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3500 and 3550 series Switch Utilization


As the "show process cpu" command doesn't give the "Total Switch Load" in 3500 Series switches.

I have to use "show controllers switch" command to find the Bandwidth Usage. Is there an SNMP OID that i can use for collecting this info remotely ?

Is the above observation also true for 3550 series switches ? OR Does "show process cpu" gives an indication of switch load for 3550 series switches ?

Other than the above procedures, what the is best method for finding Switch BW utilization for 3500\3550 series switches using SNMP ?

Regards \\ Naman

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Re: 3500 and 3550 series Switch Utilization


try the following.




The current bandwidth consumed. The measurement unit is

in megabits per second (1 , 000 , 000 bits/second).

This value gives a reasonable estimate of the amount of

traffic currently flowing through the switch.

It is calculated as follows:

Octets*8 + Frames*(96 + 64)


Measurement Interval * 1 , 000 , 000 * 2


Measurement Interval is the amount of time over which

the Octets and Frames were collected , in seconds.

Measurement Interval is always one second in current


Octets is the total number of octets transmitted

or received by all network interfaces , excluding

framing data but including FCS. This includes octets

in frames which were partially transmitted or

received (due to collisions , for example).

Frames is the total number of frames transmitted

or received by all network interfaces , including

frames with errors.

The number of frames is multiplied by 96 plus 64 in

order to estimate the delay between each frame for

Ethernet's IPG and preamble/SFD.

The '2' in the divisor makes this a forwarding bandwidth

counter. A frame received on one interface is typically

forwarded out another interface. In order to avoid double-

counting this frame's bandwidth , once on the receiving

interface and once on the transmitting interface , the

total bandwidth is divided by two.

Since multicast and broadcast frames can be sent to multiple

ports , the above is at best a lower bound.

Community Member

Re: 3500 and 3550 series Switch Utilization

Thanx. This works great for 3500 series switches.

However doesn't work for 3550 series switches. Maybe for 3550 , the usual cputotal1min OID gives useful information (As it does for IOS routers) ?

Community Member

Re: 3500 and 3550 series Switch Utilization

Both the 3500XL and the 3550 series of switches move packets in

hardware. You should *not* expect the CPU load to be in any way

related to the total number of packets (or bits) moved through the


Sorry, I don't know of any useful OID for the 3550.

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