[e2e] a problem...

Cannara cannara at attglobal.net
Sat Feb 19 00:12:52 PST 2005


Why not go to the folks who make large switch fabric chips, with redundant,
failover serial links, and see what they do.  Maybe Vitesse (Gigastream...),
etc.?  Clock presence doesn't mean data presence, by the way.  And, DC
polarity is information -- pay phones have always returned your coins by
reversal from the CO.

Alex

Puddinhead Wilson wrote:
> 
> So while discussing this with folks I ran into another
> interesting case
> 
> We have
> N1------------------>N2
> |                    |
>  ------------------->
> 
> one wishes to have redundant links, so that if N1
> fails, N2 should be used the links are long and huge..
> 
> Some folks prefer to send data over both links
> simultaneously and let the receiver side decide which
> one to use...funnily they still need to "signal" the
> failure of a link across N1 and N2, rather than simply
> rely on absence of clock (??)..the going word for it
> is APS.
> 
> Another option could be to let N1 decide which link to
> use.
> 
> Obviously both links have to terminate on different
> ports, so it wont matter one way or the other... the
> clock detection still seems simpler :(, another
> advantage being you could use "both", but lets leave
> that aside for now..
> 
> also say:
> if we do "short 2 wires" and send data over both,
> we need an arbitrator/switch to decide which wire to
> use.
> should this arbitrator be on the ingress side or the
> egress side?
> 
>  --- Puddinhead Wilson
> <puddinghead_wilson007 at yahoo.co.uk> wrote:
> > exactly,
> >
> > A constant DC is "no information" :)
> >
> > You best put my question.
> >
> > but it's "presence or absence" is.
> >
> > Say for example I have
> > N1--->N2
> > if both N1 and N2 use the same frequency/channel etc
> > to txmt, it would result in distortion of
> > information
> >
> > What is that component that I always need to
> > transmit
> > the information but does use up my channel capacity.




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