic flowing through the LSP. An LSP set-up with some arbitrary (including zero) bandwidth value, automatically 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 traffic flow. This 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.
This document defines extensions needed to support Auto-Bandwidth feature on the LSPs in a active stateful PCE model using PCEP.
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].
The following terminology is used in this document.
Note the Auto-Bandwidth feature specific terms defined in Section 4.1.
There are two deployment models considered in this document for automatic bandwidth adjustments in case of active stateful PCE. In the model where PCC decides the adjusted bandwidth, PCC can report the new requested bandwidth and an active stateful PCE can update the bandwidth for a delegated LSP via existing mechanisms defined in [I-D.ietf-pce-stateful-pce]. Additional PCEP extensions required are summarized in the following table.
| Model | PCC Initiated | PCE Initiated |
|---|---|---|
| PCC to decide adjusted bandwidth | PCC monitors the traffic and reports the calculated bandwidth to be adjusted to the PCE. | At the time of initiation, PCE request PCC to monitor the traffic and reports the 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. | |
| Optionally AUTO-BANDWIDTH-ATTRIBUTE TLV can be used to identify the LSP with Auto-Bandwidth Feature enabled. | Refer the AUTO-BANDWIDTH-ATTRIBUTE TLV (and sub-TLVs e.g. Adjustment-Interval, Minimum-Bandwidth) in Section 5.1. | |
| ------ | -------------------------- | --------------------------- |
| PCC reports real-time traffic and PCE to decide adjusted bandwidth | PCC monitors the traffic and reports the real-time traffic to the PCE. It is PCE that decides the calculated bandwidth to be adjusted and updates the LSP accordingly. | At the time of initiation, PCE request PCC to monitor the traffic and reports the real-time traffic to the PCE. It is PCE that decides the calculated bandwidth to be adjusted and updates the LSP accordingly. |
| Extension is needed for PCC to pass on the adjustment parameters at the time of delegation to PCE. | Extension is needed for PCE to pass on the real-time traffic reporting parameters at the time of Initiation. | |
| Refer the AUTO-BANDWIDTH-ATTRIBUTE TLV (and sub-TLVs e.g. Adjustment-Threshold, Real-time-Traffic-Report-Interval) in Section 5.1. | Refer the Real-time Traffic Reporting (e.g. Real-time-Traffic-Report-Interval, Real-time-Traffic-Report-Threshold) in Section 5.1.2. | |
| Further extension to report the real-time traffic to PCE are also needed (Refer Bandwidth-Usage type in Section 5.2.2). | Further extension to report the real-time traffic to PCE are also needed (Refer Bandwidth-Usage type in Section 5.2.2). | |
Additional Auto-Bandwidth deployment considerations are summarized below:
Auto-Bandwidth feature allows an LSP to automatically and dynamically 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:
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).
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 traffic information and the PCE decides the adjusted bandwidth. Multiple bandwidth samples are collected every report-interval, and reported together to the PCE. To avoid reporting minor changes in real-time traffic, 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 real-time traffic, 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.
There are potential scaling concerns for the model where PCC (ingress LSR) reports real-time traffic information to the stateful PCE for a large number of LSPs. It is recommended to combine multiple bandwidth samples (BwSample) 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.
The AUTO-BANDWIDTH-ATTRIBUTE TLV can be included as an optional TLV in the LSPA object (as described in [RFC5440]). Whenever the LSP with Auto-Bandwidth feature enabled is delegated, AUTO-BANDWIDTH-ATTRIBUTE TLV is carried in PCRpt message in LSPA object. The TLV provides PCE with the 'configurable knobs' of this feature. In case of PCE-Initiated LSP ([I-D.ietf-pce-pce-initiated-lsp]) with Auto-Bandwidth feature enabled, this TLV is included in LSPA object with PCInitiate message.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type=[TBD] | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
// sub-TLVs //
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
AUTO-BANDWIDTH-ATTRIBUTE TLV format
The format of the AUTO-BANDWIDTH-ATTRIBUTE TLV is shown in the following figure:
Type: TBD
Length: Variable
Value: This comprises one or more sub-TLVs.
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 11 4 Real-time-Traffic-Report-Interval sub-TLV 12 4 Real-time-Traffic-Report-Threshold sub-TLV 13 4 Real-time-Traffic-Report-Threshold-Percentage sub-TLV 14 4 Real-time-Traffic-Report-Flow-Threshold sub-TLV 15 4 Real-time-Traffic-Report-Flow-Threshold-Percentage sub-TLV
Following sub-TLVs are defined in this document:
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 any others MUST be ignored.
If the sub-TLV are not encoded, the defaults based on the local policy are assumed.
The following sub-sections describe the sub-TLVs which are currently defined to be carried within the AUTO-BANDWIDTH-ATTRIBUTE TLV.
The sub-TLVs in this section are encoded to inform the PCEP peer the various sampling and adjustment parameters, and serves the following purpose -
The Sample-Interval sub-TLV specifies a time interval in seconds at which traffic samples are collected at the PCC.
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
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.
The Adjustment-Interval sub-TLV specifies a time interval in seconds at which bandwidth adjustment should be made.
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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Adjustment-Interval |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Adjustment-Interval sub-TLV format
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.
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.
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 Adjustment-Threshold sub-TLV is used to decide when the LSP bandwidth should be adjusted.
The Type is 3, Length is 4, and the value comprises of -
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=4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved | Percentage |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Adjustment-Threshold-Percentage sub-TLV format
The Adjustment-Threshold-Percentage sub-TLV is used to decide when the LSP bandwidth should be adjusted.
The Type is 4, Length is 4, and the value comprises of -
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.
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
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.
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.
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
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.
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.
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 Overflow-Threshold sub-TLV is used to decide if the bandwidth should be adjusted immediately.
The Type is 7, Length is 4, and the value comprises of -
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 Overflow-Threshold-Percentage sub-TLV is used to decide if the bandwidth should be adjusted immediately.
The Type is 8, Length is 4, and the value comprises of -
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 Underflow-Threshold sub-TLV is used to decide if the bandwidth should be adjusted immediately.
The Type is 9, Length is 8, and the value comprises of -
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 Underflow-Threshold-Percentage sub-TLV is used to decide if the bandwidth should be adjusted immediately.
The Type is 10, Length is 4, and the value comprises of -
The sub-TLVs in this section are encoded to inform the PCEP peer the various real-time traffic reporting parameters in the Deployment Model 2 (where PCE decides the adjusted bandwidth). In this model, Real-time-Traffic-Report-Interval sub-TLV MUST be included to specify the frequency of reporting.
The report threshold is used to decide if the collected bandwidth samples should be reported or skipped. An implementation MAY include both sub-TLVs for the absolute value and the percentage, in which case the real-time traffic is reported when either of the report threshold conditions are met.
The report flow threshold is used to decide when the collected bandwidth samples should be reported immediately, bypassing the report interval. An implementation MAY include both sub-TLVs for the absolute value and the percentage, in which case the real-time traffic is reported immediately when either of the report flow threshold conditions are met.
The Real-time-Traffic-Report-Interval sub-TLV specifies a time interval in seconds in which collected bandwidth samples should be reported to PCE.
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=11 | Length=4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Real-time-Traffic-Report-Interval |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Real-time-Traffic-Report-Interval sub-TLV format
The Type is 11, Length is 4, and the value comprises of 4-octet time interval, the valid range is from 1 to 604800, in seconds.
There is no default value. This sub-TLV MUST be included to enable the real-time traffic reporting.
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=12 | Length=4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Real-time-Traffic-Report Threshold |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Real-time-Traffic-Report-Threshold sub-TLV format
The Real-time-Traffic-Report-Threshold sub-TLV is used to decide when the bandwidth samples collected should be reported immediately, bypassing the report-interval.
The Type is 12, Length is 4, and the value comprises of -
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=13 | Length=4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved | Percentage |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Real-time-Traffic-Report-Threshold-Percentage sub-TLV format
The Real-time-Traffic-Report-Threshold sub-TLV is used to decide when the bandwidth samples collected should be reported immediately, bypassing the report-interval.
The Type is 13, Length is 4, and the value comprises of -
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=14 | Length=4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Real-time-Traffic-Report-Flow Threshold |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Real-time-Traffic-Report-Flow-Threshold sub-TLV format
The Real-time-Traffic-Report-Flow-Threshold sub-TLV is used to decide when the bandwidth samples collected should be reported immediately, bypassing the report-interval.
The Type is 14, Length is 4, and the value comprises of -
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=15 | Length=4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved | Percentage |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Real-time-Traffic-Report-Flow-Threshold-Percentage sub-TLV format
The Real-time-Traffic-Report-Flow-Threshold sub-TLV is used to decide when the bandwidth samples collected should be reported immediately, bypassing the report-interval.
The Type is 15, Length is 4, and the value comprises of -
As per [RFC5440], the BANDWIDTH object is defined with two Object-Type values as following:
In the first model, where PCC calculates the adjusted bandwidth, PCC only 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'.
A new BANDWIDTH object type is defined to report the actual bandwidth usage of a TE LSP.
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
The Object type is [TBD], the object body has a variable length, multiples of 4 bytes. The payload format is as follows:
The Bandwidth-Usage object can be 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 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. The details of which are beyond the scope of this document.
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, and Real-time-Traffic-Report-Interval sub-TLV is not present (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, and Real-time-Traffic-Report-Interval sub-TLV is present (Deployment model 2), PCC SHOULD include the BANDWIDTH object of type [TBD] to report the real-time traffic 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.
For PCE-initiated LSP [I-D.ietf-pce-pce-initiated-lsp] with Auto-Bandwidth feature enabled, AUTO-BANDWIDTH-ATTRIBUTE TLV MUST be included in LSPA object with the PCInitiate message. The rest of the processing remains unchanged.
This document defines a new BANDWIDTH type and AUTO-BANDWIDTH-ATTRIBUTE TLV which do not add any new security concerns beyond those discussed in [RFC5440] and [I-D.ietf-pce-stateful-pce] in itself.
Some deployments may find the reporting of the real-time traffic information as extra sensitive and thus should employ suitable PCEP security mechanisms like TCP-AO or [I-D.ietf-pce-pceps].
The Auto-Bandwidth feature MUST BE controlled per tunnel (at Ingress (PCC) or PCE), the values for parameters like sample-interval, adjustment- interval, minimum-bandwidth, maximum-bandwidth, adjustment-threshold, report-interval, report-threshold SHOULD be configurable by an operator.
[RFC7420] describes the PCEP MIB, there are no new MIB Objects for this document.
Mechanisms defined in this document do not imply any new liveness detection and monitoring requirements in addition to those already listed in [RFC5440].
Mechanisms defined in this document do not imply any new operation verification requirements in addition to those already listed in [RFC5440].
Mechanisms defined in this document do not imply any new requirements on other protocols.
Mechanisms defined in this document do not have any impact on network operations in addition to those already listed in [RFC5440].
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 TBD AUTO-BANDWIDTH-ATTRIBUTE [This I.D.]
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 Real-time-Traffic-Report-Interval sub-TLV [This I.D.]
12 Real-time-Traffic-Report-Threshold sub-TLV [This I.D.]
13 Real-time-Traffic-Report-Threshold-Percentage [This I.D.]
sub-TLV
14 Real-time-Traffic-Report-Flow-Threshold [This I.D.]
sub-TLV
15 Real-time-Traffic-Report-Flow-Threshold [This I.D.]
-Percentage sub-TLV
16- Unassigned [This I.D.]
65535
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:
This document defines new object type for the BANDWIDTH object; IANA is requested to make the following allocations from this registry. http://www.iana.org/assignments/pcep/pcep.xhtml#pcep-objects
Object-Class Value Name Reference
5 BANDWIDTH [This I.D.]
Object-Type
TBD: Bandwidth-Usage Report
We would like to thank Venugopal Reddy, Reeja Paul, Sandeep Boina and Avantika for their useful comments and suggestions.
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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", Internet-Draft draft-ietf-pce-stateful-pce-11, April 2015. |
| [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", Internet-Draft draft-ietf-pce-pce-initiated-lsp-04, April 2015. |
| [IEEE.754.1985] | Institute of Electrical and Electronics Engineers, "Standard for Binary Floating-Point Arithmetic", IEEE Standard 754, August 1985. |
| [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)", Internet-Draft draft-ietf-pce-stateful-pce-app-04, April 2015. |
| [I-D.ietf-pce-pceps] | Lopez, D., Dios, O., Wu, W. and D. Dhody, "Secure Transport for PCEP", Internet-Draft draft-ietf-pce-pceps-04, May 2015. |
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