iwato Posted July 28, 2011 Share Posted July 28, 2011 Question ONE: What is DDI-TCP?Question TWO: How does it differ from TCP?Question THREE: When and how is it used? For example, should it be used to replace TCP when setting the $protocol parameter of the socket_create() function?Roddy Link to comment Share on other sites More sharing options...
justsomeguy Posted July 28, 2011 Share Posted July 28, 2011 As far as I can tell DDI is an industry term that refers to DNS, DHCP, and IP address management tools. It's not a protocol, just a term people use to refer to those three things. Link to comment Share on other sites More sharing options...
iwato Posted July 29, 2011 Author Share Posted July 29, 2011 As far as I can tell DDI is an industry term that refers to DNS, DHCP, and IP address management tools. It's not a protocol, just a term people use to refer to those three things.If it is not a protocol, then why do you think it would be the return value of the getservbyport() function?Roddy Link to comment Share on other sites More sharing options...
justsomeguy Posted July 29, 2011 Share Posted July 29, 2011 The getservbyport function doesn't return a protocol, it returns a service (hence the "getserv"). If you're talking about port 8888, the service on that port (a NewsEdge server) is referred to as ddi-tcp-1. That doesn't make it a protocol. The protocol is TCP.http://www.grc.com/port_8888.htm Link to comment Share on other sites More sharing options...
iwato Posted August 8, 2011 Author Share Posted August 8, 2011 The getservbyport function doesn't return a protocol, it returns a service (hence the "getserv"). If you're talking about port 8888, the service on that port (a NewsEdge server) is referred to as ddi-tcp-1. That doesn't make it a protocol. The protocol is TCP.Thanks. That was very helpful, and I feel a little silly as a result.Still I am having trouble understanding what a service is, and this lack of understanding surely contributed to my confusion with regard to ddi-tcp-[some_number].Roddy Link to comment Share on other sites More sharing options...
justsomeguy Posted August 8, 2011 Share Posted August 8, 2011 A service is just a generic name for whatever is responding on a certain port. HTTP is a service, for example (HTTP is also a protocol, but as far as TCP goes HTTP is a service running over TCP). For that matter, "protocol" is also fairly vague in that it's basically an agreed-upon way for 2 machines to communicate. TCP is a protocol for network communication in general, but there are also other protocols built on top of TCP (like HTTP or FTP).So I may have misspoke, DDI-TCP might in fact be a protocol, but it's not a replacement for TCP, it would run on top of TCP. It may be a protocol to look up DNS and DHCP information, for example. It's also possible to have something like HTTP work on something other than TCP, for example IP Over Avian Carriers (ok, it would take a lot of work to get HTTP working there, but it's possible).It's easy to get confused though when terms like "protocol" and "service" are so generic. Link to comment Share on other sites More sharing options...
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