Subject: Re: [ppsp] IETF-82 meeting minutes for PPSP

From: Martin Stiemerling <[email-masked]>
Date: Fri, 2 Dec 2011 14:14:50 +0000

Hi Arno,

I have fixed the points you have noted below and uploaded the minutes to:
http://www.ietf.org/proceedings/82/minutes/ppsp.txt

Thanks,

  Martin

[email-masked]

NEC Laboratories Europe - Network Research Division NEC Europe Limited | Registered Office: NEC House, 1 Victoria Road, London W3 6BL | Registered in England 2832014 

> -----Original Message-----
> From: [email-masked] [mailto:[email-masked]] On Behalf Of
> Arno Bakker
> Sent: Monday, November 28, 2011 10:29 AM
> To: [email-masked]
> Subject: Re: [ppsp] IETF-82 meeting minutes for PPSP
> 
> Hi
> 
> some corrections inline:
> 
> 
> > Arno Bakker: How to avoid malicious peers to act as LIVESEEDs?
> 
> AB: "How to prevent malicious peers claiming to be LIVESEEDs?"
> 
> > Rui Cruz: Security aspects for swarms are not easy to achieve.
> > Arno Bakker: You have to add information to verify content, that's not in the
> ID now. How to protect
> > LIVESEED label?
> 
> AB: "You somehow need to say 'live source for this swarm has this public
> key'. Need to link swarm to real injector. How you do this should be in
> the draft as well."
> 
> >
> > Rui Cruz presented Peer Protocol (draft-gu-ppsp-peer-protocol)
> > Arno Bakker: If you use pull based model for chunk maps, then you may be
> lacking behind in information.
>  > You need actual information about content you really can supply. How
> do you ensure actuality?
> 
> AB: "If you use pull based model for chunk maps, then you may be lagging
> behind on the real situation. You need actual information to be able to
> do rarest first. How do you ensure the peer's upload is utilized as much
> as possible?"
> 
> > Rui Cruz: Sequential method to fetch chunks. E.g. the rarest can be addressed
> first. What chunk do I
> > need for immediate presentation?
> > Arno Bakker: There is an asymmetric situation. You can come into a situation,
> where nobody has certain
> > chunks to provide, due to the delay in information.
> 
> AB: "The implication of this design is only people further in playback
> time can provide pieces. If these people leave the swarm because
> download is complete you can come into a situation where nobobdy has the
> last chunks to provide."
> 
> > Rui Cruz: This is not part of protocol primitives.
> > Arno Bakker: They can have influence.
> 
> AB: "They do influence how up to date the information is that you have
> to do piece picking with. In pull-based there is delay between what is
> known locally and what is happening in the system."
> 
> 
> > Arno Bakker: We have to protect the content against malicious modifications.
> 
> AB: "We have to protect the RTP header against malicious modification too."
> 
> > Enrico Marocco: Does HTTP here really make sense? Better explain why HTTP
> does not make sense.
> > Arno Bakker: Agreed.
> 
> AB: "Yes please, no HTTP. We only discuss it because it is in the charter."
> 
> Regards,
>       Arno
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