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Capability Information Advertising for CDN Interconnection
draft-he-cdni-cap-info-advertising-00

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This is an older version of an Internet-Draft whose latest revision state is "Expired".
Authors Xiaoyan He , Spencer Dawkins , Ge Chen , Yunfei Zhang , Wei Ni
Last updated 2012-02-16
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draft-he-cdni-cap-info-advertising-00
CDNI Working Group                                              Xiaoyan.He 
Internet Draft                                             Spencer.Dawkins 
Intended status: Standards Track                                    Huawei  
Expires: August 2012                                               Ge.Chen 
                                                             China Telecom 
                                                              Yunfei.Zhang 
                                                                    Wei.Ni 
                                                              China Mobile 
                                                         February 16, 2012 
 
 
                                     
            Capability Information Advertising for CDN Interconnection 
                   draft-he-cdni-cap-info-advertising-00.txt 

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), its areas, and its working groups.  Note that other groups may also 
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  This Internet-Draft will expire on August 16, 2012. 

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 
 
 
 
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  Components extracted from this document must 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. 

   

Abstract 
  This document describes protocol for Capability Information Advertising which is 
  used to communicate capability information among interconnected Content Delivery 
  Networks(CDNs). 
 
Table of Contents 

   
  1. Introduction ..................................................... 2 
     1.1. Terminology ................................................. 3 
     1.2. Reference Model .............................................. 3 
  2. Conventions used in this document.................................... 4 
  3. Capability information description ................................... 4 
  4. Protocol Function and Operation Overview ............................. 5 
  5. Protocol Specification ............................................. 5 
     5.1. Capability information description .............................. 5 
     5.2. Message description........................................... 6 
        5.2.1. Report mode............................................. 7 
        5.2.2. Query mode ............................................. 7 
     5.3. Message examples ............................................. 7 
        5.3.1. Report mode............................................. 7 
        5.3.2. Query mode ............................................. 8 
  6. Security Considerations ............................................ 8 
  7. IANA Considerations ............................................... 9 
  8. References ....................................................... 9 
     8.1. Normative References .......................................... 9 
     8.2. Informative References ........................................ 9 
  9. Acknowledgments.................................................. 10 
   
1. Introduction 
  Some discussion happened on request routing interface of CDNI among the CDNI 
  working group, consensus has been achieved that the request routing interface 
  comprises two main parts and these two parts should be addressed in different 
  documents to progress separately: 
    
  * the asynchronous advertisement of footprint and capabilities by a 
   dCDN that allows a uCDN to decide whether to redirect particular user requests to 
   that dCDN; and 
    
   * The synchronous operation of actually redirecting a user request.  
    
 
 
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  This document hence focuses on defining the Capability Information Advertising 
  Protocol for CDNI, which is one of the main building blocks of request routing 
  interface. 
      

1.1. Terminology 
  This document reuses the terminology defined in [I-D.draft-cdni-problem-statement]. 
 
1.2. Reference Model 
  Figure 1 from [I-D.draft-cdni-problem-statement] illustrating the 
  CDNI model and the CDNI interfaces are replicated below.  

  The Capability Information Advertising Protocol is not explicitly shown in figure 
  1. Although that might be changed later upon the working group's decision, but now 
  it is thought that capability advertisement is part of the function of the Request 
  Routing interface. 

 
     -------- 
    /        \ 
    |   CSP  | 
    \        / 
     -------- 
         * 
         * 
         *                         /\ 
         *                        /  \ 
     ----------------------      |CDNI|        ---------------------- 
    /     Upstream CDN     \     |    |       /    Downstream CDN    \ 
    |      +-------------+ | Control Interface| +-------------+      | 
    |*******   Control   |<======|====|========>|   Control   *******| 
    |*     +------*----*-+ |     |    |       | +-*----*------+     *| 
    |*            *    *   |     |    |       |   *    *            *| 
    |*     +------*------+ | Logging Interface| +------*------+     *| 
    |* *****   Logging   |<======|====|========>|   Logging   ***** *| 
    |* *   +-*-----------+ |     |    |       | +-----------*-+   * *| 
    |* *     *         *   | Request Routing  |   *         *     * *| 
  .....*...+-*---------*-+ |    Interface     | +-*---------*-+...*.*... 
  . |* * *** Req-Routing |<======|====|========>| Req-Routing *** * *| . 
  . |* * * +-------------+.|     |    |       | +-------------+ * * *| . 
  . |* * *                 .  CDNI Metadata   |                 * * *| . 
  . |* * * +-------------+ |.   Interface     | +-------------+ * * *| . 
  . |* * * | Distribution|<==.===|====|========>| Distribution| * * *| . 
  . |* * * |             | |  .   \  /        | |             | * * *| . 
  . |* * * |+---------+  | |   .   \/         | |  +---------+| * * *| . 
 
 
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  . |* * ***| +---------+| |    ....Request......+---------+ |*** * *| . 
  . |* *****+-|Surrogate|************************|Surrogate|-+***** *| . 
  . |*******  +---------+| |   Acquisition    | |+----------+ *******| . 
  . |      +-------------+ |                  | +-------*-----+      | . 
  . \                      /                  \         *            / . 
  .  ----------------------                    ---------*------------  . 
  .                                                     *              . 
  .                                                     * Delivery     . 
  .                                                     *              . 
  .                                                  +--*---+          . 
  ...............Request.............................| User |..Request.. 
                                                     | Agent| 
                                                     +------+ 
 
 
                  <==>  interfaces inside the scope of CDNI 
                  ****  interfaces outside the scope of CDNI 
                  ....  interfaces outside the scope of CDNI 
                          Figure 1: CDNI Model 
 
 
 
2. Conventions used in this document 

  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]. 

3. Capability information description 

  The Capability Information Advertising Protocol allows the Downstream CDN to 
  provide the Upstream CDN with information (e.g. resources, footprint, load) to 
  facilitate selection of the Downstream CDN by the Upstream CDN request routing 
  system when processing subsequent content requests from User Agents. 

  From the perspective of an Upstream CDN, to make a routing decision from multiple 
  Downstream CDNs which will meet the local policy or requirement of the CP, the 
  information needed may includes: 

  O Status of each CDN, e.g. in service or out of service; 

  O Resource status of each Downstream CDN, e.g. usage percentage of acquisition 
  bandwidth, usage percentage of delivery bandwidth, available acquisition bandwidth, 
  available delivery bandwidth etc.; 

  O Footprint of each Downstream CDN; 

 
 
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  O Delivery protocol supported by each Downstream CDN; 

  O Cost information of each Downstream CDN; 

  O Authentication type to end user supported by each of the Downstream CDNs 
  (Optional) 

   

4. Protocol Function and Operation Overview 
  CDN capability is information coupling with a specified application (CDNI), it 
  should be conveyed via an application layer protocol rather than any other 
  underlying layer protocol e.g. IP layer which should de-coupling with any 
  application. In this document HTTP/1.1 protocol [RFC2616] is used for capability 
  information advertising. The CDNs which have contracted for providing 
  interconnection service to each other send capability advertisement messages to 
  their interconnected peers. The detailed capability information description and 
  message definition is described in section 5 of this document. 
   
  The Capability Information Advertising Protocol takes two modes. One is report 
  mode, where the Downstream CDN advertises its capability information to the 
  Upstream CDN during at a periodic interval, e.g. every 5 minutes. The other one is 
  query mode, where the Upstream CDN acquires the capability information from the 
  Downstream CDN periodically, e.g. every 5 minutes. The Upstream CDN utilizes the 
  capability information to makes its routing decision upon receiving a content 
  request from an end user. 
   
  To enable the communications over the Capability Information Advertising Protocol, 
  the two interconnected CDNs need to know each other's contact address. The contact 
  address may be statically pre-configured, dynamically discovered via control 
  interface, or other means. However, they are not specified in this document, as 
  this is considered not in the scope of the CDNI Capability Information Advertising 
  Protocol. 
   

5. Protocol Specification 

  This section describes the details of the Capability Information Advertising 
  Protocol. 

5.1. Capability information description 
  The Downstream CDN exposes its capability information to an Upstream CDN to 
  facilitate CDN selection among other functions. The exposure should be of 
  appropriate granularity to ensure the self-administrative nature of Downstream CDN. 
   
  The following information in Table 2 is considered for capability exchange. 
 
  +----------+-----------+-----------------+------+-------------------------+ 
  | Name     |  Type     |   Value         | Cat. | Description             | 
  +----------+-----------+-----------------+------+-------------------------+ 
 
 
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  | IPVersion|ENUM,4 byte|1:IPV4;2:IPV6    | M    |IP address version of    | 
  |          |           |3:IPV4&IPV6      |      |which a CDN can serve for| 
  |          |           |                 |      |end users                | 
  +----------+-----------+-----------------+------+-------------------------+ 
  | Service- |ENUM,4 byte|1:in-service;    | M    | CDNI service status     | 
  | Status   |           |2:out-of-service |      |                         | 
  +----------+-----------+-----------------+------+-------------------------+ 
  |maxDelive-|           |  Integer starts |      |Maximum bandwidth commit-| 
  |ryBW      |  UNIT32   |  from zero      | M    |ted for content delivery | 
  |          |           |  Unit:Mbps      |      |                         | 
  +----------+-----------+-----------------+------+-------------------------+ 
  |          |           | Integer starts  |      | Current usage percentage|   
  |DeliveryBW|  UNIT8    |from zero to 100 | M    | of  bandwidth for       | 
  |Usage     |           |                 |      | content delivery        | 
  +----------+-----------+-----------------+------+-------------------------+ 
  |maxConnec-| UNIT32    |  Integer starts | M    |Maximum number of simult-| 
  |tion      |           |  from zero      |      |neous HTTP connections   | 
  |          |           |                 |      |committed for content    | 
  |          |           |                 |      |delivery                 | 
  +----------+-----------+-----------------+------+-------------------------+ 
  |usedConne-| UNIT32    | Integer starts  | M    |Number of HTTP connection| 
  |ction     |           | from zero       |      | for content delivery    | 
  +----------+-----------+-----------------+------+-------------------------+ 
  |Delivery- |  List     |A list of protoc-| M    | Supported delivery      | 
  |Protocol  |           |ols,e.g.HTTP,RTSP|      |   protocols             | 
  +----------+-----------+-----------------+------+-------------------------+ 
  |Coverage  |  List     |Coverage represe-|      | CDN coverage            | 
  |          |           |nted by ASN or   |      |                         | 
  |          |           |Contry,State,City| M    |                         | 
  |          |           |combination of   |      |                         | 
  |          |           |the covered      |      |                         | 
  |          |           |region           |      |                         | 
  +----------+-----------+-----------------+------+-------------------------+ 
  |Cost      | Object    |A Currency and a | M    | CDN Cost                | 
  |          |           |Price subelement |      |                         |                        
  +----------+-----------+-----------------+------+-------------------------+ 
  |Currency  | String    |USD,CNY, EUR etc.| M    | CDN Currency            | 
  +----------+-----------+-----------------+------+-------------------------+ 
  |Price     | UNIT32    |  Integer starts |      | CDN Price for per GB    |            
  |          |           |  From zero      | M    | data delivery           | 
  +----------+-----------+-----------------+------+-------------------------+ 
  |UserAuth  |ENUM,4 byte| 1:urlSigning;   |      | Authentication type to  | 
  |          |           | 2:urlToken      | O    | end user supported byCDN| 
  +----------+-----------+-----------------+------+-------------------------+ 
 
  Note: The value of "maxDeliveryBW" and "DeliveryBWUsage" may be 
  an absolute value taking only the physical bandwidth of the CDN into 
  account or it may be a normalized value which may also consider the disk I/O 
  capacity and CPU usage as a whole. This depends on the CDN specific implementation 
  and is out of scope of CDNI.  
                   Table 2 capability information description 
   
5.2. Message description 
  The HTTP/1.1 protocol is used for capability advertising. 
   
 
 
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  The HTTP request is HTTP POST for Report mode and HTTP GET for Query mode 
  respectively. 
   
  The request URI in both modes conforms to [RFC3986]. The URI format in this 
  document is as follows: HTTP://<host>/<url-path>, where the <host> specifies a 
  destination, and the <url-path>  conveys the message name. 
   
  The message body representation specified in this document is JavaScript Object 
  Notation(JSON). 

5.2.1. Report mode 
  The Downstream CDN issues an HTTP POST message to the Upstream CDN to report its 
  capability information. 
   
  The message name in the request URI is "CdniCapReport". 
   
  The Content-Type header field is "application/json". 
   
  The message body includes capability information. 
   
  Upon successful receipt of the POST request, the Upstream CDN responds with a 200 
  OK message. 
 
 
5.2.2. Query mode 
  The Upstream CDN issues a HTTP GET message to a Downstream CDN to query its 
  capability information. 
   
  The message name in the request URI is "CdniCapQuery". 
   
  Upon successful receipt of the GET request, the Downstream CDN responds a 200 OK 
  message with its capability information. 
   
  The Content-Type header field for the response is "application/json". 
   

5.3. Message examples 

  This section gives some message examples for Capability Information Advertising 
  Protocol. 

5.3.1. Report mode 
  The POST request and corresponding response are illustrated as below. 
   
  Request example (Downstream CDN to Upstream CDN): 
   
  POST http://contact-address.ucdn.example/CdniCapReport HTTP/1.1 
  Content-Type: application/json 
  Content-Length: 350 
 
 
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   {  
       "IPVersion":1,  
       "ServiceStatus":1,   
       "maxDeliveryBW":5000,  
       "DeliveryBWUsage":40,   
       "maxConnection": 2000, 
       "usedConnection": 600, 
       "DeliveryProtocol":["HTTP","RSTP"],  
       "Cost": 
      {"Currency":USD,  
       "Price":200, 
      }, 
       
       "Coverage": 
       [  
           {  
              "ASN":1000 
           },  
 
           {  
               "ASN":2000    
           }  
        ]  
    }  
   
   
  Response example: 
   
      HTTP/1.1 200 OK 
5.3.2. Query mode 
  The GET request and corresponding response are illustrated as below. 
   
  Request example (Upstream CDN to Downstream CDN): 
   
  GET http://contact-address.dcdn.example/CdniCapQuery HTTP/1.1 
   
   
  Response example: 
   
  HTTP/1.1 200 OK 
  Content-Type: application/json 
  Content-Length: 350 
   
  The content of message body is the same as that of POST message illustrated in 
  section 4.3.1. 
 
   

6. Security Considerations 
  Capability advertising is a main function which will affect the final routing 
  decision of an upstream CDN, security threats on it 

 
 
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  include that any identity spoofing of the downstream CDN or changing of the 
  capability advertising message with malicious intent which would cause the 
  upstream CDN redirect an end user request to an inappropriate downstream CDN which 
  possible cannot provide service to the end user.   
    
  It is mentioned in section 8 of the requirement draft [I-D.draft-cdni-
  requirements], all the CDNI interface shall support secure operation over 
  unsecured IP connectivity (e.g. The Internet).  This includes authentication, 
  confidentiality, integrity protection as well as protection against spoofing and 
  replay. As this security requirement applies to all the CDNI interfaces and it is 
  recommended that the working group addresses this issue and considers a consistent 
  solution in another separate document later. 
 
7. IANA Considerations 
  If the approach described in this document is adopted, we would request that IANA 
  allocate the message name "CdniCapReport" and CdniCapQuery" in the HTTP Parameters 
  registry. 
   
8. References 

8.1. Normative References 
   [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 
   Requirement Levels", BCP 14, RFC 2119, March 1997. 
    
   [RFC2616] Fielding, R., Gettys, J., Mogul, J., Frystyk, H., 
   Masinter, L., Leach, P., and T. Berners-Lee, "Hypertext 
   Transfer Protocol -- HTTP/1.1", RFC 2616, June 1999. 
    
    
   [RFC3986] Berners-Lee, T., Fielding, R. and L. Masinter, "Uniform 
   Resource Identifiers (URI): Generic Syntax and Semantics", 
   RFC 3986, January 2005. 
 
 
8.2. Informative References 
   [I-D.draft-cdni-use-cases] 
   "Use Cases for Content Delivery Network Interconnection", 
   Gilles Bertrand, Stephan Emile, Grant Watson, Trevor 
   Burbridge, Philip Eardley, Kevin Ma, 22-Sep-11, <draft-ietf- 
   cdni-use-cases-03.txt>. 
    
   [I-D.draft-cdni-problem-statement] 
   "Content Distribution Network Interconnection (CDNI) Problem 
   Statement", Ben Niven-Jenkins, Francois Faucheur, Nabil 
   Bitar, 9-Sep-11, <draft-ietf-cdni-problem-statement-03.txt>. 
    
    
  [I-D.draft-cdni-requirements] 
   "Content Distribution Network Interconnection (CDNI) 
   Requirements", Kent Leung, Yiu Lee, 9-Sep-11, <draft-ietf- 
   cdni-requirements-02.txt>. 
 
 
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   [I-D.davie-cdni-framework] 
   Davie, B. and L. Peterson, "Framework for CDN 
   Interconnection", draft-davie-cdni-framework-01 (work in 
   progress), July 2011. 
 
9. Acknowledgments 

  This document was prepared using 2-Word-v2.0.template.dot. 

 
 
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Authors' Addresses 
   Xiaoyan He 
   Huawei 
   B2, Huawei Industrial Base, 518129 
   China 
    
   Email: hexiaoyan@huawei.com 
    
    
   Spencer Dawkins 
   Huawei 
    
   Email: spencer@wonderhamster.org 
 
    
   Ge Chen 
   China Telecom 
   109 West Zhongshan Ave,Tianhe District,Guangzhou,P.R.C 
 
   Email: cheng@gsta.com 

    
   Yunfei Zhang 
   China Mobile 
    
   Email: zhangyunfei@chinamobile.com 
 
   Wei Ni  
   China Mobile  
   No.32 Xuanwumen West Street Xicheng District Beijing, 100053  
   China  
     
   Email: niwei@chinamobile.com 

 
 
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