Optimizing Tunneled Grid Connectivity across Firewalls

Tan, J., Abramson, D. and Enticott, C.

    Grids today generally assume that concurrent network connections are possible among many processors attached to high-capacity networks. However, inter-network boundaries dividing independent institutions often have firewalls, typically to restrict how many and which ports are accessible. In some cases, ports are opened indefinitely for Grid applications, but this compromises security significantly. On the other hand, solutions that manage port openings in an ad-hoc manner for applications are non-trivial to implement. An alternative firewall traversal technique is required that will provide manageable openings with less complexity involved. This is possible through proxies and managed tunnels using ports already authorized across the firewalls. We have developed a transparent connectivity mechanism for this, called Remus, which reroutes Grid connections through a tunnel on ports allowed across firewalls. However, a single tunnel presents a performance bottleneck. In this paper, we present the method by which Remus distributes several connections over multiple tunnels, improving throughput as a result. Rerouting wrappers hide the tunneling from applications, intercepting outgoing connections and rerouting them transparently. Wellknown and mature tools and protocols, such as SSH and/or SOCKS, are utilized, instead of imposing customized, non-standard mechanisms. Results of our experiments are also presented for large file transfers over a Globus-based Grid that uses Remus.
Cite as: Tan, J., Abramson, D. and Enticott, C. (2009). Optimizing Tunneled Grid Connectivity across Firewalls. In Proc. Seventh Australasian Symposium on Grid Computing and e-Research (AusGrid 2009), Wellington, New Zealand. CRPIT, 99. Roe, P. and Kelly, W., Eds. ACS. 21-27.
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