============== Captured from Cisco Web FAQ ==============

Q. When should 64-bit counters be used?

A. RFC 2233 leavingcisco.com adopted expanded 64-bit counters for high capacity interfaces in which 32-bit counters do not provide enough capacity and wrap too fast.

As the speed of network media increases, the minimum time in which a 32-bit counter wraps decreases. For example, a 10 Mbps stream of back-to-back, full-size packets causes ifInOctets to wrap in just over 57 minutes. At 100 Mbps, the minimum wrap time is 5.7 minutes, and at 1 Gbps, the minimum is 34 seconds.

Note: The SNMP counters wrap, the command line interface (CLI) counters do not.

For interfaces that operate at 20,000,000 (20 million) bits per second or less, you must use 32-bit byte and packet counters. For interfaces that operate faster than 20 million bits per second, and slower than 650,000,000 bits per second, you must use 32-bit packet counters and 64-bit octet counters. For interfaces that operate at 650,000,000 bits/second or faster, 64-bit packet and octet counters must be used.

Correspondingly, Cisco IOS® Software does not support 64-bit counters for interface speeds of less than 20 Mbps. This means that 64-bit counters are not supported on 10 Mb Ethernet ports, only 100 Mb Fast-Ethernet and other high speed ports support 64-bit counters.
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Lately I have a problem with Adding multiple MIB traffic from many devices with many interfaces.
The purpose is to summarize all of interface traffic volume.
The problem I have faced was : if the total / summary of all traffic volume more than 650 Mbps [650,000,000 bit/seconds], the graph starts to drop / broken / not smooth.

So We never saw the real of total traffic in that graph.
By Default my mrtg engine use snmp v1 to capture dan plot MIB into the graph.
According to above Cisco Website, I need to change the 32 bit counter to 64 bit counter to graph the traffic above 650 Mbit per second.
Googling around, We have to add the suffix at the end of MIB in MRTG CFG file with “:::::2″ which means that my engine is now capturing 64 bit counter information [MIB] with version 2.

There you go

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