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ICN Research Group                                            B. Ahlgren
Internet-Draft                                                      SICS
Intended status: Experimental                                  B. Ohlman
Expires: July 2, 2016                                           A. Malik
                                                                Ericsson
                                                       December 30, 2015


                    NetInf Live Video Specification
                draft-ahlgren-icnrg-netinf-live-video-00

Abstract

   This document specifies how the NetInf information-centric network
   service can be used for transport of live video streaming.  To
   illustrate this it describes a prototype system that was developed to
   be used at "events with large crowds", e.g., sports events.  The
   specification defines how the used video format is mapped to NetInf
   named data objects (NDOs).  It also describe how NetInf messages are
   used to transfer the NDOs.

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 July 2, 2016.

Copyright Notice

   Copyright (c) 2015 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



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   to this document.  Code 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.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  System Architecture . . . . . . . . . . . . . . . . . . . . .   2
   3.  Video Format  . . . . . . . . . . . . . . . . . . . . . . . .   4
   4.  Video Transport using NetInf Protocol . . . . . . . . . . . .   4
     4.1.  Video chunk NDOs  . . . . . . . . . . . . . . . . . . . .   5
     4.2.  Publishing video chunk NDOs . . . . . . . . . . . . . . .   5
     4.3.  Receiving video chunk NDOs  . . . . . . . . . . . . . . .   6
   5.  Video Manifest  . . . . . . . . . . . . . . . . . . . . . . .   6
     5.1.  Video stream header NDOs  . . . . . . . . . . . . . . . .   6
     5.2.  Publishing video header NDOs  . . . . . . . . . . . . . .   7
     5.3.  Browsing available video streams  . . . . . . . . . . . .   7
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .   7
   7.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   7
   8.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   8
     8.1.  Normative References  . . . . . . . . . . . . . . . . . .   8
     8.2.  Informative References  . . . . . . . . . . . . . . . . .   8
     8.3.  URIs  . . . . . . . . . . . . . . . . . . . . . . . . . .   8
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   8

1.  Introduction

   This specification documents how a prototype NetInf-based
   [Dannewitz2013] live video streaming system makes use of the NetInf
   information-centric network (ICN) service.  The prototype has been
   field-tested and demonstrated at numerous occasions [Malik2015a]
   [Malik2015b].  The Android client software that is part of the
   prototype system has been made available on Sourceforge [1] as open
   source with an Apache 2.0 license.

   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].

2.  System Architecture

   Figure 1 shows the architecture of the NetInf live video streaming
   system.  Users can record and publish video streams at a live event
   and at the same time other users can watch the streams live.  The
   architecture also facilitates streaming to a device anywhere on the
   internet so that users not present at the venue can also publish or
   play streams.



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   +---------------------------------------------------------------+
   | NetInf Core Network                                           |
   |                   +--------+                                  |
   |                   | NetInf |                     +-----+      |
   |           +-------+ Router +-------+             | NRS |      |
   |           |       +--------+       |             |     |      |
   |           |                        |             +-----+      |
   |       +---+----+              +----+---+                      |
   |       | NetInf |              | NetInf |                      |
   |       | Router |              | Router +---------+            |
   |       +---+----+              +--------+         |            |
   |           |                                      |            |
   +---------------------------------------------------------------+
               |                                      |
               |                        +--------------------------+
    XXXXXXXXXXX+XXXXXXXXXXXXXXXXXXXXXX  | NetInf      |            |
    X                                X  | Access +----+---+        |
    X             Internet           X  | Network| NetInf |        |
    X                                X  | at     | Router |        |
    XXXXXXX+XXXXXXXXXXXXXXXX+XXXXXXXXX  | event  ++------++        |
           |                |           | venue   |      |         |
           |                |           |         |      |         |
    XXXXXXX+XXXXXXX  XXXXXXXXXXXXXXXXX  |  +------+-+  +-+------+  |
    X WiFi Access X  X Mobile Access X  |  | NetInf |  | NetInf |  |
    XXXXXXX+XXXXXXX  XXXX+XXXXXX+XXXXX  |  | Router |  | Router |  |
           |             |      |       |  +----+---+  +----+---+  |
           |             |      |       |       |           |      |
           |             |      |       |  XXXXX+XXXXXXXXXXX+XXX   |
         +-+-+         +-+-+    |       |  X    WiFi Access    X   |
         | P |         | P |    |       |  XXXXXXX+XXXXXX+XXXX+X   |
         +---+         +---+    |       |         |      |    |    |
                                |       | +---+ +-+-+  +-+-+ ++--+ |
                                +---------+ R | | P |  | R | | P | |
     R:   Recording client              | +---+ +---+  +---+ +---+ |
     P:   Playing client                |                          |
     NRS: Name Resolution Service       +--------------------------+


                       Figure 1: System architecture

   Recording and playing clients at the event venue can connect to the
   system using local WiFi or mobile internet (3G/4G).  Before a client
   can start publishing or playing, it first connects to a NetInf
   router.  Consequently this router acts as the first hop NetInf node
   for the client.  Clients on local WiFi at the event venue connect to
   a NetInf router in the local access network.  Clients on the internet
   connect to a NetInf router in the NetInf core network.




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   The NetInf core network hosts a Name Resolution Service (NRS).  This
   service is responsible for resolving object names into locators.  It
   also provides search function for the registered Named Data Objects
   (NDOs).

   ICN employs ubiquitous caching.  Therefore every NetInf router in the
   architecture is coupled with a local cache.  These routers cache NDOs
   on-path and serve them to corresponding GET requests when there is a
   cache hit.  This ensures that clients are served data from the local
   network (if the data is cached) and that the edge links (like the one
   between the NetInf access network and the NetInf core network as seen
   in Figure 1) are not choked with traffic.

3.  Video Format

   The transport of video chunks using NetInf described in this
   specification can be used for video with any type of encoding.  As an
   example we describe the mpeg4/H.264 encoding used at the above
   referenced events.

   When transporting video over an best effort network, such an ICN
   network, there are two main goals: to minimize the delay and to avoid
   rebuffering events.  Unfortunately the means to achieve these goals
   are conflicting.  Small buffers are needed to minimize delay, large
   buffers are needed to minimize the risk of rebuffering.

   At the events referenced above the video generated by the recording
   device were encoded using H.264/AVC video format and had the mime
   type "video/avc".  The video is split into chunks so that each chunk
   fits into an NDO.  Chunking is done at I-frames in order to ensure
   that video chunks are independent of each other.  The H.264 encoded
   chunks are packaged into MP4 containers.  The frame rate and I-frame
   intervals are configurable.  The parameters can be tweaked to achieve
   different tradeoffs between the playback latency and the NDO header
   overhead.  The I-frame interval controls the size of the generated
   video chunks.  A typical setting of 30 fps and 2 seconds,
   respectively, was used with the largest available 16:9 resolution
   less than 864x480, resulting in a video data rate of about 1 Mbps.
   Each chunk corresponds, in this case, to a video playout of 2
   seconds.  To avoid rebuffering the playing application buffers of
   video data was typically set to 10 seconds.

4.  Video Transport using NetInf Protocol

   This section describes how NetInf named data objects (NDOs) are
   created from the video chunks in the previous section, and how the
   NDOs are made available to clients using the NetInf protocol
   [I-D.kutscher-icnrg-netinf-proto] with extensions for subscriptions



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   using the NetInf SUBSCRIBE and NOTIFY messages.  As described in the
   NetInf protocol specification, a NetInf NDO consists of the object's
   data and, optionally, associated JSON-encoded meta-data.

   Two kinds of NetInf NDOs are created for a video stream: one carrying
   the video chunks, and another carrying a "header", or manifest, that
   describes the stream of video chunks.  The latter is described in the
   next section.

4.1.  Video chunk NDOs

   Each video chunk is turned into one NetInf NDO.  The bytes of the
   video chunk are directly put into the data content of the NDO.

   The following meta-data items MUST be supplied with video chunk NDOs:

   chunk_number      The sequence number of the chunk in the video
                     starting with zero.  (Integer)

   video_name        The name (ni hash [RFC6920]) of the video stream
                     header NDO encoded with the URL-SAFE variant of
                     BASE64 without padding.  (ASCII string)

   start_time        The starting time of the chunk in microseconds
                     since the start of the video.  (Long integer)

   duration          The duration of the video chunk in microseconds.
                     (Long integer)

   signature         A digital signature for the chunk.  The signature
                     is an RSA signature on the SHA-256 hash of the
                     content as defined in the PKCS #1: RSA Cryptography
                     Standard.  The result is BASE64 encoded without
                     padding or wrapping, using the URL-SAFE encoding
                     variant.  (ASCII string)

4.2.  Publishing video chunk NDOs

   Video chunk NDOs are published using NetInf PUBLISH as described in
   the NetInf protocol specification [I-D.kutscher-icnrg-netinf-proto].
   The JSON-encoded meta-data is supplied as a "meta" item of the "ext"
   parameter in the PUBLISH message.

   In addition, a NetInf NOTIFY message MUST be sent for each
   successfully published video chunk.  The NOTIFY message contains the
   ni URI [RFC6920] of the stream header NDO and the ni URI of the just
   published video chunk NDO.  It also contains the sequence number and
   signature of the video chunk NDO.



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   The destination for both of these messages is normally a designated
   next-hop NetInf router for the client.  How the client finds this
   destination is out of scope for this specification.

4.3.  Receiving video chunk NDOs

   Clients that wish to receive video chunks MAY register to receive the
   above notifications using the NetInf SUBSCRIBE extension.  They will
   then receive the NetInf NOTIFY, and can then issue a NetInf GET to
   retrieve the newly published video chunk.

5.  Video Manifest

   This section describes the video stream header and how it is encoded
   and published as a NetInf NDO.

5.1.  Video stream header NDOs

   Each video stream MUST be described and identified by publishing a
   stream header NDO.  It contains various information about the stream
   and a public key that can be used by clients to verify the
   authenticity of the video chunk NDOs.  The hash part the NetInf "ni"
   name of the header NDO is used to name the video stream.  That hash
   is included as meta-data of the video chunk NDOs.

   The NDO data (content) MUST be constructed by concatenating the bytes
   of the following items in binary form:

   MAGIC             The ASCII character sequence "ENS0".

   Public key length Four-byte integer with the length of the public
                     key.  (Note: needs to be network byte order/big
                     endian, but the implementation likely uses little
                     endian.)

   Public key        The public key for the stream encoded according to
                     X.509 ASN.1 SubjectPublicKeyInfo.

   Contents          Any additional data provided by the client.
                     (optional)

   The following JSON-encoded meta-data MUST be included with header
   NDOs:

   title             A title for the video stream as provided by the
                     client.  (ASCII string)





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   description       A descriptive text provided by the client.  (ASCII
                     string)

   region            A short text description of the location where the
                     video is recorded.  (ASCII string)

   stream-start      The time of the start of the stream in Unix time in
                     milliseconds.  (Long integer)

   The following JSON-encoded meta-data SHOULD be included with header
   NDOs:

   stream-end        The time of the end of the stream in Unix time in
                     milliseconds.  The NDO SHOULD be updated with this
                     item when the recording has completed.  (Long
                     integer)

   gps-x             The X coordinate (longitude) of the location of the
                     recorded video in degrees.  (Double floating point
                     number)

   gps-y             The Y coordinate (latitude) of the location of the
                     recorded video in degrees.  (Double floating point
                     number)

5.2.  Publishing video header NDOs

   Video header NDOs are published using NetInf PUBLISH as described in
   the NetInf protocol specification [I-D.kutscher-icnrg-netinf-proto].
   The JSON-encoded meta-data is supplied as a "meta" item of the "ext"
   parameter in the PUBLISH message.

5.3.  Browsing available video streams

   Clients can use the NetInf SEARCH message to collect information
   about the published video stream headers, and with the result
   populate a browser listing in the user interface.  The user can with
   that choose a video to play.

6.  Security Considerations

   TBD

7.  Acknowledgements

   The work behind and the writing of this document are supported by the
   activity `14082 Networks for Future Media Distribution' within EIT
   Digital (formerly EIT ICT labs).



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8.  References

8.1.  Normative References

   [I-D.kutscher-icnrg-netinf-proto]
              Kutscher, D., Farrell, S., and E. Davies, "The NetInf
              Protocol", draft-kutscher-icnrg-netinf-proto-01 (work in
              progress), February 2013.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC6920]  Farrell, S., Kutscher, D., Dannewitz, C., Ohlman, B.,
              Keranen, A., and P. Hallam-Baker, "Naming Things with
              Hashes", RFC 6920, DOI 10.17487/RFC6920, April 2013,
              <http://www.rfc-editor.org/info/rfc6920>.

8.2.  Informative References

   [Dannewitz2013]
              Dannewitz, C., Kutscher, D., Ohlman, B., Farrell, S.,
              Ahlgren, B., and H. Karl, "Network of Information (NetInf)
              - An Information-Centric Networking Architecture",
              Computer Communications 36 (7). pp. 721-735. ISSN
              0140-3664, April 2013.

   [Malik2015a]
              Malik, A., Ahlgren, B., Ohlman, B., Lindgren, A., Ngai,
              E., Klingsbo, L., and M. Laeng, "Experiences from a field
              test using ICN for live video streaming", Proc. Workshop
              on Multimedia Streaming in Information-Centric Networks,
              in conjunction with ICME 2015, Turin, Italy, July 2015.

   [Malik2015b]
              Malik, A., Ahlgren, B., and B. Ohlman, "NetInf Live Video
              Streaming for Events with Large Crowds (demo)", Proc. 2nd
              ACM Conference on Information-Centric Networking (ICN),
              San Francisco, California, USA, Sept-Oct 2015.

8.3.  URIs

   [1] https://sourceforge.net/projects/netinf/

Authors' Addresses







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   Bengt Ahlgren
   SICS Swedish ICT
   Box 1263
   Kista  SE-164 29
   SE

   Phone: +46703141562
   Email: bengta@sics.se
   URI:   http://www.sics.se/people/bengt-ahlgren


   Boerje Ohlman
   Ericsson
   Kista  SE-164 80
   SE

   Phone: +46705193187
   Email: borje.ohlman@ericsson.com


   Adeel Mohammad Malik
   Ericsson
   Kista  SE-164 80
   SE

   Phone: +46725074492
   Email: adeel.mohammad.malik@ericsson.com
























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