4f81
PPSP G. Le
Internet-Draft Beijing University of Posts and
Intended status: Standards Track Telecommunicaions
Expires: January 12, 2012 L. Li
ZTE Corporation
K. Xu
M. Song
Beijing University of Posts and
Telecommunicaions
J. Wang
ZTE Corporation
July 11, 2011
PPSP Usage for DECADE
draft-le-ppsp-decade-interoperation-01
Abstract
P2P Streaming has become popular application in the Internet.
Currently, most home subscribers access Internet via ADSL, in which
downlink bandwidth and uplink bandwidth are not symmetric. This
feature would influence the performance of P2P Streaming, and the
problem may be worse in mobile scenarios. This draft presents the
interoperation between PPSP protocol and DECADE protocol to provide
DECADE service for PPSP applications. Typically, there are two
solution to achieve interoperation, loose interoperation among peers,
and close interoperation via connection of peer and tracker. By
introducing DECADE in both tracker protocol and peer protocol, PPSP
streaming can alleviate strength of upload bandwidth and improve
performance for fix and mobile scenario.
Status of this Memo
This Internet-Draft is submitted to IETF 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
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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 January 12, 2012.
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Copyright Notice
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document authors. All rights reserved.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Reference Model . . . . . . . . . . . . . . . . . . . . . . . 4
4. Interoperation Solution . . . . . . . . . . . . . . . . . . . 5
4.1. Loose Interoperation . . . . . . . . . . . . . . . . . . . 5
4.1.1. Protocol Description . . . . . . . . . . . . . . . . . 5
4.1.2. Message Flow . . . . . . . . . . . . . . . . . . . . . 6
4.2. Close Interoperation . . . . . . . . . . . . . . . . . . . 6
4.2.1. Protocol Description . . . . . . . . . . . . . . . . . 6
4.2.2. Message Flow . . . . . . . . . . . . . . . . . . . . . 7
4.2.2.1. Content Transfer . . . . . . . . . . . . . . . . . 7
4.2.2.2. Content Download . . . . . . . . . . . . . . . . . 11
5. Open Issues . . . . . . . . . . . . . . . . . . . . . . . . . 14
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 14
7. Security Considerations . . . . . . . . . . . . . . . . . . . 14
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 14
9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 14
9.1. Normative References . . . . . . . . . . . . . . . . . . . 14
9.2. Informative References . . . . . . . . . . . . . . . . . . 15
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 15
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1. Introduction
P2P Streaming has become popular application in the Internet.
Currently, most home subscribers access Internet via ADSL, in which
downlink bandwidth and uplink bandwidth are not symmetric. This
feature would influence the performance of P2P Streaming, for P2P
applications are based on symmetric collaboration among peers. The
problem may be worse in mobile scenarios. The wireless channels are
more symmetric, and the mobility of device leads to the churn of
networks [I-D.lu-ppsp-mobile].
DECADE is an open, standard protocol to access in-network storage for
P2P application data access that is decoupled from P2P application
control and signaling [I-D.ietf-decade-problem-statement]. DECADE
can provide infrastructure support and save usage of last-mile
uplink. [I-D.ietf-decade-integration-example] and
[I-D.huang-decade-integration-example] presents instance of P2P
Streaming integration with DECADE. However, these integration
examples focus on the modification of peer protocol to support in-
network storage for P2P Streaming.
This draft presents the interoperation between PPSP protocol and
DECADE protocol to provide DECADE service for PPSP applications. In
this model, Peer has its own DECADE server. When Peer registers to
Tracker, it would carry additional information of DECADE server, such
as availability, content, or authorized token. Then Tracker would
store the information to enable in-network storage functions. In the
data transfer process, there are two ways to achieve interoperation
of DECADE and PPSP, loose interoperation via peer communication and
close interoperation via the connection of peer and tracker. By
introducing DECADE in both tracker protocol and peer protocol, PPSP
streaming can alleviate strength of upload bandwidth and improve
performance for fix and mobile scenario.
2. Terminology
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].
This document makes extensive use of the terminology and definitions
from PPSP Problem Statements [I-D.ietf-decade-problem-statement],
PPSP Tracker Protocol [I-D.gu-ppsp-tracker-protocol] and DECADE
Architecture [I-D.ietf-decade-arch]. The additional definitions are
list as follows:
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o Tracker: Tracker maintain not only peer status defined in PPSP
Tracker, but also include the information of DECADE server.
o Peer: Due to the existence of in-network storage, Peer should
interact with DECADE entities. Also, streaming data transfer via
the communication between DECADE servers, instead of communication
between peers directly.
o DECADE Server: DECADE Server provides in-network storage service
and relevant access control and resource schedule scheme as
defined in DECADE architecture.
3. Reference Model
This document provides the transparent combination of PPSP
architecture and DECADE architecture to introduce in-network storage
for PPSP service. As shown in Figure 1, there are three entities in
the system, tracker, DECADE server and peer.
+-----------+
| |
| Tracker |
| |
+-----------+
^ ^
+----------+ | | +----------+
| DECADE | | | | DECADE |
| Server | | | | Server |
+----------+ | | +----------+
^ Tracker ^
| Protocol |
| | | |
DECADE | | DECADE
Protocol | | Protocol
| | | |
| | | |
v | | v
+----------+ | | +----------+
| |<-------------- ----------->| |
| Peer | | Peer |
| |<--------Peer Protocol------->| |
+----------+ +----------+
Figure 1: Concept Model
In this model, peer has its own DECADE server and tracker would
maintain the information of peers and their DECADE servers to enable
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in-network storage functions. When peer request initial peer list,
tracker return optimal list based on the knowledge of DECADE server.
If peer decide to require content from particular DECADE server, it
requests authorized token by communicating with target peer or asking
tracker directly. After peer gets authority of data request, peer
generate content retrieve request via DECADE server. DECADE server
retrieves content on behalf of peer by DECADE protocol and transfer
content to peer.
4. Interoperation Solution
There are two ways to achieve interoperation of DECADE and PPSP,
loose interoperation and close interoperation.
4.1. Loose Interoperation
Peer reports its DECADE availability to tracker and tracker only
knows whether peer has enabled DECADE service. Then tracker return
peer list including DECADE availability. Peer check peer list and
select DECADE-enable peer with priority. Then peer communicate with
each other to get DECADE authority and conduct data transfer. In
this solution, tracker has no knowledge about the detail of DECADE
server, that is, "loose interoperation".
4.1.1. Protocol Description
To fulfill this purpose, only tracker protocol should be revised:
1. When peer connects to tracker, it should inform about DECADE
availability. The method specific XML of the CONNECT request
takes the form shown below:
###
ON or OFF
2. When peer request initial peer list, tracker should response list
including DECADE status. The method specific XML of the FIND
response takes the form shown below:
###
Peer list with DECADE_Status
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4.1.2. Message Flow
Peer communicates with tracker as PPSP tracker protocol
[I-D.gu-ppsp-peer-protocol] defined. After peer receives peer list
and selects target peer, it communicates with corresponding peer
according to data transfer scenarios defined in
[I-D.ietf-decade-problem-statement]. Typically, there are four
methods as bellow:
o If both request peer and target peer has implemented DECADE
server, message transfer follows Usage Scenario 1 (Sender and
receiver Accounts used);
o If request peer has not implemented DECADE server but target peer
has, message transfer follows Usage Scenario 2 (Sender account
used);
o If request peer has implemented DECADE server but target peer has
not, message transfer follows Usage Scenario 3 (Receiver account
used);
o If neither request peer nor target peer has implemented DECADE
server, message transfer follows Usage Scenario 4 (no storage
accounts used).
4.2. Close Interoperation
Peer reports detailed information of DECADE server to tracker, like
stored content, address, and authorized token. Tracker returns both
peer list and DECADE server list, including DECADE information. Peer
request target DECADE server with authorized token based on its
scheduling algorithms. After peer down any data, it uploads content
to its DECADE server. In this solution, tracker maintains overall
status of peers and related DECADE server, that is, "close
interoperation".
4.2.1. Protocol Description
In close interoperation solution, data transfer would not go through
the connection among peer. Then peer protocol lack data transfer
function, only providing neighborhood maintain and exchange of peer
list. Also, tracker protocol should be revised to adapt demand of
DECADE server.
1. When peer connects to tracker, it should inform about detailed
DECADE information. The revised method specific XML of the
CONNECT request takes the form shown below:
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###
Authorized token
Address
2. When peer request initial peer list, tracker should response list
including DECADE information. Tracker also inform peer about
content store in DECADE server. The revised method specific XML
of the FIND response takes the form shown below:
###
###
Content ID
Authorized token
Address
3. Tracker should update DECADE status periodically to get the
latest content availability. The revised method specific XML of
the STAT_REPORT response takes the form shown below:
###
***
List of Content ID
...more stats...
4.2.2. Message Flow
There are two stages in close interoperation. First, peer who has
content should transfer content to corresponding DECADE server.
Second, peer who request content get content from DECADE server.
4.2.2.1. Content Transfer
In this section, we specify content transfer process. Either peer or
P2P application vendor can implement DECADE server to provide in-
network service. So there are two scenarios:
o Transfer content to DECADE server rent by peer
In this scenario, peer upload content to DECADE server automatically.
We consider the case of a peer B transfer content to its DECADE
server C. Message flows are shown as follows:
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1) Peer B uploads content to DECADE server C automatically.
2) DECADE server C stores content and returns Upload successful
response to Peer B.
3) Peer B sends Report C's information to tracker.
4) Tracker records C's information and returns report response
message to Peer B.
+--------+ +---------------+ +---------+
| Peer B | |DECADE Server C| | Tracker |
+--------+ +---------------+ +---------+
| | |
| Upload content | |
|--------------------------->| |
| | |
| +----------------+ |
| | Store content | |
| +----------------+ |
| | |
| Upload success response | |
|<---------------------------| |
| | |
| Report C's information |
|------------------------------------------------->|
| (adreess,content list,auth data) |
| | |
| | |
| | +-------------+
| | | Record C's |
| | | information |
| | +-------------+
| | |
| Report response |
|<-------------------------------------------------|
| | |
| | |
Figure 2: Content transfer with peer's DECADE server
o Transfer content to DECADE server rent by P2P Streaming vendor
In this scenario, tracker request specific content from peer
periodically. Also, we consider the case of a peer B transfer
content to its DECADE server C. Tracker may communicate with peer B
or DECADE server C.
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If tracker sends request to DECADE server C, message flows are shown
as follows:
1) Tracker send request to DECADE server C to download specific
content from B.
2) DECADE server C request content from peer B.
3) Peer B uploads content to DECADE server C.
4) DECADE server C stores content and returns download success
response to tracker.
5) Tracker updates C's information.
+--------+ +---------------+ +---------+
| Peer B | |DECADE Server C| | Tracker |
+--------+ +---------------+ +---------+
| | |
| | |
| |Request download specific |
| |<-------------------------|
| | content from B |
| Request content | |
|<--------------------| |
| | |
| Upload content | |
|-------------------->| |
3584
| | |
| +----------------+ |
| | Store content | |
| +----------------+ |
| | |
| |Download success response |
| |------------------------->|
| | |
| | +-------------+
| | | Update C's |
| | | information |
| | +-------------+
| | |
| | |
Figure 3: Content transfer with P2P vendor's DECADE server 1
If tracker sends request to peer B, message flows are shown as
follows:
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1) Tracker send request to peer B to download specific content.
2) Peer B uploads content to DECADE server C.
3) DECADE server C stores content and returns upload success
response to peer B.
4) Peer B return upload success response to tracker and Tracker
updates C's information.
+--------+ +---------------+ +---------+
| Peer B | |DECADE Server C| | Tracker |
+--------+ +---------------+ +---------+
| | |
| | |
| Request download specific content from B |
|<-----------------------------------------------|
| | |
| Upload content | |
|-------------------->| |
| | |
| +----------------+ |
| | Store content | |
| +----------------+ |
| | |
| Upload success | |
|<--------------------| |
| response | |
| | |
| Upload success response |
|----------------------------------------------->|
| | |
| | +-------------+
| | | Update C's |
| | | information |
| | +-------------+
| | |
| | |
Figure 4: Content transfer with P2P vendor's DECADE server 2
As we can see, if DECADE server is rent by peer, peer transfer
content actively; However, if DECADE server is rent by P2P Streaming
vendor, peer transfer content passively.
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4.2.2.2. Content Download
In this section, we specify content transfer process. Request peer
could download content directly, or download content via its DECADE
server. So there are two scenarios:
o Direct Download
In this scenario, peer download content directly. We consider the
case of a peer A download content from DECADE server C. Message flows
are shown as follows:
1) Peer A send content location request to tracker.
2) Tracker return related peer list and DECADE list to Peer A.
3) Peer A select specific DECADE server and request content to
DECADE server C.
4) DECADE server C return content to peer A.
+--------+ +---------+ +-----------------+
| Peer A | | Tracker | | DECADE server C |
+--------+ +---------+ +-----------------+
| | |
| Request content | |
|-------------------->| |
| location | |
| | |
| Return peer list | |
|<--------------------| |
| and DECADE list | |
| | |
| Request content |
|------------------------------------------>|
| | |
| Return content |
|<------------------------------------------|
| | |
| |
Figure 5: Direct download scenario
o Indirect Download
In this scenario, peer download content via its DECADE server. Then
local DECADE server acts as proxy to download content and transmit
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content to peer. We consider the case of a peer A download content
from DECADE server C via local DECADE D. Message flows are shown as
follows:
1) Peer A send content location request to tracker.
2) Tracker return related peer list and DECADE list to Peer A.
3) Peer A select specific DECADE server and request local DECADE D
to download content.
4) Local DECADE D request content from DECADE server C.
5) DECADE server C return content to DECADE D and DECADE D store
content.
6) DECADE D return content to peer A.
7) Peer A report local DECADE information to tracker.
8) Tracker update DECADE D's information and return report response
to peer A.
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+--------+ +---------+ +----------+ +----------+
| Peer A | | Tracker | | Local | | DECADE |
| | | | | DECADE D | | Sever C |
+--------+ +---------+ +----------+ +----------+
| | | |
| Request content | | |
|----------------->| | |
| location | | |
| | | |
| Return peer list | | |
|<-----------------| | |
| and DECADE list | | |
| | | |
| Request to proxy content download | |
|----------------------------------->| |
| | | |
| | | Request content |
| | |---------------->|
| | | |
| | | Return content |
| | |<----------------|
| | | |
| | +-------------+ |
| | |Store content| |
| | +-------------+ |
| | | |
| Return content | |
|<-----------------------------------| |
| | | |
| Report local | | |
|----------------->| | |
|DECADE information| | |
| | | |
| +--------------+ | |
| | Update D's | | |
| | information | | |
| +--------------+ | |
| | | |
| report response | | |
|<-----------------| | |
| | | |
| | | |
Figure 6: Indirect download scenario
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5. Open Issues
o Recently DECADE protocol support pull-based P2P streaming. How to
enhance DECADE protocol to support push-based P2P streaming
applications as well? In push-based model, peer should transfer
data to its descendants whenever it receives data. Then DECADE
protocol should support one-to-many data relay.
6. IANA Considerations
This document does not have any IANA Considerations.
7. Security Considerations
This document does not contain any security considerations.
8. Acknowledgements
We would like to acknowledge Lichun Li, Yunfei zhang, Denglingli to
provide feedback and suggestions to this document.
9. References
9.1. Normative References
[I-D.gu-ppsp-peer-protocol]
Yingjie, G. and D. Bryan, "Peer Protocol",
draft-gu-ppsp-peer-protocol-02 (work in progress),
June 2011.
[I-D.gu-ppsp-tracker-protocol]
Yingjie, G., Bryan, D., and D. Lingli, "PPSP Tracker
Protocol", draft-gu-ppsp-tracker-protocol-04 (work in
progress), May 2011.
[I-D.ietf-decade-arch]
Alimi, R., Yang, Y., Rahman, A., Kutscher, D., and H. Liu,
"DECADE Architecture", draft-ietf-decade-arch-01 (work in
progress), May 2011.
[I-D.ietf-decade-problem-statement]
Song, H., Zong, N., Yang, Y., and R. Alimi, "DECoupled
Application Data Enroute (DECADE) Problem Statement",
draft-ietf-decade-problem-statement-03 (work in progress),
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March 2011.
[I-D.lu-ppsp-mobile]
Lu, G., Zuniga, J., and A. Rahman, "P2P Streaming for
Mobile Nodes: Scenarios and Related Issues",
draft-lu-ppsp-mobile-04 (work in progress),
September 2010.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
9.2. Informative References
[I-D.huang-decade-integration-example]
Huang, Z. and X. Chen, "An integration example of DECADE
system", draft-huang-decade-integration-example-01 (work
in progress), October 2010.
[I-D.ietf-decade-integration-example]
Chen, L., Liu, H., Huang, Z., and X. Chen, "Integration
Examples of DECADE System",
draft-ietf-decade-integration-example-01 (work in
progress), May 2011.
Authors' Addresses
Guan Le
Beijing University of Posts and Telecommunicaions
No.10 Xi Tu Cheng Road
Beijing, Haidian District
P.R.China
Phone: +86-010-62282718
Email: optimism1226@gmail.com
Lichun Li
ZTE Corporation
4F,RD Building 2,Zijinghua Road No.68
Nanjing, Yuhuatai District 210012
P.R.China
Phone: +86-025-5287-7612
Email: li.lichun1@zte.com.cn
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Ke Xu
Beijing University of Posts and Telecommunicaions
No.10 Xi Tu Cheng Road
Beijing, Haidian District
P.R.China
Phone: +86-010-62282754
Email: xu_ke@bupt.edu.cn
Meina Song
Beijing University of Posts and Telecommunicaions
No.10 Xi Tu Cheng Road
Beijing, Haidian District
P.R.China
Phone: +86-010-62282718
Email: mnsong@bupt.edu.cn
Jun Wang
ZTE Corporation
4F,RD Building 2,Zijinghua Road No.68
Nanjing, Yuhuatai District 210012
P.R.China
Phone: +86-025-5287-7648
Email: wang.jun17@zte.com.cn
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