[rabbitmq-discuss] Federation Topologies & Limitations

[Simon MacMullen]

On 15/01/14 19:19, Josh West wrote:
> I am experimenting with different architectures and it seems that in
> order to prevent message duplications, I'll have to go with a complete
> graph and max-hops set to 1 -- or in other words, each broker will have
> to directly federate with the other 100-200 brokers.

Yeah, there isn't any cycle detection in federated exchanges (yet). I 
keep wondering about adding it, but the trouble is that I suspect people 
really want deduplication rather than cycle detection. So that means 
either deduplication buffers that can get arbitrarily large (when do you 
drop message IDs from them) or some sort of routing algorithm to 
automatically remove duplicate routes from the federated broker set 
(which requires a global view at least, and is also probably quite 
complicated and error prone).

So I don't know of any good solutions for large federations other than 
max-hops = 1.

Cheers, Simon

-- 
Simon MacMullen
RabbitMQ, Pivotal