Internet DRAFT - draft-wang-decade-alto-integration

draft-wang-decade-alto-integration






ALTO                                                             D. Wang
Internet-Draft                                                   H. Song
Intended status: Standards Track                                 N. Zong
Expires: April 18, 2013                                           Huawei
                                                            Oct 15, 2012


                      DECADE and ALTO Integration
                 draft-wang-decade-alto-integration-00

Abstract

   While DECADE architecture is going to provide a framework to use in-
   network storage with standard interface for content distribution,
   there are still cases when many in-network storage servers provide
   the same content.  Then traffic optimization mechanism is needed to
   select one best replica for the user request.  This document is going
   to discuss the integration of Application Layer Traffic Optimization
   (ALTO) protocol into DECADE so as to optimize network traffic.

Status of this Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at http://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on April 18, 2013.

Copyright Notice

   Copyright (c) 2012 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must



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   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.


Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
   2.  Terminology  . . . . . . . . . . . . . . . . . . . . . . . . .  3
   3.  Integration Architecture . . . . . . . . . . . . . . . . . . .  3
     3.1.  Function Entity  . . . . . . . . . . . . . . . . . . . . .  3
     3.2.  Integration Architecture . . . . . . . . . . . . . . . . .  3
     3.3.  Process Flow . . . . . . . . . . . . . . . . . . . . . . .  5
   4.  Use cases  . . . . . . . . . . . . . . . . . . . . . . . . . .  6
     4.1.  P2P File Sharing . . . . . . . . . . . . . . . . . . . . .  6
     4.2.  Offline P2P live streaming . . . . . . . . . . . . . . . .  7
   5.  ALTO Protocol Considerations . . . . . . . . . . . . . . . . .  9
   6.  Security Considerations  . . . . . . . . . . . . . . . . . . . 10
   7.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 11
   8.  References . . . . . . . . . . . . . . . . . . . . . . . . . . 11
     8.1.  Normative References . . . . . . . . . . . . . . . . . . . 11
     8.2.  Informative Reference  . . . . . . . . . . . . . . . . . . 11
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 11




























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1.  Introduction

   In-network storage is popular for content distribution, but existing
   framework either keeps applications out of the control loop or need
   to support variety of application protocol and implementations.
   DECADE architecture provides the general content distribution
   framework with standard interface for resource control and data
   transport.  But either using the DECADE compatible in-network storage
   servers as personal storage or using it as content distribution
   platform for applications, there are possibilities that multiple
   servers provide the same content, which would a good scenario to
   consider using Application Traffic Optimization (ALTO) Protocol to
   select a better-than-random server.


2.  Terminology

   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]..

   This document reuses the terminology defined in
   [I-D.draft-alto-problem-statement] and
   [I-D.draft-decade-problem-statement].


3.  Integration Architecture

3.1.  Function Entity

   ALTO Server: The logical entity that provides interfaces to the
   queries to the ALTO service [RFC5693].

   DECADE Server: A DECADE Server stores DECADE data inside the network,
   and thereafter manages both the stored data and access to that data
   [I-D.ietf-decade-arch-02].

   DECADE Client: A DECADE Client stores and retrieves data at DECADE
   Servers [I-D.ietf-decade-arch-02].

   App Tracker: Index Server that stores current peer list which is
   sharing certain network resource, such as movies or music, and so on.

3.2.  Integration Architecture

   Figure 1 shows the basic integration architecture framework of
   integrating DECADE and ALTO.  It indicates that integrating DECADE
   and ALTO can provide optimized network traffic by selecting serving



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   peers in a better-than-random model.

             +----------+         +----------+         +----------+
             | DECADE   |         | DECADE   |         | DECADE   |
             | Client A |         | Client B |         | Client C |
             +----------+         +----------+         +----------+
                  |                    |^                    |
                  |       4.Request for|| 7.Return chosen    |
                  |         resource X ||   serving peer     |
                  |                    V|                    |
             +----------+         +----------+         +----------+
             | DECADE   |         | DECADE   |         | DECADE   |
             | Server A |         | Server B |         | Server C |
             +----------+         +----------+         +----------+
                  |       5.Request for|^ 6.Return chosen    |
                  |         resource X ||   serving peer     |
                  |   (carry identifier||                    |
                  |    of Client B)    ||                    |
                  |                    V|                    |
                  |               +----------+               |
                  --------------->|   App    |<---------------
       1.Add A into the peer list |  Tracker |  2.Add C into the peer list
         holding resource X       +----------+    holding resource X
                                       ^
                          3.Download   |
                            Cost map   |
                                       |
                                  +----------+
                                  |  ALTO    |
                                  |  Server  |
                                  +----------+
             Figure 1 ALTO and DECADE Integration Architecture Framework

   In this framework, DECADE Client requests certain network resources
   from its in-network storage (DECADE Server).  If its DECADE Server
   contains such resources, the request would be satisfied immediately
   and DECADE Client can download the resource directly.  Otherwise, its
   DECADE Server will query the App Tracker for the best serving peer
   which contains those resources, carrying the identifier of the
   requesting DECADE Client in the request.  Each time when App Tracker
   receives DECADE Server's request for certain resources, it queries
   for all current serving peers that contain such resources.  It then
   looks up the network map it already downloaded from the ALTO Server
   in advance.  The cost between the requesting DECADE Client and each
   serving peer in the peer list will be calculated.  Finally, the best
   serving replica at the lowest cost will be returned and the
   requesting resources can be downloaded from it.  This scheme embodies
   the idea of integration of DECADE and ALTO, which may bring many



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   benefits, such as saving network bandwidth.

   In this framework, the cost between every two serving peers can be
   looked up from ALTO Server, however, the cost between a DECADE Client
   and any other Client's DECADE Server cannot be obtained.  Therefore,
   it'd better to pre-store network map with cost between each DECADE
   Client and its DECADE Server in App Tracker.  In this way, combining
   with cost map provided by ALTO Server, the cost between a DECADE
   Client and any other Client's DECADE Server can be calculated, and
   the lowest cost can be decided.

3.3.  Process Flow

   Figure 2 shows the process flow of integrating DECADE and ALTO .
                      DECADE Server-x           ALTO Server
          DECADE Client           App Tracker             DECADE Server-y
                |           |           |     Pre    |           |
                |           |           |<-----------|           |
                |    1      |           |            |           |
                |---------->|           |            |           |
                |           |     2     |            |           |
                |           |---------->|            |           |
                |           |           |            |           |
                |           |     3     |            |           |
                |           |<----------|            |           |
                |           |           |     4      |           |
                |           |<---------------------------------->|
                |     5     |           |            |           |
                |<----------|           |            |           |
                |           |           |            |           |
              Figure 2 Process Flow of Integrating DECADE and ALTO

   Pre: App Tracker downloads cost map from ALTO Server in advance.
   This step can happens any time before step 3.

   1.  DECADE Client requests for certain network resources from its
   DECADE Server (here we name it DECADE Server-x).

   2.  If DECADE Server-x doesn't include the requested resources, it
   will ask for App Tracker's suggestion.  The identifier of DECADE
   Client will be sent to the App Tracker.

   3.  APP Tracker looks up all current serving peers that contain such
   resources.  It then calculate the cost between the requesting Client
   and each serving peers based on the cost map it downloaded from ALTO
   Server in advance and the pre-stored network map with cost between
   each DECADE Client and its DECADE Server.  Finally, the most suitable
   serving peer (here we name it DECADE Server-y) at the lowest cost



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   will be picked up and returned to DECADE Server-x.

   4.  DECADE Server-x downloads the data object from DECADE Server-y.

   5.  DECADE Client downloads the data object from its DECADE Server
   (DECADE Server-x).


4.  Use cases

4.1.  P2P File Sharing

   Related Applications: There are many P2P file sharing applications,
   e.g., BitTorrent, Shareaza, Ares.  The most widely used is
   BitTorrent.

   Original setting: In BitTorrent without DECADE and ALTO, a client
   uploads to other clients using its last mile.  This consumes
   expensive last-mile uplink bandwidth.

   BitTorrent with DECADE: A client first uploads files to a DECADE
   Server, who can then serve other clients.

   BitTorrent with DECADE and ALTO: While two DECADE Servers hold the
   same file that a client wants, integration DECADE with ALTO can help
   the client decide which DECADE Server is the best replica to get this
   file.  And in this scheme, it may bring many benefits, such as saving
   network bandwidth.

   Figure 3 shows an example.  In this example, DECADE Client B wants to
   get a file which both DECADE Server A and DECADE Server C hold.  In
   the original setting without integrating DECADE with ALTO, DECADE
   Client B could randomly get the file by its DECADE Server (DECADE
   Server B) from either DECADE Server A or DECADE Server C. In this
   case, DECADE Client B would consult App Server which DECADE Sever is
   the most suitable serving peer.  In this process, ALTO Server
   provides cost map, and the network map with cost between each DECADE
   Client and its DECADE Server is pre-stored in App Tracker.  Based on
   those two maps, the cost between each serving DECADE Server and the
   requesting DECADE Client can be calculated, finally the serving peer
   at the lowest cost would be selected.










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                +----------+      +----------+      +----------+
                | DECADE   |      | DECADE   |      | DECADE   |
                | Client A |      | Client B |      | Client C |
                +----------+      +----------+      +----------+
                     |                  ^                |
                     |                  |                |
                     |                  |                |
                     |                  |                |
                     |            +----------+           |
                     |            | DECADE   |           |
                     |          ^ | Server B |^          |
                     |         /  +----------+ \         |
                     V        /        ||       \        V
                +----------+ /         ||        \ +----------+
                | DECADE   |/          ||         \| DECADE   |
                | Server A |           ||          | Server C |
                +----------+           ||          +----------+
                                  +----------+
                                  |   App    |
                                  |  Tracker |
                                  +----------+
                                       ||
                                       ||
                                       ||
                                  +----------+
                                  |  ALTO    |
                                  |  Server  |
                                  +----------+
                         Figure 3 P2P File Sharing

   Benefits: DECADE Client can get file by its DECADE Sever from a
   serving peer at the lowest cost, which may saving traffic.  Of
   course, last mile uplink bandwidth is saved, which is expensive.

4.2.  Offline P2P live streaming

   Related Applications: There are many P2P live streaming applications,
   e.g., PPLive, PPStream.

   Original setting: In P2P live streaming without DECADE and ALTO,
   clients may get a bad user experience when they watch the streaming
   after broadcasting at a later time, since there will be not enough
   audiences to watch it after living broadcast.

   PPLive with DECADE: By using DECADE, a client can watch a live
   streaming at a later time, and still have a good video quality.

   PPLive with DECADE and ALTO: While a client wants to watch a live



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   streaming at a later time, integrating DECADE and ALTO can help it
   decide a DECADE Server which hold the content and also at the lowest
   cost.  The client can also enjoy a good user experience, instead of
   having a bad video quality.

   Figure 4 shows an example.  In this example, Client B is broadcasting
   a live streaming.  Client A is online and watching the live
   streaming, and DECADE Server A downloads this streaming from DECADE
   Server B in real time.  Client C is offline and wants to watch this
   streaming at a later time.  DECADE Server C can download this
   streaming from DECADE Server A and DECADE Server B after comparing
   their cost by consulting App Tracker and ALTO Server.  Then DECADE
   Server C will hold the living streaming data for Client C. After
   Client C once is online, it can get the streaming directly for its
   DECADE Server C.




































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                +----------+      +----------+      +----------+
                | DECADE   |      | DECADE   |      | DECADE   |
                | Client A |      | Client B |      | Client C |
                +----------+      +----------+      +----------+
                     ^                  |                ^
                     |                  |                |
                     |                  |                .
                     |                  |                |
                     |                  |                .
                     |                  |                |
                +----------+            |          +----------+
                | DECADE   |---------------------->| DECADE   |
                | Server A |            |          | Server C |
                +----------+            |          +----------+
                            ^           |         ^
                             \          |        /
                              \         V       /
                               \  +----------+ /
                                \ | DECADE   |/
                                  | Server B |
                                  +----------+
                                       ||
                                       ||
                                  +----------+
                                  |   App    |
                                  |  Tracker |
                                  +----------+
                                       ||
                                       ||
                                  +----------+
                                  |  ALTO    |
                                  |  Server  |
                                  +----------+
                   Figure 4 Offline P2P Live Streaming

   Benefits: In original setting, clients missed live streaming
   broadcast, may get a bad video quality when they watch it at a later
   time.  While in integrating DECADE with ALTO, the video quality is
   also good since Client C downloads it directly from it DECADE Server.
   Also, the new setting can help save network traffic as well as last
   mile uplink bandwidth in this use case.


5.  ALTO Protocol Considerations

   In this context, App Tracker may currently need a variety of
   information to perform serving peer selection, for example, ALTO Cost
   Map from ALTO Server.  Via embedding ALTO Client in App Tracker, App



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   Tracker can obtain and locally store ALTO Cost Map from ALTO Server
   by ALTO Protocol, and benefit from this ALTO information to enable
   network-efficient traffic patterns and improve serving performance.
   Figure 5 shows the interactions among the main entities in our
   integration framework where App Tracker is an ALTO Client and applies
   cost map when selecting the best serving peer.
           +------------+                  +-------------+
           |    ALTO    |<---------------> | App Tracker |
           |   Server   | 1.Get Cost Map   |(ALTO Client)|
           +------------+ (ALTO Protocol)  +-------------+
                                                 ^ |
                                    2.Get best   | | 3.Return best
                                    serving Peer | | serving peer
                                                 | |
                                                 | V
                                           +-------------+
                                           |    DECADE   |
                                           |    Server   |
                                           +-------------+
             Figure 5 ALTO Client Embedded in App Tracker

   1.  The App Tracker requests the Cost Map amongst all PIDs from the
   ALTO Server by ALTO Protocol.

   2.  A DECADE Server requests current serving peer at lowest cost from
   the App Tracker.

   3.  The App Tracker returns current best serving peer, which is
   computed based on the ALTO Cost Map as well as other information pre-
   stored in the App Tracker.

   Since App Tracker acts as the ALTO Client in our scheme, while
   applying ALTO Protocol, "Endpoint" in the protocol is used to carry/
   define information of the App Tracker, `including address type,
   address of App Tracker, et, al.  ALTO Cost Map is obtained from ALTO
   Server via an HTTP GET method without any input parameters.  The
   media type is "application/alto-costmap+json".  And ALTO Server would
   return cost map or an error code to the App Tracker after receiving
   such request.


6.  Security Considerations

   This document does not consider security issues.  Security will be
   considered in further version of this draft.






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7.  IANA Considerations

   There is no IANA consideration for this document.


8.  References

8.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", March 1997.

   [RFC5693]  Seedorf, J. and E. Burger, "Application-Layer Traffic
              Optimization (ALTO) Problem Statement", October 2009.

8.2.  Informative Reference

   [I-D.ietf-decade-arch]
              Alimi , R., Yang, Y., Rahman, A., Kutscher, D., and H.
              Liu, "DECADE Architecture", July 2011.

   [I-D.ietf-decade-problem-statement]
              Song, H., Zong, N., Yang, Y., and R. Alimi, "DECoupled
              Application Data Enroute (DECADE) Problem Statement".

   [I-D.draft-alto-problem-statement]
              Seedorf, J. and E. Burger, "Application-Layer Traffic
              Optimization (ALTO) Problem Statement", March 2009.


Authors' Addresses

   Danhua Wang
   Huawei

   Email: wangdanhua@huawei.com


   Haibin Song
   Huawei

   Email: haibin.song@huawei.com









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   Ning Zong
   Huawei

   Email: zongning@huawei.com















































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