The last option you can set for external component connections is load balancer class.
The load balancer plugin is used if you have multiple connections for the same component (external domain name) and you want to spread load over all connections. Perhaps you have an installation with huge number of MUC rooms and you want to spread the load over all MUC instances.
An example configuration with load balancer plugin specified:
--comp-name-1 = ext --comp-class-1 = tigase.server.ext.ComponentProtocol --external = muc.devel.tigase.org:mucsecret:listen:5270:devel.tigase.org:accept:ReceiverBareJidLB, \ pubsub.devel.tigase.org:pubsub_pass:listen:5270:devel.tigase.org:accept:SenderBareJidLB
It defines two listeners for external component with different load balancer plugins. The first load-balance traffic by a packet destination BareJID, which makes sense for MUC component. This way each MUC instance handles a different set of rooms which allows for a good load distribution.
For PubSub component we use a different load balancer plugin which distributes load by the sender BareJID instead. This is because for PubSub destination BareJID is always the same so we cannot use it to distribute the load.
Either the ReceiverBareJidLB or SenderBareJidLB are class names from package: tigase.server.ext.lb however, you can use any class name as a plugin, you just have to provide a full class name and the class name must implement LoadBalancerIfc interface.