Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!cwjcc!gatech!galbp!wittsend.lbp.harris.com!mhw From: mhw@wittsend.lbp.harris.com (Michael H. Warfield (Mike)) Newsgroups: comp.dcom.lans Subject: Re: What services does X.25 provide? Keywords: x.25, services, login, e-mail, file transfer, IPC Message-ID: <8672@galbp.LBP.HARRIS.COM> Date: 13 Sep 89 17:02:10 GMT References: <796@maxim.erbe.se> <3279@wasatch.utah.edu> <522@wet.UUCP> <3290@wasatch.utah.edu> Sender: news@galbp.LBP.HARRIS.COM Reply-To: mhw@wittsend.UUCP (Michael H. Warfield (Mike)) Organization: Lanier Network Knitting Circle - Thaumaturgy & Speculums Division Lines: 65 In article <3290@wasatch.utah.edu> haas@wasatch.utah.edu (Walt Haas) writes: >Unfortunately the Internet's definition of "reliable" isn't reliable, >since the TCP layer gives no notice at all when the route to the remote >host goes down. Bear in mind that TCP is a military protocol designed >primarily for an environment in which a hostile enemy is shooting holes >in the network, and many compromises are forced on TCP users in order >for the protocol to meet this goal. In the world of commercial applications >that most of us work in, the environment and requirements are far different >from the military world. The massive inefficiencies forced by using >military protocols for everything regardless of the environment would >preclude TCP/IP from civilian use if the government didn't heavily subsidize >its use. Point #1 - If a host becomes unreachable, TCP certainly does notify you. The fact that routers underneath you may change your route, if one route becomes unusable, I would certainly call desirable in commercial environment. At first glance this would appear to be more efficient than restarting a session from scratch as the situations on a complex network shift. TCP is a "connected" service protocol. As long as it can maintain the connection, through whatever route, it is doing is job. And it most certainly does notify you when a connection goes down. Point #2 - Calling tcp/ip a military protocol is a misnomer at best. TCP/IP was not designed to "military spec". Rather the DoD specifications are based on the Internet (ARPA net) "RFC" specifications. These were largely developed in the university environment. While it is true that the universities have a large interest in military contracts, ARPA net developed around the needs of the computing community of the universities. The "openness" of the tcp/ip type protocols and their lack of security is hardly within normal military interests. The DoD specs, which parallel the Internet RFC's, even have a disclaimer that, if there is any discrepancy between the DoD spec and an Internet RFC, that the Internet RFC holds precedence as is assumed to be the authoritative document! When is comes to true military specification, the word of the military is God and nothing holds precedence over the military spec. Point #3 - Blaiming TCP/IP inefficiencies on the military is pure BULLSH*T! There is still a debate on the subject, but many consider OSI even WORSE as far as network efficiency goes. The techniques and structures of OSI take many of the principles behind TCP/IP to extremes. And our military had absolutely nothing to do with its design. TCP/IP's wide spread use is due to the fact that it is a large multivendor standard, not because the military has subsidized it. Does the "gossip" specifications (requiring eventual convertion to OSI in government) mean that the OSI protocols were writen to military spec or that the military has somehow subsidized the Europeans? Hardly! The TCP/IP protocols were designed to operate over absolutely trashy networks by todays standards. You might think that as network technology has advanced that the overkill in network protocol principles would evolve into simpler methods. Unfortunatly OSI has proved that such is not the case. I would cringe to think of a network protocol truely developed to military specification. It would, no doubt, be hugh and inefficient. However, unlike TCP/IP, I doubt it would work and I doubt the civilian population would be interested in it. ---- Michael H. Warfield (The Mad Wizard) | gatech.edu!galbp!wittsend!mhw (404) 270-2123 / 270-2098 | mhw@wittsend.LBP.HARRIS.COM An optimist believes we live in the best of all possible worlds. A pessimist is sure of it!