1. Models for adaptive-streaming-aware CDNI - Content Acquisition and Content Collections draft-brandenburg-cdni-has-01, section 3.2
CDNI Extended Design Team Meeting
Virtual Meeting
May 29, 2012
Ray van Brandenburg

2. Key Considerations regarding Content Acquisition
Content Collection may consists of very large number of files (e.g. 100s to 1000s)
Large numbers of files increases transaction overhead when acquiring content from uCDN by dCDN
Lots of very small transactions instead of single big one

3. Option 2.1: “Do-Nothing” Approach - 1
Assumes no HAS awareness in uCDN/dCDN and no additions to CDNI Interfaces
Result: the dCDN will acquire each file as a separate independent chunk
i.e chunks results in 1000 content acquisition transactions between dCDN and uCDN

4. Option 2.1: “Do-Nothing” Approach - 2
Effect on CDNI Interfaces:
None
Advantages/Drawbacks:
+ Extremely flexible, dCDN only acquires chunks that are necessary
- Creates more transaction overhead between dCDN and uCDN
- More latency for first client requesting a particular chunk from dCDN

5. Option 2.2: “Allow single file acquisition of fragmented content” - 1
Might be useful to allow dCDN to acquire the entire Content Collection in one transaction
Either as part of a single file (fragmented content), or
As a folder of files, or
As a compressed file containing all chunks
Requires HAS awareness in both dCDN and uCDN

6. Option 2.2: “Allow single file acquisition of fragmented content” - 2
Effect on CDNI Interfaces:
CDNI Metadata Interface: Add fields for indicating the particular type of HAS (e.g. MPEG DASH or HLS) that is used and whether segments or fragments are used
CDNI Metadata Interface: Add field for indicating the name and type of the manifest file(s)
Advantages/Drawbacks:
+ Allows for more efficient content acquisition in all HAS-specific supported forms
- Creates bandwidth and storage overhead in case where clients only request a very small portion of the available chunks
Requires full HAS awareness on part of dCDN/uCDN
Requires significant CDNI Metadata Interface extensions