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ALTO Working Group                                            Young Lee
                                                            Dhruv Dhody
                                                                 Qin Wu
Internet Draft                                                   Huawei
Intended status: standard                                Greg Bernstein
                                                      Grotto Networking
                                                          Tae Sang Choi
                                                                   ETRI







                                                       October 21, 2013

        ALTO Extensions to Support Application and Network Resource
    Information Exchange for High Bandwidth Applications in TE networks


                draft-lee-alto-app-net-info-exchange-04.txt


Status of this Memo

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   the provisions of BCP 78 and BCP 79.

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   This Internet-Draft will expire on April 21, 2014.

Copyright Notice



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Internet-Draft Application and Network Information Exchange October 2013


   Copyright (c) 2013 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.

Abstract

This draft proposes ALTO information model and protocol extensions to
support application and network resource information exchange for high
bandwidth applications in partially controlled and controlled
environments as part of the infrastructure to application information
exposure (i2aex) initiative.



Table of Contents

    1. Introduction..................................................3
   2. Problem Statement..............................................5
   3. ALTO Constraints Filtering Extension Model.....................8
      3.1. ALTO Query from Application Stratum to Network Stratum....8
      3.2. ALTO Response from Network Stratum to Application Stratum10
      3.3. Information Model of ALTO Query from Application Stratum to
      Network Stratum...............................................10
      3.4. Information Model of ALTO Response from Network Stratum to
      Application Stratum...........................................11
      3.5. ALTO Protocol Extension for Constraints Filtering Mechanism
      ..............................................................11
      3.6. Multiple Service Class...................................13
         3.6.1. Gold Service........................................13
         3.6.2. Silver Service......................................15
         3.6.3. Bronze Service......................................17
   4. ALTO Protocol Extension for Graph Representation Mechanism....19
   5. Summary and Conclusion........................................19
   6. Security Considerations.......................................19
   7. IANA Considerations...........................................19
   8. References....................................................19
      8.1. Informative References...................................19
   Author's Addresses...............................................21
   Intellectual Property Statement..................................21
   Disclaimer of Validity...........................................22



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1. Introduction

   This draft proposes ALTO information model and protocol extensions
   to support application and network resource information exchange for
   high bandwidth applications in partially controlled and controlled
   environments as part of the infrastructure to application
   information exposure (i2aex) initiative. The Controlled and
   partially controlled ALTO environments referred to here are those
   where general access to a specific ALTO server may be restricted to
   a qualified list of clients.

   This draft is build upon the previously introduced High Bandwidth
   Use Cases [HighBW] and assumes that the network type carrying high
   bandwidth is a Traffic-Engineered (TE) network. In [HighBW], we have
   discussed two generic use cases that motivate the usefulness of
   general interfaces for cross stratum optimization in the network
   core. In our first use case, network resource usage became
   significant due to the aggregation of many individually unique
   client demands. In the second use case where data centers are
   sending large amount of data with each other, bandwidth usage was
   already significant enough to warrant the use of traffic engineered
   "express lanes" (e.g., private line service). We introduce third use
   case where inter-CDN providers may want to expose controlled network
   resource usage information so that CDN applications (e.g., request
   routing server) can utilize such information when appropriate
   decisions (e.g., request routing redirection) are needed.

   These use cases result in optimization problems that trade off
   computational versus network costs and constraints. Both featured
   use cases show the usefulness of an ALTO interface between the
   application and network strata in optimizing the networked
   applications.

   In particular, this draft introduces: (i) enhanced constraints
   filtering extensions to the ALTO protocol to reduce extraneous
   information transfer and enhance information hiding from the
   network's perspective; (ii) constrained cost graph mechanism
   encoding that enables enhanced application traffic optimization that
   was introduced by [HighBW].

   In controlled and partially controlled environments in which
   operators are willing to share additional network stratum resource
   information such as bandwidth constraints or additional cost types
   of topology (e.g., graph or summary), it can be useful to reduce the
   amount of information transferred from the ALTO server to the ALTO
   client.


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   In considering information exchange between the application stratum
   and the network stratum, especially from the network stratum to the
   application stratum, the degree of information details is one of the
   key concerns from the network providers' standpoint. On the one
   hand, the network information has to be useful to the application;
   on the other hand, the provided network information should hide
   details about the network. In order to achieve these desired goals,
   a simple enhancement to ALTO protocol would help significantly both
   in reducing/filtering the amount of information and in increasing
   the usefulness of the information from network to application.

   Figure 1 shows ALTO Client-Server Architecture for Application-
   Network information Exchange. Figure 1 shows that ALTO Client in the
   application stratum can interface with ALTO Server in the network
   stratum. With this architecture, a simple ALTO query mechanism from
   application (via ALTO client) to network (via ALTO server) can be
   implemented. According to this architecture, ALTO Client is assumed
   to interact with the Application Orchestrator that has the knowledge
   of the end-user (i.e., source) application requirement, Data Center
   locations (i.e., destinations) and their resource information.



                             +--------------+
           Resource Request  | Application  |
                -----------> | Orchestrator |
                             +--------------+
                             |  ALTO Client |
                             +--------------+
                                |       /|\
                   ALTO Query   |        |  ALTO Response
                                |        |
                                |        |
                                |        |
                               \|/       |
                             +--------------+
                             |  ALTO Server |
                             +--------------+
                             |   Network    |
                             | Orchestrator |
                             +--------------+


     Figure 1 ALTO Client-Server Architecture for Application-Network
                           information Exchange


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   The Application Orchestration functions depicted in Figure 1
   interfacing data centers and end-users are out of the scope of this
   document. For simplicity purpose, Figure 1 doesn't depict the
   detailed relationship between ALTO client and server.  In fact, both
   client and server don't need to be in the same administration
   boundary.  It can be inter-operator and one to many relationships.
   For example, in the cases of inter-CDN environment or generic multi-
   domain environment, ALTO client represents a request routing server
   of upstream CDN operator and it interacts with multiple downstream
   CDN operators for their network resource information to make
   efficient decisions for desired quality CDN services.  Interaction
   methods can either iterative or recursive.  That is, ALTO client can
   interact with multiple ALTO servers directly or ALTO client can
   interact with one representative ALTO server and subsequent
   interaction is done by the representative one to rest of ALTO
   servers.

   The organization of this document is as follows. Section 2 discusses
   the ALTO architecture in the context of the application and network
   strata interaction. Section 3 provides ALTO Information model and
   protocol extension to support ALTO Constraints Filtering Mechanism.
   Section 4 provides ALTO information model and the protocol extension
   to support ALTO Constrained Cost Graph Mechanism.

2. Problem Statement

   One critical issue in Application-Network information exchange in
   ALTO is the amount of information exchanged between the application
   and network strata. The information provided by network providers
   can be not so useful to the application stratum unless such
   information is abstracted into an appropriate level the that
   application stratum can understand.

   In partially controlled and controlled environments, network
   providers can furnish appropriately abstracted and pruned
   information to the application stratum with the cooperation of the
   application stratum that can indicate some level of filtering and
   pruning in its query.

   To reduce extraneous information this draft allows for "filtering"
   (or "pruning") of the following information in query/response of the
   ALTO pull model:

      . Topology Filtering - reduction of the results to only those
         specified set of source(s) and destination(s) instead of the
         entire network cost map. Note that this mechanism is not new
         in the current ALTO protocol. In the context of application-
         network information exchange, this topology filtering can be


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         of a tremendous help in reducing the amount of data exchanged
         between application and network.
      . Multiple Service Class: ALTO server may provide multiple class
         of service (Gold, Silver, or Bronze) and allow application to
         request them accordingly.
      . Multiple Cost: Alto server should be able to provide multiple
         cost for a end to end path or abstract links in the graph.
      . Optimization Criteria: The optimization criteria that the ALTO
         server may use. For example, the criteria can be least number
         of hops, least amount of delay (latency), etc.
      . Constraint Filtering on paths or graphs (e.g., bandwidth,
         latency, hop count, packet loss, etc.) - reduction of results
         to only those that meet ALTO client specified cost bounds.

   As discussed in [HighBW], in a controlled environment optimization
   is significantly enhanced by sharing data related to bandwidth
   constraints and additional cost measures [MultiCost], [TE-cost].
   Such information may be considered sensitive to the network provider
   just as application data, e.g., usage, demand, etc., may be
   considered sensitive to an application provider. Section 3 provides
   ALTO information model and protocol extensions to support topology,
   multiple service class, constraints filtering mechanism.

   Multiple Service Class (such as gold, silver and bronze services)
   MAY be supported by the ALTO server. These service classes could
   specify how the network is used (for ex exclusively reserved for the
   application, protection provided etc). The Application should
   further provision/reserve the network using some mechanisms which
   are out of scope of this document. Some example of services:  _

     . Gold Service

   This service could be used to specify that an exact path meeting the
   application needs should be found. This path would be provisioned
   and resources reserved exclusively for its use. An example could be
   a private enterprise DC, which wish to offload to a public DC during
   peak load.

     . Silver Service

   This service could be used to get the path properties between User
   regions and DC. It could also specify some basic constraints that
   all of them should satisfy. These paths would be provisioned and
   resources maybe reserved. The Application may further assign end
   user request to a particular DC by using the network information of
   these paths. An example could be a gaming server geographically
   dispersed at multiple DC. The end-user (gamer) could be dynamically



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   assigned to the DC by looking at the past assignment, DC load and
   network properties.

     . Bronze Service

   This service could be used to specify that a simple best effort path
   should be found. This path would not be provisioned and resources
   will not be reserved. The service could still return the network
   information to the application which can use this information for DC
   selection by taking network information into consideration. An
   example could be a HD video service, which may use the network info
   to select video source for the end user.



   While it is important to reduce and filter the information amount
   from network to application, for some applications that require
   stringent QoS objectives (e.g., bandwidth and latency), simple
   summary source-destination network resource information (i.e.,
   summary form of topology) may not provide sufficient details to the
   application stratum. For example, suppose that a multiple number of
   large concurrent flows need to be scheduled from application to
   network. In such a case, a summary form of network topology that
   only shows source-destination bandwidth availability may not show
   the bottleneck links over which more than one flow may compete for
   the link bandwidth resource. This problem was indicated by [HighBW].
   The following are the excerpts from [HighBW].

   Consider the network shown in Figure 2, where DC indicates a
   datacenter, ER an end user region (as in the end user aggregation
   use case), N a switching node of some sort, and L a link. The link
   capacities and costs are also shown on the figure as well as a cost
   map between [ER1, ER2] and [DC1, DC2, DC3]. Since the network has a
   tree structure (very unusual but easier to draw in ASCII art), the
   cost map is unique.

   As an illustration, assume that the maximum available capacity
   between any individual end region and a data center is 5 units(i.e.,
   L1=L2=L5=L6=5). However, link L3 (capacity 8 units) represents a
   bottle neck to all the data centers (L3 is on all the paths to DC1,
   DC2, or DC3 from all end regions, ER1 and ER2).

   ALTO Cost Map is shown in the lower right corner of Figure 2. This
   summary cost map does not provide enough details on the bottle
   necks. The lower left corner shows Link Capacity Cost, from which
   the bottle necks can be shown such that multi-flow commodity
   scheduling can be made possible to avoid such bottle necks.



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    ,---.    L1                                  +----+
   ( ER1 )`-.                              L5  .'|DC1 |
    `---'    `-._ ,-.                         /  +----+
                 ( N1)    L3             ,-..'
               .-'`-' `-.__         L4--(N3 )
    ,---.    .'          `-.  ,-..--''   `-'`.   +----+
   ( ER2 ).-'L2              (N2 )         L6 `-.|DC2 |
    `---'                     `-'`-._            +----+
                                     `-.
           Link Capacity Cost            `-._L7
           L1    5                         `-.
           L2    5                            `-._
           L3    8                               `-.
           L4    6           ALTO Cost Map          `-.+----+
           L5    5           DC1  DC2  DC3 _           |DC3 |
           L6    5       ER1  5    5    8              +----+
           L7    10      ER2  6    6    9

               Figure 2. Example network illustrating bottlenecks



   With the current ALTO cost map structure, the least cost path from
   ER1 would be either to DC1 or DC2. However, with the proposed
   capacitated cost map, the connection from ER1 to DC3 could be a
   better choice than the rest depending on the relative cost of
   network resources to data center resources.

   A more general and relatively efficient alternative is to provide
   the requestor with a capacitated and multiply weighted graph that
   approximates and abstracts the capabilities of the network as seen
   by the source and destination location sets. This document provides
   ALTO information model and protocol extensions to support the graph
   model in Section 4.



3. ALTO Constraints Filtering Extension Model

3.1. ALTO Query from Application Stratum to Network Stratum

   In order for the network stratum to provide its resource
   information, the application stratum needs to provide the End Point
   Cost Map to the network stratum. The End Point Cost Map should
   include the following information at a minimum:




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     . End Point Source Address(es) /* these are the respective
        addresses of the nearest PE's to the user/client location */

     . End Point Destination Address(es) /* these are the respective
        addresses of the nearest PE's to a set of the candidate Data
        Center locations that can provide service to the user request.
        */

   Note that how ALTO client derives the End Point Source/Destination
   addresses in terms of the nearest PE's is beyond the scope of this
   document.

     . Service-Class:= {gold, silver, bronze} /*the service class as
        described in this document*/

     . Cost Type:= 'routingcost' as defined by base specification.
        Additional cost (ex. latency, hopcount) are defined in
        [MultiCost] and [TE-cost].

     . Cost Mode :={summary, graph} /* the cost map can be either a
        summary form or a graph form */

          o Cost Mode: summary

             This cost mode is indicated by string 'summary'. This mode
             indicates that the returned costs contain end-to-end
             values which can be used by application stratum for better
             selection of resources.

          o Cost Mode: gragh

             This cost mode is indicated by string 'gragh' in which
             case an abstract topology is returned to the application.

     . Constraints /* a set of constraints that apply to the requested
        path summary or graph for filtering. For instance, constraints
        can be like bandwidth greater than 'x', latency less than 'y',
        hopcount less than 'z', packetloss less than 'a' etc. */

     . Objective-function (or Optimization Criteria): The summary or
        the graph should be computed based on optimizing which
        parameter - IGP cost, latency, residual bandwidth, etc. This is
        for future use.







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3.2. ALTO Response from Network Stratum to Application Stratum

   In response to the ALTO Query from the Application Stratum, the
   Network Stratum needs to provide the filtered Cost Map Data of the
   feasible path found. The Filtered End Cost Map Data should include
   the following information at a minimum:

     . The list of feasible Source-Destination pair and its Cost Type

     . For each feasible S-D pair, indicate the following as specified
        in Section 3.4:

          o Service Class;

          o Cost Mode;

          o Cost Type;

          o Endpoint Cost Map Data

     . Parameter Values /* indicate the actual values of each
        constraint requested */

   Note that in case of Graph, each S-D pair is the source of the
   abstract link and the destination of the abstract link.



3.3. Information Model of ALTO Query from Application Stratum to
   Network Stratum

   Alto query:

   Object{
     TypedEndpointAddr   Src<1...*>; /*atleast one source*/
     TypedEndpointAddr   Dsts<2...*>; /*atleast two destinations*/
   }EndpointList;

   Object{
     ServiceClass      service-class;
     CostMode         cost-mode;
     CostType           cost-type;
     [JSONString        constraints<0...*>; ]
     [JSONString        ObjectiveFunction]
     EndpointList      endpoints;
   }EndpointCostMapReq;


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3.4. Information Model of ALTO Response from Network Stratum to
   Application Stratum



   Alto response:

   Object-map{
       JSONString        costparam;
   } EndpointCostParam ;

   Object-map{
    TypedEndpointAddr -> EndpointCostParam<1...*>;
   } EndpointCosts ;

   Object-map{
    TypedEndpointAddr -> EndpointCosts;
   } EndpointCostMapData ;

   Object{
        ServiceClass              service-class;
        CostMode                  cost-mode;
        CostType                     cost-type;
       [EndpointCostMapData      map;]
   }EndpointCostMapRsp;



   The Alto response consist of map (EndpointCostMapData) which is map
   containing the S-D pairs information. For each destination, its
   parameters (rank, cost etc) is included using EndpointCostParam.





3.5. ALTO Protocol Extension for Constraints Filtering Mechanism

   This section provides the ALTO protocol extensions based on the
   information model discussed in Sections 3.3. and 3.4. The scenario
   provided in this section is that the ALTO client in the Application
   Stratum requests the summary cost map from the network with one
   source and three destinations.



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   In this particular example, the ALTO client requests the filtered
   summary of the network path subject to:  bandwidth >= 20, latency <
   10, hop count < 5 and packet loss < 0.03.

   The ALTO server provides the resulted network paths in summary.

   POST /endpointcost/lookup HTTP/1.1
     Host: alto.example.com
     Content-Length: [TODO]
     Content-Type: application/alto-csoendpointcostparams+json
     Accept: application/alto-csoendpointsummary+json,application/alto-
   error+json
     {
       "service-class" : "silver",
       "cost-mode" : "summary",
       "cost-type" : "routingcost",
       "constraints": ["availbw gt 20", "delay lt 10", "hopcount lt 5",
   "pktloss lt 0.03"],
       "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-csoendpointsummary+json
     {
       "meta" : {},
       "data" : {
         "service-class" : "silver",
         "cost-mode" : "summary",
         "cost-type" : "routingcost",
         "map" : {
           "ipv4:192.0.2.2": {
           "ipv4:192.0.2.89"    : [ "delay eq 5",
                            "hopcount eq 8", "pktloss eq 0.01", cost eq
   100" ],
           "ipv4:18.51.100.34"  : [ "delay eq 9",


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                            "hopcount eq 10", "pktloss eq 0.02", cost
   eq 120" ],
           "ipv4:203.0.113.45"  : [ "delay eq 40",
                            "hopcount eq 12", "pktloss eq 0.02", cost
   eq 50" ]
           }
         }
       }
     }
3.6.  Multiple Service Class

   The examples of various class of service is as follows, note that
   these examples are for illustrative purpose only.

3.6.1. Gold Service

   As an example of a Gold service, consider a customer (say an
   Enterprise Private DC) who pays Top-Dollor to setup network based on
   the actual demand. The Path (maybe a TE LSP) would not be used by
   any other customer / application giving guarantee of service and
   best QoE to the application. The ALTO request/response may be used
   first to get the network states and later the path may also be
   provisioned by some mechanism which is out of scope of this
   document.



   In this example, the application may like to find out the ranking of
   the destinations (DC) from the network point of view. It may further
   set the filtering constraints for bandwidth (bw), delay etc. The
   ALTO server first filter the destination that do not meet the
   constraints, further it provides ranking information based on the
   requested costtype.


   Alto Request:
   POST /endpointcost/lookup HTTP/1.1
        Host: alto.example.com
        Content-Length: [TODO]
        Content-Type: application/alto-csoendpointcostparams+json
        Accept: application/alto-
   csoendpointsummary+json,application/alto-
      error+json
        {
          "service-class" : "gold",


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          "cost-mode" : "summary",
          "cost-type" : "routingcost",
          "constraints": ["availbwgt 20", "delay lt 10",
                         "pktloss lt 0.03", "jitter lt 10", "hopcount
   lt 5" ],
          "endpoints" : {
          "srcs": [ "ipv4:192.0.2.2" ],
            "dsts": [
              "ipv4:192.0.2.89",
              "ipv4:198.51.100.34",
              "ipv4:203.0.113.45"
            ]
          }
     }
   ALTO server would factor in the filtering constraints and provide
   only the ranking information to the application.

   Alto Response:


   HTTP/1.1 200 OK
   Content-Length: [TODO]
   Content-Type: application/alto-csoendpointsummary+json
     {
       "meta" : {},
       "data" : {
         "service-class" : "gold",
         "cost-mode" : "summary",
         "cost-type" : "routingcost",
         "map" : {
           "ipv4:192.0.2.2": {
           "ipv4:192.0.2.89"    : [ "rank eq 3" ],
           "ipv4:198.51.100.34"  : [ "rank eq 1" ],
           "ipv4:203.0.113.45"  : [ "rank eq 2" ]
           }
         }
       }
     }
Note that above is just an example, a gold service may also choose to
get detailed end to end information or an abstract graph.





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3.6.2. Silver Service

   As an example of a Silver service, consider a customer (say a Online
   Gaming Company) which will pay flat subscription fees to connect end
   user-regions to the DC hosting the online gaming servers.. In this
   case during the setup phase a flat full mesh of paths are
   established between the User regions and the Data Centers.

   The Application gaming load balancer would handle the gaming end
   user by allocating him to a particular DC (gaming server). The
   reserved resources during admin setup are allocated to multiple end
   user requests.



   In this example, application may want to know the end to end
   properties of the path between the user-regions and the DC. It may
   further set the filtering constraints for bandwidth (bw), delay etc.

   Alto Request:

   POST /endpointcost/lookup HTTP/1.1

     Host: alto.example.com
     Content-Length: [TODO]
     Content-Type: application/alto-csoendpointcostparams+json
     Accept: application/alto-csoendpointsummary+json,application/alto-
   error+json
     {
       "service-class" : "silver",
       "cost-mode" : "summary",
       "cost-type" : "routingcost",
       "constraints": ["availbwgt 20", "delay lt 10",
                         "pktloss lt 0.03", "jitter lt 10", "hopcount
   lt 5" ],

       "endpoints" : {
         "srcs": [
           "ipv4:192.0.2.2",
           "ipv4:192.0.2.10"
         ],
         "dsts": [
           "ipv4:192.0.2.89",
           "ipv4:198.51.100.34",
           "ipv4:203.0.113.45"


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         ]
       }
     }
   ALTO server would factor in the filtering constraints and provide
   the end to end cost parameters to the application.



   Alto Response:
    HTTP/1.1 200 OK
      Content-Length: [TODO]
      Content-Type: application/alto-csoendpointsummary+json
        {
          "meta" : {},
          "data" : {
            "service-class" : "silver",
            "cost-mode" : "summary",
            "cost-type" : "routingcost",
            "map" : {
              "ipv4:192.0.2.2": {
              "ipv4:192.0.2.89"    : [ "delay eq 5", "jitter eq 5",
                               "pktloss eq 0.01", "hopcount eq 8",
   "cost eq 100" ],
              "ipv4:198.51.100.34"  : [ "delay eq 9", "jitter eq 3",
                               "pktloss eq 0.02", "hopcount eq 10",
   "cost eq 500" ],
              "ipv4:203.0.113.45"  : [ "delay eq 4", "jitter eq 4",
                               "pktloss eq 0.02", "hopcount eq 12",
   "cost eq 200" ]
              }

              "ipv4:192.0.2.10": {
              "ipv4:192.0.2.89"    : [ "delay eq 4", "jitter eq 4",
                               "pktloss eq 0.03", "hopcount eq 6",
   "cost eq 300" ],
              "ipv4:203.0.113.45"  : [ "delay eq 6", "jitter eq 6",
                               "pktloss eq 0.04", "hopcount eq 8",
   "cost eq 400"]
              }
            }
          }
        }



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Note that above is just an example, a silver service may also choose to
get an abstract graph in response.

3.6.3. Bronze Service

   As an example of a Bronze service, consider a customer (say a Video
   service) doesnt reserve resources but pays a small fees to get an
   abstract view of the network. Best effort service, use IP best
   effort path(instead of reserved paths used by gold, silver). The
   application (global load balancer) could get the network abstract
   topology and would further handle the end user request by allocating
   them to a particular DC or CDN.



   In this example, application may rely on the basic IP best effort
   but would like to know the abstract topology that could be used by
   the application to find out bottleneck etc. Note that no constraints
   are passed in this example and graph is requested.

   Alto Request:
    POST /endpointcost/lookup HTTP/1.1
        Host: alto.example.com
        Content-Length: [TODO]
        Content-Type: application/alto-csoendpointcostparams+json
        Accept: application/alto-
   csoendpointsummary+json,application/alto-
      error+json
        {
          "service-class" : "bronze",
          "cost-mode" : "graph",
          "cost-type" : "routingcost",
           "endpoints" : {
            "srcs": [
              "ipv4:192.0.2.2",
              "ipv4:192.0.2.10"         ],
            "dsts": [
              "ipv4:192.0.2.89",
              "ipv4:198.51.100.34",
              "ipv4:203.0.113.45"
            ]
          }
        }



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   ALTO server would prepare an abstract network graph based on the
   source(s) and destination(s). The graph may also include some
   internal (maybe abstract) nodes (ex 192.0.2.20 and 192.0.2.30).
   Alto Response:
      HTTP/1.1 200 OK
      Content-Length: [TODO]
      Content-Type: application/alto-csoendpointsummary+json
        {
          "meta" : {},
          "data" : {
            "service-class" : "bronze",
            "cost-mode" : "graph",
            "cost-type" : "routingcost",
            "map": {
              "ipv4:192.0.2.2": {
              "ipv4:192.0.2.20"    : [ "delay eq 9",  "jitter eq 2",
                               "pktloss eq 0.04", "availbw eq 20",
   "cost eq 100" ]
              }

              "ipv4:192.0.2.20": {
              "ipv4:192.0.2.89"    : [ "delay eq 5", "jitter eq 2",
                               "pktloss eq 0.02", "availbw eq 30",
   "cost eq 100" ],
              "ipv4:198.51.100.34"    : [ "delay eq 3", "jitter eq 2",
                               "pktloss eq 0.01", "availbw eq 50",
   "cost eq 400" ]
              }

              "ipv4:192.0.2.10": {
              "ipv4:192.0.2.30"    : [ "delay eq 4", "jitter eq 2",
                               "pktloss eq 0.01", "availbw eq 60",
   "cost eq 300" ]
              }

              "ipv4:192.0.2.30": {
              "ipv4:203.0.113.45"    : [ "delay eq 2", "jitter eq 2",
                               "pktloss eq 0.03", "availbw eq 10",
   "cost eq 200" ]
              }
            }
          }


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        }
Note that above is just an example, a bronze service may also choose to
get end to end information instead of an abstract graph in response.


   Note that the EndpointCostMapData can be used for both the Graph
   representation as well as the end to end path.




4. ALTO Protocol Extension for Graph Representation Mechanism

   The encoding details for graph representation mechanism are shown in
   Section 3.6.3 where the use of graph in a Bronze service is
   described.



5. Summary and Conclusion

   TBD

6. Security Considerations

   TBD

7. IANA Considerations

   TBD

8. Acknowledgements

   The authors would like to thank Richard Yang and Sabine Randriamasy
   for many helpful comments that greatly improved the contents of this
   draft.

9. References

9.1. Informative References

   [HighBW] G. Bernstein and Y. Lee, "Use Cases for High Bandwidth
             Query and Control of Core Networks," draft-bernstein-alto-
             large-bandwidth-cases, work in progress.

   [MultiCost] S. Randriamasy, Ed., "Multi-Cost ALTO," draft-
             randriamasy-alto-multi-cost, work in progress.


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   [TE-cost] Q. Wu, et. al. "JSON Format Extensions for Traffic
             Engineering (TE) performance metrics in the ALTO
             Information Resource Directory, draft-wu-alto-json-te,
             work in progress.














































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Author's Addresses


   Young Lee
   Huawei Technologies
   1700 Alma Drive, Suite 500
   Plano, TX 75075
   USA
   Phone: (972) 509-5599
   Email: leeyoung@huawei.com

   Dhruv Dhody
   Huawei Technologies, India
   Email: dhruv.dhody@huawei.com

   Qin Wu
   Huawei Technologies, China
   Email: bill.wu@huawei.com


   Greg M. Bernstein
   Grotto Networking
   Fremont California, USA
   Phone: (510) 573-2237
   Email: gregb@grotto-networking.com


   Tae-Sang Choi
   ETRI
   161 Gajong-Dong, Yusong-Gu
   Daejon, Republic of Korea
   Phone: (8242) 860-5628
   Email: choits@etri.re.kr


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Internet-Draft Application and Network Information Exchange October 2013


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