Web Cache Design for Efficient SNMP Monitoring Towards Realizing Globalization of Network Management

摘要

In this paper, we propose a RESTful active proxy, called Tambourine, towards realizing globalization in network management. Tambourine radically changes the landscape of traditional closed-domain SNMP monitoring into a multi-domain, multi-user monitoring activity by translating HTTP requests from a huge number of Internet users into adequate SNMP requests to network devices. Implementation of cache in Tambourine is vital to ensure that SNMP traffic is kept at a minimum level to avoid burdening network devices with repetitions of SNMP requests. Existing web cache technology however could not be implemented in Tambourine due to two main reasons (i) SNMP is not a cache-aware protocol, and (ii) the value for several OIDs, such as system uptime, changes in real-time causing stale data if it is cached. To solve these problems, our cache design applies a four-state transition to determine the optimum TTL for each OID. Tambourine also aggregates multiple HTTP requests from the same user into a single SNMP request to further reduce the SNMP traffic. In our experiments where three users used a modified MRTG to generate HTTP requests to Tambourine, our cache design converges to zero staleness ratio after five 5-minute cycles.