Picking an SNMP Version – 1 or 2c

As a system administrator I have always just used SNMP (Simple Network Management Protocol) version 1 to connect to everything (without really knowing why), I know there is the added security in version 3 but it isn’t something I need in my environment.

To me version 1 being the original would  be the best supported version. Also having read some materials that say version 1 and version 2c are practically identical why not just pick version 1.

Well through-out the development of Switch Buddy I have come to know SNMP very well, kind of feels like I can look at a raw packet and see the data inside just like in The Matrix. The biggest addition to the SNMP functionality with version 2c is the Bulk Request PDU (Protocol Data Unit). With a Bulk Request you can ask your device for many values in just one request, without this Bulk Request every single value retrieved is another request.

To put this into perspective, using Switch Buddy to poll one of my 48 port Juniper switches with SNMP version 1 took a total of 563 individual requests and taking 2 minutes and 26 seconds. If I switch this to version 2c it takes just 22 requests and takes 16 seconds. These tests are run over a PPTP VPN connection, so each one of those packets that needs to be sent has a little extra overhead. Version 2c uses only 3.9% of the requests required for version 1 and a tenth of the time.

Version 15632:26 (146 Seconds)
Version 2c220:16 (16 Seconds)

As a developer utilising SNMP I found that my application would be woeful to use if it wasn’t for SNMP Version 2c, you can clearly see the difference it makes by being able to use those Bulk Requests.

So from now on as a system administrator I will be using SNMP version 2c, cause you never know when the developer of an application has been helpful enough to implement Bulk Requests if they are appropriate to improve performance.

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