Re: QFX 5100 SFP compatability

This page, found via Google search, lists the "officially" supported Juniper Optics for QFX5100:

http://www.juniper.net/documentation/en_US/release-independent/junos/topics/reference/specifications/interface-qfx5100-support.html

So for 10GE LR the correct "official" Optic is  QFX-SFP-10GE-LR

Now this does not mean any 10GE SFP based optic you have from MX or 3rd party will not work, as they most likely due if made to proper LR standards.  You can use 3rd party optics on any Juniper product, only down side is if you run into any issue that might involve the optic, Juniper might not assist until the optic is change to one "officially" support.  So best if you go 3rd party route, to keep some Juniper branded around just in case.

Best approach is to talk to you partner/Juniper account team about getting the price of Juniper optics you need to purchase down close to what 3rd party might charge you.