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163RE: [bacnet-ip-wg] Re: CLB-013 - Network Port Object

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  • Matsen, Dean C
    May 27, 2011
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      I understand what you mean.  But that's assuming the device is able to automatically choose its home port in all cases.

       

      I think the ultimate benefit of the NetworkPort object is that anyone can configure anyone else's devices.  If we leave this concept out of the NetworkPort object, then control of the home port will become hidden in the "local matter" realm and kind of defeat the purpose.  Since single-homing is a current practice with some vendors, a standard way of controlling it should be included in the NetworkPort object.  

       

      I'm not saying we should overly specify the behavior of this property either.  I wouldn't want to force all vendors that do single-homing to allow the property to be writable.  It could be read-only and informational in some vendor's devices.  I do think the presence or absence of the property would be a good way to determine if a device is a single- homed implementation or not.

       

      Dean Matsen

      Engineer Software Pr

      Alerton Dealer Business

      Honeywell Automation & Control Solutions

      6670 185th Ave NE

      Redmond WA 98052

      Phone – 425.897.3980

      Fax – 425.869.8445

      dean.matsen@...

       


      From: bacnet-ip-wg@yahoogroups.com [mailto:bacnet-ip-wg@yahoogroups.com] On Behalf Of Coleman Brumley
      Sent: Friday, May 27, 2011 5:44 AM
      To: bacnet-ip-wg@yahoogroups.com
      Subject: RE: [bacnet-ip-wg] Re: CLB-013 - Network Port Object

       

       

      Dean,

       

      I don't think removing the property necessarily removes the option of being a single homed device.  It just removes the BACnet application visible aspect of it.  Meaning, that if we remove the property, then there's no way to tell via ReadProperty (for example) if a device is single homed or not.  I'm not certain that's a problem or not, and that's the only use case I envision for that property.  There may be others, especially regarding NS, but I'm having a hard time coming up with anything else. 

       

      Coleman

       

      From: bacnet-ip-wg@yahoogroups.com [mailto:bacnet-ip-wg@yahoogroups.com] On Behalf Of deanmatsen
      Sent: Thursday, May 26, 2011 9:54 PM
      To: bacnet-ip-wg@yahoogroups.com
      Subject: [bacnet-ip-wg] Re: CLB-013 - Network Port Object

       

       

      Regarding single-homed devices, I always thought it was optional to be a single-homed device, but this just gives us a way to describe the NetworkPort object for such devices.

      Last time I looked at the NetworkPort object, it seemed like the idea was that single-homed implementations would have the property, and other devices wouldn't.

      My conclusion is that secure devices pretty much do need to be single-homed, because of the relationship between the device base security and the individual network policies. I also think single-homing solves some problems with NAT.

      If nothing else, we need to keep the idea of single-homed implementations available as an option.

      --- In bacnet-ip-wg@yahoogroups.com, "Carl Neilson" <cneilson@...> wrote:

      >
      > BACneteers,
      >
      >
      >
      > I have received a few comments on the Network Port object from a
      > developer at Delta Controls and would like to share those comments
      > before Montreal:
      >
      >
      >
      > - NetworkPort.MAC_Address is defined as type BACnetMACAddress. The
      > BACnetMACAddress is defined as a Sequence with only one field, a
      > mac-address octet string. It would be cleaner if
      > NetworkPort.MAC_Address were defined as an octet string type directly,
      > skipping the extra sequence tagging.
      >
      >
      >
      > - NetworkPort.BACnet_IP_Subnet_Mask is defined as type
      > BACnetHostAddress. An IPv4 subnet mask can never be specified by DNS
      > hostname so a base octet string would be a more appropriate type than
      > BACnetHostAddress.
      >
      >
      >
      > - NetworkPort.BACnet_IP_Default_Gateway is defined as type
      > BACnetHostAddress. A default gateway isn't defined by DNS hostname so a
      > base octet string would probably be more appropriate.
      >
      >
      >
      > - Dev.Home-Port - It is not clear why devices have to be single homed.
      >
      >
      >
      > There has been a comment in CLB-013 since revision 11 indicating that
      > the need for a Home network be reviewed with respect to the requirements
      > for Network Security and that if it is to remain in the document that a
      > definition of a home port be added. At this point I am not convinced
      > that the standard, including network security, requires single homed
      > devices. This should be evaluated before Montreal and removed if we
      > cannot find the requirement in the existing standard.
      >
      >
      >
      > Carl
      >

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