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Mpps to Gbps Conversion

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  • 1.  Mpps to Gbps Conversion

    Posted 10-04-2008 23:11

    Hi,

     

    Can any body please let me know if there any calculation to convert the Mpps values to Gbps..and also how to calculate the effective forwarding rate of a switch

     

    regards, ruwini



  • 2.  RE: Mpps to Gbps Conversion

    Posted 10-08-2008 03:36

    Hi Ruwini,

     

    In my opinion, you can not really calculate this, because packet sizes differ offcourse...

    Of which switches are you speaking ? The EX4200 en EX3200 datasheets might help you out to determine if the capacity is enough for your goals:

     

    EX3200 Series:

     

    Packet Switching Capacities

    24P/24T: 88 Gbps
    48P/48T: 136 Gbps

     

    Layer 2 Throughput (Mpps)

    24P/24T: 65 Mpps (wire speed)
    48P/48T: 101 Mpps (wire speed)

     

    EX4200 Series:

     

    Packet Switching Capacities

    24P/24T: 88 Gbps
    48P/48T: 136 Gbps
    24F: 88 Gbps


    Layer 2 Throughput (Mpps)

    24P/24T: 65 Mpps (wire speed)
    48P/48T: 101 Mpps (wire speed)
    24F: 65 Mpps (wire speed)

     

    As you can see, they claim wire speed connectivity, so is there a specific reason why you are asking ?

     

    G's Dennis



  • 3.  RE: Mpps to Gbps Conversion

    Posted 10-08-2008 05:55

    Hi Ruwini,

     

    You can convert Mbps to Gbps by simply dividing by 1000.  That's derived from the definitions of Mega (x 10^6) and Giga (x 10^9).  Be careful though... when referring to Bytes (rather than bits) you need to divide by 1024 to get from Megabytes to Gigabytes.

     

    Anyway... As pointed out by dennish, calculating a throughput in packets per second is possible only when a particular packet size is used.

     

    If we take the 65Mpps and look at a "worst case" 64byte frame, you'll need to add to that the headers (14 or 18 bytes, depending upon whether there is a VLAN tag or not) and the inter-packet gap (12 bytes, IIRC).  So, each 64 byte frame actually consumes 64+14+12 (90 bytes) or 64+18+12 (94 bytes).  

     

    24 GE ports with 1Gbps in and 1Gbps out = 48 Gbps

     

    (48000000000/8)/90 =~ 66Mpps

    (48000000000/8)/94 =~ 64Mpps

     

    65Mpps is a reasonable average.

     

    Those are the Layer 2 switching capabilities of a 24 port switch based on the available capacity on the ports.  The actual switching capacity of the PFE is much higher than that (declared at 88 Gbps for the 24 port switch).  So, the PFE is capable of significantly more throughput than the interfaces can offer to it.

     

    Rgds,

     

    Guy 



  • 4.  RE: Mpps to Gbps Conversion
    Best Answer

    Posted 10-30-2008 08:29

    We got a mix of terms here.

     

    Mpps = Million packets per second

    Gbps = Gigabits per second

    Mbps = Megabits per second

     

    you can't turn Mpps into Gbps as Dennis said, Guy showed how to turn Mbps into Gbps.


  • 5.  RE: Mpps to Gbps Conversion

    Posted 04-19-2018 02:56

    Hi All,

     

    Anyone please suggest me MX104 Layer-3 Switching how many maximum MAC address space supported and how much Switch has forwarding rate supported in million packets (64 Bytes) per second (MPPS)

     

    Regards,

    Yasir Shaikh