[OpenDHT-Users] Re: Transaction like capability in openDHT

Zahir Koradia zahir.koradia at gmail.com
Wed Aug 23 18:14:12 PDT 2006


That may just work. Thanks.

Zahir

On 8/24/06, Sean Rhea <sean.c.rhea at gmail.com> wrote:
> Zahir,
>
> Do you know that OpenDHT will store multiple values per key?  I think
> you can solve your problem like this: when a node A registers with a
> gateway G, that gateway does
>
>   put_removable(A, G, SHA1(S))
>
> where S is a secret chosen by G.  When A subsequently registers with a
> different gateway H, that gateway in turn does
>
>   put_removable(A, H, SHA1(T))
>
> where T is a secret chosen by H.  When a node B wants to route a
> message to A, it does
>
>   get(A)
>
> which returns [G, H].  B then picks one of G or H and contacts A
> through that gateway.
>
> If A later unregisters with G, then G does
>
>   remove(A, SHA(G), S)
>
> so that subsequent calls to
>
>   get(A)
>
> will return only [H].
>
> Does that not work for some reason?
>
> Sean
>
>
>
> On 8/22/06, Zahir Koradia <zahir.koradia at gmail.com> wrote:
> > I am working with the Tetherless Computing group at university of
> > Waterloo and am working on a routing protocol for Delay Tolerant
> > Networks. What I need is that when a Node registers its existence this
> > registeration message reaches multiple "gateways". All these gateways
> > will try to register this node in the DHT by making an entry in it. If
> > an entry for the node is already there then the gateway simply appends
> > its id to the entry. The entry will basically indicate the list of
> > gateways through which the node is reachable. Now if two gateways read
> > an entry together and then update it without knowing that the otehr is
> > working with it then only one of the two updates will be present
> > leading to incorrectness. What I want is that when a gateway plans to
> > update an entry it must be able to tell the otehr gateways that it is
> > working on that entry and that no one else touch it. If two people
> > send out the same message then a "collision" occurs and they need to
> > agree upon who among the two should go ahead. Currently I am trying to
> > use a group communication toolkit for the purpose but want to know my
> > options before I go ahead.
> --
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>



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