[nsp] PPS Interface Counters

[Ryan O'Connell]

Lawrence Wong wrote:

>Hi all,
>
>I would like to check with you on how do we read the
>"pps" counters on a Cisco router interface?
>
>Meaning for example with a router of 2 interfaces so
>traffic either goes from 0/0 to 0/1 or from 0/1 to 0/0
>or gets dropped :
>
> fa0/0 says 100pps in, 200pps out
> fa0/1 says 300pps in and 150pps out
>
>Does that mean that the router is altogther forwarding
>100+200+300+150 = 750pps?
>
>Or is it just forwarding 100 + 200 = 300pps?
>  
>

The router is forwarding (100 + 200 + 300 + 150) / 2 = 375pps. 
Presumably, some packets are going in one interface and back out the 
same interface if the statistics you quoted are real-world, but they 
seem a bit low for a production network.

In any reasonable real-world network not using Multicast for production 
traffic, Multicast/Broadcast shouldn't account for anything close to a 
significant portion of total pps. (Ditto for packets originated by the 
router itself - although someone is now going to pipe up and say they 
have a network with a significant amount of broadcast on it I'm sure :-)

If you're using Cricket/MRTG/etc, .1.3.6.1.2.1.4.6.0 will give you the 
total number of packets switched by a Cisco device where supported. (I 
know 7200s do support it and 2900s don't, I haven't checked other kit I 
have here to see if they're reporting it)

-- 
         Ryan O'Connell - CCIE #8174

I'm not losing my mind, no I'm not changing my lines,
I'm just learning new things with the passage of time