Cacti Bandwidth ADSL

[lechat]

Hello
Very good tool !
i have 2 questions :

1)how to have the bandwidth on a interface . I know the formul (last_value-current_value)*8, but i don't know how to configure this formul in cacti (in CEDF may be, how to have the last value. I use snmp to catch ifinoctet and ifoutoctect.

2)how to know the bandwidth of a ADSL connection. I d'ont have a permanent IP, so it change every, that mean i can not use the same OID (via SNMP) to have the ifinoctet an difoutoctect. In MRTG i was used the mac address, but know i don't know to configure that in cacti

Thank a lot for your help.

A friend from france

[bulek]

1)how to have the bandwidth on a interface . I know the formul (last_value-current_value)*8, but i don't know how to configure this formul in cacti (in CEDF may be, how to have the last value. I use snmp to catch ifinoctet and ifoutoctect.

You don't have to write your own CDEF function. Just create data source with type COUNTER and then for every graph item use bulit-in CDEF function called "Turn bytes into bits".

2)how to know the bandwidth of a ADSL connection. I d'ont have a permanent IP, so it change every, that mean i can not use the same OID (via SNMP) to have the ifinoctet an difoutoctect. In MRTG i was used the mac address, but know i don't know to configure that in cacti

Cacti does not care of IP addresses actually (unless it is a management one). It uses SNMP interface index instead. The index may change during the time as well but in many cases it is fixed. You need to check with your equipment.

- bulek

[lechat]

Thanks for your answer Bulek

I done what you say, but the pb is not solve.

it's an ADSL (512/128) connection. What maximum value in data source i have to configure for out and in traffic, and in the graph configuration what upper limit i have to configure for the out and in traffic.
May be the problem is here.
I have a graph but the values are impossible inbound outbound traffic : cacti say inbound 270 Kbit in reality 36Kbit (with netmeter) and outbound 68 Kbit in reality 16Kbit

i don't understand !

thanks a lot

[bulek]

ifInOctets and ifOutOctets are just constantly growing byte counters. Values they are providing are not stored in RRD file (if you use COUNTER type for collection). Instead bytes per second rate is stored inside. This means you should put 65536 for incoming and 16284 for outgoing as a maximum value in data source configuration. For graphs it is not so important because they are scaled unless you check "Use Rigid Boundaries Mode" option in graph settings. Anyway if you use "Turn bytes into bits" CDEF the upper limit should be 512 kbps.

I don't have netmeter installed but looking at its screenshots I can see the speed in bytes per sec while your graph shows speed in bits per second.

- bulek