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However our view is that an ESB is more of a container of integration components, so we view Apache ServiceMix to be a true ESB based around JBI to provide a standards based integration platform of componetscomponents.
We view Camel as being a routing & mediation rule engine which can be used inside a full blown ESB, a message broker or a web services smart client. Though if you want to, you could consider that Camel is a small, lightweight embeddable ESB since it can provide many of the common ESB services like smart routing, transformation, mediation, monitoring, orchestration etc.