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

[Tim O'Rourke]

Ken
I just tried installing a Trendnet TEG-S50g Gigibit 5 port Switch.
No issues just plug and play, $19.95 on sale a while back at Newegg.
Tim 


-----Original Message-----
>From: Ken N9VV <n9vv at wowway.com>
>Sent: Nov 26, 2012 6:16 PM
>To: Tom McDermott <tom.mcdermott4 at yahoo.com>
>Cc: HPSDR Lists <hpsdr at lists.openhpsdr.org>
>Subject: Re: [hpsdr] A note about consumer-grade Ethernet switch/router	throughput
>
>***** High Performance Software Defined Radio Discussion List *****
>
>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]
>_______________________________________________
>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/


Tim O'Rourke 
W4YN at ARRL.Net
Low Power Amateur Radio Rocks 
Member of Flying Pigs,ARCI,GQRP,RSGB,ARRL Life Member
NHRA Life Member

 1353987060.0