Can you explain Rockwell BootP Server

Rob S.

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Join Date
Sep 2008
Location
Maryland
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We have many 1794-AENT in our plant.I am trying to set it up ,but I really don't understand it enough.

What is BootP ?
What is it's purpose ?
What happens when you Disable and enable ?
Does it go out and search for the new 1794-AENT address or do you need to type it in ?
Etc,

Is there any good information that explains the setup and how
BootP works. The Rockwell 1794-AENT Ethernet Adaptor manual is somewhat helpful.

Thanks in advance.
 
Does it go out and search for the new 1794-AENT address...... if it is enabled.
or do you need to type it in ?.... if it is disabled
basicaly used to setup ip without other coms. you must have it running on pc to work, I think. Im sure someone will chime in with more info though...
one more thing if you leave it enabled and power cycles you could lose manual ip settings
 
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When BootP is enabled and you add a new device to your network it will go out and find it by mac address. It will display the device and allow you to set an ip address based on the mac address. You will have to know the mac address of the devic so you can make sure you set the right IP for it.

Typically once you set the IP address and download it to the flash of the devie it's there until changed again. This will only happen if the device is bootp enabled though.

This is how I remeber it but it's been a few years since I've used bootp on AB devices.
 
When BootP is enabled and you add a new device to your network it will go out and find it by mac address. It will display the device and allow you to set an ip address based on the mac address. You will have to know the mac address of the devic so you can make sure you set the right IP for it.

Typically once you set the IP address and download it to the flash of the devie it's there until changed again. This will only happen if the device is bootp enabled though.

This is how I remeber it but it's been a few years since I've used bootp on AB devices.

Actually, after assigning your IP address you do want to disable BootP. If you don't it will drop your IP as soon as power is cycled.
 
Let's ,for an example, say that you have a bad 1794-AENT Ethernet Adaptor. You change it out with a new one. What would you do to apply the same IP Address to this new one. Step by step.

Thank you so much for your help.
 
I can't help you as I don't have any Rockwell software installed right now but I know the docs from rockwell cover it in detail and you should be able to set it up no problem.
 
The MAC ID is a hardware identification that is unique for each device (for our purposes) this MAC ID never changes...think of it as a serial number for the ethernet portion of the device.

The IP address is intended to be changed and there are a number of schemes to acoomplish this.

For most PLC networks, you will want to end up with a fixed IP address that doesn't change dynamically once it is set (unlike the office PC world where it's no big deal to wait a few seconds to get a dynamic address from a server).

So a brand new device from A/B will normally come "out of the box" with BootP enabled. BootP is a way for the device to send a specific type of message out on to the wire and say "Hey, I need an IP address, is there a BootP server out there that can give me one?".

The BootP server, if one exists on the network, looks for these types of messages (which will include the MAC ID) and lists them, allowing the user to pick the item from the list that matches the MAC ID of the device that needs assignment. The user then chooses the IP address desired, and the BootP server sends a message to the device saying "Okay, device with MAC ID x, here is your IP address", and then should indicate that the device accepted the IP address successfully. It also contains a mechanism to turn off the BootP requests so that following the next power cycle, the process does not start over, but the assigned IP address is stored and used indefinitely.

The Rockwell BootP server has been reported to be less than 100% reliable in some particular situations. I would have to search for the threads where this has been mentioned, but for me, it has always worked as advertised.

This is an oversimplified street talk description but hopefully helps with a basic understanding. Hopefully, one of the network gurus can come along and expand on the details and correct any mistakes I may have made in my simplified explanation.
 
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Let's ,for an example, say that you have a bad 1794-AENT Ethernet Adaptor. You change it out with a new one. What would you do to apply the same IP Address to this new one. Step by step.

Thank you so much for your help.

Rob- this document will tell you all you want to know.... and then some. Zip on down to pg. 45.

http://literature.rockwellautomation.com/idc/groups/literature/documents/um/enet-um001_-en-p.pdf

I will tell you something that I don't believe is covered, indirectly maybe it is. If you get the IP loaded and disable BootP, then decide you want to change that IP address BootP will not see it.... until you reset it back to factory defaults. This is done by changing the switches on the front to 888 and cycling the power to it.

It should also be noted that if your little network is happy with the standard off the shelf 192.168.1.XXX with a subnet of 255.255.255.0, then all you have to do is set the switches on the front to some value from 1-254. Then you never have to bother with BootP.
 
It also contains a mechanism to turn off the BootP requests so that following the next power cycle, the process does not start over, but the assigned IP address is stored and used indefinitely.

So, once BootP is disabled for a particular device, you can no longer use BootP Server to change the IP for that device?

My scenario:

I have taken a used Allen Bradley InView Ethernet module from our store and installed it in plant. As the IP is unknown I tried to use Rockwell BootP Server but nothing is showing in the Request History. Could the reason be that this device has the BootP setting disabled?
 
do you know the IP address of the device?
if so, you use the MAC address and use the IP address to activate the buttons.
In bottom section of BootP using the new button. enter MAC and IP then the bootp options will be available.
 

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