Simple Network Management Protocol

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==See also== ==See also==
* [[Multi Router Traffic Grapher]] * [[Multi Router Traffic Grapher]]
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Revision as of 18:07, 15 May 2006

Contents

Introduction

The Simple Network Management Protocol (SNMP) is a protocol for monitoring of network-attached devices for any conditions that warrant administrative attention.


Wireless Rate Via SNMP

This particular setup is for creating new SNMP values that monitor the Rate setting of the wireless and the RSSI values of specific clients/WDS. I borrowed some of this code and modified it to work with v23. Someone said this came from the Sveasoft forums. Assumes use of DD-WRT v23.


Tools: Getif (SNMP MIB browser)


1) Turn on SNMP in DD-WRT (Administration->Services)

2) Turn on JFFS and clean it (Administration->Management)

3) Log in via SSH and create the following scripts:


/jffs/snmpd/wlrate:

#!/bin/sh
/usr/sbin/wl rate |/usr/bin/cut -b 9-10


/jffs/snmpd/wlrssi1:

#!/bin/sh
/usr/sbin/wl rssi <mac_address_of_client_or_wds> | /usr/bin/cut -b 10-11


You can repeat wlrssi1 multiple times for each client or WDS you want to monitor. Just increment the number.


Next, type the following into the command-line:

nvram set snmpd_conf="syslocation <your_location>
syscontact <your_email>
sysname <your_system_name>
rocommunity <your_password>
rwcommunity <your_other_password>
exec Rate /jffs/snmpd/wlrate
exec RSSI-CLIENT1 /jffs/snmpd/wlrssi1
"
nvram commit
reboot


Again, repeat the "RSSI-CLIENT1" line if you have more than 1 client to monitor (incrementing the number, of course).


Test the settings with Getif. You will need to look for .1.3.6.1.4.1.2021.8.1 in the "MBrowser" screen.


Steps:


In "Parameters", type in the IP of the router and the read and write community passwords. Press "Start" and you should see the bottom status say something like "Sysinfo variables OK". Next, go to the "MBrowser" tab and put ".1.3.6.1.4.1.2021.8.1" in the second entry box (it probably says ".1"). Press "Start" and you should see a list of values pop into the lower output screen. You will see your configuration variables, then a list of numbers in the values side. The first 3 numbers will be "0", then your values will show up. First is your "Rate", then each of your RSSI values that you entered above.


Using SNMP for bandwith monitoring

You can also use SNMP for bandwith monitoring by using programs like MRTG or PRTG Traffic Graphers.

The routers SNMP traffic layout:

                   (___br0___) 
                    / | \ \_ \____ 
                   /  |  \  \__   \_____ 
                  /   |   \    \        \ 
       | [0]    [1]  [2]  [3]  [4] | | [wlan] | 
       |vlan1    ---- vlan0 -----  | |        | 
       | WAN           LAN         | |  WLAN  | 
       |                           | |        | 
       |Internet 1    2    3    4  | |  WLAN  | <-- label 
       +---------------------------+ +--------+ 
             ethernet switch          wireless 
            eth0 (cpu port 5)           eth1


See also