This appendix describes each of the protocols currently available in Version 3.3 of the x-kernel . (Additional protocols are available in Version 3.2.) The description for each protocol provides the following information.
Name of the protocol. This name, given in all lower-case letters, can be given as an argument to xGetProtlByName to get a capability for (pointer to) the protocol. Note that there are multiple implementations of various protocols; i.e., a given name might map to multiple implementations. The implementation bound to a name in a given kernel is set in graph.comp.
Reference to a document that gives the specification for the protocol. In cases where no formal specification exists, this section gives a high-level description of the protocol.
A brief description of what the protocol does. Outlines any unusual features and bugs, including any features of the protocol specification not implemented.
Indicates whether the protocol is in the ASYNC realm (supporting push, demux and pop), the RPC realm (supporting call, calldemux and callpop), the CONTROL realm (existing only to allow control operations), or the ANCHOR realm (interfacing with the host system).
A discussion of the number of participants the protocol expects to see and what it expects to see on the participants' stacks.
Non-standard control operations supported by the protocol. For each control operation, the type of the input and output argument is given (i.e., the type used to interpret the buffer argument). In the case of control operations that take multiple arguments, a set of types is given. Non-primitive types are generally defined in the protocol's .h file.
A description of interfaces not encapsulated within x-kernel operations
A description of configuration options for the protocol, including descriptions of of what this protocol expects of the protocols below it. If the protocol can only be configured above a certain protocol, the appropriate graph.comp line is given explicitly.
Who to complain to if the protocol fails to work as advertised.