Achieving Flexible Cache Consistency for Pervasive Internet Access

Abstract

Caching is an important

Cache invalidation strategies for Internet-based vehicular ad hoc networks

“…In the pull ap proach [15], however, whenever a query is generated which can be answered from a cached data item, a query request packet is sent to the server to verify the validity of the cached data item before it answers the query. Several push-and pull-based schemes [16] and combining both schemes [17,18] have been proposed considering the tradeoffs between query delay and communication overhead.…”

“…Thus, it may reduce the communication cost and query delay, but increase the communication overhead due to accessing stale data items. To balance strong and weak consisten cies in terms of scalability, complexity, and communication cost, a hybrid cache consistency scheme [17] is proposed, where mobile nodes can flexibly specify their consistency requirements for dif ferent types of data items.…”

“…In addition, there have been many research efforts on develop ing various caching schemes for MANETs [18,[20][21][22][23][24][25] and Internetbased MANETs, called IMANETs [16,17], where MANET technologies are combined with an Internet to provide a flexible information acces sibility and availability for users. For MANETs, Hara and Madria sug gested a replication scheme for periodically updated data items based on the previously suggested replica allocation method [20].…”

“…However, estimation of optimal reallocation period and remaining time to the next update are not practically feasible. There are few invalidation approaches [16,17] for IMANETs. In [16], several push and pull-based cache invalidation schemes are pro posed based on the aggregate cache [26], in which the aggregated local caches of the nodes can be considered as an unified large cache for the IMANET. In summary, little effort has been devoted in exploring the cache invalidation issue for IVANETs, where the high-speed mobility and scalability algorithm are primary concerns.…”

“…For example, map, video clip, and weather information are not update sensitive and thus, occasional inconsistency between the source and its cached copy would be acceptable. Little effort has been devoted in developing a flexible consistency-based technique [17,39]. We expect that this tech nique can effectively balance among the cost of accessing data item, complexity of consistency maintenance, and query latency.…”