Subject: Re: "dribbling bit"
To: Michael Richardson <>
From: None <>
List: tech-net
Date: 01/22/2003 16:41:47
I've never encountered a case where problems were caused by a line being too
cold, but I have to admit that it doesn't happen all that often that a line
gets cold.

On 22-Jan-2003 Michael Richardson wrote:
>>>>>> "seth" == seth  <> writes:
>     seth> That's not what I meant.  In no sense can the ethernet encoding be
> viewed as
>     seth> bits on the wire.  There is no simple explanation, but basically
> the
>     seth> interpretation of the signal on the wire depends on the history of
> the signal.
>   Yes, FastEthernet encodes as sequences of MII symbols in a star pattern,
> like modems, of which 16 of them encode 4 bits of data at a
> time. GigEthernet, depending upon the media does other various things.
>   However, on FE, you can send a non-integral number of bytes, by sending an
> odd number of nibbles.
>   In this case, it is 10Mb/s UTP, so there really are 8 bit times worth of
> data, with appropriate manchester encoding. As this goes into a ADSL box, 
> and that box is *certainly* regenerating the signal on the wire (since it has
> to shop it up in various ways to spread the bit errors over the FEC, and then
> there is ATM encoding on top of that), it seems like some kind of cabling
> issue.
>   For what it's worth, I think it went away! I did change the cable, but that
> didn't immediately help. It is next to a cold basement wall, and it has been
> - -40, so...
> ]       ON HUMILITY: to err is human. To moo, bovine.           |  firewalls 
> [
> ]   Michael Richardson, Sandelman Software Works, Ottawa, ON    |net
> architect[
> ] |device
> driver[
> ] panic("Just another Debian GNU/Linux using, kernel hacking, security guy");
> [
> Version: GnuPG v1.0.7 (GNU/Linux)
> Comment: Finger me for keys
> iQCVAwUBPi8k6IqHRg3pndX9AQElOgQAx8QadCmvt7xRksu17V4xN8aiaAYRrgX/
> S5mekIHWfCWkZ4B9bbrzFl1Gn5eMCz5kMO3B1viEgfiT4QEEQw7MDInJuCGQvH0P
> 6GjSU09FXjm1NF9vXit/jeDNEuTCsmUzSUj6bZ43QdV64xCXXmPf4o0VRVyLdnlL
> luQK4TvAdnE=
> =rhJ7

Seth Kurtzberg
M. I. S. Corp.
Date: 22-Jan-2003
Time: 16:41:13

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