[GTALUG] OpenWrt vs TP-Link Archer C7 v2

[D. Hugh Redelmeier]

For a while it has looked as if the C7 v2 was a very good choice if
one wanted to run open firmware.  In particular, it uses an Atheros
radio that has open drivers.

Based on my criteria, OpenWrt is the firmware to run (or something based 
on it).  DD-WRT and others have problems that make them not open by my 
standards.

I haven't actually run OpenWrt on a C7.  But I learned a few things last 
night that dismayed me.  You can find these in "Note:" entries on the
wiki page but they don't stick out.
<https://wiki.openwrt.org/toh/tp-link/archer-c5-c7-wdr7500>

0) It is "OpenWrt", not "OpenWRT".

1) Recent stock firmware from TP-Link locks out flashing third-party 
firmware.
<http://ml.ninux.org/pipermail/battlemesh/2016-February/004379.html>
If you have a C7 with older stock firmware, don't upgrade it to the
current stock firmware if you ever hope to use OpenWrt.  There are
apparently work-arounds but they seem a bit intricate.

2) The C7 (and a number of other routers) have a hardware fast-path to do 
NAT.  This hardware is undocumented and hacky so OpenWrt will never use 
it.  Without using it it is impossible to get gigabit wire-speed NATting.  
But the stock firmware does use it.
<https://dev.openwrt.org/ticket/11779>

3) For mysterious reasons OpenWrt is significantly less efficient handling 
5GHz 802.11ac.  You won't notice this unless you are using a 3-antenna 
client (or, I speculate, multiple 2-antenna clients)
<https://forum.openwrt.org/viewtopic.php?id=53703>
This thread is pretty frustrating because the first message very
carefully posts observations and yet most of the following 168 messages
ask questions already answered or veer off-topic.  There appears to be
no resolution.

All this reinforces my decision to build gateways out of small
PCs rather than consumer routers.  I do use an off-the-shelf wireless
router as an access point.