Internet DRAFT - draft-randriamasy-alto-cost-schedule
draft-randriamasy-alto-cost-schedule
Network Working Group S. Randriamasy, Ed.
Internet-Draft Alcatel-Lucent Bell Labs
Intended status: Experimental N. Schwan
Expires: August 18, 2014
February 14, 2014
ALTO Cost Schedule
draft-randriamasy-alto-cost-schedule-03
Abstract
The goal of Application-Layer Traffic Optimization (ALTO) is to
bridge the gap between network and applications by provisioning
network related information. This allows applications to make
informed decisions, for example when selecting a target host from a
set of candidates. The ALTO problem statement [RFC5693] considers
typical applications as file sharing, real-time communication and
live streaming peer-to-peer networks. Recently other use cases
focused on Content Distribution Networks and Data Centers have
emerged.
The present draft proposes to extend the cost information provided by
the ALTO protocol. The purpose is to broaden the decision
possibilities of applications to not only decide 'where' to connect
to, but also 'when'. This is useful to applications that have a
degree of freedom on when to schedule data transfers, such as non-
instantaneous data replication between data centers or service
provisioning to end systems with irregular connectivity. The draft
therefore specifies a new cost mode, called the "schedule" mode. In
this mode the ALTO server offers cost maps that contain path ratings
that are valid for a given timeframe (e.g. hourly) for a period of
time (e.g. a day). Besides the functional time-shift enhancement
providing multi-timeframe cost values, the ALTO Cost Schedule also
allows to save a number of ALTO transactions and thus resources on
the ALTO server and clients. Last, guidance to schedule application
traffic can also efficiently help for load balancing and resources
efficiency.
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].
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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
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This Internet-Draft will expire on August 18, 2014.
Copyright Notice
Copyright (c) 2014 IETF Trust and the persons identified as the
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Use cases for ALTO Cost Schedule . . . . . . . . . . . . . . 4
2.1. Bulk Data Transfer scheduling . . . . . . . . . . . . . . 5
2.2. Endsystems with limited connectivity or access to
datacenters . . . . . . . . . . . . . . . . . . . . . . . 5
2.3. SDN Controller guided access to application endpoints . . 7
2.4. Large flow scheduling on extended ALTO topologies . . . . 9
2.5. Providing values for time-sensitve TE metrics . . . . . . 10
3. ALTO Cost Schedule extension . . . . . . . . . . . . . . . . 10
3.1. Cost Schedule Attributes . . . . . . . . . . . . . . . . 11
3.1.1. ALTO Cost-Mode: Schedule . . . . . . . . . . . . . . 11
3.2. ALTO Capability: Cost-Scope . . . . . . . . . . . . . . . 11
3.2.1. Example of time scope for a cost schedule . . . . . . 12
3.3. Example of scheduled information resources in the IRD . . 12
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3.3.1. Example scenario and ALTO transaction with a Cost
Schedule . . . . . . . . . . . . . . . . . . . . . . 15
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 16
4.1. Information for IANA on proposed Cost Types . . . . . . . 17
4.2. Information for IANA on proposed Endpoint Propeeries . . 17
5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 17
6. References . . . . . . . . . . . . . . . . . . . . . . . . . 17
6.1. Normative References . . . . . . . . . . . . . . . . . . 17
6.2. Informative References . . . . . . . . . . . . . . . . . 17
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 18
1. Introduction
IETF is currently standardizing the ALTO protocol which aims for
providing guidance to overlay applications, that need to select one
or several hosts from a set of candidates that are able to provide a
desired resource. This guidance is based on parameters that affect
performance and efficiency of the data transmission between the
hosts, e.g., the topological distance. The goal of ALTO is to
improve the Quality of Experience (QoE) in the application while
simultaneously optimizing resource usage in the underlying network
infrastructure.
The ALTO protocol therefore [ID-alto-protocol] specifies a Network
Map, which defines groupings of endpoints in a network region (called
a PID) as seen by the ALTO server. The Endpoint Cost Service and the
Endpoint (EP) Ranking Service then provide rankings for connections
between the specified network regions and thus incentives for
application clients to connect to ISP preferred endpoints, e.g. to
reduce costs imposed to the network provider. Thereby ALTO
intentionally avoids the provisioning of realtime information (cmp.
ALTO Problem Statement [RFC5693] and ALTO Requirements [RFC5693]), as
"Such information is better suited to be transferred through an in-
band technique at the transport layer instead". Thus the current
Cost Map and Endpoint Cost Service are providing, for a given Cost
Type, exactly one rating per link between two PIDs or to an Endpoint.
Applications are expected to query one of these two services in order
to retrieve the currently valid cost values. They therefore need to
plan their ALTO information requests according to the estimated
frequency of cost value change. In case these value changes are
predicable over a certain period of time and the application does not
require immediate data transfer, it would save time to get the whole
set of cost values over the period in one ALTO response and using
these values to schedule data transfers would allow to optimise the
network resources usage and QoE.
In this draft we introduce use cases that describe applications that
have a degree of freedom on scheduling data transfers over a period
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of time, thus they do not need to start a transfer instantaneously on
a retrieved request. For this kind of applications we propose to
extend the Cost Map and Endpoint Cost Services by adding a schedule
on the cost values, allowing applications to time-shift data
transfers.
In addition to this functional ALTO enhancement, we expect to further
gain by gathering multiple Cost Values for one cost type as firstly
one Cost Map reporting on N Cost Values is less bulky than N Cost
Maps containing one Cost value each and secondly, this reduces N ALTO
transactions to a single one. This is valuable for both the storage
of these ALTO maps and their transfer. Similar gains can be obtained
for the ALTO Endpoint Cost Service.
The remainder of this draft first provides use cases that motivate
the need for a 'schedule' cost mode. It then specifies the needed
extensions to the ALTO protocol and details some example messages.
Note that the example ALTO transactions are provided with the ALTO
syntax as specified in previous ALTO protocol draft versions, see
[ID-alto-protocol-13]. The syntax will be updated when the base ALTO
protocol will be finalized.
2. Use cases for ALTO Cost Schedule
This section introduces use cases showing the benefits of providing
ALTO Cost values in 'schedule' mode. Most likely, the ALTO Cost
Schedule would be used for the Endpoint Cost Service where a limited
set of feasible non real time application Endpoints is already
identified, they need to be accessed neither simultaneously nor
immediately and their access can be scheduled within a given time
period. The Filtered Cost Map service is also applicable as long as
the size of the Map is manageable. An ALTO Cost schedule can be used
in several ways:
o the ALTO Server may provide values on past time periods that can
be interpreted as historical experience and used to anticipate
future cost values in order to schedule transfers of application
data or services,
o the ALTO Server may provide stationary values on present or future
time periods that can be interpreted as predictions on cost values
and used to schedule transfers of application data or services,
o the ALTO Server may provide stationary values on time periods
covering the past, present and future and logically be all
interpreted as predictions and used to schedule transfers of
application data or services.
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2.1. Bulk Data Transfer scheduling
Some CDNs are prepopulating caches with content before it actually
gets available for the user and thus there is a degree of freedom on
when the content is transmitted from the origin server to the caching
node. Other applications like Facebook or YouTube rely on data
replication across multiple sites for several reasons, such as
offloading the core network or increasing user experience through
short latency. Typically the usage pattern of these data centers or
caches follows a location dependent diurnal pattern.
In the examples above, data needs to be replicated across the various
locations of a CDN provider, leading to bulk data transfers between
datacenters. Scheduling these data transfers is a non-trivial task
as the transfer should not infer with the user peak demand to avoid
degradation of user experience and to decrease billing costs for the
datacenter operator by leveraging off-peak hours for the transfer.
This peak demand typically follows a diurnal pattern according to the
geographic region of the datacenter. One precondition to schedule
transfers however is to have a good knowledge about the demand and
link utilization patterns between the different datacenters and
networks.
While this usage data today already is gathered and also used for the
scheduling of data transfer, provisioning this data gets increasingly
complex with the number of CDN nodes and in particular the number of
datacenter operators that are involved. For example, privacy
concerns prevent that this kind of data is shared across
administrative domains. The ALTO Cost Schedule specified later in
this document avoids this problem by presenting an abstracted view of
time sensitive utilization maps through a dedicated ALTO service to
allow CDN operators a mutual scheduling of such data transfers across
administrative domains.
2.2. Endsystems with limited connectivity or access to datacenters
Another use case that benefits from the availability of multi-
timeframe cost information is based on applications that are limited
by their connectivity either in time or resources or both. For
example applications running on devices in remote locations or in
developing countries that need to synchronize their state with a data
center periodically, in particular if sometimes there is no
connection at all. Example applications is enterprise database
update, remote learning, remote computation distributed on several
data center endpoints.
Wireless connectivity has a variable quality or may even be
intermittent. On the other hand, the connectivity conditions are
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often predicable. For non real time applications, it is thus
desirable to provide ALTO clients with routing costs to connection
nodes (i.e. Application Endpoints) over different time periods.
This would allow end systems using ALTO aware application clients to
schedule their connections to application endpoints.
Another challenge arises with end systems using resources located in
datacenters and trading content and resources scattered around the
world. For non-real time applications, the interaction with
Endpoints can be scheduled at the time slots corresponding to the
best possible QoE. For instance, resource Ra downloaded from
Endpoint EPa at time t1, Resource Rb uploaded to EPb at time t2, some
batch computation involving Ra and Rb done on EPc at time t3 and
results R(A,B) downloaded to EPd and EPe at time t4. Example
applications are similar to the ones cited in the previous paragraph.
+-----+ +-----+
| EPa | | EPb | <----- Rb
+-----+ +-----+ (t2=50)
| +-------+ |
Ra --------------> | EPc | |
(time t1=10) | | |
|t3=100 | <----------------- Rb
+-------+
| \
| \
R(Ra,Rb)
(t4=200)
| \
| -------------------.
V V
+-----+ +-----+
| EPd | | EPe |
+-----+ +-----+
These examples describe situations where a client has the choice of
trading content or resources with several Endpoints and needs to
decide with which Endpoint it will trade and at what time. For
instance, one may assume that the Endpoints are spread over different
time-zones, or have intermittent access. The ALTO Schedule mode
specified below allows these clients to retrieve Endpoint cost maps
valid for a certain timeframe (e.g. 24 hours), and get a set of
values, each applicable on a (e.g. hourly) slot. Thus the
application can optimize the needed data transfer according to this
information.
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Last, the ALTO Cost schedule is beneficial to optimizing ALTO
transactions themselves. Indeed, let us assume that an Application
Client is located in an end sytem with limited resources and/or has
an access to the network that is either intermittent or provides an
acceptable QoE in limited but predictable time periods. In that
case, it needs to both schedule its resources demanding networking
activities and its ALTO requests. Instead of having to figure out
when the cost values may change and having to carefully schedule
multiple ALTO requests, it could aviod this by relying on Cost
Shedule attributes that indicate the time granularity, the validity
and time scope of the cost information, together with the time
related cost values themselves.
Suppose that for some Cost Types, the ALTO cost values are available
in the "schedule" mode. If the values of Cost type 'routingcost' and
/or another time-sensitive Cost Type named for example
'pathoccupationcost' are available in the "schedule" mode for the 24
hours following the last update, the ALTO Client embedded in the
Application Client may query ALTO information on 'routingcost' or
'pathoccupationcost' for these 24 hours, and get a set of values,
each applicable to an hour slot. If appropriate Cost Attributes are
provided together with the cost values, the Application client also
knows the date of their last update. An example ALTO transaction is
provided later in this draft.
2.3. SDN Controller guided access to application endpoints
The Software Defined Networking (SDN), see [sdnrg], is a model that
attempts to manage and reconfigure networks in a more flexible way in
order to better cope with the traffic challenges posed by nowadays
resources greedy applications. To this end, one option is "moving
the control plane out of the network elements into "controllers", see
[SDN charter, http://www.1-4-5.net/~dmm/sdnrg/sdnrg.html], that
implements the network control and management. The SDN Controllers
are deemed to gather the network state information and provide it in
an abstracted form to SDN aware applications while gathering their
requirements in QoE and exchanging other application "management"
information and commands.
The relevance of ALTO to perform a number of SDN functions has been
recently highlighted. An ALTO Server can assist an SDN Controller by
hosting abstracted network information that can be provided to SDN
aware applications via an ALTO Client. It can also assist other SDN
Control operations using information in and outside the ALTO scope.
In particular, [article-gslh-alto-sdn] identifies SDN Controller
functions that ALTO is well suited to perform: the primitives of
Abstraction, Get network topology, Get network resources and Event
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notification. Additonally, the interaction between ALTO and SDN has
been investigated in [draft-xie-alto-sdn] to provide applications
with a path selection meeting QoS requirements on bandwidth and
delay.
Currently, the base ALTO protocol allows to perform the following SDN
services, see [article-gslh-alto-sdn]:
1. Abstraction: through aggregation into PIDs, ranking and a generic
cost type.
2. Get network topology: through the Map and the Cost Map Services
3. Get device capabilities: through the Endpoint Property Service.
Another SDN primitive "Get network resources" provides applications
with informations allowing them to evaluate the expected QoE. QoE
related information includes delay and bandwidth at the application
endpoints as well as on the network paths. Such information may be
provided via the ALTO Service by proposed extensions of the ALTO
protocol that define new ALTO Cost Types allowing to abstract and
report QoE to applications.
One key objective of an SDN controller is the ability to balance the
application traffic whenever possible. For non real time
applications, data and resources transfer can be time shifted,
resources availability may often be predicable and last, strong
incentives for applications to time shift their traffic may be given
by network operators appropriately setting routing cost values at
different time values, according to their policy to cope with network
occupation over time.
To achieve this objective, the SDN controller can:
1. get the network state history from its controlled network
elements through its southbound API
2. possibly derive an estimation or a prediction of these values
over given time frames
3. store their abstraction in an ALTO Server in the form of ALTO
Cost Schedule values defined for different time periods
4. deliver these values to the SDN applications via the ALTO
Endpoint Cost Service, either as history or prediction or as
estimations covering both the past and the future.
This way:
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o One one hand, the applications get the best possible QoE, as they
can pick the best time for them to access one or more Endpoints,
o One the other hand the SDN controller achieves load balancing as
it may guide the application traffic so as to better distribute
the traffic over time, and thus optimize its resources usage.
2.4. Large flow scheduling on extended ALTO topologies
[draft-yang-alto-topology-00] presents initial thinking on extending
ALTO for topology exposure services, that would provide flexible
abstractions based on the raw network topology. Among other
features, an ALTO topology may expose several paths between a source
(src) and destination (dst), or topology details may be provided on
restricted parts. This work was presented to the ALTO WG at IETF88.
The presentation slides [slides-88-alto-5-topology] on
[draft-yang-alto-topology-00] expose a use case entitled "Large Flow
Scheduling". This case includes a "daylife example" where a Google
Map service proposes multiple routes between 2 points A and B, each
calculated w.r.t. length and estimated time. For each of these
selected paths, the map service exposes a time-sensitive qualitative
value taking 4 values between Slow and Fast. A user of this
application may thus organize its transfer w.r.t. metrics, paths and
time, provided s/he does not have to commute immediately.
The use case on Large flow scheduling on extended ALTO topologies in
the present section illustrates one modality of ALTO topology
service, that would expose several paths between end to end (src,
dst) pairs, computed w.r.t. one of more metrics, possibly under given
constraints. On top of this enriched topology service, non real-time
applications may also choose the time of data/resources transfer,
taking thus advantage of a richer set of decision variables.
The use case "Large Flow Scheduling" of presentation
[slides-88-alto-5-topology]can thus be adapted as follows:
o Step1 - obtain the set T transfer tasks {(src, dest, data)}
o Step2 - identify one or more paths for each (src, dst): several
information sources exist among which:
* (a) ALTO CostMap with a "path" metric, // not specified here
* (b) an ALTO Topology Service providing a path computation hint
(e.g. w.r.t. routingcost and/or other metrics)
o Step 3- while T not empty:
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* 1 - query for example values for some metric 'available
bandwidth' on paths:
+ to this end, query the values in the ALTO 'schedule' Mode:
on the selected (src, dst) for a set of time intervals.
With this mode, the ALTO client will receive an array of
values, each applicable to a time slot .
* 2 - schedule data transfer at the time slots corresponding to
the preferred value.
2.5. Providing values for time-sensitve TE metrics
Draft [draft-wu-alto-te-metrics-01], proposes to extend the set of
ALTO metrics with traffic engineering (TE) metrics, in order to
closely meet applications requirementsand under appropriate trust
agreements. This draft exposes a number of TE metrics that are time-
sensitive, either by nature such as bandwidth and delay related
metrics, or due to "normally" changing network conditions or both.
The draft assumes that the values of ALTO TE metrics are typically
collected from routing protocols and provided in a non-real time
manner. In "normally" changing network conditions TE metric values
remain uniformly distributed over given time intervals and can be
aggregated over bigger sample intervals of periodic patterns. For
instance an ALTO Server may collect values from a routing protocol
produced by measurements done every second over a period of 30
seconds. The ALTO Server may then aggregate these values over ALTO
Sample intervals of 60 seconds and every hour, provide the values in
'schedule' mode endcoded as an array of 60 values.
All time sensitive ALTO TE metrics are potentially applicable to a
cost schedule. The real applicability actually depend on the network
topology and structure. A small topology with low density and
capacity that carries inpredictable heavy and bursty traffic has few
chances to exhibit stationary TE metric value patterns over large
periods and would benefit to use the ALTO Schedule over smaller time
slots.
3. ALTO Cost Schedule extension
One example of non-real time information that can be provisioned in a
'schedule' is the expected path bandwidth. While the transmission
rate can be measured in real time by end systems, the operator of a
data center is in the position of formulating preferences for given
paths, at given time periods of given time scales, for example to
avoid hotspots due to diurnal usage patterns. The entity managing
the ALTO Server values can decide to integrate path bandwidth in the
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ALTO 'routingcost' metric. However to better highlight the purpose
of the cost schedule the remainder of this document will use a Cost
Type named 'pathoccupationcost' and assumed to report an abstracted
form of available bandwidth. A definition and usage of such a Cost-
Type is proposed in [draft-randriamasy-multi-cost-alto].
The usage of a time related cost is rather proactive in that it can
be used like a "time table" to figure out the best time to schedule
data transfer and also anticipate predictable events including
predictable flash crowds. An ALTO Cost Schedule should be viewed as
a synthetic abstraction of real measurements that can be historic or
be a prediction for upcoming time periods.
3.1. Cost Schedule Attributes
Specifications on the cost "schedule" are proposed here and will be
completed in further versions of this draft.
3.1.1. ALTO Cost-Mode: Schedule
The "schedule" mode applies to Costs that are eligible for a single-
valued Cost Mode and can also be expressed as such. In that sense,
when the "numerical" mode is available for a Cost-Type, the cost
expressed in the "schedule" mode is an extension of its expression
from one value in the "numerical" mode to an array of several values
varying over time.
Types of Cost values such as JSONBool can also be expressed in the
"schedule" mode, as states may be "true" or "false" depending on
given time periods. It may be expressed as a single value which is
either "true" or "false" following a decision rule outside the ALTO
protocol.
3.2. ALTO Capability: Cost-Scope
To ensure that the application client uses the NP provided
information in the cost schedule in an unambiguous way we define the
Cost Scope capability, which defines the validity of the "scheduled"
cost values.
For Cost Types whose values are provided in a mode different than
'schedule', the Cost Scope capability is specified by the string
"permanent". The Cost Scope attributes provided for the 'schedule'
mode are listed below. The reference time zone for the provided
values is UTC.
o Unit: expresses the time interval applicable to each value. A two
element array where the first element is the time unit, ranging
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from "second" to "year", and the second one the number of units of
this duration. For example: '["minute", 5]' means that each value
is provided on a time interval lasting 5 minutes.
o Size: the number of values of the cost schedule array,
o Begin: the index of the first unit in the array,
o Reference time zone: set to "UTC",
o Next update: the date at which the sample will be re-computed,
o Last update: the last re-computation date.
The reference time zone is UTC.
Attributes 'Last update 'and 'Next update' report on the update
frequency and age of the information.
3.2.1. Example of time scope for a cost schedule
Let us assume that the metric 'pathoccupationcost' (POC for short) is
computed for 24 hours, on time intervals lasting 2 hours, with the
first interval starting at 0h00. The ALTO Server thus provides an
array 12 values. This information is then used to enable
applications to see which time intervals in a day are the most
favorable to operate, and which "busy " time intervals should be
avoided. If the "Begin" date is past, the application can also use
the information to compute statistics or infer a some customized
prediction.
3.3. Example of scheduled information resources in the IRD
The example IRD given in this Section includes 2 particular URIs:
o "http://alto.example.com/endpointcost/lookup", in which the ALTO
Server offers several Endpoint Cost Types, including a Cost called
"pathoccupationcost" for which the "schedule" Cost Mode is
available. The Endpoint Costs available are the "hopcount",
"routingcost" and "pathoccupationcost" Cost Types, with the two
first ones in the "numerical" Cost Mode and "pathoccupationcost"
in the "schedule" Cost Mode.
o "http://custom.alto.example.com/endpointcost/schedule/lookup", in
which the ALTO Server provides the 'routingcost' in both
"numerical" and "schedule" modes. This resource is accessible via
a separate subdomain called "custom.alto.example.com". The ALTO
Client may either get the last update of the 'routingcost' value
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or request for a previsonal sample of 24 values established each
for 1 hour. An ALTO Client can discover the services available at
"custom.alto.example.com" by successfully performing an OPTIONS
request to "http://custom.alto.example.com/endpointcost".
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GET /directory HTTP/1.1
Host: alto.example.com
Accept: application/alto-directory+json,application/alto-error+json
HTTP/1.1 200 OK
Content-Length: [TODO]
Content-Type: application/alto-directory+json
{
... usual ALTO resources ...
"resources" : [
{
"uri" : "http://alto.example.com/endpointcost/lookup",
"media-types" : [ "application/alto-endpointcost+json" ],
"accepts" : [ "application/alto-endpointcostparams+json" ],
"capabilities" : {
"cost-constraints" : true,
"cost-modes" : [ "numerical", "numerical", "schedule" ],
"cost-types" : [ "routingcost", "hopcount", "pathoccupationcost" ],
"cost-scope": [ "permanent", "permanent",
{"unit": ["hour", 1], "size": 24, "begin": 0,
"time zone": "UTC",
"lastupdate": mm/hh/dd/mm/yyyy,
"nextupdate": mm/hh/dd/mm/yyyy}
]
},
{
"uri" : "http://custom.alto.example.com/endpointcost/schedule/lookup",
"media-types" : [ "application/alto-endpointcost+json" ],
"accepts" : [ "application/alto-endpointcostparams+json" ],
"capabilities" : {
"cost-constraints" : true,
"cost-modes" : [ "numerical", "schedule" ],
"cost-types" : [ "routingcost", "routingcost" ],
"cost-scope": [ "permanent",
{"unit": ["hour", 1], "size": 24, "begin": 0,
"time zone": "UTC",
"lastupdate": mm/hh/dd/mm/yyyy,
"nextupdate": mm/hh/dd/mm/yyyy}
]
}
}
]
}
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3.3.1. Example scenario and ALTO transaction with a Cost Schedule
Let us assume an Application Client located in an end sytem with
limited resources and having an access to the network that is either
intermittent or provides an acceptable quality in limited but
possibly predictable time periods. Therefore, it needs to both
schedule its resources demanding networking activities and minimize
its ALTO transactions.
The Application Client has the choice to trade content or resources
with a set of Endpoints of moderate 'routingcost', and needs to
decide with which Endpoint it will trade at what time. For instance,
one may assume that the Endpoints are spread on different time-zones,
or have intermittent access. In this example, the 'routingcost' is
assumed constant for the scheduling period and the time sentitive
decision metric is the path bandwidth reflected by a Cost type called
'pathoccupationcost'.
The ALTO Client embedded in the Application Client queries ALTO
information on 'pathoccupationcost' for the 24 hours following
(implicitely) the date of "lastupdate", as this resource is listed in
the IRD.
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POST /endpointcost/lookup HTTP/1.1
Host: alto.example.com
Content-Length: [TODO]
Content-Type: application/alto-endpointcostparams+json
Accept: application/alto-endpointcost+json,application/alto-error+json
{
"cost-type" : ["pathoccupationcost"],
"cost-mode" : ["schedule"],
"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: [TODO]
Content-Type: application/alto-endpointcost+json
{
"meta" : {},
"data" : {
"cost-type" : ["pathoccupationcost"],
"cost-mode" : ["schedule"],
"map" : {
"ipv4:192.0.2.2": {
"ipv4:192.0.2.89" : [7, ... 24 values],
"ipv4:198.51.100.34" : [4, ... 24 values],
"ipv4:203.0.113.45" : [2, ... 24 values]
}
}
}
}
4. IANA Considerations
Information for the ALTO Endpoint property registry maintained by the
IANA and related to the new Endpoints supported by the acting ALTO
server. These definitions will be formulated according to the syntax
defined in Section on "ALTO Endpoint Property Registry" of
[ID-alto-protocol],
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Information for the ALTO Cost Type Registry maintained by the IANA
and related to the new Cost Types supported by the acting ALTO
server. These definitions will be formulated according to the syntax
defined in Section on "ALTO Cost Type Registry" of
[ID-alto-protocol],
4.1. Information for IANA on proposed Cost Types
When a new ALTO Cost Type is defined, accepted by the ALTO working
group and requests for IANA registration MUST include the following
information, detailed in Section 11.2: Identifier, Intended
Semantics, Security Considerations.
4.2. Information for IANA on proposed Endpoint Propeeries
Likewise, an ALTO Endpoint Property Registry could serve the same
purposes as the ALTO Cost Type registry. Application to IANA
registration for Endpoint Properties would follow a similar process.
5. Acknowledgements
Thank you to D. Lopez, R. Yang, H. Peng, Q. Wu and the ALTO WG for
fruitful discussions.
6. References
6.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC5693] Seedorf, J. and E. Burger, "Application-Layer Traffic
Optimization (ALTO) Problem Statement", RFC 5693, October
2009.
6.2. Informative References
[ID-alto-protocol-13]
R.Alimi, R. Penno, Y. Yang, Eds., "ALTO Protocol, draft-
ietf-alto-protocol-13.txt", September 2012.
[ID-alto-protocol]
R.Alimi, R. Penno, Y. Yang, Eds., "ALTO Protocol, draft-
ietf-alto-protocol-25.txt", January 2014.
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[article-gslh-alto-sdn]
V. Gurbani, M. Scharf, T.Lakshman, and V. Hilt, ,
"Abstracting network state in Software Defined Networks
(SDN) for rendezvous services, IEEE International
Conference on Communications (ICC) Workshop on Software
Defined Networks (SDN)", June 2012.
[draft-jenkins-alto-cdn-use-cases-01]
B. Niven-Jenkins (Ed.), G. Watson, N. Bitar, J. Medved, S.
Previdi, , "Use Cases for ALTO within CDNs, draft-jenkins-
alto-cdn-use-cases-01", June 2011.
[draft-randriamasy-multi-cost-alto]
S. Randriamasy, Ed., B. Roome, N. Schwan, , "Multi-Cost
ALTO, draft-randriamasy-alto-multi-cost-07", October 2012.
[draft-wu-alto-te-metrics-01]
Q. Wu, Y. Yang, Y. Lee, D. Dhody, S. Randriamasy, , "ALTO
Traffic Engineering Cost Metrics (work in progress)",
February 2014.
[draft-xie-alto-sdn]
H. Xie, T. Tsou, D. Lopez, H. Yin, , "Use Cases for ALTO
with Software Defined Networks, draft-xie-alto-sdn-
extension-use-cases-00", June 2012.
[draft-yang-alto-topology-00]
Y. Yang, , "ALTO Topology Considerations (work in
progress)", July 2013.
[sdnrg] "Software Defined Network Research Group,
http://trac.tools.ietf.org/group/irtf/trac/wiki/sdnrg", .
[slides-88-alto-5-topology]
G. Bernstein, Y. Lee, Y. Yang, , , "ALTO Topology Service:
Use Cases, Requirements and Framework (presentation slides
IETF88 ALTO WG session), http://tools.ietf.org/agenda/88/
slides/slides-88-alto-5.pdf", November 2013.
Authors' Addresses
Sabine Randriamasy (editor)
Alcatel-Lucent Bell Labs
Route de Villejust
NOZAY 91460
FRANCE
Email: Sabine.Randriamasy@alcatel-lucent.com
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Nico Schwan
Email: ietf@nico-schwan.de
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