North American Network Operators Group

Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical

Re: Weird GigE Media Converter Behavior

  • From: John R. Sosebee
  • Date: Tue Aug 24 22:50:18 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, [email protected] <[email protected]> wrote:

>
> 2 quick things come to mind-
>
> single mode vs multimode, or the signal is too hot and you need attenuators.
>
>
> -----Original Message-----
> From: [email protected] [mailto:[email protected]]
> Sent: Tuesday, August 24, 2004 12:48 PM
> To: [email protected]
> 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