[c-nsp] 3845 maxing out at 400 Mbps

[Pierre Emeriaud]

Hi Frank, all,

2011/3/29 Frank Bulk <frnkblk at iname.com>:
> We have two 3845's as border routers, each with three GigE interfaces (one
> facing upstream, the other downstream, the third facing the other 3845).
> The first 3845 has a typical packet-size mix (residential/business Internet)
> is consistently maxing out at 400 Mbps (predominately ingress because of
> asymmetric routing) running at about 43 kpps and 40% CPU.  It's flat-lines
> very evenly, uncannily so.  We checked and double-checked transport and it's
> set much higher, the same as the second 3845.


I guess you're using a hwic-1ge-sfp in your 3845 ?

Quote from http://www.cisco.com/en/US/prod/collateral/routers/ps5854/prod_qas0900aecd80169bf0_ps5855_Products_Q_and_A_Item.html
:

Q. What is the maximum throughput on the Gigabit Ethernet HWIC?
A. The HWIC bus interface is limited to 400 Mbps of full duplex. The
actual throughput of the Gigabit Ethernet HWIC is limited by the
throughput of individual platforms. Under bidirectional traffic of
1518 bytes or larger, the Gigabit Ethernet HWIC can support up to an
aggregate of 350 Mbps on Cisco 2811 and 2821 routers, 400 Mbps on
Cisco 2851 routers, and 500 Mbps on Cisco 3800 Series platforms.

So your 400Mbps limit could be hardware and not from configuration or software.


Regards,
Pierre.