Replacing the Core switch from 6500 to 6800

[atifali.zaidi1]

Hello Experts ,

currently my core switch which is a 6500 is connected to one of my access switches ( which is a 3750E  ) as mentioned below

Core 6500 ---X2-10G-LX4 --------------- OM2 ------------------ X2-10G-LX4 ( 3750E)

now my core switch will be replaced by a 6800 which will have the C6800-32P10G line card which does not support X2 SFP modules but it supports SFP-10G-SR-S SFP + modules 

now if i connect my new core to the 3750E access switches , the fiber cable does not come using the following combinations

Core 6800 ---SFP-10G-SR-S --------------- OM2 ------------------ X2-10G-LX4 ( 3750E)

Core 6800 ---SFP-10G-SR-S --------------- OM2 ------------------ X2-10G-SR ( 3750E)

now i think we might have to upgrade to OM3 fiber to support SFP + modules for the new core , isn't that right ?

is there any other possibility here to connect ?

[Reza Sharifi]

Hi,

You should not need to change the OM2 fiber as long as the distance between the 3750e and the new 6800 is 82 meters or less. All you have to do is to change you fiber patch from SC/SC to SC/LC.

HTH

[atifali.zaidi1]

the distance between the core and the 3750 is like 200 meters.

[Reza Sharifi]

In that case, I would upgrade to OM4 as there isn't much of price difference between OM3 and OM4. Most of the cost is for labor.

HTH

[Predrag Jovic]

Core 6800 ---SFP-10G-SR-S --------------- OM2 ------------------ X2-10G-LX4 ( 3750E)

This combination can't work - generally, you can't mix SM and MM SFPs.

Core 6800 ---SFP-10G-SR-S --------------- OM2 ------------------ X2-10G-SR ( 3750E)

Max distance via OM2 - 82m

Core 6800 ---SFP-10G-LRM --------------- OM2 ------------------ X2-10G-LX4 ( 3750E)

+ conditioning cables  on both ends - Max distance 220m since modal bandwidth of OM2 is 500

[atifali.zaidi1]

thanks for the response , but i suppose that X2-10G-SR and X2-10G-LX4 both are for multi-mode fiber SFP's with the only difference of 850-nm and 1310-nm.

the distance between the core and the 3750E is like 200 meters , so either we shud have SFP-10G-LR-LR on the new core OR we shud upgrade the fiber to OM3 ?

[Predrag Jovic]

LX is marking typically used for SM SFPs.

Quote from Cisco web page:

Cisco X2-10GB-LX4

The Cisco 10GBASE-LX4 Module supports link lengths of 300m on standard FDDI grade MMF. To ensure that specifications are met, the transmitter output should be coupled through a mode conditioning patch cord. For additional information on mode conditioning patch cord requirements please see: http://www.cisco.com/en/US/prod/collateral/modules/ps5455/product_bulletin_c25-530836.html.

Typically, conditioning patch cables are needed only when SM SFPs are used via MMF.

Additionally, SFP of different wavelength can't be mixed. If different wavelengths are mixed, there will be no signal (other side expect different wavelength). Typical wavelength SM 1310nm, MM 850nm.

I see now that 10GBASE-LX4 has 4 lanes (I am not sure what is compatible with that one in that case).

Four lanes; overall range: 1269 to 1356