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17Re: SGD-004-05 - Network Object

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  • Leslie Douglas Lott
    Feb 7, 2006
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      Please accept my apologies if I cover any ground that has already
      been covered.

      1) When I first heard of a "Network Object" proprosal, my first
      assumption was that this would be used to show network status (like
      busy, down, available, etc). I think the name is misleading and a
      better name might be NIC or NetworkConnection object. I won't argue
      the point too much.

      2) I don't understand point 2 in the overview and am not sure it
      matters. From a programming perspective (I am a software/firmware
      engineer after all):
      a) most OSs I have programmed with supply a function that takes a
      string and determines if it is a hostname or ip address and acts
      appropiately to come up with the "net-ready" address. Internet
      Explorer and Netscape both do this.
      b)ALL communication across the IP network is done with the IP
      address (hostnames are for user convience). The sending device/os is
      responsibiliy for using DNS to resolve a host name to an IP address.
      c) Many OSs have a DNS cache that can get out of date. Try
      typing "ipconfig /displaydns" in a Windows command prompt and you
      can see for yourself. This means that error recover becomes an issue
      when using hostnames.

      3) I don't agree with the paragraph at the top of page 3 about
      binding to the enet adapter when DHCP is used. Windows and at least
      1 RTOS I have programmed with seem to have notification message that
      can notify high level functionality of DHCP changes (of course,
      someone or something has to be watching). Assuming that this is
      true, a device could send a new I-am (or I-Am-Router-To-Network) on
      addresse changes without having to bind to the enet adapter. The
      real trick is with respect to BBMDs and FDs.

      4) IP can be built on a wide variety of layer 1&2 protocols (PPP is
      a good example). It sounds like we are assuming that it always exist
      in conjunction with an Ethernet adapter. Is this really valid

      --- In bacnet-ip-wg@yahoogroups.com, Stuart.Donaldson@... wrote:
      > Here is an updated version of SGD-004 with some additional use
      cases and
      > resolving some issues that those brought up.
      > I realize that we don't have a lot of time in Chicago, but it
      would be
      > great if we have an opportunity to discuss this. Otherwise, I
      will gladly
      > accept comments via e-mail.
      > Cheers...
      > -Stuart Donaldson-
      > Software Engineering Lead
      > Alerton / Honeywell
      > Redmond, Washington
      > 425-869-8400
      > This email has been scanned by the MessageLabs Email Security
      > For more information please visit http://www.messagelabs.com/email
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