ISR 4000 series Performance with Mpps

[prashanma]

Hi Team,

What are the Mpps values for ISR 4000 router series ? I can find Gbps values for those routers. Do ISR has Mpps values ? Or is there way to calculate Mpps value ?

[balaji.bandi]

here is the calculations :

(GBPS/2)*1.488 = Mpps

[Joseph W. Doherty]

The reason the ISR 4K series don't note their PPS is they usually can maintain wire-speed up to their supported bandwidth regardless of traffic or configuration. (Basically, the ISR 4k series is capped at their stated bandwidth capacity but their CPU is sized, generally, to handle worst case at maximum [capped] bandwidth. [The downside, though, you cannot take advantage of the excess CPU capacity, when the traffic mix would allow for greater bandwidth than the capped value. I believe Cisco sees this as a "feature", as sizing earlier ISRs correctly was somewhat of a black art.])

Oh, BTW, Balaji's calculation is a bit off. He's dividing the BPS by 2 when using 1.488 and he didn't note the 1.488 applies to a specific packet size.

(about) 1.488 Mpps supports 1 Gbps of minimum size, non-tagged, Ethernet (PPS drops as packet size increases).

Also don't forget you need PPS for duplex traffic. E.g. a gig Ethernet link, running at 100% in both directions {assuming full duplex), with minimum size Ethernet packets, requires about 3 Mpps from a router. (I.e., two gig [duplex] links, connected to a router may need up to, about, 3 Mpps.)

[prashanma]

So there is no specific "Mpps" for ISR4k routers, is it ?

[Joseph W. Doherty]

Not documented as such (at least that I'm aware of). However, you can calculate effective PPS given consumed bandwidth and packet size. (BTW, prior ISRs' PPS was generally documented as their maximum for untagged Ethernet at minimum packet size, also with nothing else configured. Using just that value, you might receive more or less throughput, again depending on your traffic and your device configuration. At least with the new 4K ISR approach, you pretty much always know the maximum throughput you'll obtain regardless of packet size, device config and/or traffic mix.)

[prashanma]

Thank you @Joseph W. Doherty for clarification.

But I saw following in the datasheet. Which data need to get to calculate PPS ?

Aggregate Throughput (Default)
Aggregate Throughput (Performance License)
Aggregate CEF Only[5] Throughput (Boost License)

[Joseph W. Doherty]

To calculate PPS, you need to know consumed bandwidth and packet size.

BPS = packet size (in bits) * PPS, so if you want PPS, divide BPS by packet size.

e.g. 1 Gbps / (84 bytes [84 bytes is for L1 "space" on wire for 64 byte packet) * 8) = 1.4881 Mpps
or 1 Gbps / (1520 bytes * 8) = 82.2 Kpps

Somewhere on the datasheets, the license should document the bandwidth cap.