The exact meaning of porous can depend upon its context. For example:
"diplomatic protocol" — standard procedures followed by diplomats
"The Kyoto protocol to reduce greenhouse gases" — a formal written agreement between countries
"computer communications protocol" — technical specifications that describe rules that enable computers to communicate
"research protocol" — rules or procedures followed during a research project such as a medical trial
"concussion protocol" — rules or procedures followed after an athlete has a concussion
"business protocol" — standard etiquette or conventions practiced in business
So by such subtle points of protocol a crisis can be contained?
Chapter 20 (51% in)
Catherine and Ian had met at one of those bureaucratically dull dinners demanded by consular protocol, and after prolonged conversation laced with wit and appraisal of his table partner, Ballantyne had leaned over and said simply: 'Do you think we can still do it, old girl?'
Chapter 15 (68% in)
Any other way, including a confidential conference, would entail protocol, and even if I got him alone, without his aides, I couldn't touch him.
Chapter 37 (16% in)
There are no more uses of "protocol" in The Bourne Supremacy.