A Protocol for Network Level Caching

Master of Engineering Thesis, May 1998.


Edwin N. Johnson


John Guttag, and Ulana Legedza


This thesis presents Client-side TCP (CTCP), a new transport protocol that supports network level caching of data packets. By doing so, CTCP enables the retransmission of lost packets from network nodes closer to the client instead of only from the server. Currently, TCP exhibits inefficiencies in terms of bandwidth consumption, retransmission latency, and server processing. CTCP attempts to reduce TCP's transmission inefficiencies by both caching individual data packets in the nodes of the network and by shifting the reliability burden from the server to the client. Network level caching, enabled by CTCP, reduces network traffic near the server as well as packet latency. Specific design and implementation details of CTCP are presented, and an extensive probabilistic analysis of both TCP and CTCP shows CTCP's advantages. Analysis shows that network level caching using CTCP leads to a reduction of up to 88% in redundant bandwidth consumed and redundant packet latency.


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