SNMP

[IrfanKhan4904]

We are using Cacti for monitoring. So the question is Could SNMP slow down the network?

[Richard Burts · Accepted solution]

We do not know much about your environment - how big is the network (how many devices report to Cacti), what kind of links connect the devices in the network to the Cacti server, what (actually now much) data are the devices reporting to Cacti? Without knowing these things it is difficult to give good advice. But in general I would say that in absolute terms monitoring data might have some impact on network performance. But in practical terms for most networks the impact of monitoring data on network performance is minimal.

[IrfanKhan4904]

48 Cisco Switch and 2 Routers 

[Georg Pauwen · Accepted solution]

Hello,

in addition to Richard's remarks, it obviously all depends on what you are monitoring, and the interval at which you are polling the devices.

I would say under 'normal' circumstances you will not notice any 'slowdown' at all. If you run into something SNMP and CPU related, it is usually due to a bug (and a specific OID you are polling).

If you want to, you can post the (SNMP) configuration of your devices, maybe we can spot something.

Cacti is open source and free (as opposed to a lot of management solutions that can get VERY expensive).

[IrfanKhan4904]

snmp-server community academic RO

snmp-server location ACADEMIC BLOCK

snmp-server contact faisal

[Joseph W. Doherty]

Yes it can, as noted by others.

The big criterial for possible impact, how much "excess" CPU you have for processing/supporting SNMP, on a particular device, how often you poll the device (and/or how much traps/informs are being generated by device), and how much data are you passing via SNMP.

As also noted by the others, often "typical" SNMP stats polling doesn't cause issues, but then, often, "typical" SNMP polling might be every 5 minutes and you might only be pulling stats for CPU average load and/or interface receive/transmit rates with also, possibly, queue drops.

As to "slowing" the network, with SNMP, possibly the biggest potential issue is passing much SNMP data on a "slow" link.  You might also push a CPU to 100%, but likely (hopefully) SNMP is a lower priority than dataplane and/or other more important control plane functions.

Also BTW, how SNMP polls for data can make a difference too.  It might poll for each datum (i.e. leaf OID) individually, or ask for a dump of all the data under an non-leaf OID.

[Richard Burts]

I am glad that our explanations have been helpful.  Thank you for marking this question as solved. This will help other participants in the community to identify discussions which have helpful information. This community is an excellent place to ask questions and to learn about networking. I hope to see you continue to be active in the community.

[ammar80]

Hi Anupam, i just want to confirm can i set same user same group name and same authentication set in snmp version 3 configuration on multiple device in my network if yes then please assist me how it can be possible to push snmp v 3 configuration on multiple device at a time any method please help .