[hpsdr] A note about consumer-grade Ethernet switch/router throughput

[Ken N9VV]

Hi Tom,
Today I indulged myself with a Christmas present. I purchased a new 
Mikrotik 450G rated at 77,000 packets-per-second (1500byte/packets).
<URL: 
http://www.balticnetworks.com/mikrotik-routerboard-450g-complete-with-case-and-power-supply.html
 >
It was recommended to me by a old-time Network Engineer Bill KC9XG. He 
used Skype screen-share with me and showed me the software tools that 
are available for this router/switch. *WOW* both "The Dude" and one 
called "WinBox" were absolutely stunning -- with graphics and text about 
every node and access point on his system.

It showed 23Mbps Rx from the ANAN-10 to his PC and 3Mbps from his PC to 
the ANAN-10 Tx. It was fascinating to watch it and I was hooked for 
sure. I have never owned a router or switch with such fine SNMP (free) 
tools.

I hope my PC and miTX Atom 330 can keep up with the network data rate 
<g> I'll find out shortly and report.

A good switch or router makes a tremendous difference. My ISP told me 
that a year ago and I am now a true believer (with 8Mbps down and 
500kbps up).

GL and 73 de Ken N9VV

On 11/26/2012 2:41 PM, Tom McDermott wrote:
> ***** High Performance Software Defined Radio Discussion List *****
>
>
>
> One item to consider in home-network performance issues is the
> throughput of some consumer-grade ethernet switches and routers.
> The HPSDR protocol puts 126 IQ samples per 1032-byte Ethernet frame (one
> Rx), and the same for transmit.
> This makes the data rate for one 192k receiver equal to 12.58
> megabits/sec, and the data rate for the 48k transmitter equal to 3.15
> megabits/sec. Thus one T+R is 15.73 megabits/sec (ignoring some minor
> ethernet overhead)
> Some common terminology: an ethernet switch in consumer products usually
> is just a dumb switch with only LAN ports. The router usually refers to
> a device that has at least one WAN port intended to connect to the
> outside world (i.e. your DSL modem, cable modem, whatever), plus usually
> some number of LAN ports.
> My ethernet router is about 8 years old. It has 8 x 100M LAN ports, and
> one 100M WAN port. Back when it was built, the manufacturer (a very
> large well known supplier) used a low-power embedded microprocessor and
> firmware to do switch and route each individual frame. The switching
> effort is minor, but packets destined to / from the WAN port undergo
> more processing. Usually there's a NAT, a firewall, TCP port checking,
> etc. Since my Windows computer already has a firewall, and the DSL IP
> provider modem also has a firewall, I am blessed with triple redundancy
> in the firewall department.
> However because of the lack of horsepower, my ethernet switch does not
> come anywhere close to actually being able to forward at 100M/s.  In
> fact the WAN throughput on my device maxes out at 5.6 megabits/sec
> (reported on the internet for my device, and I've confirmed it). Note
> that this is much slower than the HSPDR frame rates. Makes you wonder
> why the manufacturer even bothered to put a 100M port on the WAN jack.
> The LAN throughput is higher.  I've been able to almost run 15.73
> megabit/sec from LAN port to LAN port through my router. While I cannot
> measure LAN-LAN throughput, I suspect that 16 megabits/sec is right on
> the hairy edge of what my switch can do. Turning on 2 HPSDR receivers,
> or having any other local network traffic would drop a lot of packets
> through my home Ethernet switch.
> More modern ethernet switches and routers (particularly gigabit
> switches) have migrated to using an actual VLSI switch chip for the
> fast-path ethernet frames. The specification on these devices lists
> throughput equal to the actual line rate (i.e. 1 gb/s per port). I don't
> know if that's accurate, but it's probably fast enough not to be a
> concern for HPSDR.
> -- Tom, N5EG
>
>
> _______________________________________________
> HPSDR Discussion List
> To post msg: hpsdr at openhpsdr.org
> Subscription help: http://lists.openhpsdr.org/listinfo.cgi/hpsdr-openhpsdr.org
> HPSDR web page: http://openhpsdr.org
> Archives: http://lists.openhpsdr.org/pipermail/hpsdr-openhpsdr.org/
>

-- 
http://groups.yahoo.com/group/apache-labs/
http://www.n9vv.com/
[GMT-5]

 1353971766.0