| = Multipoint Considerations |
| :index-group: Discovery and Failover |
| :jbake-date: 2018-12-05 |
| :jbake-type: page |
| :jbake-status: published |
| |
| |
| == Network size |
| |
| The general disadvantage of this topology is the number of connections |
| required. The number of connections for the network of servers is equal |
| to `(n * n - n) / 2`, where n is the number of servers. For example, |
| with 5 servers you need 10 connections, with 10 servers you need 45 |
| connections, and with 50 servers you need 1225 connections. This is of |
| course the number of connections across the entire network, each |
| individual server only needs `n - 1` connections. |
| |
| The handling of these sockets is all asynchronous Java NIO code which |
| allows the server to handle many connections (all of them) with one |
| thread. From a pure threading perspective, the option is extremely |
| efficient with just one thread to listen and broadcast to many peers. |
| |
| == Double connect |
| |
| It is possible in this process that two servers learn of each other at |
| the same time and each attempts to connect to the other simultaneously, |
| resulting in two connections between the same two servers. When this |
| happens both servers will detect the extra connection and one of the |
| connections will be dropped and one will be kept. In practice this race |
| condition rarely happens and can be avoided almost entirely by fanning |
| out server startup by as little as 100 milliseconds. |
