SNMP bandwidth requirements

I've been looking at setting up some bandwidth usage monitoring utilities...

One of the most popular seems to be MRTG.

I have it setup at home, but I want to do it for a client of mine. It'll be very helpful info to have for me since I'm not a full time admin, and I'm only around some of the time.

At home, its just on my LAN monitoring my router. Not a big deal... I have plenty of bandwidth to spare.

At my clients, it would be across a WAN and I don't want to use much bandwidth.

I know about the security implications.. and I'll place the propper access control.

I'm very curious as to how much bandwidth is used up by the reporting of SNMP?

Some things to consider:
- how many routers to monitor
- for each router, how many interfaces to monitor
- default polling period is every 5 minutes

Those three are configurable in mrtg.conf.

I believe MRTG sends one SNMP get traffic to each router every polling period. This should be small (less than 512 bytes). Every router then will send reply for the SNMP get, back to MRTG. This varies in size, depending # of interfaces to monitor, probably less than 512 bytes for the general info (sysContact, sysLocation, etc) and less than 1 kb for each interface (ipAddrTable, ifName, ifType, ifSpeed, ifInOctets, ifOutOctets, etc).

Bottom line, it should not be a big issue. Even here where some of my clients are still using VSAT with bandwidth of 19.2 kbps for their WAN. Yes, I understand, they always ask about bandwidth requirements. But after some explanation they usually has no problem accepting it.

Hope this helps.

Peace always,
<jdenny>

Is you client computer savvy? Linux / apache type?
I have many that are not.

I like MRTG too but for Windows centric users, I like to use Cybergauge.
http://www.neon.com/CGwin.html
It's commercial but not too pricy for the low device count version.

Will walk many devices from Cisco to Riverstone with ease.
Easy peasy for novice users looking to view bandwidth usage...

Once the initial walk is done, snmp queries are pretty much a nothing hit
to the network.
Unless of course you have many (sub)interfaces on your device(s).

Hope this helps..

Quote:

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Originally posted here by phishphreek80
At my clients, it would be across a WAN and I don't want to use much bandwidth.

I know about the security implications.. and I'll place the propper access control.

I'm very curious as to how much bandwidth is used up by the reporting of SNMP?

---

We have lots of connections across the country, all locations are monitored from a central location using MRTG. I've found that a user browsing the Internet puts more strain on the bandwidth than MRTG/SNMP will ever do.

And just as a note: If you want to really secure SNMP try SNMPv2 or even better v3. Most equipment seems to support v2 and if you're lucky v3.

To pick up an older thread...

Now that I've got some major projects taken care of... its time to pick this one back up.

I've been running MRTG and it has been working well. I have not seen any negative effects of using MRTG across a WAN.

Now I want to start logging all the router logs to one syslog server.

Anyone have any idea how much bandwidth will be used by remote logging?
Bandwidth is very scarce... and I want to make sure that the links are better utilized for business usage rather than administrative usage...

I'll only be logging critical errors (link down, bouncing, over utilizing, etc.).

I can't imagine it using too much.. but wanted to get some opinions of people who do remote logging.