SNMP implementation

[Mark_Yedinak]

I suspect it is a community name thing then. Can you point me to any documentation on the device itself that covers communications with it? Specifically anything related to SNMP.

[smit9741]

The only source of information that I've found so far is the controller datasheet and manual, but I think it covers very vaguely the communication with it, I will attach them to  you, but there haven't been helpful for me. In the controller manual they mention SNMP on page 101

[Mark_Yedinak]

You may want to look at this document. The NTCP stuff may not be using pure SNMP for communications which might explain why the MIB walk is not returning anything. I am not familiar with NTCP and beyond what I have looked for so far I don't have the time to dig into it further. Have you tried contacting Peek Traffic and asking if the support direct SNMP communications?

[smit9741]

okay, I have some good news, I finally got the MIB Walk to work (sometimes it gives me an error, sometimes don't) with my OID numbers, through a careful reserach over NTCIP rules to complete the unkown parts you said yesterday, I can see the type of variables, Integer so far and a value that I believe it has stored in it. That should mean it is SNMPv1 compliant, and that's great but the simple SNMP get vi you posted yesterday is not working at this time, what could it be?

[Mark_Yedinak]

Are you providing the complete OID? The items you posted are all in a table and the index for the table must be speficied correctly? Can you post an example of the MIB walk and what you are passing to the simple GET vi?

[smit9741]

I don't know how it works with a sequence of elements yet, but for example I put an OID and it should have 8 elements, sometimes the MIB walk show me just 1 or 2 elements, maximum 3 but I never get to see more than that, and some times I don't even get 1 element within the same address I tried before. I can attach you an image where it shows just 2 elements, and are missing the first one (.....4.1) and also from 4.4 through 4.8 and I know the device has those elements defined  

[Mark_Yedinak]

I would suggest you try to capture a network trace (Wireshark would work well for this) so you can see what is actually happening on the network. You are getting timeouts which means the device is not responding. You may try putting a small delay between requests in the MIB Walk. The simple_snmp_get has a default timeout of 1000 ms. This may not be long enough for the device. Here is where a trace would be very helpful.

[smit9741]

now I want to get a all the elements of an object, let's say a sequence (it should have 8 elements in my case) is there any way to achieve this goal just sending its full OID without the program needing to enter each element sequentially to get? That would be awesome because I would avoid the delay that comes with each access to each element, one after another. My goal is to get all the elements in the minimum time and as far as I know the GET NEXT( as well as your MIB WALK) enters each element in a table sequentially and that is taking me a long time, and that also means timeouts of the VI. Could I access those values in the table almost simultaneously and store it in an array?

Thanks for your answers, are always helpful

[Mark_Yedinak]

The simple_snmp_get.vi I included will send all of the OIDs specified in a single SNMP PDU. The device should then return all of the elements in a single response. To use this you must specify the complete OID for each element.

I recommended you use the walk so that you could identify the missing sections of the OIDs. After that I recommend that you use specific GET requests to retrieve your data.

[smit9741]

yes, I did that and I'm having good response from my device, although I had to put a longer timeout as you said and a frame relay to make sure all the data is available before showing up in screen, with this I reduced the timeouts ocurrencies but I'm still geting some