A framework in which computing devices can divide messages into chunks or sub-portions for transmission in accordance with a topic-based messaging protocol. A caching service facilitates the receipt of a set of messages with individual sub-portions. The caching service uses embedded information in the sub-portion messages to determine when a full set of sub-portions have been received. The caching service can release a completed set of sub-portion messages to an intended network service recipient or utilizing time expiration caching criteria to wait for additional messages.