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Versions: 00 01 02

Network Working Group                                       N. Zong, Ed.
Internet-Draft                                                   X. Chen
Intended status: Informational                                  Z. Huang
Expires: March 03, 2014                              Huawei Technologies
                                                                 L. Chen
                                                                 HP Labs
                                                                  H. Liu
                                                         Yale University
                                                         August 30, 2013


                 Integration Examples of DECADE System
                   draft-zong-integration-example-02

Abstract

   Decoupled Application Data Enroute (DECADE) system is an in-network
   storage infrastructure which was discussed in IETF.  This document
   presents two detailed examples of how to integrate such in-network
   storage infrastructure into peer-to-peer (P2P) applications to
   achieve more efficient content distribution, and Application Layer
   Traffic Optimization (ALTO) system to build a content distribution
   platform for Content Providers (CPs).

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 March 03, 2014.

Copyright Notice

   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



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   (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
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   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   4
     2.1.  Native Application Client . . . . . . . . . . . . . . . .   4
     2.2.  INS Server  . . . . . . . . . . . . . . . . . . . . . . .   4
     2.3.  INS Client  . . . . . . . . . . . . . . . . . . . . . . .   4
     2.4.  INS Operations  . . . . . . . . . . . . . . . . . . . . .   4
     2.5.  INS System  . . . . . . . . . . . . . . . . . . . . . . .   4
     2.6.  INS Client API  . . . . . . . . . . . . . . . . . . . . .   5
     2.7.  INS-enabled Application Client  . . . . . . . . . . . . .   5
     2.8.  INS Service Provider  . . . . . . . . . . . . . . . . . .   5
     2.9.  INS Portal  . . . . . . . . . . . . . . . . . . . . . . .   5
   3.  INS Client API  . . . . . . . . . . . . . . . . . . . . . . .   5
   4.  Integration of P2P File Sharing and INS System  . . . . . . .   6
     4.1.  Integration Architecture  . . . . . . . . . . . . . . . .   6
       4.1.1.  Message Flow  . . . . . . . . . . . . . . . . . . . .   6
     4.2.  Concluding Remarks  . . . . . . . . . . . . . . . . . . .   8
   5.  Integration of P2P Live Streaming and INS System  . . . . . .   8
     5.1.  Integration Architecture  . . . . . . . . . . . . . . . .   8
       5.1.1.  Data Access Messages  . . . . . . . . . . . . . . . .   8
       5.1.2.  Control Messages  . . . . . . . . . . . . . . . . . .   9
     5.2.  Design Considerations . . . . . . . . . . . . . . . . . .   9
       5.2.1.  Improve Efficiency for Each Connection  . . . . . . .   9
       5.2.2.  Reduce Control Latency  . . . . . . . . . . . . . . .  10
   6.  Integration of ALTO and INS System for File Distribution  . .  10
     6.1.  Architecture  . . . . . . . . . . . . . . . . . . . . . .  10
       6.1.1.  CP Uploading Procedure  . . . . . . . . . . . . . . .  11
       6.1.2.  End User Downloading Procedure  . . . . . . . . . . .  12
   7.  Test Environment and Settings . . . . . . . . . . . . . . . .  13
     7.1.  Test Settings . . . . . . . . . . . . . . . . . . . . . .  14
     7.2.  Test Environment for P2P Live Streaming Example . . . . .  14
       7.2.1.  INS Server  . . . . . . . . . . . . . . . . . . . . .  15
       7.2.2.  P2P Live Streaming Client . . . . . . . . . . . . . .  15
       7.2.3.  Tracker . . . . . . . . . . . . . . . . . . . . . . .  15
       7.2.4.  Streaming Source Server . . . . . . . . . . . . . . .  15
       7.2.5.  Test Controller . . . . . . . . . . . . . . . . . . .  15
     7.3.  Test Environment for P2P File Sharing Example . . . . . .  15
       7.3.1.  INS Server  . . . . . . . . . . . . . . . . . . . . .  16
       7.3.2.  Vuze Client . . . . . . . . . . . . . . . . . . . . .  16



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       7.3.3.  Tracker . . . . . . . . . . . . . . . . . . . . . . .  16
       7.3.4.  Test Controller . . . . . . . . . . . . . . . . . . .  16
       7.3.5.  HTTP Server . . . . . . . . . . . . . . . . . . . . .  17
       7.3.6.  PlanetLab Manager . . . . . . . . . . . . . . . . . .  17
     7.4.  Test Environment for Combined ALTO and INS File
           Distribution System . . . . . . . . . . . . . . . . . . .  17
   8.  Performance Analysis  . . . . . . . . . . . . . . . . . . . .  17
     8.1.  Performance Metrics . . . . . . . . . . . . . . . . . . .  17
       8.1.1.  P2P Live Streaming  . . . . . . . . . . . . . . . . .  17
       8.1.2.  P2P File Sharing  . . . . . . . . . . . . . . . . . .  18
       8.1.3.  Integration of ALTO and INS System for File
               Distribution  . . . . . . . . . . . . . . . . . . . .  18
     8.2.  Results and Analysis  . . . . . . . . . . . . . . . . . .  18
       8.2.1.  P2P Live Streaming  . . . . . . . . . . . . . . . . .  18
       8.2.2.  P2P File Sharing  . . . . . . . . . . . . . . . . . .  19
       8.2.3.  Integrated ALTO and INS System for File Distribution   19
   9.  Conclusion and Next Step  . . . . . . . . . . . . . . . . . .  20
   10. Security Considerations . . . . . . . . . . . . . . . . . . .  20
   11. IANA Considerations . . . . . . . . . . . . . . . . . . . . .  20
   12. References  . . . . . . . . . . . . . . . . . . . . . . . . .  20
     12.1.  Normative References . . . . . . . . . . . . . . . . . .  21
     12.2.  Informative References . . . . . . . . . . . . . . . . .  21
   13. References  . . . . . . . . . . . . . . . . . . . . . . . . .  21
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  21

1.  Introduction

   Decoupled Application Data Enroute (DECADE) system is an in-network
   storage infrastructure which was discussed in IETF.  We implemented
   such in-network storage infrastructure to simulate DECADE system
   including DECADE servers, DECADE clients and DECADE protocols [I-D
   .alimi-decade].  Therefore, in the whole draft, we use the terms of
   in-network storage (INS) system, INS server, INS client, INS
   operations, etc.

   This draft introduces some examples of integrating INS system with
   existing applications.  In our example systems, the core components
   include INS server and INS-enabled application client.  An INS server
   stores data inside the network, and thereafter manages both the
   stored data and access to that data.  An INS-enabled application
   client including INS client and native application client uses a set
   of Application Programming Interfaces (APIs) to enable native
   application client to utilize INS operations such as data get, data
   put, storage status query, etc.

   This draft presents two detailed examples of how to integrate INS
   system into peer-to-peer (P2P) applications, i.e. live streaming and
   file sharing, as well as an example integration of Application Layer



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   Traffic Optimization (ALTO) [I-D.ietf-alto-protocol] and INS system
   to support file distribution.  We show how to extend native P2P
   applications by designing the INS-enabled P2P clients and describing
   the corresponding flows of INS-enabled data transmission.  Then we
   introduce the functional architecture and working flows of integrated
   ALTO and INS system for file distribution of Content Providers (CPs).
   Finally we illustrate the performance gain to P2P applications and
   more efficient content distribution by effectively leveraging the INS
   system.

   Please note that the P2P applications mentioned in this draft only
   represent some cases out of a large number of P2P applications, while
   the INS system itself can support a variety of other applications.
   Moreover, the set of APIs used in our integration examples is an
   experimental implementation, which is not standard and still under
   development.  The INS system described in this draft is only a
   preliminary functional set of in-network storage infrastructure for
   applications.  It is designed to test the pros and cons of INS system
   utilized by P2P applications and verify the feasibility of utilizing
   INS system to support content distribution.  We hope our examples
   would be useful for further standard protocol design, rather than to
   present a solution for standardization purpose.

2.  Terminology

   The following terms will be used in this document.

2.1.  Native Application Client

   A client running original application operations including control
   and data messages defined by applications.

2.2.  INS Server

   A server to simulate DECADE server defined in [I-D.alimi-decade].

2.3.  INS Client

   A client to simulate DECADE client defined in [I-D.alimi-decade].

2.4.  INS Operations

   A set of communications between INS server and INS client to simulate
   DECADE protocols defined in [I-D.alimi-decade].

2.5.  INS System

   A system including INS servers, INS clients, and INS operations.



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2.6.  INS Client API

   A set of APIs to enable native application client to utilize INS
   operations.

2.7.  INS-enabled Application Client

   An INS-enabled application client includes INS client and native
   application client communicating through INS client API.

2.8.  INS Service Provider

   An INS service provider deploys INS system and provides INS service
   to applications/end users.  It can be Internet Service Provider (ISP)
   or other parties.

2.9.  INS Portal

   A functional entity operated by INS service provider to offer
   applications/end users a point to access (e.g. upload, download)
   files stored in INS servers.

3.  INS Client API

   In order to simplify the integration of INS system with P2P
   applications, we provide INS client API to native P2P clients for
   accomplishing INS operations such as data get, data put, etc.  On top
   of the INS client API, a native P2P client can develop its own
   application specific control and data distribution flows.

   We currently developed the following five basic interfaces.

   o Generate_Token: Generate an authorization token.  An authorization
   token is usually generated by an entity that is trusted by an INS
   client which is sharing its data and passed to the other INS clients
   for data access control.  Please see [I-D.alimi-decade] for more
   details.

   o Get_Object: Get a data object from an INS server with an
   authorization token.

   o Put_Object: Store a data object into an INS server with an
   authorization token.

   o Delete_Object: Delete a data object in an INS server explicitly
   with an authorization token.  Note that a data object can also be
   deleted implicitly by setting a Time-To-Live (TTL) value.




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   o Status_Query: Query current status of an application itself,
   including listing stored data objects, resource (e.g. storage space)
   usage, etc.

4.  Integration of P2P File Sharing and INS System

   We integrate an INS client into Vuze - a BitTorrent based file
   sharing application [VzApp].

4.1.  Integration Architecture

   The architecture of the integration of Vuze and INS system is shown
   in Figure 1.  An INS-enabled Vuze client uses INS client to
   communicate with INS server and transmit data between itself and INS
   server.  It is also compatible with original Vuze signaling messages
   such as peer discovery, data availability announcement, etc.  Note
   that the same architecture applies to the other example of
   integration of P2P live streaming and INS system.

       +------------------+                       +------------------+
       |    INS-enabled   |                       |    INS-enabled   |
       |       Client     |                       |       Client     |
       |+----------------+|   +---------------+   |+----------------+|
       ||    INS         |+---|    INS Server |---+|    INS         ||
       ||    Client      ||   +---------------+   ||    Client      ||
       ||                |+-----------------------+|                ||
       |+------+---------+|                       |+------+---------+|
       |   API |          |                       |   API |          |
       |+------+---------+|                       |+------+---------+|
       || Native Client  |+-----------------------+| Native Client  ||
       |+----------------+|                       |+----------------+|
       +------------------+                       +------------------+

                                  Figure 1


4.1.1.  Message Flow

   In order for a better comparison, we briefly show the below diagram
   of the native Vuze message exchange, and then show the corresponding
   diagram including the INS system.

      +--------+                            +--------+
      | Vuze   |                            | Vuze   |
      | Client1|                            | Client2|
      +--------+                            +--------+
          |                                     |
          |               HandShake             |



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          |<----------------------------------->|
          |              BT_BitField            |
          |<----------------------------------->|
          |              BT_Request             |
          |------------------------------------>|
          |              BT_Piece               |
          |<------------------------------------|
          |                                     |

                          Figure 2


   In the above diagram, one can see that the key messages for data
   sharing in native Vuze are "BT_BitField", "BT_Request" and
   "BT_Piece".  Vuze client1 and client2 exchange "BT_BitField" messages
   to announce the available data objects to each other.  If Vuze
   client1 wants to get certain data object from client2, it sends a
   "BT_Request" message to client2.  Vuze client2 then return the
   requested data object to client1 by a "BT_Piece" message.  Please
   refer to [VzMsg] for the detailed description of Vuze messages.

   As shown in the below diagram, in the integration of Vuze and INS
   system, INS client inserts itself into the Vuze client by
   intercepting certain Vuze messages, and adjusting their handling to
   send/receive data using the INS operations instead.

       ________   __________   __________   ________   _________
      | Vuze  |  | INS     |  | INS     |  | Vuze  |  | INS     |
      |Client1|  | Client1 |  | Client2 |  |Client2|  | Server  |
      |_______|  |_________|  |_________|  |_______|  |_________|
          |           |            |           |           |
          |           |  HandShake |           |           |
          |<----------|------------|---------->|           |
          |           | BT_BitField|           |           |
          |<----------|------------|---------->|           |
          |           | BT_Request |           |           |
          |-----------|----------->|           |           |
          |           |            |           |           |
          |           |  Redirect  |           |           |
          |           |<-----------|           |           |
          |           |            |  Get Data |           |
          |           |----------------------------------->|
          |           |            |Data Object|           |
          |           |<-----------------------------------|
          |           |            |           |           |
          | BT_Piece  |            |           |           |
          |<----------|            |           |           |
          |           |            |           |           |



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                             Figure 3


   o Vuze client1 sends a "BT_Request" message to Vuze client2 to
   request a data object as usual.

   o INS client2 embedded in Vuze client2 intercepts the incoming
   "BT_Request" message and then replies with a "Redirect" message which
   includes INS server's address and authorization token.

   o INS client1 receives the "Redirect" message and then sends an INS
   message "Get Data" to the INS server to request the data object.

   o INS server receives the "Get Data" message and sends the requested
   data object back to INS client1 after the token check.

   o INS client1 encapsulates the received data object into a "BT_Piece"
   message and sends to Vuze client1.

   In this example, the file to be shared is divided into many objects,
   with each object being named as "filename_author_partn" where author
   is the original author of the file or the user who uploads the file,
   n is the sequence number of the object.

4.2.  Concluding Remarks

   In this example, we feel that the INS system can effectively improve
   the file sharing efficiency due to following reasons: 1) utilizing
   in-network storage as the data location of the peer will achieve
   statistical multiplexing gain of the data sharing; 2) shorter data
   delivery path based on in-network storage could not only improve the
   application performance, but avoid the potential bottleneck in the
   ISP network.

5.  Integration of P2P Live Streaming and INS System

   We integrate an INS client into a P2P live streaming application.

5.1.  Integration Architecture

   The architecture of the integration of P2P live streaming application
   and INS system is shown in Figure 1.  An INS-enabled P2P live
   streaming client uses INS client to communicate with INS server and
   transmit data between itself and INS server.

5.1.1.  Data Access Messages





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   INS client API is called whenever an INS-enabled P2P live streaming
   client wants to get data objects from (or put data objects into) the
   INS server.  Each data object transferred between the application
   client and the INS server should go through the INS client.  Each
   data object can be a variable-sized block to cater to different
   application requirements (e.g. latency and throughput).

   We use the hash of a data object's content for the name of the data
   object.  The name of a data object is generated and distributed by
   the source streaming server in this example.

5.1.2.  Control Messages

   We used a lab-based P2P live streaming system for research purpose
   only.  The basic control messages between the native P2P live
   streaming clients are similar to Vuze control protocols in the sense
   that the data piece information is exchanged between the peers.  The
   INS-enabled P2P live streaming client adds an additional control
   message for authorization token distribution, as shown as the line
   between the INS clients in Figure 1.  In this example, the
   authorization token is generated by the INS client that is sharing
   its data.  By exchanging the authorization tokens, the application
   clients can retrieve the data objects from the INS servers.

5.2.  Design Considerations

   One essential objective of the integration is to improve the
   performance of P2P live streaming application.  In order to achieve
   such goal, we have some important design considerations that would be
   helpful to the future work of protocol development.

5.2.1.  Improve Efficiency for Each Connection

   In a native P2P system, a peer can establish tens or hundreds of
   concurrent connections with other peers.  On the other hand, it may
   be expensive for an INS server to maintain many connections for a
   large number of INS clients.  Typically, each INS server may only
   allocate and maintain M connections (in our examples, M=1) with each
   INS client at a time.  Therefore, we have the following design
   considerations to improve the efficiency for each connection between
   INS server and INS client to achieve satisfying data downloading
   performance.

   o Batch Request: In order to fully utilize the connection bandwidth
   of INS server and reduce the overhead, an application client may
   request a batch of data objects in a single request.





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   o Larger Data Object: Data object size in existing P2P live streaming
   application may be small and thus incur large control overhead and
   low transport utilization.  A larger data object may be needed to
   more efficiently utilize the data connection between INS server and
   INS client.

5.2.2.  Reduce Control Latency

   In a native P2P system, a serving peer sends data objects to the
   requesting peer directly.  Nevertheless, in an INS system, the
   serving client typically only replies with an authorization token to
   the requesting client, and then the requesting client uses this token
   to fetch the data objects from the INS server.  This process
   introduces an additional control latency compared with the native P2P
   system.  It is even more serious in latency sensitive applications
   such as P2P live streaming.  Therefore, we need to consider how to
   reduce such control latency.

   o Range Token: One way to reduce control latency is to use range
   token.  An INS-enabled P2P live streaming client may piggyback a
   range token when announcing data availability to other peers,
   indicating that all available data objects are accessible by this
   range token.  Then instead of requesting some specific data object
   and waiting for the response, a peer can use this range token to
   access all available data objects that it was permitted to access in
   the INS server.

6.  Integration of ALTO and INS System for File Distribution

   The objective of ALTO service is to give guidance to applications
   about which content servers to select to improve content distribution
   performance in an ISP-friendly way (e.g. reducing network usage
   within the ISP).  The core component of ALTO service is called ALTO
   server which generates the guidance based on the ISP network
   information.  The ALTO protocol conveys such guidance from the ALTO
   server to the applications.  The detailed description of ALTO
   protocol can be found in [I-D.ietf-alto-protocol].

   In this example, we integrate ALTO and INS system to build a content
   distribution platform for CPs.

6.1.  Architecture









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   The integrated system allows CPs to upload files to INS servers, and
   guides end users to download files from the INS servers suggested by
   ALTO service.  The architecture diagram is shown as below.  Note that
   this diagram just shows a basic set of connections between the
   components.  Some redirection including that the INS portal redirects
   end users to the INS servers can also happen between the components.

                  __________                   __________
                 | End User |                 | End User |
                 |__________|                 |__________|
                            \                 /
                             \ _____________ /
                              |  CP Portal  |
                              |_____________|
                                     |
               ______________________|______________________
               | INS           ______|_____                 |   +--------+
               | Service      |  INS       |                |   | ALTO   |
               | Provider     |  Portal    |----------------+---| Server |
               |             /|____________| \              |   +--------+
               |           /     |      |      \            |
               | ________/  _____|__   _|______  \________  |
               || INS    | | INS    | | INS    | | INS    | |
               ||Server1 | |Server2 | |Server3 | |Servern | |
               ||________| |________| |________| |________| |
               |____________________________________________|

                                Figure 4


   Four key components are defined as follow.

   o INS Servers: operated by an INS service provider to store files
   from CPs.

   o INS Portal: operated by an INS service provider to 1) upload files
   from CPs to the dedicated INS servers; 2) direct end users to the INS
   servers suggested by ALTO service to download files.

   o CP Portal: operated by a CP to publish the URLs of the uploaded
   files for end user downloading.

   o End User: End users use standard web browser with INS extensions
   such that INS client APIs can be called for fetching the data from
   INS servers.

6.1.1.  CP Uploading Procedure




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   CP uploads the files into INS servers first, then gets the URLs of
   the uploaded files and publishes the URLs on the CP portal for end
   user downloading.  The flow is shown below.

          _________          _________         _________
         |         |        | INS     |       | INS     |
         |   CP    |        | Portal  |       | Server  |
         |_________|        |_________|       |_________|
             |                   |                  |
             |     HTTP POST     |                  |
             |------------------>|                  |
             |                   |    Put Data      |
             |                   |----------------->|
             |                   |    Response      |
             |                   |<-----------------|
             |        URLs       |                  |
             |<------------------|                  |
             |                   |                  |

                              Figure 5


   o CP uploads the file to the INS portal site via HTTP POST message.

   o INS portal distributes the file to the dedicated INS severs using
   INS message "Put Data".  Note that the data distribution policies
   (e.g. how many copies of the data to which INS servers) can be
   specified by CP.  The dedicated INS servers can be also decided by
   the INS service provider based on policies or system status (e.g.
   INS server load).  These issues are out of the scope of this draft.

   In this example, the data stored in INS server is divided into many
   objects, with each object being named as "filename_CPname_partn"
   where CPname is the name of the CP who uploads the file, n is the
   sequence number of the object.

   o When the file is uploaded successfully, CP portal will list the
   URLs of the file for end use downloading.

6.1.2.  End User Downloading Procedure

   End users can visit the CP portal web pages and click the URLs for
   downloading the desired files.  The flow is shown below.

      _________     ____________     _________     _________     _________
     |         |   |            |   | INS     |   |  ALTO   |   |  INS    |
     | End User|   | CP Portal  |   | Portal  |   |  Server |   |  Server |
     |_________|   |____________|   |_________|   |_________|   |_________|



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         |              |                |             |             |
         |   HTTP Get   |                |             |             |
         |------------->|                |             |             |
         |    Token     |                |             |             |
         |<-------------|                |             |             |
         |              |                |             |             |
         |            HTTP Get           |             |             |
         |------------------------------>|             |             |
         |              |                |   ALTO Req  |             |
         |              |                |------------>|             |
         |              |                |   ALTO Resp |             |
         |              |                |<------------|             |
         |    Optimal INS Server address |             |             |
         |<------------------------------|             |             |
         |              |                |             |             |
         |              |            Get Data          |             |
         |---------------------------------------------------------->|
         |              |                |             |             |
         |              |           Data Object        |             |
         |<----------------------------------------------------------|
         |              |                |             |             |

                                     Figure 6


   o End user visits CP portal web page, and finds the URLs for the
   desired file.

   o End user clicks the hyper link, CP portal returns authorization
   token to the end user and redirects the end user to INS portal via
   HTTP Get message.

   o INS portal communicates with ALTO server to get the suggested INS
   server storing the requested file.  In this example, ALTO server just
   selects the INS server within the same IP subset of the end user.
   Please see [I-D.ietf-alto-protocol] for more details on how ALTO
   select content server.

   o INS portal returns the INS server address suggested by ALTO service
   to the end user.

   o End user connects to the suggested INS server to get data via INS
   message "Get Data" after the token check.

7.  Test Environment and Settings

   We conduct some tests to show the results of our integration
   examples.  For a better performance comparison, we ran experiments



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   (i.e.  INS integrated P2P application v.s. native P2P application) in
   the same environment using the same settings.

7.1.  Test Settings

   Our tests ran on a wide-spread area and diverse platforms, including
   a famous commercial platform - Amazon EC2 [EC2] and a well known
   test-bed - PlanetLab [PL].  The experimental settings are as follows.

   o Amazon EC2: We setup INS servers in Amazon EC2 platform, including
   four regions around the world - US east, US west, Europe and Asia.

   o PlanetLab: We ran our P2P live streaming clients and P2P file
   sharing clients (both INS-enabled and native clients) on PlanetLab on
   a wild-spread area.

   o Flash-crowd: Flash-crowd is an important scenario in P2P live
   streaming system due to the live nature, i.e. a large number of users
   join the live channel during the startup period of the event.
   Therefore, we conduct experiments to test the system performance for
   flash-crowd in our P2P live streaming example.

   o Total supply bandwidth: Total supply bandwidth is the sum of the
   capacity of bandwidth used to serve the streaming/file content, from
   both servers (including source servers and INS servers) and the P2P
   clients.  For a fair comparison, we set the total supply bandwidth to
   be the same in both tests of native and INS-enabled P2P applications.

7.2.  Test Environment for P2P Live Streaming Example

   In the tests, we have some functional components running in different
   platforms, including INS servers, P2P live streaming clients (INS-
   enabled or native), native P2P live streaming tracker, streaming
   source server and test controller, as shown in below figure.

                       +------------+    +------------+
                       |   INS      |----|   INS      |
                       |   Server   |    |   Server   |
                       +-----+------+    +------+-----+ Amazon EC2
       ______________________|__________________|_________________
                             |                  |
                       +-----+------+    +------+-----+
                       | Streaming  |----|  Streaming |
                       |   Client   |\  /|    Client  |
                       +------+-----+ \/ +------+-----+ PlanetLab
       _______________________|_______/\________|_________________
                              |      /  \       |       Yale Lab
     +--------------+  +------+-----+    +------+-----+



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     | Streaming    |  |   Tracker  |    |    Test    |
     | Source Server|  |            |    | Controller |
     +--------------+  +------------+    +------------+

                                   Figure 7


7.2.1.  INS Server

   INS servers ran on Amazon EC2.

7.2.2.  P2P Live Streaming Client

   Both INS-enabled and native P2P live streaming clients ran on
   PlanetLab.  Each INS-enabled P2P live streaming client connects to
   the dedicated INS server.  In this example, we decide which client
   connects to which server based on the IP address.  So, it is roughly
   region-based and still coarse.  Each INS-enabled P2P live streaming
   client uses its INS server to share streaming content to other peers.

7.2.3.  Tracker

   A native P2P live streaming tracker ran at Yale's laboratory and
   served both INS-enabled and native P2P live streaming clients during
   the test.

7.2.4.  Streaming Source Server

   A streaming source server ran at Yale's laboratory and served both
   INS-enabled and native P2P live streaming clients during the test.

7.2.5.  Test Controller

   Test controller is a manager running at Yale's laboratory to control
   all machines' behaviors in both Amazon EC2 and PlanetLab during the
   test.

7.3.  Test Environment for P2P File Sharing Example

   Functional components include Vuze client (with and without INS
   client), INS servers, native Vuze tracker, HTTP server, PlanetLab
   manager and test controller, as shown in below figure.

                       +-----------+    +-----------+
                       |   INS     |----|   INS     |
                       |   Server  |    |   Server  |
                       +-----+-----+    +-----+-----+ Amazon EC2
       ______________________|________________|_________________



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                             |                |
                       +-----+-----+    +-----+-----+
                       |    Vuze   |----|    Vuze   |
                       |   Client  |\  /|   Client  |
                       +-----+-----+ \/ +-----+-----+ PlanetLab
       ______________________|_______/\_______|_________________
                             |      /  \      |       Yale Lab
     +-------------+  +------+-----+    +-----+------+  +-----------+
     | HTTP Server |  |   Tracker  |    |    Test    |  | PlanetLab |
     |             |  |            |    | Controller |  |  Manager  |
     +-------------+  +------------+    +------------+  +-----------+

                                   Figure 8


7.3.1.  INS Server

   INS servers ran on Amazon EC2.

7.3.2.  Vuze Client

   Vuze clients were divided into one seeding client and multiple
   leechers.  The seeding client ran at a Window 2003 server at Yale's
   laboratory.  Both INS-enabled and native Vuze clients (leechers) ran
   on PlanetLab.  INS client embedded in Vuze client was automatically
   loaded and ran after Vuze client start up.

7.3.3.  Tracker

   Vuze software includes tracker implementation, so we didn't deploy
   our own tracker.  Tracker ran at Yale's laboratory and was enabled
   when making a BitTorrent file.  Tracker ran at the same Window 2003
   server with the seeding client.

7.3.4.  Test Controller

   Similar to the test controller in P2P live streaming case, the test
   controller in Vuze example can also control all machines' behaviors
   in Amazon EC2 and PlanetLab.  For example, it lists all the Vuze
   clients via GUI and controls them to download a specific BitTorrent
   file.  Test controller ran at the same Window 2003 server with the
   seeding client.









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7.3.5.  HTTP Server

   BitTorrent file was put in the HTTP server and the leechers retrieved
   the BitTorrent file from the HTTP server after receiving the
   downloading command from the test controller.  We used Apache Tomcat
   for HTTP server.

7.3.6.  PlanetLab Manager

   PlanetLab manager is a tool developed by University of Washington.
   It presents a simple GUI to control PlanetLab nodes and perform
   common tasks such as: 1) selecting nodes for your slice; 2) choosing
   nodes for your experiment based on the information about the nodes;
   3) reliably deploying you experiment files; 4) executing commands on
   every node in parallel; 5) monitoring the progress of the experiment
   as a whole, as well as viewing console output from the nodes.

7.4.  Test Environment for Combined ALTO and INS File Distribution
      System

   For the integration of ALTO and INS systems for supporting file
   distribution of CPs, we built 6 Linux virtual machines (VMs) with
   Fedora13 operating system.  ALTO server, INS portal, CP portal and
   two INS servers ran on these VMs.  Each VM is allocated with 4 cores
   from a 16-core 1Ghz CPU, and has 2GB memory space and 10GB disk
   space.  CP uploaded files to the INS server via INS portal.  End user
   can choose desired file through the CP portal, and download it from
   the optimal INS server chosen by the INS portal using ALTO service.

8.  Performance Analysis

   We illustrate the performance gain to P2P applications and more
   efficient content distribution by effectively leveraging the INS
   system.  For the example of integrating ALTO and INS systems to
   support file distribution of CPs, we show the feasibility of such
   integration.

8.1.  Performance Metrics

8.1.1.  P2P Live Streaming

   To measure the performance of a P2P live streaming application, we
   mainly employed the following four metrics.

   o Startup delay: The duration from a peer joins the streaming channel
   to the moment it starts to play.





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   o Piece missed rate: The number of pieces a peer loses when playing
   over the total number of pieces.

   o Freeze times: The number of times a peer re-buffers during playing.

   o Average peer uploading rate: Average uploading bandwidth of a peer.

8.1.2.  P2P File Sharing

   To measure the performance of a P2P file sharing application, we
   mainly employed the following three metrics.

   o Download traffic: The total amount of traffic representing the
   network downlink resource usage.

   o Upload traffic: The total amount of traffic representing the
   network uplink resource usage.

   o Network resource efficiency: The ratio of P2P system download rate
   to the total network (downlink) bandwidth.

8.1.3.  Integration of ALTO and INS System for File Distribution

   We consider some common capacity metrics for content distribution
   system, i.e. the bandwidth usage of each INS server, and the total
   online users supported by each INS server.

8.2.  Results and Analysis

8.2.1.  P2P Live Streaming

   o Startup delay: In the test, INS-enabled P2P live streaming clients
   startup around 35~40 seconds and some of them startup around 10
   seconds.  Native P2P live streaming clients startup around 110~120
   seconds and less than 20% of them startup within 100 seconds.

   o Piece missed rate: In the test, both INS-enabled P2P live streaming
   clients and native P2P live streaming clients achieved a good
   performance in piece missed rate.  Only about 0.02% of total pieces
   missed in both cases.

   o Freeze times: In the test, native P2P live streaming clients
   suffered from more freezing times than INS-enabled P2P live streaming
   clients by 40%.

   o Average peer uploading rate: In the test, according to our
   settings, INS-enabled P2P live streaming clients had no data upload
   in their "last mile" access network, while in the native P2P live



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   streaming system, most peers uploaded streaming data for serving
   other peers.  In another word, INS system can shift uploading traffic
   from clients' "last mile" to in-network devices, which saves a lot of
   expensive bandwidth on access links.

8.2.2.  P2P File Sharing

   The test result is illustrated in below figure.  We can see that
   there is very few upload traffic from the INS-enabled Vuze clients,
   while in the native Vuze case, the upload traffic from Vuze clients
   is the same as the download traffic.  Network resource usage is thus
   reduced in the "last mile" in the INS-enabled Vuze case.  This result
   also verifies that the INS system can shift uploading traffic from
   clients' "last mile" to in-network devices.  Note that because not
   all clients finish downloading process, there are different total
   download traffic for the independent tests, as shown in below figure.

           +--------------------+--------------------+--------------------+
           |                    |                    |                    |
           |                    |  Download Traffic  |   Upload Traffic   |
           |                    |                    |                    |
           +--------------------+--------------------+--------------------+
           |                    |                    |                    |
           | INS-Enabled Vuze   |       480MB        |       12MB         |
           |                    |                    |                    |
           +--------------------+--------------------+--------------------+
           |                    |                    |                    |
           |    Native Vuze     |       430MB        |       430MB        |
           |                    |                    |                    |
           +--------------------+--------------------+--------------------+

                                      Figure 9


   We also found higher network resource efficiency in the INS-enabled
   Vuze case where the network resource efficiency is defined as the
   ratio of P2P system download rate to the total network (downlink)
   bandwidth.  The test result is that the network resource efficiency
   of native Vuze is 65% while that of INS-enabled Vuze is 88%. A
   possible reason behind the higher network resource efficiency is that
   the INS server can always serve content to the peers, while in
   traditional P2P applications, peer has to finish downloading content
   before sharing with other peers.

8.2.3.  Integrated ALTO and INS System for File Distribution

   Each INS server can supply the bandwidth usage of at most 94% of
   network interface card (NIC) - e.g. 1Gbps NIC server can supply



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   bandwidth of 940Mbps at most.  We did tests on 100Mbps and 1Gbps NIC,
   and got same result of 94% bandwidth usage.

   Each INS server can support about 400 online users for file
   downloading simultaneously.  When we tried 450 concurrent online
   users, 50 users didn't start downloading on time, but wait for the
   other 400 users to finish downloading.

9.  Conclusion and Next Step

   This document presents two examples of integrating INS system into
   P2P applications (i.e. P2P live streaming and Vuze) by developing INS
   client API for native P2P clients.  To better adopt INS system, we
   found some important design considerations including efficiency for
   INS connection, control latency caused by INS operations, and
   developed some mechanisms to address them.  We ran some tests to show
   the results of our integration examples on Amazon EC2 and PlanetLab
   for deploying INS servers and clients, respectively.  It can be
   observed from our test results that integrating INS system into
   native P2P applications could achieve performance gain to P2P
   applications and more network efficient content distribution.  For
   the example of integrating ALTO and INS system to support file
   distribution of CPs, we have shown the feasibility of such
   integration.

   Our next step work will continue on implementing more features of INS
   servers and clients based on the protocol ideas developed in protocol
   document [I-D.alimi-decade], such as OAUTH based authorization and
   naming scheme for data objects.

10.  Security Considerations

   The authorization token can be passed from one INS client to other
   INS clients to authorize other INS clients to access data objects
   from its INS storage.  Detailed mechanisms of token based
   authentication and authorization can be found in [I-D.alimi-decade].

11.  IANA Considerations

   This document does not have any IANA considerations.

12.  References









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12.1.  Normative References

   [I-D.alimi-decade] Alimi, R., Rahman, A., Kutscher, D., Yang, Y.,
   Song, H., and K. Pentikousis, "DECoupled Application Data Enroute
   (DECADE)", draft-alimi-decade-03 (work in progress), August 2013.

   [I-D.ietf-alto-protocol] Alimi, R., Penno, R., and Y. Yang, "ALTO
   Protocol", draft-ietf-alto-protocol-11 (work in progress), March
   2012.

12.2.  Informative References

   [VzApp] "http://www.vuze.com"

   [VzMsg] "http://wiki.vuze.com/w/Azureus_messaging_protocol"

   [EC2] "http://aws.amazon.com/ec2/"

   [PL] "http://www.planet-lab.org/"

13.  References

Authors' Addresses

   Ning Zong (editor)
   Huawei Technologies

   Email: zongning@huawei.com


   Xiaohui Chen
   Huawei Technologies

   Email: risker.chen@huawei.com


   Zhigang Huang
   Huawei Technologies

   Email: andy.huangzhigang@huawei.com


   Lijiang Chen
   HP Labs

   Email: lijiang.chen@hp.com





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   Hongqiang Liu
   Yale University

   Email: hongqiang.liu@yale.edu















































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