North American Network Operators Group|
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Weirder issues ... resolved
On Tue, 24 Aug 2004, 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". > > Your subject says "GigE Media converter" but you say you are deploying > an OC12. Which is it? Apologies. An OC12 was layed down, and I was running the drops from building to building. This is the exact deal of what happened (now that I can sit down for moment and think on a level head): I was setting up the fiber lines (multi mode already layed down) to connect the media converters to my switches. There are altogether about 8 buildings but for clarity I'll focus on the three which the event occurred... Building A - Main point Building B - about 1200 feet from Building A Building C - about 600 feet from Building A In Building A, I hooked up my media converter (Netgear) to Building B. Light was on, I had a signal going out. Walked over to Building B to hook up that media converter (Netgear) and this oddity occurred - link droppage when SC connector was fully plugged. Walked back over to Building A to replicate the incident, meaning I fully plugged Building B and wanted to see if I slightly pulled out Building A's SC if it would drop link. Sure enough it did. Now back in Building A, I took off Building C's media converter (Netgear) and swapped it with Building C which worked fine. Building C took Building B's media converter and pushed light with no problem. Now Building C is ALMOST twice as far as Building B is so if attenuation was the case, when I swapped out the media converters it should have done the same thing. Weirder was, everthing worked except I could not open the browser interface for the switches. At first I thought it was a VLAN issue so I walked back to the main building and added a port to have connectivity to every VLAN on the switch. Didn't work. So... One funky connection for a moment: Linked, pings out everywhere, could ssh everywhere, could do anything BUT open a browser throughout the entire Building B. Just bizarre. > 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 > 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. All in all it's up now. After playing switcharoonee with these silly little Netgears, they seemed to bork themselves into working. Thanks to all of the responses from everyone. =+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+ J. Oquendo GPG Key ID 0x51F9D78D Fingerprint 2A48 BA18 1851 4C99 CA22 0619 DB63 F2F7 51F9 D78D http://pgp.mit.edu:11371/pks/lookup?op=get&search=0x51F9D78D sil @ politrix . org http://www.politrix.org sil @ infiltrated . net http://www.infiltrated.net "How can we account for our present situation unless we believe that men high in this government are concerting to deliver us to disaster?" Joseph McCarthy "America's Retreat from Victory"