2 quick things come to mind-
single mode vs multimode, or the signal is too hot and you need attenuators.
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?
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.
Can't wait until more routers start to incorporate inline optical
power readings in "show interface" commands the way Procket did 
Cheers,
-Lane
Can't wait until more routers start to incorporate inline optical
power readings in "show interface" commands the way Procket did
Don't SFPs provide this sort of optical digital diagnostics?
DJ
Apparently the CRS-1 supports this, as well as a few other types of
GBIC's.
* lane@laneandmimi.com (Lane Patterson) writes:
Can't wait until more routers start to incorporate inline optical
power readings in "show interface" commands the way Procket did
* deepak@ai.net (Deepak Jain) adds:
Don't SFPs provide this sort of optical digital diagnostics?
Yes, but hardly any vendor provides ways to extract this highly useful
information from the hardware.
I think the Cat6.5k does. The Foundry MG8 shows you the serial #'s of
inserted SFPs and XENPAKs in `show media'; useful in a different way.
-- Niels.
Also, some of the SFP vendors did not necessarily provide all the optical
power reading, transmit bias current, voltage, temperature etc few years
ago. Nowadays it is more common for the SFP vendors to provide this
information (and in a standard fashion) enabling system vendors to be more
"bold" about displaying these parameters from their CLI/management systems.
Vinay Bannai
Luminous Networks
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
At the huge markup Cisco does regarding their optics, they have the margin
to do this without hiking the price. They're already pricing in a complete
SDH system in their optics markup.
I noticed that the CRS-1 is now in the Cisco pricelist.
4 port OC192 VSR $330k
4 port OC192 SR $630k
4 port OC192 IR $1030k
I happen to know a 10GE SR Xenpak can be had at $1600 and LR (80km) at
$5900 from manufacturer. The same laser can do OC192.
Is there anyone who can justify this pricing with anything else than
"because we can?"
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.
Cool, upon further discussion with hardware guys, most of this functionality
is being built into the 3rd party optical components these days, so all the
vendor has to do is augment the CLI to pass this data through. If the
capability is there, why not use it? I must say it would be cool to graph
dBm over months/years in Cricket, and see if you could spot fiber degradation.
However, as you point out, it is important for vendors to document the
accuracy of the readings in their spec sheets. +/-5 dBm sounds a bit lame.
As I understand, these components split off about 2% of the light to take
the optical power readings. Don't know if any of them can measure
reflection to get distance as well?
-Lane
There are even some with simple OTDR functionality built into them, just
like there are some copper ethernet PHYs that also have this (CTDR).
<http://www.opticalzonu.com/products/P2P%20Gig%20Ethernet%20OTDR%20Transceivers.html>
Mikael Abrahamsson <swmike@swm.pp.se> writes:
Is there anyone who can justify this pricing with anything else than
"because we can?"
To expand on what I said to you privately, let's follow the money:
Assume $200,000/board as the marginal cost of manufacturing one.
Assume a minimum of 65 points off for any customer who buys a CRS-1
(hint: large telcos do not pay list price... and nobody, not even
certain well-known crazy people, is going to pay money for one to use
as a SOHO router).
So now we have a strawman marginal profit per board sold of $150,000.
Assume that Cisco actually has about a billion dollars into the HFR
project (offhand comment by a usually reliable source).
That means that ignoring the chassis sales side, we're looking at
about 6700 interface cards (> 26500) OC192 IR ports sold to get back
the initial engineering investment. That's not figuring in the cost
of support for those 6700 cards out in the field; you're probably
looking at 8500 or more cards (> 34000 ports) sold in order to hit
break-even.
Now consider the size of the market. You're not selling PAs for
people's 7200s here, and you're selling a card that replaces *four*
cards on a lesser platform.
Under the circumstances, I'm not sure that Cisco's list price is high
enough, but I'll defer judgement on that to the people who run the
numbers behind the scenes in San Jose. They're the ones whose jobs
are on the line if this product turns out to be $1b bragging rights
exercise with no hope for payback.
If you find the prices staggering, it's likely that you and your
organization don't need this product. Arguments about price gouging
on memory, GBICs, power cords, and other commodity items that your
organization actually *does* need are orthogonal to this discussion.
---Rob
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Nordunet has one. Nice box.