[hpsdr] Running Heterodyne through multiple wifi hops

[Mark Leone]

Forwarding some clarification in further exchange with George. I replied to
him off-list inadvertently. Thanks for the additional reply, George.

Mark - K4XML

> -----Original Message-----
> From: george byrkit [mailto:ghbyrkit at chartermi.net]
> Sent: Thursday, January 19, 2012 4:40 PM
> To: 'Mark Leone'
> Subject: RE: [hpsdr] Running Heterodyne through multiple wifi hops
> 
> Mark,
> 
> I agree about your reading of the Metis spec requiring a full duplex
> connection/link.  THis is usually met by a 'switch'.  It is definitely
> not
> met by a classic 'hub'.  Routers MIGHT be either, but often were only
> hubs.
> If a Router supports full duplex, and routes between ethernet ports
> (RJ45
> connectors) based on address, and doesn't send all packets to all
> ports, it
> may well be usable.
> 
> Things may well get different when using a WAP or other wireless
> device.
> 
> The best evaluation is whether the scheme works or not!
> 
> Ones mileage may vary, of course.
> 
> 73,
> George K9TRV
> 
> -----Original Message-----
> From: Mark Leone [mailto:midnightjava at verizon.net]
> Sent: Thursday, January 19, 2012 4:13 PM
> To: 'george byrkit'
> Subject: RE: [hpsdr] Running Heterodyne through multiple wifi hops
> 
> > -----Original Message-----
> >
> > Dear Mark,
> >
> > Glad to hear of your success.
> >
> > I think that when you say 'routers' you mean 'switches'.  Routers are
> > old
> > and 'half-duplex' and Metis will NOT actually work with a real
> router.
> >
> 
> Hi George,
> 
> You're right about Metis not going through routers of course, but I'm
> not
> using an Ethernet switch either, in the usual sense of that word. I
> guess
> the best way to describe it is a hardware device that is most often
> configured to operate as a Router, configured via software to act as a
> bridge. The manufacturer describes what I have as a Router, and most
> people
> probably use it as such. But by loading the DD-WRT firmware in it and
> configuring it in "client-bridge" mode, it no longer does Layer 3
> routing,
> and acts as a LAN bridge instead. The bridge device thus created has
> multiple ports, and whether they're interconnected as a hub or a
> switch, I
> don't know. I suspect the former, but that question is not relevant for
> Metis support.
> 
> I don't mean to split hairs, but just wanted to point out that the
> device
> I'm using is actually identified as a router, though it's configured in
> a
> non-router mode in order to work with Metis. I didn't buy an Ethernet
> switch
> because I needed the device to wirelessly connect to my wireless access
> point. Maybe some switches have that capability; I don't know. But a
> router
> re-purposed as a bridge was a cheap easy solution for me.
> 
> As best I can tell by reading the Metis documentation, the underlying
> technical requirement wrt mediating LAN hardware is that Layer 2 (i.e.
> Ethernet) broadcast frames must be passed between Metis and the SDR
> host,
> and the connection must be full-duplex. Do you agree? If so, then since
> Routers generally don't pass these and switches and bridges generally
> do,
> the requirement to use a switch instead of a router is generally valid.
> But
> off-nominal configurations like the one I described should be evaluated
> against the underlying technical requirement.
> 
> 73
> 
> Mark - K4XML


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