Path: utzoo!attcan!uunet!lll-winken!lll-tis!ames!mailrus!ukma!rutgers!mit-eddie!interlan!backman From: backman@interlan.UUCP (Larry Backman) Newsgroups: comp.protocols.misc Subject: Re: TCP/IP vis Netware. Message-ID: <570@interlan.UUCP> Date: 27 Oct 88 12:25:35 GMT References: <132@icarus.kulcs.uucp> Reply-To: backman@interlan.UUCP (Larry Backman) Organization: Interlan, Inc., Boxborough, MA (1-800-LAN-TALK) Lines: 73 In article latzko@zydeco.rutgers.edu (Alexander Latzko) writes: >> >1> Boards which do TCP on board are generally a waste of time and >> >2> The Micom/Interlan Gateway lists for $3995 and has performance >> >limitations. You also probably don't want to use it in anything >> >smaller than a 386. > > >2> The Micom/Interlan gateway does indeed list for US$3995. It is >limited in the number of IP connections it can maintain. The last >time I looked to would only handle 24 connections. In a fairly large >network this is simply not enough. The last time I saw one in action >it was chewing up over 10% of the cpu on a compaq 386/16 for 4 >telnets. Unfortunatly, I didn't get a chance to see if that was a >constant. I suspect Larry Backman of Interlan will come breating down >my neck if I am too far off the mark. I expect it will get better as [] Hpoe I'm not breathing too hard... However, we argue the smart board dumb board, gateway question a lot here; so. a few points to ponder.. 1. Generally speaking, a smart board can match an 8 or 10 MHz. AT in performance. Our smart board as well as others can actually out-perform an equivilent speed AT running the same code. Why? The smart board has some sort of communication oriented OS that is dedicated to two things, responding to host requests, and picking packets off of the wire. This OS does not have to deal with keyboards, screens, disks, etc.. 2. Smart boards save host memory. This is a big win in DOS-land; not so important in UNIX, OS/2, and other protected mode OS's. 3. Smart boards cost more, and have memory which cannot be used outside of communications. 4. Dumb boards and host based protocols clearly out-perform the same protocol on a smmart board as soon as tou move into the 80386 family. I have an ISO-NETBIOS protocol stack that runs in both DOS and OS/2 on both smart and dumb boards. On a 386-16 the host based protocol stack is 70% faster than the board based protocol stack, on a 386-20 it was 120% faster; I have not measured a 386-25 yet. 5. Gateways are not for everyone. They do a lousy job of serving heavy TCP user's. On the other hand, they do a great job of serving the casual TCP access most PC user's seem to need. No, a gateway will not help 20 users who wish to spend 80% of the time doing keyboard intensive TELNET apps. It will help a workgroup of 30 or 40 users who do casual TELNET, FTP, and SMTP access, casual being defined as less than 33% TCP usage. 6. A well-designed gateway provides minimal disruption of the host CPU. I believe that the CPU usage you saw with 4 TELNET's would be duplicated by those 4 Novell workstations doing any sort of continous file server access using IPX. Gateway's (and for that matter, all intelligent boards) are nice in that they remove the Ethernet receive function from the host. All those broadcasts that IP drops, all those keepalives that TCP drops never make it up to the host. A dumb board, with a host based protocol stack, can swamp even the fastest host, provided the network has a lot of traffic. This argument is fun, its one of those religious wars that has no correct answer. Another good one (next time) is the correct hardware architecture needed to do fastt protocols. Larry Backman Interlan, Inc.