[Cerowrt-devel] Comcast upped service levels -> WNDR3800 can't cope...

Aaron Wood woody77 at gmail.com
Fri Aug 29 12:57:26 EDT 2014

Comcast has upped the download rates in my area, from 50Mbps to 100Mbps.
 This morning I tried to find the limit of the WNDR3800.  And I found it.
 50Mbps is still well within capabilities, 100Mbps isn't.

And as I've seen Dave say previously, it's right around 80Mbps total
(download + upload).


I tried disabling downstream shaping to see what the result was, and it
wasn't pretty.  I also tried using the "simplest.qos" script, and that
didn't really gain me anything, so I went back to the simple.qos script
(those results aren't included above).

It looks like it's definitely time for a new router platform (for me).

Or, we need to find a way to implement the system such that it doesn't max
out a 680MHz mips core just to push 100Mbps of data.  That's roughly 10K
cpu cycles per packet, which seems like an awful lot.  Unless the other
problem is that the memory bus just can't keep up.  My experience of a lot
of these processors is that the low-level offload engines have great DMA
capabilities for "wire-speed" operation, but that the processor core itself
can't move data to save it's life.

What's the limit of the EdgeRouter Lite?

Or should I start looking for something like this:


(although that's an expensive board, given the very low production volume,
for the same cost I could probably build a small passively-cooled
mini/micro-atx setup running x86 and dual NICs).

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