Subject: [ppsp] [Fwd: Re: problem statement of ppsp(new version)]

From: Jun Lei <[email-masked]>
Date: Mon, 10 Nov 2008 11:34:56 +0100

the following email was sent yesterday, but not received by the mailing 
list.

Just for your info.

Subject: Re: [ppsp] problem statement of ppsp(new version)
From: Jun Lei <[email-masked]>
To: [email-masked]
Cc: Hui Zhang <[email-masked]>, [email-masked]
Date: Sun, 09 Nov 2008 17:18:41 +0100

Hi, everyone,

Jun Lei (Julie) again.
> Dear all, this is Hui Zhang from NEC Labs at Princeton. Say hello to
> everyone!
>
> Yunfei, the new version is much better than the first one. Following are
> several comments/questions on the problem statement:
>
> 1. The motivation/selling point for PPSP is not very strong/clear. If
> PPSP is to offer a full stack (signaling+transport) of specification,
> will service providers like PPLive be willing to rewrite their code from
> scratch? 
> Should we more consider PPSP as an incremental part to the existing many
> P2P multimedia applications?
>   
I agree that the motivations of PPSP is not very clear yet. Hopefully, 
after this BOF meeting it would be much clearer and specific.
> 2. Should we consider VoD application in PPSP? Given the nature of VoD
> requests is one-to-one (video server to a requestor), we might want to
> focus PPSP on broadcast-based video streaming applications. Do current
> service providers like PPlive really use P2P tech for VoD delivery?
>   
As the PPSP refers to "P2P streaming protocol", I am quite confused 
about considering VoD services in PPSP.  P2P streaming applications 
might have different requirements from that of P2P VoD systems. 
Moreover, it is more complicated to support VoD in a P2P environment as 
the availability of certain video chunks may vary quickly. If you have 
further interests, please refer to our report about VoD services ( 
http://www.net.informatik.uni-goettingen.de/publications/1484/Joost_experiment.pdf). 

To my knowledge, it is nowadays possible to rely on P2P tech to support 
VoD (e.g., fast forward) services. For example, Joost is one of the P2P 
VoD systems and PPLive has provided VoD functions since last year.
> 3. The idea of bringing CDN into PPSP design is interesting. This CDN
> issue can be thought of being a part of the ALTO solution in PPSP, and
> the question for discussion is where in the PPSP protocol stack an
> interface to the ALTO solution should be explicitly designed and
> provided? 
>   
I would say that including CDN can be one of the promising solutions for 
PPSP services. However, I am still not quite sure about how to find the 
tradeoff between using CDN and P2P networks for transmitting video 
services.
> 4. The discussion on PPSP transmission protocol (Step 5) got me
> confused. Do we really want to enumerate all possible parameters the
> current P2P streaming protocols implemented in their chunk
> transmissions? Or should the chunk transmission process be mainly left
> as a black box to hide individual implementations, which could be deemed
> as the core tech by P2P streaming provider, and PPSP will focus on the
> interfaces between transmission protocol and signal protocols, and the
> transmission protocol and the common new service part such as CDN or
> other ALTO parts?
>
> 4. We need a good survey on current P2P streaming technologies. I know
> there are  some surveys on internet video streaming technologies, but
> they typically cover multimedia techniques in traditional centralized
> architectures; as for the detailed technologies used by popular P2P
> video providers such as PPlive, does anyone known good related articles?
>   
My two cents. I would really like to see a good survey on current P2P 
streaming technologies, including both architectural/system design and 
protocol design.

[Hui:] If you specifically refer to PPlive technologies, I would 
recommend the following two papers:

1. Challenges, Design and Analysis of a Large-scale P2P VoD System 
(sigcomm 2008)

2. Insights into PPLive: A Measurement Study of a Large-Scale P2P IPTV 
System (2006)

Cheers

Jun
> Thanks,
>
> Hui
>
>
> -----Original Message-----
> From: [email-masked] [mailto:[email-masked]] On Behalf Of
> [email-masked]
> Sent: Tuesday, November 04, 2008 4:53 AM
> To: [email-masked]
> Subject: [ppsp] problem statement of ppsp(new version)
>
> Dear all,
>    Attached is the updated problem statement of ppsp.Comments and
> suggestions are highly welcome.
> _______________________________________________
> ppsp mailing list
> [email-masked]
> https://www.ietf.org/mailman/listinfo/ppsp
>   

-- 

===========================
Dr. Jun Lei
Research Associate

Computer Networks Group
University of Goettingen
Goldschmidtstr. 7
37077, Goettingen
Germany

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