[CentOS] Is it okay?

Sat Jan 22 02:26:20 UTC 2011
Stephen Harris <lists at spuddy.org>

On Fri, Jan 21, 2011 at 01:57:32PM -0800, John R Pierce wrote:
> On 01/21/11 12:11 PM, Stephen Harris wrote:
> > On Fri, Jan 21, 2011 at 11:13:54AM -0800, John R Pierce wrote:
> >> On 01/21/11 10:35 AM, Stephen Harris wrote:
> >>> I replaced my old redhat 6 firewall (Pentium Pro) with a wrt54g around 7
> >>> years ago when I realised just how much energy that machine was wasting
> >>> spinning up hard disks and stuff.
> >> wrt54's (I have a wrt54gs v1.0 doing  my wireless) are awfully slow
> >> little processors.   I have considered and still may get around to
> > It can handle my 30Mbit/s FIOS connection just fine, which is more
> > than I think my old Pentium Pro could do :-)
> huh, I'm surprised.   I've had trouble routing 10Mbit through them at 
> wire speeds.

With a WRT54G v2 running Tomato 1.21, connection made from a Centos 5.5
machine on the LAN (via a Gbit switch); connection to the FIOS ActionTec
router (in bridge mode) on the WAN.

% wget -O/dev/null http://cachefly.cachefly.net/100mb.test
--2011-01-21 21:03:32--  http://cachefly.cachefly.net/100mb.test
Resolving cachefly.cachefly.net...
Connecting to cachefly.cachefly.net||:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: 104857600 (100M) [application/octet-stream]
Saving to: `/dev/null'

100%[======================================>] 104,857,600 3.64M/s   in 28s

2011-01-21 21:03:59 (3.63 MB/s) - `/dev/null' saved [104857600/104857600]

So downloading 100Mbytes of data at 3.63MB/s == 29.04Mbit/s

> The wrt54g(s) internally has a single 100baseT ethernet port attached to 
> a 6 port VLAN switch.   WAN vs LAN are done with vlan switching, so 

At least on versions 1-4 and the GL series it has a 5 port 100baseT
switch which can do native VLAN.  The VLANs are presented to the OS as
sub-devices of eth0.  Ports 0-3 are LAN, port 4 is WAN with the standard
VLAN setup; third part firmware can do more.

> effectively its a half duplex device.   The CPU is also brutally slow, a 

No, it's not half-duplex.  The VLAN switching is done in the switch hardware.
The OS only needs to see traffic between LAN and WAN, which is what a router
does.  The main CPU never touches inter-LAN traffic.  Being a switch it can
receive and transmit at the same time; 100FDX on each port.

>From an OS perspective it sees two ethernet devices and it routes as
necessary.  Definitely the routing is done via the primary CPU, but
that's what makes it a cheap router :-)

As can be seen, it's very easy for the device to handle 29Mbit/s.
Since I'm only paying for 25Mbit/s this makes me happy :-)

3.64 is the constant speed wget reports over multiple tests over multiple
months; I dunno if this is the max my FIOS line will do or the max
that the router will do (or even the fastest the ActionTec will do).
It's consistent over multiple tests.  I have a spare WRT54G v4 which is
essentially the same spec; I might configure it and see how quickly it
can do 100Mbit WAN transfers.

(Interesting thought; could I get faster with a better router?  Hmm!)

But definitely this router can do 10Mbit/s without sweating.  If you
had trouble doing 10Mbit/s then you had other problems.