Weird GigE Media Converter Behavior

Wed Aug 25 02:45:22 UTC 2004

At 01:31 PM 8/24/2004 -0700, Lane Patterson wrote:

>Yes, you have experienced what is known in the field as "air gap 
>attenuation"--not
>something you want to depend on if you want a clean link!   A close relative
>is "knot-in-the-fiber attenuation".

a close relative of  "who-pulled-this-fiber-anyway" ?"  yes .. a kink  ..a 
slight kink can do much loss .. easy to hold a fiber around your finger w/a 
meter attached and watch the  atten .. as you bend the fiber ..

>Your subject says "GigE Media converter" but you say you are deploying
>an OC12.  Which is it?

I wondered that also ..

>Definitely invest in a light meter that can do the usual flavors
>of single and multimode, connector types, and at least 850 and 1310nm
>wavelengths.  Then simply test strength of light on your receive port

I'd go w/a test set if you afford it.  It'll serve more than purpose and 
you'll get more use of it ..

>on each side, compare to specifications of your equipment, and add
>in-line attenuators as necessary.  You'll usually find a range something
>like -3 to -27 dBm, and we prefer -15 dBm as our ideal.  Also, make
>sure you've got the right type of fiber jumpers--mixing up single
>(yellow) and multi (orange) mode fiber can cause similar issues.
>
>Can't wait until more routers start to incorporate inline optical
>power readings in "show interface" commands the way Procket did :-)

some flava's of the GSR will show/report this .. under show controller but 
cisco says it's +_ 5 dbm ..
they say ..  ' You want a router or a meter  ? "
I have to agree .. would want not the expense of this added in.

POS3/0
SECTION
   LOF = 0          LOS    = 0                            BIP(B1) = 0
LINE
   AIS = 0          RDI    = 0          FEBE = 0          BIP(B2) = 0
PATH
   AIS = 5          RDI    = 6          FEBE = 387        BIP(B3) = 6389
   LOP = 5          NEWPTR = 0          PSE  = 0          NSE     = 0

Framing: SONET
APS

Optical Power Monitoring
   Rx optical power in mWs and dBms
       Port 0 =   0.02 mW, - 15.738 dBm

   Tx laser diode forward bias current I(F) in milliamps
       Port 0 =  18.009 mA

   Clock source:  line

>Cheers,
>-Lane
>
>On Tue, Aug 24, 2004 at 01:10:15PM -0400, kwallace at pcconnection.com 
><kwallace at pcconnection.com> wrote:
>
> >
> > 2 quick things come to mind-
> >
> > single mode vs multimode, or the signal is too hot and you need 
> attenuators.
> >
> >
> > -----Original Message-----
> > From: owner-nanog at merit.edu [mailto:owner-nanog at merit.edu]
> > Sent: Tuesday, August 24, 2004 12:48 PM
> > To: nanog at nanog.org
> > Subject: Weird GigE Media Converter Behavior
> >
> >
> >
> >
> > Hello all, wondering if anyone has seen or experienced this same problem.
> > Currently deploying an OC12 on a campus network and am using Netgear media