NServiceBus is built on top of existing queuing technologies. In NServiceBus the choice of queuing technology is referred to as a "Transport".
NServiceBus transports can be divided into several categories.
Bus transports are inherently distributed. Each endpoint instance might potentially connect to a different node of the bus. Messages are routed transparently between the nodes but physical routing layer needs to contain information to which bus node particular endpoint is connected to.
Bus transports include:
Broker transports are inherently centralized. Even if there are multiple servers, they act as a single logical entity that hosts all the queues (and/or topics).
Broker transports include:
Unicast-only transports do not have a notion of topic; only queues. Because of that they allow only point-to-point communication. Sending message to multiple receivers (e.g. publishing an event) is composed of multiple transport-level sends. Unicast-only transports require a subscription storage to be configured.
Unicast-only transports include:
Multicast-enabled transports have some notion of a topic or a similar concept that allows to send a message once and have it received by multiple clients. These transports do not require a subscription storage.
Multicast-enabled transports include:
There are several community maintained transports that can be seen in the full list of extensions.
WebSphereMQ Transport for NServiceBus is not supported by Particular Software at this time. The code is available on GitHub as-is, for legacy, community use and reference. Contact support for licensing and support details.