6.1. OverviewΒΆ
The messaging network is composed of multiple connections. Some UDP/multicast, some TCP. Connecting to the messaging network from an user client will always use the TCP connection. It relieves the need to segment large messages (UDP) and is the only easily tunneled protocol through an SSH connection.
The TCP connection could be made to any node in the messaging network, however, it is customary to connect to a non experiment node to maintain the natural hierarachy of the network topology. This include any ‘control’ nodes as well as any other routing nodes between testbeds. The connection is created on port 17707.
Inside the testbed, other communications methods are used. Between a control node and experiment nodes in the same testbed, a tree based multicast scheme is used.