Cisco Support Community
cancel
Showing results for 
Search instead for 
Did you mean: 
Announcements

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. And see here for current known issues.

New Member

1000BASE-LX compatible with 100BASE-LX

                   I have a optical network designed over singlemode fiber. All my communication modules are based on the standard 1000BASE-LX, which is the GLC-LH-SM SFP module. However, I would like to add to my network an external component rated at 1310 nm and 100 Mbps, which is the same wavelength but a lower speed. This external component is not available on a Gigabytes speed and I am stuck with this one.

Can I connect them together, or do I have to change my SFP module with one based on the 100BASE-LX standard, like the GLC-FE-100LX ?

Also, do you have some good references where I could easily get this kind of information ?

Thank you for your time.

Everyone's tags (4)
1 ACCEPTED SOLUTION

Accepted Solutions

Re: 1000BASE-LX compatible with 100BASE-LX

You will need to use a 100Mb module to connect to another device at 100Mb.

Check optical transceiver compatibility with your equipment by reviewing the following fast ethernet compatibility document:

http://m.mcisco.com/pocket.paper?url2=http%3a%2f%2fwww.cisco.com%2fen%2fUS%2fdocs%2finterfaces_modules%2ftransceiver_modules%2fcompatibility%2fmatrix%2fOL632702.html

There are 2 module types, one for GE and one for FE slots. Choose the one it says is compatible.

Sent via BlackBerry by AT&T

10 REPLIES

Re: 1000BASE-LX compatible with 100BASE-LX

You will need to use a 100Mb module to connect to another device at 100Mb.

Check optical transceiver compatibility with your equipment by reviewing the following fast ethernet compatibility document:

http://m.mcisco.com/pocket.paper?url2=http%3a%2f%2fwww.cisco.com%2fen%2fUS%2fdocs%2finterfaces_modules%2ftransceiver_modules%2fcompatibility%2fmatrix%2fOL632702.html

There are 2 module types, one for GE and one for FE slots. Choose the one it says is compatible.

Sent via BlackBerry by AT&T

New Member

Re: 1000BASE-LX compatible with 100BASE-LX

Thank you Tom for your prompt answer!

All my switch are in the 2960 series, and seems compatible with the GLC-FE-100LX.

Hall of Fame Super Gold

1000BASE-LX compatible with 100BASE-LX

Can I connect them together, or do I have to change my SFP module with one based on the 100BASE-LX standard, like the GLC-FE-100LX ?

The GLC-LH-SM will only negotiate at one speed and nothing less.

New Member

1000BASE-LX compatible with 100BASE-LX

Thank you for the clarification.

Also, it seems that there is 2 standard for fast-ethernet at 1310 nm, 100base-fx defined in clause 26 of 802.3and 100base-lx10 defined in clause 58. The first one correspond to a shoter distance over multimode and the second one is for longer distance over singlemode.

However, I happend to notice some singlemode equipment marked as 100base-fx, are they compatible with 100base-lx10 equipment ? For a reference, I'm talking about Allied Telesis equipment where all 1310 nm fast-ethernet are rated as "100FX".

Re: 1000BASE-LX compatible with 100BASE-LX

It looks like Allied Telesis is using the "100FX" in a generic sense; an

optical interface (any wavelength) at 100Mbps. You shouldn't use a

100BASE-FX and 100BASE-LX10 at the ends of a single link. They are

designed for different fiber types.

On Wed, May 30, 2012 at 7:27 AM, poirier.j <

New Member

Re: 1000BASE-LX compatible with 100BASE-LX

As I my datasheet of my external component do not mention the communication standard that it is using. Would you assume that it is a 100BASE-LX10 if it is marked as singlemode, 1310 nm, 100 Mbps with a link budget of 30 dB? And that this component would be compatible with a "100FX" component of Allied Telesis marked as singlemode, 1310 nm, 100 Mbps over 10-15 km?

By the way, thank you for your time Tom !f

Re: 1000BASE-LX compatible with 100BASE-LX

A 100M optical interface with 30dB link budget would most likely be a 100Base-EX (extended reach).  It could interoperate with an LX10 if the link is within the LX10s budget (<10km) and the optical receive power at the LX10 transceiver is within the receiver's posted operating range (min/max). 

Many vendors have optical transceivers that reach outside the IEEE standards because they are typically bookended; the same product used at both ends of the link.  When you mix vendors, it is good to keep with the standards based optics so that it is easy to engineer and maintain the links; especially as technicians come and go and the network documentation may not be maintained. 

New Member

Re: 1000BASE-LX compatible with 100BASE-LX

I do not find the 100Base-EX and 100Base-ZX in the IEEE 802.3 standard, so I assume that they not standard. If the distance is less than 10 km, would you suggest to get a 100Base-LX10 module, or should I get a 100Base-Ex anyway.

Also, is there adverses effects, like premature degradation of the receiver, if I choose to use a 100Base-LX10 with this most likely 100Base-EX component. Would an attenuator be recommanded if my links lost are estimated to be between 3 to 7 dB ? I don't have access to the transmission power; I'm still waiting for more information from the manufacturer.

Thanks again, you are a great help!

Re: 1000BASE-LX compatible with 100BASE-LX

I would suggest to use the LX10 for SMF links of <=10 km. 

If you used a longer reach transceiver (EX or ZX) on a short link, you more likely may see bit errors (damage in severe instances); and additional $$ will be missing from your wallet.   On short fiber links using extended reach optics, a 10dB attenuator at the receiver end will bring the optical power level down to eliminate problems. 

New Member

Re: 1000BASE-LX compatible with 100BASE-LX

Thanks a lot Tom !

I'm going to use a LX10, but I will push to get the power transmit by my 30 dB component. And if needed, I will use an attenuator on those link. I appreciate your help.

4398
Views
5
Helpful
10
Replies
CreatePlease login to create content