[j-nsp] M10i FPC PIC Throughput Questions

[Christopher E. Brown]

With the std cfeb after internal overhead per bus capacity is 3.2Gbit of
traffic, this is worst case minimum small packets, etc.

Raw bus capacity is IIRC ~ 4Gbit, difference is overhead.

Unless you are doing all small packet, actual limit is higher than 3.2.

Enhanced CFEB bumps the raw bus capacity to something around 5Gbit, and
the after all overheads forwarding capacity to 4Gbit (based on the 1G
per PIC limit).

Summ...

CFEB
	Up to 1Gbit per PIC, 3.2Gbit per bus _worst case small packet_

E-CFEB
	Up to 1Gbit per PIC


These figures are
On 2/23/13 6:01 PM, Matt Bentley wrote:
> OK - so there has been a lot of discussion around this that I've seen, but
> I've searched for hours and still can't find concrete answers.  Can someone
> help?
> 
> 1.  Does the 3.2 Gbps throughput limitation include overhead?  In other
> words, Is the "raw" throughput 4 Gbps with effective throughput of 3.2
> Gbps?  Or is it 3.2 Gbps of raw throughput with effective throughput of 2.5
> Gbps?
> 2.  Is this throughput per PIC on the FPC?  So let's say I have three 4x
> GigE IQ2 PICs and one channelized DS3 IQ PIC.  Does each PIC get bandwidth
> allocated equally between them?  So is it 800 Mbps per PIC, and the PICs
> can't "steal" bandwidth from another one?
> 3.  Where, and based on what, is traffic dropped with  Juniper head of line
> blocking (ie where multiple high speed input interfaces try to go out the
> same lower speed exit interface)?
> 
> Thanks very much!
> _______________________________________________
> juniper-nsp mailing list juniper-nsp at puck.nether.net
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> 


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Christopher E. Brown   <chris.brown at acsalaska.net>   desk (907) 550-8393
                                                     cell (907) 632-8492
IP Engineer - ACS
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