Data communication efficiency

To reduce repetitive data transfers, data content of an outgoing message is stored within cache storage of an intermediate node of a data communications network. A token for identifying the cached data content is stored at the intermediate node and the sender. When a subsequent outgoing message is to be routed from a first network node to a target destination via the intermediate node, a process running at the first node checks whether the content of the message matches data cached at the intermediate node. If there is a match, a copy of the token is sent from the first node to the intermediate node instead date data content. The token is used at the intermediate node to identify the cached data, and the cached data is retrieved from the cache and forwarded to the target destination as an outgoing message.