Outline the replication scheme used in UDDI. Supposing that vector timestamps are used to support this scheme, define a pair of operations for use by registries needing to exchange data.
What will be an ideal response?
The members of a registry propagate copies of data structures to one another as follows: a server that has made changes notifies the other servers in the registry, which then request the changes.
1. all changes to a particular data structure are made at the same server;
2. updates from a particular server are received in sequential order by the other members, but no particular ordering is imposed between update operations made by different servers.
call the vector timestamp V, then the operations are
notify(Id of registry, V)
a UDDI server uses this operation to inform another that it has new updates to data structures. The recipient compares the vector V with its own vector timestamp
get(V)-> sequences of updates
a UDDI server uses this operation to requests another server to send it updates it needs. The argument is that server's vector timestamp. The recipient uses V to determine which updates the requester requires before returning them.
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