[Spread-users] Membership algorithm--continued

Ryan Caudy caudy at jhu.edu
Fri Apr 16 13:09:51 EDT 2004

Hi Kevin,

Now I understand... yes, the algorithm specification documented in 
Yair's thesis isn't exactly what's implemented in Spread, and yes I 
think that you understand now the exchange of information that leads to 
an agreement about the membership, and about the ordering/message data.

F_members refers to the list of "future members."  I'm not sure if 
there's any public documentation about the implementation of the daemon 
membership algorithm, or about the data structures in membership.c


kevin Tian wrote:

>>you explain what you 
>>mean by violating the algorithm description? 
> Here I refer to the membership algorithm description
> in Dr. Amir’s PhD thesis.
> He said, ‘In the Commit state the representatives
> reach an agreement, they agree on the set of
> representatives that will participate in the formation
> of the new ring’
> I do not think the codes detect this agreement after
> GATHER timeout, instead, because the two-round
> rotation of the form token is necessary for EVS and
> ordering semantics, it can be done in the two-round
> rotation of the form token---first fill members info,
> then read them---this way, consensus is reached. 
> BTW, Does F_members refer to the list of active daemon
> in one segment?
> I’ve just browsed a little of related codes, maybe I
> am incorrect. 
> If more notes, especially for some global variables
> and data structures, are available, it will be fine:-)
Ryan W. Caudy
Center for Networking and Distributed Systems
Department of Computer Science
Johns Hopkins University

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