Let's now take a look at two examples of
SNMP tags. Here we have the UpTime of
a network firewall.
Beside the Descriptor and the Engineering Units, we have
the generic attributes that link the tag to the interface.
We have the PointSource,
the Location1 which is set to the Instance
ID number, and the Location4
which is set to the number of the Scan Class
you want to use. The SNMP
specific attributes are Extended Descriptor, where we have
the password, the Community String,
then semicolon, and then OID,
which is the counter you want to monitor from your device.
As you can see, we only have
system.sysUptime.0. This really does not
look as the long path we use to have,
like in the second example, dot one, dot
three, dot six, dot one, and so on.
In my demonstration of the plug-in in a few minutes,
you will see that some categories in the SNMP
Hierarchy can be abbreviated. Some of
the most popular ones, such as System,
or the Interface Table that we saw
a couple of pages before,
can be abbreviated. And then you have
InstrumentTag which contains the Host, the
IP Address or the name of the device you want to monitor.
Remember, Location5 is
for debugging. Here we have zero.
That means nothing is written to the PIPC.log file for
this particular tag. The Location2
was to set -- to tell the interface
this is a Standard Tag, or you have to time
normalize the value. Here, because
this is not a Rate, the number of bytes in or out,
for example, -- well, this is not a rate. We
just keep the raw value we get out of the SNMP
agent. And Location3 being
set to one indicates the interface that
it can group this tag with other similar tags.
Let's now
demonstrate the plug-in -- how to use the plug-in in our System
Management Tools: Start Menu;
Programs;
PI System; PI System
Management Tools.
Then, under the Points Category, you have
SNMP Tag Builder.
On the first tab,
Tag Settings, you choose the interface you
want to use. Prior to this demonstration
I configured an SNMP Interface in ICU.
So, as you can see here, I can choose it.
It's been configured with PointSource Dollar
Sign, the Instance ID number is
One, and there are two Scan Classes
configured, 10 minutes and 10 seconds.
Let's use 10 seconds.
Now, what about SNMP settings?
Here is where you tell the plug-in
what device you want to monitor.
The prefix of it could be Local because I
want to monitor my local machine. The IP
Address or the Host Name should be
set to Local Host, and my
Read Community String is set to the default one,
Public. Remember that in order
to monitor a Windows machine, you have to
install the SNMP Service not the
PI SNMP Interface, the Windows SNMP
Service. We discussed about the procedure to
install this service in our introduction to the
SNMP [inaudible] . Something
interesting in this plug-in is that you can save the information
into an Agent File so you do not have to remember
all the IP Addresses and their password.
Save to File.
Enter the name of the file.
And, that's it.
So, you have your Agent File listing
all the agents that are in there.
So, you could enter a different device here --
your switch, for example.
192.168.0.1.
Read
Community String would be MyPassword.
You could save it
to the file,
to the same file.
It ask you if you want to append
the agent to the existing file. Yes.
And that's it. So you can now play with
these two devices. You could configure
different Agent Files for your different locations or different
sub-nets, different buildings, and you can
open some with this button.
When you are ready to play with the device, to
monitor the device, you can simply validate
the SNMP communication.
See, agent was validated.
I can monitor
my device which has five
interfaces, five network interfaces.
And pay attention here 'cause we often
use the word "interface." But in the
SNMP language "interface" means a network interface,
not the PI SNMP Interface, not the
software collecting data. A network interface
is a logical or a physical port.
When you monitor a
printer or a UPS or something like this,
you do not necessarily want to record the number of
bytes going in and out the ports, so you can simply
validate, as we just did.
When you monitor a switch or
a server on which you want to monitor the network
interface cards, you can get interface
info. See it lists
all the network interfaces, the number
of bytes in, out, their status,
their speed.
You can then select the one or the ones
you want to monitor, and then
go on the Build Tag tab.
See, I still have
five interfaces selected.
And you may remember, this category,
the Interface IF Table
which gives you counters to monitor
these network interfaces. This is
probably the most popular category in the
whole hierarchy: iso,
org, dot,
mgmt, mib-2,
interfaces.
You may remember I told you that
every single item in the hierarchy
has a number associated, and you
can use mib files, the aliasing
files to translate these numbers into
text. For a big part
of the hierarchy, we did provide you the
mib files, so as you can see, you can browse into
many many categories, and you do not
have to worry about downloading the mib files from the internet.
One category that's really
interesting is
not in mgmt but
private. Well, this is the public
side of SNMP. You have
private in which all the enterprises
can register. For example, Cisco
or D-Link or Microsoft, whatever
vendor of hardware or
software can register for a sub-branch
of this category. As you can see, we already
provided some mib files under the private
enterprises.
A good example of using this category here,
the private enterprises, is where you want to
get specific details about your device.
For example, if you want to get the, the voltage
in the power supplies of your switch or the
rpm of the fans,
the temperature inside your switches, you would go
into enterprise. For bytes in,
bytes out, or statuses of ports, you can always
go in mgmt, mib-2,
which is the public side of it, which is the standard.
All the SNMP devices
should support the counters in this category.
Then vendors can
provide users with more counters and they
would be in their private enterprises
and in their sub-branch. So you want
to monitor the ports, you come here.
You want to monitor some specific information about your
device, you come in the enterprises
sub-branch. So, let's
say you want to monitor a printer. You would have
to go on your printer's website,
download the mib file,
and then open the mib file
using the Load a MIB File icon.
Now let's get back to our
interfaces, mib-2,
interfaces.
You see that we have five interfaces
selected. That means every time I click
on an entry in my Interface Table,
I get five counters.
You see, five counters, one for
every single interface: the description,
you can get the type, the speed,
operational status,
inOctets, which is, which is bytes in,
and outOctets, which is bytes out.
So you Assign Tags.
You can then de-select
some, select some more here.
You can then choose one or more, and
edit its properties.
So, you can
change the Sample Rate. You can change
the Descriptor, the Engineering Units, and
some more Attributes.
When you are done, you can select a PI
Server to configure the tags on, and
then create tags.
See, it created 16 tags,
zero errors.
Or you could also write these to
a CSV file, a Comma Separated Values
file. So you can then open it in Excel
and modify the tags before to export them.
Let's now quickly recap the important categories in
the SNMP Hierarchy:
iso, org, dod, internet,
mgmt, is the public side of it.
Under mib-2 you can find
interfaces to get
information about the ports, to get information about network
interfaces, and you get System, which
contains the
system UpTime as well as,
as its description and some more information.
But UpTime is probably the most popular counter
in this category. Beside
that, you have
the private enterprises sub-branch
where you, again, go on websites and
download mib files. After
you opened it, you get
another sub-branch here, and you go
for specific information on your devices.
So that's how you would use
the SNMP Tag Builder.
And you can see, you do not really have to know about
all the internals, all the settings, in the
Attribute, but this is pretty useful if you want
to edit them after a while.
And for those having the regular
IT Monitor Class Manual, you could go for Exercise
#15, where you will have to configure tags
using the SNMP Plug-In.