How long do "tweets" stay alive in the network?

[Luca Matteis]

Hi guys,

I was reading the Twister paper and trying to understand how it all
worked. My main question is regarding how are old tweets kept alive in
the network, so that users can always fetch them. Does it require a
node to be online all the time to keep on publishing such tweets to
the DHT network?

For instance, if I broadcast a tweet and then turn-off my computer,
how long will the tweet be available to be accessed by other users
across the network?

Thanks,
Luca

[Miguel Freitas]

On Sun, Dec 27, 2015 at 2:19 PM, Luca Matteis <lmat...@gmail.com> wrote:

Hi guys,

I was reading the Twister paper and trying to understand how it all
worked. My main question is regarding how are old tweets kept alive in
the network, so that users can always fetch them. Does it require a
node to be online all the time to keep on publishing such tweets to
the DHT network?

No, the producer of the post will only keep trying to add it to the DHT until the "put" operation works (ie. the post is returned from dhtget). Then post is automatically refreshed between nodes, for about 2 months.

After this 2 months period the post might be still available from DHT but it is not refreshed anymore so as nodes go offline or the topology changes, it will eventually expire.

However, posts are always available from the producer's torrent swarm.

 

For instance, if I broadcast a tweet and then turn-off my computer,
how long will the tweet be available to be accessed by other users
across the network?

Hopefully, until the network dies ;-) 

regards,

Miguel

[Luca Matteis]

On Sun, Dec 27, 2015 at 6:41 PM, Miguel Freitas <mfre...@gmail.com> wrote:
> Then post is automatically refreshed between nodes, for about 2 months.

Interesting. Is that handled by the DHT algorithm (say Kademlia)?

I was wondering how well it all performs against spam attacks. For
instance I could literally spam the network with millions of spam
tweets and then the network would be trying to serve those millions of
tweets for 2 months. Does that hurt the network? Can the network
handle that?

Thanks,
Luca

[Miguel Freitas]

On Mon, Dec 28, 2015 at 1:09 AM, Luca Matteis <lmat...@gmail.com> wrote:

On Sun, Dec 27, 2015 at 6:41 PM, Miguel Freitas <mfre...@gmail.com> wrote:
> Then post is automatically refreshed between nodes, for about 2 months.

Interesting. Is that handled by the DHT algorithm (say Kademlia)?

No. afaict the only refresh implemented in standard bittorrent's DHT is to keep the routing tables fresh, not the contents.

 

I was wondering how well it all performs against spam attacks. For
instance I could literally spam the network with millions of spam
tweets and then the network would be trying to serve those millions of
tweets for 2 months. Does that hurt the network? Can the network
handle that?

Well, first thing to consider is the size of the network. The larger the twister network the more resilient. With current size, some attacks that wouldn't make a different might be noticeable.

That said, the DHT refresh is also limited in both duration and bandwidth used. So when bandwidth limit is reached, some requests are dropped. But everything is probabilistic, 8 nodes are supposed to be able handle requests for any given DHT resource... skipping some refreshes due to your spam attack would be enough to put legit contents to expire? I don't know. Give it a try ;-)

regards,

Miguel

[Julian Steinwachs]

Hi,

I think spam on the dht will get a big problem if twister becomes successful. Especially the reply, mention and hashtag resources can easily be flooded with spam making these features unusable. Even if we come up with a content blocking mechanism these spam posts will suppress precious real content because the dhts capacity is limited.

At #32c3 i discussed with @black_puppydog whether its possible to extend the dynamic torrent scheme of twister so that multiple people can write to a torrent. Then at least the capacity would be much less limited. But there are some good ideas missing to make that happen.

Greetings

@tschaul

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