Blinking Ethernet Link Light

Blinking Ethernet Link Light

Post by John Smit » Sun, 20 Jul 2003 00:27:29



What does a blinking ethernet link light mean?  have an ethernet card
connected to a 10/100 Netgear Hub. The hub light never comes on (I have
tried a straight and a cross over cables -- both known good), but the
ethernet card keeps on going on and off. How can I trouble shoot the link?

Thanks!

 
 
 

Blinking Ethernet Link Light

Post by Glen Herrmannsfeld » Sun, 20 Jul 2003 02:23:56



Quote:> What does a blinking ethernet link light mean?  have an ethernet card
> connected to a 10/100 Netgear Hub. The hub light never comes on (I have
> tried a straight and a cross over cables -- both known good), but the
> ethernet card keeps on going on and off. How can I trouble shoot the link?

Last I saw that was an Asante 10baseT card connected to a 3com 10/100 hub.
Apparently auto-negotiation failed, and it didn't know what to do.

-- glen

 
 
 

Blinking Ethernet Link Light

Post by Terry Baransk » Sun, 20 Jul 2003 10:36:35


On Fri, 18 Jul 2003 17:23:56 GMT, "Glen Herrmannsfeldt"




>> What does a blinking ethernet link light mean?  have an ethernet card
>> connected to a 10/100 Netgear Hub. The hub light never comes on (I have
>> tried a straight and a cross over cables -- both known good), but the
>> ethernet card keeps on going on and off. How can I trouble shoot the link?

>Last I saw that was an Asante 10baseT card connected to a 3com 10/100 hub.
>Apparently auto-negotiation failed, and it didn't know what to do.

I just saw this yesterday trying to connect two Nortel fiber modules,
one 100FX and the other 1000FX, neither of which (as I learned shortly
thereafter) support auto-negotiation.

I didn't know anyone still made Ethernet products that don't support
auto.

 
 
 

Blinking Ethernet Link Light

Post by Rich Seifer » Sun, 20 Jul 2003 23:49:01




Quote:> I just saw this yesterday trying to connect two Nortel fiber modules,
> one 100FX and the other 1000FX, neither of which (as I learned shortly
> thereafter) support auto-negotiation.

> I didn't know anyone still made Ethernet products that don't support
> auto.

First of all, there IS NO STANDARD for Auto-Negotiation at 100 Mb/s on
fiber, much less for negotiation of data rate between 100 and 1000 Mb/s
(as your post implies). Thus, it is not surprising that products do not
support such negotiation; I would be surprised by a device that *did*.

Second, there is no such thing as 1000BASE-FX; there is 1000BASE-SX and
-LX for fiber.

Auto-Negotiation was specifically designed for use on twisted-pair
media; A-N was designed to resolve the difficulties of using the same
RJ-45 connector for a wide variety of technologies. While we later
defined a sort of "Auto-Negotiation" for 1000 Mb/s fiber, it is much
more limited in scope (it resolves only duplexity and flow control, and
cannot do anything about data rate or signaling method).

--
Rich Seifert              Networks and Communications Consulting

(408) 395-5700            Los Gatos, CA 95033
(408) 395-1966 FAX

 
 
 

Blinking Ethernet Link Light

Post by Terry Baransk » Mon, 21 Jul 2003 03:53:38


On Sat, 19 Jul 2003 07:49:01 -0700, Rich Seifert




>> I just saw this yesterday trying to connect two Nortel fiber modules,
>> one 100FX and the other 1000FX, neither of which (as I learned shortly
>> thereafter) support auto-negotiation.

>> I didn't know anyone still made Ethernet products that don't support
>> auto.

>First of all, there IS NO STANDARD for Auto-Negotiation at 100 Mb/s on
>fiber, much less for negotiation of data rate between 100 and 1000 Mb/s
>(as your post implies). Thus, it is not surprising that products do not
>support such negotiation; I would be surprised by a device that *did*.

>Second, there is no such thing as 1000BASE-FX; there is 1000BASE-SX and
>-LX for fiber.

>Auto-Negotiation was specifically designed for use on twisted-pair
>media; A-N was designed to resolve the difficulties of using the same
>RJ-45 connector for a wide variety of technologies. While we later
>defined a sort of "Auto-Negotiation" for 1000 Mb/s fiber, it is much
>more limited in scope (it resolves only duplexity and flow control, and
>cannot do anything about data rate or signaling method).

Thanks for the information.  I haven't worked much with Ethernet over
fiber, and it shows.  I coincidentally ran across some
fiber/auto-negotiation information shortly after my post, though some
of it was contradictory so I was going to ask for clarification.  
 
 
 

Blinking Ethernet Link Light

Post by John Smit » Mon, 21 Jul 2003 10:02:57





> > What does a blinking ethernet link light mean?  have an ethernet card
> > connected to a 10/100 Netgear Hub. The hub light never comes on (I have
> > tried a straight and a cross over cables -- both known good), but the
> > ethernet card keeps on going on and off. How can I trouble shoot the
link?

> Last I saw that was an Asante 10baseT card connected to a 3com 10/100 hub.
> Apparently auto-negotiation failed, and it didn't know what to do.

> -- glen

I did some research the NIC uses 80223 dual port Ethernet Chip. The Hub is a
Netgear 10/100 Mbps. Incidently, this NIC works fine with a 10MBps Netgear
Hub.