The handler concept allowed network protocol stacks to be outside the kernel, which greatly eased development and improved overall reliability, though at a performance cost.
en.wikipedia.org Similar to a communication protocol stack, this modularity provides great flexibility: each layer can be easily replaced with another as far as it provides the same interface.
en.wikipedia.org Much more common, however, were systems that ran entirely on microcomputers, including a complete protocol stack that included any required networking or file translation support.
en.wikipedia.org Traditional operating system functions, such as device drivers, protocol stacks and file systems, are removed from the microkernel to run in user space.
en.wikipedia.org To understand a particular protocol stack, network engineers must understand both the payload and delivery protocol sets.
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