Independent Submission R. van Brandenburg
Request for Comments: 6983 O. van Deventer
Category: Informational TNO
ISSN: 2070-1721 F. Le Faucheur
K. Leung
Cisco Systems
July 2013
Models for HTTP-Adaptive-Streaming-Aware
Content Distribution Network Interconnection (CDNI)
Abstract
This document presents thoughts on the potential impact of supporting
HTTP Adaptive Streaming (HAS) technologies in Content Distribution
Network Interconnection (CDNI) scenarios. The intent is to present
the authors' analysis of the CDNI-HAS problem space and discuss
different options put forward by the authors (and by others during
informal discussions) on how to deal with HAS in the context of CDNI.
This document has been used as input information during the CDNI
working group process for making a decision regarding support for
HAS.
Status of This Memo
This document is not an Internet Standards Track specification; it is
published for informational purposes.
This is a contribution to the RFC Series, independently of any other
RFC stream. The RFC Editor has chosen to publish this document at
its discretion and makes no statement about its value for
implementation or deployment. Documents approved for publication by
the RFC Editor are not a candidate for any level of Internet
Standard; see Section 2 of RFC 5741.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc6983.
van Brandenburg, et al. Informational [Page 1]
RFC 6983 HTTP Adaptive Streaming and CDNI July 2013
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
(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.
Table of Contents
1. Introduction ....................................................4
1.1. Terminology ................................................5
2. HTTP Adaptive Streaming Aspects Relevant to CDNI ................6
2.1. Segmentation versus Fragmentation ..........................6
2.2. Addressing Chunks ..........................................7
2.2.1. Relative URLs .......................................8
2.2.2. Absolute URLs with Redirection ......................9
2.2.3. Absolute URLs without Redirection ..................10
2.3. Live Content versus VoD Content ...........................11
2.4. Stream Splicing ...........................................12
3. Possible HAS Optimizations .....................................12
3.1. File Management and Content Collections ...................13
3.1.1. General Remarks ....................................13
3.1.2. Candidate Approaches ...............................13
3.1.2.1. Option 1.1: Do Nothing ....................13
3.1.2.2. Option 1.2: Allow Single-File
Storage of Fragmented Content .............14
3.1.2.3. Option 1.3: Access Correlation Hint .......14
3.1.3. Recommendations ....................................15
3.2. Content Acquisition of Content Collections ................15
3.2.1. General Remarks ....................................15
3.2.2. Candidate Approaches ...............................16
3.2.2.1. Option 2.1: No HAS Awareness ..............16
3.2.2.2. Option 2.2: Allow Single-File
Acquisition of Fragmented Content .........17
3.2.3. Recommendations ....................................17
van Brandenburg, et al. Informational [Page 2]
RFC 6983 HTTP Adaptive Streaming and CDNI July 2013
3.3. Request Routing of HAS Content ............................17
3.3.1. General Remarks ....................................17
3.3.2. Candidate Approaches ...............................18
3.3.2.1. Option 3.1: No HAS Awareness ..............18
3.3.2.2. Option 3.2: Manifest File Rewriting
by uCDN ...................................20
3.3.2.3. Option 3.3: Two-Step Manifest File
Rewriting .................................21
3.3.3. Recommendations ....................................22
3.4. Logging ...................................................23
3.4.1. General Remarks ....................................23
3.4.2. Candidate Approaches ...............................24
3.4.2.1. Option 4.1: Do Nothing ....................24
3.4.2.2. Option 4.2: CDNI Metadata Content
Collection ID .............................26
3.4.2.3. Option 4.3: CDNI Logging Interface
Compression ...............................28
3.4.2.4. Option 4.4: Full HAS
Awareness/Per-Session Logs ................29
3.4.3. Recommendations ....................................30
3.5. URL Signing ...............................................32
3.5.1. HAS Implications ...................................32
3.5.2. CDNI Considerations ................................33
3.5.3. Option 5.1: Do Nothing .............................34
3.5.4. Option 5.2: Flexible URL Signing by CSP ............34
3.5.5. Option 5.3: Flexible URL Signing by uCDN ...........37
3.5.6. Option 5.4: Authorization Group ID and HTTP
Cookie .............................................37
3.5.7. Option 5.5: HAS Awareness with HTTP Cookie in CDN ..38
3.5.8. Option 5.6: HAS Awareness with Manifest
File in CDN ........................................40
3.5.9. Recommendations ....................................41