LowLat Related Work

Server-side Anticipation


LowLat uses a server-side presending mechanism with a receiver-side cache. The protocol is transparent to the server and client. The design uses available bandwidth – either excess capacity or idle periods – when available. Client cache hits are forwarded to the presender (but not the server), to loosely couple the presender/cache interaction. It degenerates to a conventional request/response interaction when the server is loaded, bandwidth isn’t available, or the client cache is small or not implemented (i.e., it’s backward compatible). LowLat is based on the Mirage formal model of communication latency.Key feature: server tries to presends the contents of ALL linked items. Order and history statistics can be used to limit the presender’s actions. Client cache hits are forwarded to presender to loosely couple the interaction.

OCEANS group

Key feature: server tries to presends the contents of linked items based on prior request history.
  • Object Caching Environments for Applications and Network Services group
  • Prefetching and Speculative Service on the Web project
  • Prof. Azer Bestavros, Carlos Cunha

Jeff Mogul’s server-side mechanisms

Key feature: Server-side presending using Markov chains to model the prediction stream.

Vino (Harvard)

Key feature: Geographical push caching.

Client-side anticipation

Improving World-Wide Web Performance project

Predictive prefetching (client-side), using pipelined GETALL and GETLIST to avoid multiple RTTs, and pipelining in a long-lived connections. Performed by Venkata while a summer intern at DECWRL.Key feature: Optimize time per traditional request/response interaction, by aggregating requests and caching connections.

WcolE – WWW Collector (Japan)

Fetches anchors and in-line images in HTML, and prefetches. Cache saves its own prefetches.Key feature: Supports Internet Cache Protocol (ICP) (QUERY, HIT, and MISS), also supports “catalyst mode”, in which separates the prefetching proxy from the primary caching proxy.

ICS-FORTH (Greece)

Key feature: Third-party prefetching, at a “broker” that manages cache coherence and updates when items are stale. Uses statistical usage information.




(from the Siva pages:) Siva is a hierarchical caching HTTP proxy server. The goal is to greatly increase performance of WWW access by reducing overall traffic, through highly-distributed caching of documents. See the project notes for more information. The current implementation is highly experimental, but the source could be useful to some.

Intelligent Bandwidth

Connection optimizations

Request optimizations

Test sites


Provides a public WWW cache for the Higher Education community in the UK. The UK has terrible problems with international bandwidth and we would be willing to act as a test site for any worthy schemes. As we run a real user service any scheme would have to be pretty stable, but our user-base is large and realistic. We currently serve about 1,000,000 requests a day. We can’t contribute a great deal except testing other people’s ideas. Neil Smith