Low Level Comms

more ugh

how are messages passed over the network

as byte stream with no structure, in sockets or datagram packets

socket

abstraction of a network port

stream socket 1

reliable, no errors and failures are eventually detected

stream socket 2

bi-directional byte stream

datagram socket 1

unreliable, messages can be dropped or re-ordered

datagram socket 2

bi-directional exchange, bounded-length messages

what must both sides agree on?

data format, what type of data appears when

what do we need to define when defining a communications protocol?

how we use the comms medium, different host encodings for base types and value boundaries and framing

type of middleware 1

transaction oriented

type of middleware 2

procedure oriented

type of middleware 3

object oriented

type of middleware 4

message oriented

type of middleware 5

service oriented

transaction oriented middleware 1

perform transactions across machines

transaction oriented middleware 2

components are large grained, complete database applications

procedure oriented

remote procedure call