4331 Router throughput

[GRANT3779]

I see the above router can be upgraded in software from 100Mbps throughput to 300Mbps.

What exactly are we talking here? Is this how quickly the router process packets coming into it from one interface to another?

My understanding is the actual 1Gbps interfaces routers have can forward at 1Gbps speeds due to it having their own hardware built into the Interface.

When we talk throughput for the 4331 though is this the limit the router can process within software before it starts to drop packets?

[Joseph W. Doherty · Accepted solution]

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The gig interfaces' hardware does send and receive a single frame/packet at gig rate.  Yes, you're correct, the router's "performance" provides the moving of frame/packets between interfaces and its capacity is often much less than interface capacity.  If you exceed the capacity of the router, effectively packets get dropped.

[GRANT3779]

Thanks Joseph. For these packets that are dropped due the routers 'performance' e.g the 100Mbps limit, what type of drops do these show as? Are they counted on the interface stats and if so, which ones?

[Joseph W. Doherty]

Hmm, not really sure how the lost packets would be recorded, if recorded.

Not sure about the 4xxx series, but on older series, your CPU will hit 100% and often other bad things might begin to happen, like dynamic routing hellos also being lost.  As a rule of thumb, you don't want your average CPU utilization to exceed about 75%.

[Ann]

Hey, i am facing same issue. My 4331 router is exceeding its throughput & hence it is facing packet drop issue.

Do you know how can I solve the issue?

[Leo Laohoo]

what type of drops do these show as

In addition to Joe's reply (below), sometimes the drop packets show up as "Output Drops" of the interface.