Download Content distribution network should be layered.

INTERNATIONAL TELECOMMUNICATION UNION
FOCUS GROUP ON IPTV
TELECOMMUNICATION
STANDARDIZATION SECTOR
FG IPTV-C-0158
English only
STUDY PERIOD 2005-2008
2nd FG IPTV meeting:
Busan, 16-20 October 2006
WG(s): 4
CONTRIBUTION
Source: ZTE Corporation
Title:
The network control requirements for content distribution aspects
1. Abstract
This proposal provides some requirements on the areas of IPTV service content delivery, and
suggests using both CDN and streaming technique to construct IPTV service content delivery
network.
2. Discussion
In order to meet the demand of large scale IPTV services, providing plenty of broadband media
contents in the IP bearer network and delivering the contents to the edge network, it is necessary to
introduce CDN cooperate with stream media technique to support non real-time and real-time IPTV
services. The following network control requirements should be considered as CDN based content
delivery.
Content distribution network should be layered.
 Each layer has several serving node.

The IPTV service network should be constructed flexibly by serving nodes.

The serving node should be constructed by a node controller and several stream servers.
Same network layer should adopt distributed structure.
 The serving node in same layer can communicate with each other to exchange the contents.

The node controller provides the load balance among the stream servers in the serving node,
and adjusts the deployment of the contents between serving nodes.
Contact:
Huang Zheng
ZTE Corporation
P.R. China
Tel: +86-25-52871266
Fax: +86-25-52871000
Email: [email protected]
Yang Wei
ZTE Corporation
P.R. China
Tel: +86-25-52871121
Fax: +86-25-52871124
Email: [email protected]
Attention: This is a document submitted to the work of ITU-T and is intended for use by the participants to the activities of ITU-T's
Focus Group on IPTV, and their respective staff and collaborators in their ITU-related work. It is made publicly available for
information purposes but shall not be redistributed without the prior written consent of ITU. Copyright on this document is owned by
the author, unless otherwise mentioned. This document is not an ITU-T Recommendation, an ITU publication, or part thereof.
-2FG IPTV-C-0158

Stream server provides stream serving in real-time to nearby users under the control of the node
controller.
Use case
a. The following diagram illustrates the CDN briefly:
Roof
node
control
Stream Server
Stream Server
Leaf
node
control
Leaf
node
control
Stream Server
Stream Server
Stream Server
Leaf
node
control
Stream Server
Stream Server
Stream Server
Leaf
node
control
Leaf
node
control
Stream Server
Stream Server
Stream Server
Stream Server
Stream Server
b. The following is sketch map of real time content delivery in CDN network
Root
node
control
Stream
Server
3
Leaf node
control 1
Stream
Server
2
Stream
Server
Stream
Server
4
Leaf
node
control 2
Stream
Server
5
Stream
Stream
Server
Server1
6
7
1
B
A
8
STB
Stream
Server 2
Stream
Server
-3FG IPTV-C-0158
1.
The STB transmits the user’s request to the stream server 1.
2.
The stream server 1 sends the request of real-time content pull to Leaf node control 1 after
finding that local storage has no needed content.
3.
The leaf node control 1 pitches on Leaf node 2 which is one of its depending leaf nodes and
sends the request of real-time contents pull to it.
4.
The leaf node control 2 pitches on the stream server 2 according the load balance principle and
sends the relevant parameters of the stream server 2 to the leaf node control 1.
5.
The leaf node control 1 notifies the stream server 1 to pull the media content from the stream
server 2.
6.
The stream server 1 pulls the real-time stream from the stream server 2 through RTSP.
7.
The stream server 1 transports the real-time steam to user terminal through RTSP.
8.
The A and B thick arrows illustrate the direction of the stream flow.
3. Proposal
It is proposed to add above requirements to section 8 of ‘FGIPTV-OD-0010e’.
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