Jan 29

In the major writeup called “GlassFish ESB v2.2 Field Notes – Exercising Load Balanced, Highly Available, Horizontally Scalable HL7 v2 Processing Solutions”, at http://blogs.czapski.id.au/?p=13, in section called “WS Projects”, pages 35-36 , I discuss how NMProperties in BPEL 2.0 can be used to force the HTTP BC to send the “connection: close” HTTP header, instead of the “connection: keep-alive” HTTP header, which it sends by default. Normally this does not matter but if a load balancer is to be used as a proxy, and a round robin load balancing is desired, the “connection: keep-alive” gets in the way. Rather then closing a connection after each HTTP request/response, as HTTP protocol was designed to do, “connection: keep-alive” HTTP header indicates to the server that connection is not to be closed in anticipation of another request coming form the same source “shortly”. Since the HTTP BC does not seem to have a place where this header can be removed or changed to “connection: close”, NMProperties in BPEL have to be used to force connection closure and enable correct load balancing behavior.

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