ALTO Working Group Q. Wu
Internet-Draft Huawei
Intended status: Standards Track Y. Yang
Expires: September 22, 2016 Yale University
Y. Lee
D. Dhody
Huawei
S. Randriamasy
Alcatel-Lucent
March 21, 2016
ALTO Traffic Engineering Cost Metrics
draft-wu-alto-te-metrics-07
Abstract
Cost Metric is a basic concept in Application-Layer Traffic
Optimization (ALTO). It is used in both the Cost Map Service and the
Endpoint Cost Service. Future extensions to ALTO may also use Cost
Metric.
Different applications may benefit from different Cost Metrics. For
example, a Resource Consumer may prefer Resource Providers that have
low delay to the Resource Consumer. However the base ALTO protocol
[ALTO] has defined only a single cost metric, i.e., the generic
"routingcost" metric (Sec. 14.2 of ALTO base specification [ALTO]).
In this document, we define eleven Cost Metrics, derived from OSPF-TE
and ISIS-TE, to measure network delay, jitter, packet loss, hop
count, and bandwidth. The metrics defined in this document provide a
relatively comprehensive set of Cost Metrics for ALTO focusing on
traffic engineering (TE). Additional Cost Metrics such as financial
cost metrics may be defined in other documents.
Requirements Language The key words "MUST", "MUST NOT", "REQUIRED",
"SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY",
and "OPTIONAL" in this document are to be interpreted as described in
RFC 2119 [RFC2119].
Status of This Memo
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
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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 September 22, 2016.
Copyright Notice
Copyright (c) 2016 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
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the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Data sources, computation of defined cost metrics . . . . . . 4
2.1. Data sources . . . . . . . . . . . . . . . . . . . . . . 4
2.2. Computation of metrics . . . . . . . . . . . . . . . . . 4
3. Cost Metric: Delay . . . . . . . . . . . . . . . . . . . . . 5
4. Cost Metric: Delay Jitter . . . . . . . . . . . . . . . . . . 7
5. Cost Metric: Packet Loss . . . . . . . . . . . . . . . . . . 8
6. Cost Metric: Hop Count . . . . . . . . . . . . . . . . . . . 10
7. Cost Metric: Bandwidth . . . . . . . . . . . . . . . . . . . 12
8. Cost Metric: Maximum Bandwidth . . . . . . . . . . . . . . . 13
9. Cost Metric: Maximum Reservable Bandwidth . . . . . . . . . . 15
10. Cost Metric: Unreserved Bandwidth . . . . . . . . . . . . . . 17
11. Cost Metric: Residue Bandwidth . . . . . . . . . . . . . . . 20
12. Cost Metric: Available Bandwidth . . . . . . . . . . . . . . 21
13. Cost Metric: Utilized Bandwidth . . . . . . . . . . . . . . . 23
14. Security Considerations . . . . . . . . . . . . . . . . . . . 25
15. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 26
16. References . . . . . . . . . . . . . . . . . . . . . . . . . 26
16.1. Normative References . . . . . . . . . . . . . . . . . . 26
16.2. Informative References . . . . . . . . . . . . . . . . . 27
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 27
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1. Introduction
Cost Metric is a basic concept in Application-Layer Traffic
Optimization (ALTO). It is used in both the Cost Map Service and the
Endpoint Cost Service. In particular, applications may benefit from
knowing network performance measured on several Cost Metrics. For
example, a more delay sensitive application may focus on latency, and
a more bandwidth-sensitive application may focus on available
bandwidth.
The objective of this document is to define eleven cost metrics,
listed in Table 1, to support the aforementioned applications.
Hence, this document extends the base ALTO protocol [ALTO], which
defines only a single cost metric, i.e., the generic "routingcost"
metric (Sec. 14.2 of ALTO base specification [ALTO]).
+-----------+--------------+------------------------+
| Namespace | Property | Reference |
+-----------+--------------+------------------------+
| | delay | [RFCxxxx], Section 3 |
| | delayjitter | [RFCxxxx], Section 4 |
| | pktloss | [RFCxxxx], Section 5 |
| | hopcount | [RFCxxxx], Section 6 |
| | bandwidth | [RFCxxxx], Section 7 |
| | maxbw | [RFCxxxx], Section 8 |
| | maxresbw | [RFCxxxx], Section 9 |
| | unresdbw | [RFCxxxx], Section 10 |
| | residbw | [RFCxxxx], Section 11 |
| | availbw | [RFCxxxx], Section 12 |
| | utilbw | [RFCxxxx], Section 13 |
+-----------+--------------+------------------------+
Table 1.
An ALTO server may provide a subset of the cost metrics defined in
this document. When an ALTO server supports a cost metric defined in
this document, the server SHOULD announce the metric in its IRD.
The definitions of a set of cost metrics can allow us to extend the
ALTO base protocol (e.g., allowing output and constraints use
different cost metrics), but such extensions are not in the scope of
this document.
One challenge in defining the metrics is that performance metrics
often depend on configuration parameters. For example, the value of
packet loss rate depends on the measurement interval and varies over
time. To handle this issue, ALTO server may collect data on time
periods covering the past, present or only collect data on present
time.
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Following the ALTO base protocol, this document uses JSON to specify
the value type of each defined metric. See [RFC4627] for JSON data
type specification.
2. Data sources, computation of defined cost metrics
The cost metrics defined in this document are similar, in that they
may use similar data sources and have similar issues in their
calculation. Hence, instead of specifying such issues for each
metric individually, we specify the common issue in this section.
2.1. Data sources
An ALTO server needs data sources to compute the cost metrics defined
in this document. This document does not define the exact data
sources. For example, the ALTO server may use log servers or the OAM
system as its data source [ALTO-DEPLOYMENT]. In particular, the cost
metrics defined in this document can be computed using routing
systems as the data sources. Mechanisms defined in [RFC3630],
[RFC3784], [OSPF-TE], [ISIS-TE], [BGP-LS] and [BGP-PM] that allow an
ALTO Server to retrieve and derive the necessary information to
compute the metrics that we define in this document.
2.2. Computation of metrics
An ALTO server process measurements from data sources to compute
exposed metrics. It may need performance data processing tasks such
as aggregating the results across multiple systems, removing
outliers, and creating additional statistics.
One specific challenge in deriving the metrics in this document is
that these performance metrics depend on some configuration
parameters. For example, the value of packet loss rate depends on
the measurement interval and varies over time. If the ALTO server
uses aforementioned routing protocol based mechanisms as data
sources, then the measurement interval may be preconfigured by the
routing protocol. For example, Section 5 of [ISIS-TE] defines a
default measurement interval of 30 seconds. This document uses the
term Measurement Interval to refer to the measurement interval used
by the data sources. In the [ISIS-TE] case, it is a measurement
interval set by routing protocol. The Measurement Interval(s) of the
data sources can be different from the interval that this document
derives the metric, e.g., the interval used by this document is
multiple of measurement interval of the data sources. Hence, an ALTO
server needs to resolve the mismatch, when it happens.
Another issue of converting from data source measurements to ALTO
exposed metric values is that the measurement results that the ALTO
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Server retrieves may be defined for only links, and hence, the server
will need to compose the link metrics to obtain path metrics used in
services such as the Cost Map Service. In this definition, we define
the metrics to be independent of link or path, considering that
future ALTO extensions may define link-based services, and hence the
defined metrics should still be usable.
3. Cost Metric: Delay
Metric name:
Delay
Metric Description:
To specify spatial and temporal aggregated delay between the
specified source and destination or the time that the packet
spends to travel from source to destination. The spatial
aggregation unit is specified in the query context (e.g., PID to
PID, or endpoint to endpoint); and the temporal unit is specified
as the measurement interval in the query context.
Method of Measurement or Calculation:
See section 2.2, Computation of metrics.
Units of Measurement:
The unit is microsecond.
Measurement Point(s) with Potential Measurement Domain:
See section 2.1, Data sources.
Measurement Timing:
See section 2.1, second paragraph for Measurement Timing.
Use and Applications:
This is intended to be a constraint attribute value. A Cost Mode
is encoded as a US-ASCII string. The Metric value Type is a
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single 'JSONNumber' type value containing a non-negative integer
component that may be followed by an exponent part.
This metric could be used as a cost metric constraint attribute
used either together with cost metric attribute 'routingcost' or
on its own or as a returned cost metric in the response.
Example 1: Delay value on source-destination endpoint pairs
POST /endpointcost/lookup HTTP/1.1
Host: alto.example.com
Content-Length: TBA
Content-Type: application/alto-endpointcostparams+json
Accept: application/alto-endpointcost+json,application/alto-error+json
{
"cost-type": {"cost-mode" : "numerical",
"cost-metric" : "delay"},
"endpoints" : {
"srcs": [ "ipv4:192.0.2.2" ],
"dsts": [
"ipv4:192.0.2.89",
"ipv4:198.51.100.34",
"ipv4:203.0.113.45"
]
}
}
HTTP/1.1 200 OK
Content-Length: TBA
Content-Type: application/alto-endpointcost+json
{
"meta" :{
"cost-type": {"cost-mode" : "numerical",
"cost-metric" : "delay"
}
},
"endpoint-cost-map" : {
"ipv4:192.0.2.2": {
"ipv4:192.0.2.89" : 10,
"ipv4:198.51.100.34" : 20,
"ipv4:203.0.113.45" : 30,
}
}
}
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4. Cost Metric: Delay Jitter
Metric name:
Delay jitter
Metric Description:
To specify spatial and temporal aggregated jitter (latency
variation) over the specified source and destination. The spatial
aggregation unit is specified in the query context (e.g., PID to
PID, or endpoint to endpoint); and the temporal unit is specified
as the measurement interval in the query context.
Method of Measurement or Calculation:
See section 2.2, Computation of metrics.
Units of Measurement:
The unit is microsecond.
Measurement Point(s) with Potential Measurement Domain:
See section 2.1, Data sources.
Measurement Timing:
See section 2.1, second paragraph for Measurement Timing.
Measurement Timing:Use and Applications:
See section 3 for use and application.
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Example 2: Delayjitter value on source-destination endpoint pairs
POST /endpointcost/lookup HTTP/1.1
Host: alto.example.com
Content-Length: TBA
Content-Type: application/alto-endpointcostparams+json
Accept: application/alto-endpointcost+json,application/alto-error+json
{
"cost-type": {"cost-mode" : "numerical",
"cost-metric" : "delayjitter"},
"endpoints" : {
"srcs": [ "ipv4:192.0.2.2" ],
"dsts": [
"ipv4:192.0.2.89",
"ipv4:198.51.100.34",
"ipv4:203.0.113.45"
]
}
}
HTTP/1.1 200 OK
Content-Length: TBA
Content-Type: application/alto-endpointcost+json
{
"meta": {
"cost type": {
"cost-mode": "numerical",
"cost-metric":"delayjitter"
}
},
"endpoint-cost-map": {
"ipv4:192.0.2.2": {
"ipv4:192.0.2.89" : 0
"ipv4:198.51.100.34" : 1
"ipv4:203.0.113.45" : 5
}
}
}
5. Cost Metric: Packet Loss
Metric name:
Packet loss
Metric Description:
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To specify spatial and temporal aggregated packet loss over the
specified source and destination. The spatial aggregation unit is
specified in the query context (e.g., PID to PID, or endpoint to
endpoint); and the temporal unit is specified as the measurement
interval in the query context.
Method of Measurement or Calculation:
See section 2.2, Computation of metrics.
Units of Measurement:
The unit is percentile.
Measurement Point(s) with Potential Measurement Domain:
See section 2.1, Data sources.
Measurement Timing:
See section 2.1, second paragraph for Measurement Timing.
Use and Applications:
See section 3 for use and application.
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Example 3: pktloss value on source-destination endpoint pairs
POST /endpointcost/lookup HTTP/1.1
Host: alto.example.com
Content-Length: TBA
Content-Type: application/alto-endpointcostparams+json
Accept: application/alto-endpointcost+json,application/alto-error+json
{
"cost-type": {"cost-mode" : "numerical",
"cost-metric" : "pktloss"},
"endpoints" : {
"srcs": [ "ipv4:192.0.2.2" ],
"dsts": [
"ipv4:192.0.2.89",
"ipv4:198.51.100.34",
"ipv4:203.0.113.45"
]
}
}
HTTP/1.1 200 OK
Content-Length: TBA
Content-Type: application/alto-endpointcost+json
{
"meta": {
"cost type": {
"cost-mode": "numerical",
"cost-metric":"pktloss"}
}
},
"endpoint-cost-map": {
"ipv4:192.0.2.2": {
"ipv4:192.0.2.89" : 0,
"ipv4:198.51.100.34": 1,
"ipv4:203.0.113.45" : 2,
}
}
}
6. Cost Metric: Hop Count
The metric hopcount is mentioned in [ALTO] as an example. This
section further clarifies its properties.
Metric name:
Hop count
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Metric Description:
To specify the number of hops in the path between the source
endpoint and the destination endpoint.
[Editor Note: Need to specify which level (AS, IP perhaps),
details TBD for multiple-layer aspect.]
Method of Measurement or Calculation:
See section 2.2, Computation of metrics.
Units of Measurement:
The unit is integer number.
Measurement Point(s) with Potential Measurement Domain:
See section 2.1, Data sources.
Measurement Timing:
See section 2.1, second paragraph for Measurement Timing.
Use and Applications:
See section 3 for use and application.
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Example 4: hopcount value on source-destination endpoint pairs
POST /endpointcost/lookup HTTP/1.1
Host: alto.example.com
Content-Length: TBA
Content-Type: application/alto-endpointcostparams+json
Accept: application/alto-endpointcost+json,application/alto-error+json
{
"cost-type": {"cost-mode" : "numerical",
"cost-metric" : "hopcount"},
"endpoints" : {
"srcs": [ "ipv4:192.0.2.2" ],
"dsts": [
"ipv4:192.0.2.89",
"ipv4:198.51.100.34",
"ipv4:203.0.113.45"
]
}
}
HTTP/1.1 200 OK
Content-Length: TBA
Content-Type: application/alto-endpointcost+json
{
"meta": {
"cost type": {
"cost-mode": "numerical",
"cost-metric":"hopcount"}
}
},
"endpoint-cost-map": {
"ipv4:192.0.2.2": {
"ipv4:192.0.2.89" : 5,
"ipv4:198.51.100.34": 3,
"ipv4:203.0.113.45" : 2,
}
}
}
7. Cost Metric: Bandwidth
Metric name:
Bandwidth
Metric Description:
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To specify spatial and temporal aggregated bandwidth over the
specified source and destination. The spatial aggregation unit is
specified in the query context (e.g., PID to PID, or endhost to
endhost); and the temporal unit is specified as the measurement
interval in the query context.
This is just a definition of a class of cost metric 'bandwidth'.
The use of this cost metric is always in conjunction with what it
represents, which could be Max Bandwidth (maxbw), Residual
Bandwidth (residuebw) etc.
Method of Measurement or Calculation:
See section 2.2, Computation of metrics.
Units of Measurement:
The units are bytes per second.
Measurement Point(s) with Potential Measurement Domain:
See section 2.1, Data sources.
Measurement Timing:
See section 2.1, second paragraph for Measurement Timing.
Use and Applications:
See section 3 for use and application.
8. Cost Metric: Maximum Bandwidth
Metric name:
Maximum Bandwidth
Metric Description:
To specify spatial and temporal maximum bandwidth over the
specified source and destination. The values correspond to the
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maximum bandwidth that can be used (motivated from RFC 3630 Sec.
2.5.6.). The spatial aggregation unit is specified in the query
context (e.g., PID to PID, or endhost to endhost); and the
temporal unit is specified as the measurement interval in the
query context.
Method of Measurement or Calculation:
See section 2.2, Computation of metrics.
Units of Measurement:
See definition for the Bandwidth Cost Metric.
Measurement Point(s) with Potential Measurement Domain:
See section 2.1, Data sources.
Measurement Timing:
See section 2.1, second paragraph for Measurement Timing.
Use and Applications:
See section 3 for use and application.
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Example 5: maxbw value on source-destination endpoint pairs
POST/ endpointcost/lookup HTTP/1.1
Host: alto.example.com
Content-Length: TBA
Content-Type: application/alto-endpointcostparams+json
Accept: application/alto-endpointcost+json,application/alto-error+json
{
"cost-type": { "cost-mode": "numerical",
"cost-metric": "maxbw"},
"endpoints": {
"srcs": [ "ipv4 : 192.0.2.2" ],
"dsts": [
"ipv4:192.0.2.89",
"ipv4:198.51.100.34",
"ipv4:203.0.113.45"
]
}
}
HTTP/1.1 200 OK
Content-Length: TBA
Content-Type: application/alto-endpointcost+json
{
"meta": {
"cost-type": {
"cost-mode": "numerical",
"cost-metric": "maxbw"
}
},
"endpoint-cost-map": {
"ipv4:192.0.2.2": {
"ipv4:192.0.2.89": 0,
"ipv4:198.51.100.34" : 2000,
"ipv4:203.0.113.45": 5000,
}
}
}
9. Cost Metric: Maximum Reservable Bandwidth
Metric name:
Maximum Reservable Bandwidth
Metric Description:
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To specify spatial and temporal maximum reservable bandwidth over
the specified source and destination. The value is corresponding
to the maximum bandwidth that can be reserved (motivated from RFC
3630 Sec. 2.5.7.). The spatial aggregation unit is specified in
the query context (e.g., PID to PID, or endpoint to endpoint); and
the temporal unit is specified as the measurement interval in the
query context.
Method of Measurement or Calculation:
See section 2.2, Computation of metrics.
Units of Measurement:
See definition of the Bandwidth Cost Metric.
Measurement Point(s) with Potential Measurement Domain:
See section 2.1, Data sources.
Measurement Timing:
See section 2.1, second paragraph for Measurement Timing.
Use and Applications:
See section 3 for use and application.
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Example 6: maxresbw value on source-destination endpoint pairs
POST/ endpointcost/lookup HTTP/1.1
Host: alto.example.com
Content-Length: TBA
Content-Type: application/alto-endpointcostparams+json
Accept: application/alto-endpointcost+json,application/alto-error+json
{
"cost-type" { "cost-mode": "numerical",
"cost-metric": "maxresbw"},
"endpoints": {
"srcs": [ "ipv4 : 192.0.2.2" ],
"dsts": [
"ipv4:192.0.2.89",
"ipv4:198.51.100.34",
"ipv4:203.0.113.45"
]
}
}
HTTP/1.1 200 OK
Content-Length: TBA
Content-Type: application/alto-endpointcost+json
{
"meta": {
"cost-type": {
"cost-mode": "numerical",
"cost-metric": "maxresbw"
}
},
" endpoint-cost-map": {
"ipv4:192.0.2.2" {
"ipv4:192.0.2.89" : 0,
"ipv4:198.51.100.34": 2000,
"ipv4:203.0.113.45": 5000,
}
}
}
10. Cost Metric: Unreserved Bandwidth
Metric name:
Unreserved Bandwidth
Metric Description:
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To specify spatial and temporal unreserved bandwidth over the
specified source and destination. The values correspond to the
bandwidth that can be reserved with a setup priority of 0 through
7. Therefore this metric is endcoded as an array of 8 values.
The spatial aggregation unit is specified in the query context
(e.g., PID to PID, or endpoint to endpoint); and the temporal unit
is specified as the measurement interval in the query context.
Method of Measurement or Calculation:
See section 2.2, Computation of metrics.
Units of Measurement:
See definition for the bandwidth Cost Metric.
Measurement Point(s) with Potential Measurement Domain:
See section 2.1, Data sources.
Measurement Timing:
See section 2.1, second paragraph for Measurement Timing.
Use and Applications:
See section 3 for use and application.
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Example 7: unresbw value on source-destination endpoint pairs
In this example, the Collection method specifies that the
'unresbw' values are defined as the 'unavailable bandwidth' specified
in section 2.5.8 of RFC3630: 8 unavailable bandwidth value are
reported in the same OSPF message using the same TLV. Each value
is corresponding to the bandwidth that can be reserved with a setup
priority of 0 through 7.
POST/ endpointcost/lookup HTTP/1.1
Host: alto.example.com
Content-Length: TBA
Content-Type: application/alto-endpointcostparams+json
Accept: application/alto-endpointcost+json,application/alto-error+json
{
"cost-type" { "cost-mode": "numerical",
"cost-metric": "unresbw[1,8]" },
"endpoints": {
"srcs": [ "ipv4:192.0.2.2" ],
"dsts": [
"ipv4:192.0.2.89",
"ipv4:198.51.100.34",
"ipv4:203.0.113.45"
]
}
}
HTTP/1.1 200 OK
Content-Length: TBA
Content-Type: application/alto-endpointcost+json
{
"meta": {
"cost-type": {
"cost-mode": "numerical",
"cost-metric": "unresbw[1,8]"
}
},
"endpoint-cost-map" {
"ipv4:192.0.2.2" {
"ipv4:192.0.2.89" : [0,0,0,0,0,0,0,0],
"ipv4:198.51.100.34": [0,0,0,0,0,0,0,2000],
"ipv4:203.0.113.45": [0,0,0,0,0,0,0,5000],
}
}
}
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11. Cost Metric: Residue Bandwidth
Metric name:
Residue Bandwidth
Metric Description:
To specify spatial and temporal residual bandwidth over the
specified source and destination. The value is calculated by
subtracting tunnel reservations from Maximum Bandwidth (motivated
from [I-D. ietf-isis-te-metric-extensions], Sec.4.5.). The
spatial aggregation unit is specified in the query context (e.g.,
PID to PID, or endpoint to endpoint); and the temporal unit is
specified as the measurement interval in the query context.
Method of Measurement or Calculation:
See section 2.2, Computation of metrics.
Units of Measurement:
See definition of the general Bandwidth.
Measurement Point(s) with Potential Measurement Domain:
See section 2.1, Data sources.
Measurement Timing:
See section 2.1, second paragraph for Measurement Timing.
Use and Applications:
See section 3 for use and application.
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Example 8: residuebw value on source-destination endpoint pairs
POST/ endpointcost/lookup HTTP/1.1
Host: alto.example.com
Content-Length: TBA
Content-Type: application/alto-endpointcostparams+json
Accept: application/alto-endpointcost+json,application/alto-error+json
{
"cost-type": { "cost-mode": "numerical",
"cost-metric": "residubw"},
"endpoints": {
"srcs": [ "ipv4 : 192.0.2.2" ],
"dsts": [
"ipv4:192.0.2.89",
"ipv4:198.51.100.34",
"ipv4:203.0.113.45"
]
}
}
HTTP/1.1 200 OK
Content-Length: TBA
Content-Type: application/alto-endpointcost+json
{
"meta": {
"cost-type" {
"cost-mode": "numerical",
"cost-metric": "residubw"
}
},
"endpoint-cost-map" {
"ipv4:192.0.2.2" {
"ipv4:192.0.2.89" : 0,
"ipv4:198.51.100.34": 2000,
"ipv4:203.0.113.45": 5000,
}
}
}
12. Cost Metric: Available Bandwidth
Metric name:
Available Bandwidth
Metric Description:
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To specify spatial and temporal availaible bandwidth over the
specified source and destination. The value is calculated by
subtracting the measured bandwidth used for the actual forwarding
of best effort traffic from Residue Bandwidth (motivated from
[I-D. ietf-isis-te-metric-extensions], Sec.4.6.). The spatial
aggregation unit is specified in the query context (e.g., PID to
PID, or endpoint to endpoint); and the temporal unit is specified
as the measurement interval in the query context.
Method of Measurement or Calculation:
See section 2.2, Computation of metrics.
Units of Measurement:
See definition of the general Bandwidth.
Measurement Point(s) with Potential Measurement Domain:
See section 2.1, Data sources.
Measurement Timing:
See section 2.1, second paragraph for Measurement Timing.
Use and Applications:
See section 3 for use and application.
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Example 9: availbw value on source-destination endpoint pairs
POST /endpointcost/lookup HTTP/1.1
Host: alto.example.com
Content-Length: TBA
Content-Type: application/alto-endpointcostparams+json
Accept: application/alto-endpointcost+json,application/alto-error+json
{
"cost-type": { "cost-mode": "numeric",
"cost-metric": "availbw"},
"endpoints": {
"srcs": [ "ipv4 : 192.0.2.2" ],
"dsts": [
"ipv4:192.0.2.89",
"ipv4:198.51.100.34",
"ipv4:203.0.113.45"
]
}
}
HTTP/1.1 200 OK
Content-Length: TBA
Content-Type: application/alto-endpointcost+json
{
"meta": {
"cost-type": {
"cost-mode": "numeric",
"cost-metric": "availbw"
}
},
"endpoint-cost-map": {
"ipv4:192.0.2.2" {
"ipv4:192.0.2.89" : [6,5,7,8,4,10,7,6],
"ipv4:198.51.100.34" : [7,4,6,8,5,9,6,7],
"ipv4:203.0.113.45" : [7,6,8,5,7,9,6,8],
}
}
}
13. Cost Metric: Utilized Bandwidth
Metric name:
Utilized Bandwidth
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Metric Description:
To specify spatial and temporal utilized bandwidth over the
specified source and destination. The value is corresponding to
the actual measured bandwidth used for all traffic (motivated from
[I-D. ietf-isis-te-metric-extensions], Sec.4.7.). The spatial
aggregation unit is specified in the query context (e.g., PID to
PID, or endpoint to endpoint); and the temporal unit is specified
as the measurement interval in the query context.
Method of Measurement or Calculation:
See section 2.2, Computation of metrics.
Units of Measurement:
See definition of the general Bandwidth.
Measurement Point(s) with Potential Measurement Domain:
See section 2.1, Data sources.
Measurement Timing:
See section 2.1, second paragraph for Measurement Timing.
Use and Applications:
See section 3 for use and application.
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Example 10: utilbw value on source-destination endpoint pairs
POST /endpointcost/lookup HTTP/1.1
Host: alto.example.com
Content-Length: TBA
Content-Type: application/alto-endpointcostparams+json
Accept: application/alto-endpointcost+json,application/alto-error+json
{
"cost-type": {"cost-mode" : "numerical",
"cost-metric" : "utilbw"},
"endpoints": {
"srcs" : [ "ipv4 : 192.0.2.2" ],
"dsts" : [
"ipv4:192.0.2.89",
"ipv4:198.51.100.34",
"ipv4:203.0.113.45"
]
}
}
HTTP/1.1 200 OK
Content-Length: TBA
Content-Type: application/alto-endpointcost+json
{
"meta": {
"cost type": {
"cost-mode": "numerical",
"cost-metric": "utilbw"
}
},
"endpoint-cost-map": {
"ipv4:192.0.2.2" {
"ipv4:192.0.2.89" : 0,
"ipv4:198.51.100.34" : 2000,
"ipv4:203.0.113.45" : 5000,
}
}
}
14. Security Considerations
The properties defined in this document present no security
considerations beyond those in Section 15 of the base ALTO
specification [ALTO].
However concerns addressed in Sections "15.1 Authenticity and
Integrity of ALTO Information", "15.2 Potential Undesirable Guidance
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from Authenticated ALTO Information" and "15.3 Confidentiality of
ALTO Information" remain of utmost importance. Indeed, TE
performance is a highly sensitive ISP information and sharing TE
metric values in numerical mode requires full mutual confidence
between the entities managing the ALTO Server and Client. Numerical
TE performance information will most likely be distributed by ALTO
Servers to Clients under strict and formal mutual trust agreements.
One the other hand, ALTO Clients must be cognizant on the risks
attached to such information that they would have acquired outside
formal conditions of mutual trust.
15. IANA Considerations
IANA has added the following entries to the ALTO cost map Properties
registry, defined in Section 3 of [RFCXXX].
+-----------+--------------+------------------------+
| Namespace | Property | Reference |
+-----------+--------------+------------------------+
| | delay | [RFCxxxx], Section 3 |
| | delayjitter | [RFCxxxx], Section 4 |
| | pktloss | [RFCxxxx], Section 5 |
| | hopcount | [RFCxxxx], Section 6 |
| | bandwidth | [RFCxxxx], Section 7 |
| | maxbw | [RFCxxxx], Section 8 |
| | maxresbw | [RFCxxxx] Section 9 |
| | unresdbw | [RFCxxxx], Section 10 |
| | residbw | [RFCxxxx], Section 11 |
| | availbw | [RFCxxxx], Section 12 |
| | utilbw | [RFCxxxx], Section 13 |
+-----------+--------------+------------------------+
16. References
16.1. Normative References
[I-D.ietf-idr-te-pm-bgp]
Wu, Q., Previdi, S., Gredler, H., Ray, S., and J.
Tantsura, "BGP attribute for North-Bound Distribution of
Traffic Engineering (TE) performance Metrics", draft-ietf-
idr-te-pm-bgp-02 (work in progress), January 2015.
[I-D.ietf-isis-te-metric-extensions]
Previdi, S., Giacalone, S., Ward, D., Drake, J., and W.
Wu, "IS-IS Traffic Engineering (TE) Metric Extensions",
draft-ietf-isis-te-metric-extensions-11 (work in
progress), February 2016.
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[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", March 1997.
[RFC4627] Crockford, D., "The application/json Media Type for
JavaScript Object Notation (JSON)", RFC 4627,
DOI 10.17487/RFC4627, July 2006,
<http://www.rfc-editor.org/info/rfc4627>.
[RFC5234] Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax
Specifications: ABNF", STD 68, RFC 5234,
DOI 10.17487/RFC5234, January 2008,
<http://www.rfc-editor.org/info/rfc5234>.
[RFC7285] Alimi, R., Ed., Penno, R., Ed., Yang, Y., Ed., Kiesel, S.,
Previdi, S., Roome, W., Shalunov, S., and R. Woundy,
"Application-Layer Traffic Optimization (ALTO) Protocol",
RFC 7285, DOI 10.17487/RFC7285, September 2014,
<http://www.rfc-editor.org/info/rfc7285>.
[RFC7471] Giacalone, S., Ward, D., Drake, J., Atlas, A., and S.
Previdi, "OSPF Traffic Engineering (TE) Metric
Extensions", RFC 7471, DOI 10.17487/RFC7471, March 2015,
<http://www.rfc-editor.org/info/rfc7471>.
[RFC7752] Gredler, H., Ed., Medved, J., Previdi, S., Farrel, A., and
S. Ray, "North-Bound Distribution of Link-State and
Traffic Engineering (TE) Information Using BGP", RFC 7752,
DOI 10.17487/RFC7752, March 2016,
<http://www.rfc-editor.org/info/rfc7752>.
16.2. Informative References
[I-D.ietf-alto-deployments]
Stiemerling, M., Kiesel, S., Scharf, M., Seidel, H., and
S. Previdi, "ALTO Deployment Considerations", draft-ietf-
alto-deployments-13 (work in progress), January 2016.
[RFC6390] Clark, A. and B. Claise, "Framework for Performance Metric
Development", RFC 6390, July 2011.
Authors' Addresses
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Qin Wu
Huawei
101 Software Avenue, Yuhua District
Nanjing, Jiangsu 210012
China
Email: bill.wu@huawei.com
Y. Richard Yang
Yale University
51 Prospect St
New Haven, CT 06520
USA
Email: yry@cs.yale.edu
Young Lee
Huawei
1700 Alma Drive, Suite 500
Plano, TX 75075
USA
Email: leeyoung@huawei.com
Dhruv Dhody
Huawei
Leela Palace
Bangalore, Karnataka 560008
INDIA
Email: dhruv.ietf@gmail.com
Sabine Randriamasy
Alcatel-Lucent
Route de Villejust
Nozay 91460
FRANCE
Email: Sabine.Randriamasy@alcatel-lucent.com
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